◉[Capitulum 1]

◉[Chapter 1]

1.1 ◉ Declaratum est qualiter fiat visio, et est qualitas sensus visus a forma lucis et coloris que sunt in re visa ordinatorum ita sicut sunt in superficie rei vise. Visus autem comprehendit ex rebus visibilibus multas intentiones preter lucem et colorem.

1.1 ◉ It has been shown how vision takes place, and it does so [by means of a] sensation in the eye [produced] by a form of the light and color in a visible object arranged as they actually exist in the surface of the visible object. However, sight perceives many characteristics of visible objects besides light and color.

1.2 ◉ Et etiam declaratum est in primo tractatu quod visio non erit nisi ex verticationibus linearum radialium, et linee radiales diversantur in dispositionibus suis, et similiter diversantur dispositiones formarum venientium super ipsas ad visum.

1.2 ◉ It has also been shown in the first book that vision will occur only along radial lines, but radial lines vary in their dispositions, and likewise the dispositions of the forms reaching along them to the eyes vary.⁑

1.3 ◉ Et etiam comprehensio visus a re visa non est in omnibus temporibus et in omnibus visibilibus secundum unum modum. Sed diversatur qualitas sensus visus a rebus visibilibus, et diversatur qualitas sensus visus in una re visa secundum unum situm et secundum eandem distantiam.

1.3 ◉ Moreover, the visual perception of a visible object does not occur the same way every time, nor does it occur the same way for all visible objects. Instead, the way sight perceives visible objects varies, and the visual perception of the same visible object varies [even] when it is in the same situation and lies the same distance [from the eye].

1.4 ◉ Et nos declarabimus in isto tractatu diversitatem dispositionum linearum radialium et distinguemus proprietates earum et omnes intentiones comprehensas a visu. Et declarabimus qualiter comprehendit visus quamlibet illarum et diversitatem comprehensionis visus ab eis.

1.4 ◉ And in this book we shall show the various dispositions of the radial lines, and we shall specify their characteristics along with all the visible properties that are perceived by sight. And we shall show how sight perceives each of them as well as how visual perception varies for each of them.

◉[Capitulum 2]

◉[Chapter 2]

2.1 ◉ Iam declaratum est in primo tractatu quod linee radiales ex quarum verticationibus comprehendit visus visibilia sunt linee recte quarum extremitates concurrunt apud centrum visus. Et iam declaratum est in forma visus quod membrum sentiens, quod est membrum glaciale, est compositum super extremitatem concavitatis nervi super quem compositus est oculus totus, et quod, quando iste nervus giratur, non giratur nisi a posteriori centri visus, et a posteriori totius oculi, et apud foramen quod est in concavo ossis.

2.1 ◉ It has already been shown in the first book that the radial lines along which the eye perceives visible objects are straight lines whose endpoints meet at the center of the eye.⁑ And it has been shown in [the section on] the structure of the eye that the sensitive organ, which is the glacialis, is attached at the end of the hollow of the nerve to which the entire eye is attached, and [it has been shown] that, when this nerve flexes, it only flexes behind the center of the eye in the back of the whole eye, at the opening in the eye socket.⁑

2.2 ◉ Et iam declaratum est quod linea recta transiens per omnia centra tunicarum visus extenditur in medio concavi nervi, et pervenit recte ad medium girationi concavi nervi, et transit per centrum foraminis quod est in anteriori uvee. Et iam declaratum est quod situs istius linee non diversatur respectu totius visus, nec respectu tunicarum superficierum, nec respectu partium visus. Linea ergo recta transiens per omnia centra tunicarum visus semper extenditur recte ad locum girationis concavi nervi super quem componitur oculus in omnibus dispositionibus visus, sive sit visus in motu sive in quiete. Et quia ista linea transit per centrum visus et per centrum foraminis quod est in anteriori uvee, extenditur in medio piramidis cuius conus est centrum visus, et continet ipsam circumferentia foraminis quod est in anteriori uvee; apellemus ergo istam lineam axem piramidis.

2.2 ◉ It has also been shown that the straight line passing through all the centers of the tunics of the eye extends through the middle of the nerve’s hollow, reaches straight to the middle of where the nerve’s hollow flexes, and passes through the center of the opening in the anterior of the uvea.⁑ It has been shown, moreover, that the position of this line does not change with respect to the eye as a whole, nor with respect to the surfaces of the tunics, nor with respect to the component parts of the eye.⁑ Therefore, the straight line passing through all the centers of the tunics of the eye invariably passes straight through to the hollow of the nerve to which the eye is attached where that nerve flexes, [and it does so] under all conditions, whether the eye is in motion or at rest. And since this line passes through the center of the eye as well as through the center of the opening in the front of the uvea, it extends through the middle of the cone whose vertex lies at the center of the eye, and the circumference of the opening in the front of the uvea circumscribes that cone; hence, let us call this line the »axis« of the cone.

2.3 ◉ Et declaratum est etiam in ipso tractatu primo quod piramis figurata inter rem visam et centrum visus distinguit ex superficie glacialis partem continentem totam formam rei vise que est apud basim illius piramidis. Et erit forma ordinata in ista parte superficiei glacialis per verticationes linearum radialium extensarum inter rem visam et visum secundum ordinationem partium superficiei rei vise. Cum ergo visus comprehendit aliquam rem visam, et pervenit eius forma in parte superficiei glacialis quam distinguit piramis predicta, quodlibet punctum forme predicte est super lineam radialem extensam inter illud punctum et punctum oppositum illi in superficie rei vise super quam venit forma ad illud punctum in superficie glacialis recte. Cum ergo forma rei vise fuerit in medio superficiei glacialis, erit axis predictus una linearum super quas veniunt forme punctorum que sunt in superficie rei vise, et erit punctum superficiei rei vise quod est apud extremitatem istius axis illud super quod venit forma eius super istum axem.

2.3 ◉ Furthermore, it has been demonstrated in that same first book that the cone formed between the visible object and the center of the eye demarcates an area on the surface of the glacialis that encompasses the entire form of the visible object at the base of that cone.⁑ And the form will be arranged on that area of the surface of the glacialis by the radial lines extending between the visible object and the eye according to the [actual] arrangement of parts on the surface of the visible object. Thus, when the eye perceives some visible object and that object’s form reaches the area on the surface of the glacialis demarcated by the aforesaid cone, every point on the aforesaid form lies on the radial line that extends between that point [on the surface of the glacialis] and a point facing it on the surface of the visible object, and [it is] along this line that the form comes directly to that point on the surface of the glacialis. Therefore, if the form of the visible object lies at the middle of the surface of the glacialis, the aforesaid axis will be one of the lines along which the forms of the points on the surface of the visible object extend, and the point on the surface of the visible object where the endpoint of this axis touches will be the point whose form comes [to the eye] along the axis.

2.4 ◉ Et declaratum est in primo tractatu quod forme que comprehenduntur per visum extenduntur in corpore glacialis et in concavo nervi super quem componitur oculus, et perveniunt ad nervum communem qui est apud medium anterioris cerebri —et illic erit comprehensio sentientis ultimo a formis rerum visibilium—et quod visio non completur nisi per adventum forme ad nervum communem, et quod extensio formarum a superficie glacialis intra corpus glacialis erit secundum rectitudinem linearum rectarum radialium tantum, quoniam glacialis non recipit istas formas nisi secundum verticationes linearum radialium tantum.

2.4 ◉ It has been shown in the first book, as well, that the forms perceived by the eye extend through the body of the glacialis and into the hollow of the nerve to which the eye is attached, and they reach the common nerve which is centered at the front of the brain—and this is where the forms of visible objects will be perceived by the final sensor—and [it has been shown] that vision is not fully realized until the form reaches the common nerve and that [such] forms will extend from the surface of the glacialis into the body of the glacialis along straight radial lines only, for the glacialis only receives these forms along radial lines.⁑

2.5 ◉ Et ultimum sentiens non comprehendit situs partium rei vise nisi secundum suum situm in superficie rei vise. Et cum situs partium forme adinvicem, scilicet forme pervenientis ad superficiem glacialis, sint situs partium superficiei rei vise adinvicem, et iste forme extenduntur sicut predictum est, et cum omnia ista ita sint, visio ergo non complebitur nisi post perventum forme que est in superficie glacialis ad nervum communem, et situs partium eius secundum suum esse in superficie glacialis sine aliqua admixtione.

2.5 ◉ And the final sensor perceives the locations of the [constituent] parts of the visible object only according to their locations on the surface of the visible object itself. And since the relative locations of the parts of the form, i.e., of the form reaching to the surface of the glacialis, are [the same as] the relative locations of the parts of the surface of the visible object, and since these forms are propagated as has been described, and since all these things obtain, vision will not be fully achieved until after the form on the surface of the glacialis reaches the common nerve, and its parts are situated as they actually are on the surface of the glacialis without any confusion.

2.6 ◉ Forma autem non pervenit a superficie glacialis ad nervum communem nisi per extensionem eius in concavo nervi super quem componitur glacialis. Si ergo forma non perveniret in concavo istius nervi secundum suum esse in glaciali, nec etiam perveniet ad nervum communem secundum suum esse. Forma autem non potest extendi a superficie glacialis ad concavum nervi secundum rectitudinem linearum rectarum et conservare situs partium secundum suum esse, quoniam omnes ille linee concurrunt apud centrum visus. Deinde quando fuerint extense secundum rectitudinem post centrum, convertetur situs earum, et quod est dextrum efficietur sinistrum et econverso, et superius inferius et inferius superius. Si ergo forma fuerit extensa secundum rectitudinem linearum radialium, congregabitur apud centrum visus et efficietur quasi unum punctum; et quia centrum visus est in medio totius oculi et ante locum girationis nervi concavi, si forma fuerit extensa a centro et ipsum unum punctum super unam lineam, perveniet ad locum girationis et ipsum unum punctum. Et sic non perveniet forma tota ad locum girationis, quia non nisi unum punctum, scilicet quod est in extremitate axis piramidis. Et si fuerit extensa secundum rectitudinem linearum radialium et pertransierit centrum, erit conversa secundum conversionem linearum se secantium super quas extendebatur. Non potest ergo forma pervenire a superficie glacialis ad concavum nervi ita quod situs partium sit secundum suum esse. Non potest ergo forma pervenire a superficie glacialis ad concavum nervi nisi secundum lineas reflexas secantes lineas radiales.

2.6 ◉ But the form reaches from the surface of the glacialis to the common nerve only by continuing through the hollow of the nerve to which the eye is attached. Thus, if the form does not extend through the hollow of this nerve with the same arrangement it has on the glacialis, it will not arrive at the common nerve in proper order. But the form cannot extend from the surface of the glacialis to the hollow of the nerve along straight lines and still preserve the proper arrangement of its parts, for all of those lines meet at the center of the eye. In that case, when they are extended along straight lines past that centerpoint their relative positions will be reversed, so the rightward [radial lines] will fall to the left, and vice versa, and the higher ones [will be] lower and the lower ones higher. Therefore, if the form extends along straight radial lines, it will contract at the center of the eye to form a virtual point; and since the center of the eye [in terms of its visual components] lies at the center of the entire ocular globe and in front of where the hollow of the nerve flexes, if the form is extended from the center as a single point along a single line, it will arrive at the place where the hollow of the nerve flexes as a single point. Accordingly, the whole form will not reach the place where the hollow of the nerve flexes, because it will arrive only as a single point, i.e., the one at the extremity of the axis of the [visual] cone.⁑ But if it extends along straight radial lines to pass through the center [of the eye], it will be reversed according to the reversal of the lines along which it arrived after intersection. Hence, the form cannot reach from the surface of the glacialis to the hollow of the nerve so as to have its parts arranged as they actually are [in the object]. The form can therefore only reach from the surface of the glacialis to the hollow of the nerve along refracted lines that intersect the [original] radial lines.⁑

2.7 ◉ Et cum ita est, visio ergo non complebitur nisi postquam reflectitur forma que pervenit a superficie glacialis et extenditur super lineas secantes lineas radiales. Ista ergo reflexio debet esse ante perventum ad centrum, quoniam si fuerint reflexe post transitum centri, erunt converse.

2.7 ◉ Since this is the case, then, vision will not be fully achieved until after the form that arrives at the surface of the glacialis is refracted so as to extend along lines intersecting the [original] radial lines. So this refraction must occur before the form reaches the center [of sight], for if it is refracted after passing through that centerpoint, it will be reversed.

2.8 ◉ Et iam declaratum est quod ista forma pertransit in corpore glacialis secundum rectitudinem linearum radialium, et cum non potest pervenire ad concavum nervi nisi postquam reflectitur super lineas secantes lineas radiales, forma non reflectitur nisi post pertransitum eius in corpore glacialis. Et iam predictum est in forma visus quod corpus glacialis est diverse diafonitatis et quod pars posterior eius, que dicitur vitreum, est diverse diafonitatis a parte anteriori. Et nullum corpus est in glaciali diverse forme a forma corporis anterioris preter corpus vitreum. Et ex proprietate formarum lucis et coloris est ut reflectantur quando concurrerint alii corpori diverse diafonitatis a corpore primo. Forme ergo non reflectuntur nisi apud perventum earum ad humorem vitreum, et istud corpus non fuit diverse diafonitatis a corpore anterioris glacialis nisi ut reflectantur forme in ipso.

2.8 ◉ And it has already been shown that this form passes through the body of the glacialis along straight radial lines, and since the form can reach the hollow of the nerve only after it has been refracted along lines intersecting the [original] radial lines, the form is refracted only after it passes through the body of the glacialis. And it has already been claimed in [the section on] the structure of the eye that the body of the glacialis varies in transparency and that its posterior portion, which is called the vitreous [body], differs in transparency from its front portion.⁑ Moreover, in the glacialis there is no body, other than the vitreous [body], that is different in form⁑ from the form of the anterior portion. But it is among the properties of the forms of light and color to be refracted when they meet with another body that differs in transparency from the first body [through which they were first radiating]. Thus, the forms are refracted only when they reach the vitreous humor, and this body differs in transparency from the body at the front of the glacialis only so that the forms can be refracted in it.⁑

2.9 ◉ Et debet esse superficies istius corporis antecedens centrum ut reflectantur forme apud ipsum antequam pertranseant centrum. Et debet ista superficies esse consimilis ordinationis, quoniam si non fuerit consimilis ordinationis, apparebit forma monstruosa post reflexionem. Superficies autem consimilis ordinationis aut est plana aut est sperica. Et non potest esse superficies ista ex spera cuius centrum erit centrum visus, quoniam si ita esset, essent linee radiales semper perpendiculares super ipsam, et sic extenderetur forma secundum rectitudinem earum, et non reflecteretur. Nec potest esse ex spera parva, quoniam si fuerit ex spera parva, quando forma reflectetur ab ea et elongabitur ab ea, fiet monstruosa. Ista ergo superficies aut est plana aut est sperica spere alicuius et aliquante bone quantitatis ita quod spericitas eius non operabitur in ordinatione forme.

2.9 ◉ Furthermore, the surface of this body must lie in front of the center [of eye] so that the forms can be refracted at it before they pass through that centerpoint.⁑ And this surface must be uniform in shape, for if it were not uniform in shape, the form would appear distorted after refraction. But a surface of uniform shape is either plane or spherical.⁑ Now this surface cannot be formed from a sphere whose center is the center of the eye, for it it were, the [incoming] radial lines would always be perpendicular to it, so the form would extend along those straight lines and would not be refracted. Nor can [this surface] be formed from a small sphere, for if it were formed from a small sphere, then when the form is refracted at it and continues on, it will be distorted. Hence, this surface is plane, or it is spherical [and formed] from a sphere that is the right size not to have its curvature affect the arrangement of the form.⁑

2.10 ◉ Superfices ergo humoris glacialis que est differentia communis inter istud corpus et corpus anterius glacialis est superficies consimilis ordinationis antecedens centrum visus. Et omnes forme pervenientes in superficiem glacialis extenduntur in corpore glacialis secundum rectitudinem linearum radialium quousque perveniunt ad istam superficiem, et cum pervenerint ad istam superficiem, reflectuntur apud ipsam secundum lineas consimilis ordinationis secantes lineas radiales. Linee ergo radiales non iuvant ad ordinationem formarum rerum visibilium nisi apud glacialem tantum, quoniam apud membrum istud erit principium sensus. Et declaratum est etiam in primo tractatu quod impossibile est ut forma rei vise sit ordinata in superficie visus cum magnitudine rei vise et parvitate rei sentientis nisi per istas lineas. Iste ergo linee non sunt nisi instrumentum visui per quas completur comprehensio rerum visarum secundum suum esse. Perventus autem formarum ad ultimum sentiens non indiget extensione secundum rectitudinem istarum formarum.

2.10 ◉ Hence, the surface of the glacial humor that forms the common section between that [vitreous] body and the anterior body of the glacialis is a surface of uniform shape that lies in front of the center of the eye. And all the forms reaching the surface of the glacialis extend through the body of the glacialis along straight, radial lines until they arrive at this surface, but when they arrive at this surface, they are refracted at it along uniformly arranged lines that intersect the [original] radial lines. Therefore, radial lines conduce to the proper arrangement of the forms of visible objects only at the glacialis, for it is at this organ that [visual] sensation will begin. And it has also been shown in the first book that, given the size of the visible object and the smallness of the sensitive organ, it is impossible for the form of a visible object to be properly arranged on the surface of the eye except along such lines.⁑ Hence, these lines exist solely to be the instrument of sight through which visible objects are finally perceived as they exist in reality. However, in reaching the final sensor [in proper order], the forms do not need to continue along such straight lines.⁑

2.11 ◉ Et receptio membri sentientis ad formas non est sicut receptio corporum diafonorum ad istas formas. Quoniam membrum sentiens recipit istas formas, et sentit eas, et pertranseunt in eo propter suam diafonitatem, et virtutem sensibilem que est in eo recipit ergo istas formas secundum receptionem sensus. Corpora autem diafona non recipiunt istas formas nisi receptione qua recipiunt ad redendum, et non sentiunt ipsas. Et cum receptio corporis sentientis ab istis formis non est sicut receptio corporum diafonorum non sentientium, extensio formarum in corpore sentienti non debet esse secundum verticationes quas corpora diafona exigunt. Visus ergo non est appropriatus receptioni formarum ex verticationibus linearum radialium tantum nisi quia proprietas formarum est ut extendantur in corporibus diafonis super omnes verticationes rectas. Et cum iste forme pervenerint apud membrum sentiens ordinate et comprehendantur a membro sentiente ordinate, nichil remanebit post indigens istarum verticationibus.

2.11 ◉ Now the reception of forms by the sensitive organ is not like the reception of such forms by transparent bodies. For the sensitive organ receives these forms while sensing them, and they pass through it according to its transparency, but the sensitive power it possesses receives these forms in a sensitive way. Transparent bodies, however, receive these forms only for the purpose of transmitting them, but they do not sense them. And since a sensitive body does not receive these forms in the same way as nonsensitive transparent bodies do, the forms need not continue through the sensitive body along the same [radial] lines that transparent bodies require. Therefore, the eye is constituted to receive forms along radial lines only insofar as it is a property of forms to extend through transparent bodies along all straight lines. But if these forms reach the sensing organ in proper order and are perceived by the sensing organ in proper order, there will be no need for such [radial] lines afterward.

2.12 ◉ Pars ergo anterioris tantum glacialis est appropriata receptioni formarum ex verticationibus linearum radialium; posterior autem pars, que est vitreum, et virtus recipiens que est in isto corpore non est appropriata cum sensu suo istarum formarum nisi ad custodiendum ordinationem earum tantum. Et cum ita est, qualitas ergo receptionis vitrei a formis non est sicut qualitas receptionis corporis anterioris glacialis, et virtus recipiens que est in vitreo non est virtus recipiens que est in parte anteriori.

2.12 ◉ Accordingly, only the front portion of the glacialis is constituted for the reception of forms along radial lines; the posterior portion, which is called the vitreous [body], along with the receptive capacity that is in this body, is constituted with its sensation of these forms only to maintain their arrangement. And since this is so, the way the vitreous [humor] receives the forms is not the way that the anterior portion of the glacialis receives them, and the receptive capacity of the vitreous [humor] is not the [same as] the receptive capacity in the anterior portion [of the glacialis].

2.13 ◉ Et cum qualitas receptionis vitrei a formis non est qualitas receptionis partis anterioris glacialis, reflexio ergo formarum apud superficiem vitrei non est nisi propter diversitatem qualitatis receptionis sensus inter ista duo corpora. Forme ergo reflectuntur apud vitreum duabus de causis quarum altera est diversitas diafonitatis duorum corporum, et altera est diversitas qualitatis receptionis sensus inter ista duo corpora.

2.13 ◉ Moreover, since the way the vitreous [humor] receives forms is not the way the anterior portion of the glacialis receives them, the refraction that the forms undergo at the surface of the vitreous [humor] can only be due to the difference in the receptive sensitivity of these two bodies. Thus, the refraction of forms at the vitreous [humor] has two determinants, one being the difference in transparency between the two bodies, the other being the difference in receptive sensitivity between these two bodies.

2.14 ◉ Et si diafonitas duorum corporum esset consimilis, esset forma extensa in corpore vitreo secundum rectitudinem linearum radialium propter consimilitudinem diafonitatis, et esset reflexa propter diversitatem qualitatis sensus. Et sic esset forma post reflexionem monstruosa, aut due forme essent propter istam dispositionem. Et cum diversitas diafonitatis affirmat reflexionem, scilicet obliquationem, et diversitas qualitatis sensus affirmat illam obliquationem, erit forma post obliquationem una forma, et propter hoc diversatur diafonitas corporis vitrei et diafonitas corporis anterioris glacialis. Forme ergo perveniunt ad vitreum ordinate secundum ordinationem earum in superficie visi, et recipit ipsas istud corpus, et sentit ipsas. Deinde obliquantur propter diversitatem diafonitatis et diversitatem sensus istius corporis, et sic pervenit forma secundum dispositionem suam. Deinde extendetur iste sensus, et iste forme, per hoc corpus quousque perveniat iste sensus et iste forme ad ultimum sentiens. Et erit extensio sensus et extensio forme in corpore vitrei et in corpore sentienti extenso in concavo nervi ad ultimum sentiens sicut extensio sensus tactus et sensus doloris ad ultimum sentiens.

2.14 ◉ Now if the transparency of the two bodies were uniform, the form would extend through the vitreous body along straight, radial lines on account of the uniformity of transparency, but it would be refracted on account of the difference in sensitivity. Under these circumstances, then, the form would be distorted after refraction, or else there would be two forms [created] on account of this [disparity in the] nature [of the two media]. But since the difference in transparency prompts refraction, i.e., bending, and since the difference in sensitivity prompts [such] bending, the form will remain single after refraction, and it is for this reason that the transparency of the vitreous humor and the transparency of the glacial humor are different. Therefore, the forms reach the vitreous humor arranged as they actually are on the surface of the visible object, and this body receives them and senses them. Then they are refracted according to the difference in transparency and the difference in sensitivity possessed by this body, and so the form arrives according to its proper arrangement.⁑ The resulting sensation, as well as the resulting form, will then extend through this body until the sensation and form reach the final sensor. But the passage of the sensation and the passage of the form through the body of the vitreous and through the sensitive body that fills the hollow of the optic nerve to the final sensor will be like the passage of the sensation of touch or the sensation of pain to the final sensor.

2.15 ◉ Sensus autem tactus et sensus doloris non extenduntur a membris nisi in filis nervorum et in spiritu extenso secundum illa fila. Et forme rerum visibilium quando pervenerint in corpus humoris vitrei, extendetur sensus ab isto membro in corpus sentiens extensum in concavo nervi continuati inter visum et anterius cerebri. Et secundum extensionem sensus extenduntur forme ordinate secundum suam dispositionem, quoniam corpus sentiens naturaliter conservat ordinationem istarum formarum. Et ista ordinatio conservatur in corpore sentienti, quoniam ordinatio partium corporis sentientis recipientium partes formarum, et ordinatio virtutis recipientis que est in partibus corporis recipientis, est in corpore vitrei et in omni corpore subtili extenso in concavo nervi ordinatio consimilis. Et cum ita est, quando forma pervenit ad quodlibet punctum superficiei vitrei, curret in verticatione continua, et non alterabitur eius situs in concavitate nervi in quo extenditur corpus sentiens. Et erunt omnes verticationes per quas currunt omnia puncta que sunt in forma consimilis ordinationis adinvicem, et erunt omnes iste verticationes girantes apud girationem nervi, et erunt apud girationem ordinate secundum suam ordinationem ante girationem, et post, propter qualitatem sensus istius corporis. Et sic perveniet forma ad nervum communem secundum suam dispositionem, et non est possibile ut sit extensio formarum visibilium usque ad ultimum sentiens nisi secundum hunc modum, quoniam non est possibile ut forme perveniant ad nervum communem secundum suum esse nisi sit extensio earum secundum hunc modum.

2.15 ◉ However, the sense of touch and the sense of pain extend from the [sensing] organ only through the fibers of the nerves and through the spirit pervading those fibers. And when the forms of visible objects reach the body of the vitreous humor, the sensation will extend from that organ through the sensitive body pervading the hollow of the nerve and linking the eye to the front of the brain. In tandem with sensation, moreover, the forms extend [through this nervous channel] in their proper arrangement, for the sensitive body naturally conserves the arrangement of such forms. And this arrangement is conserved in the sensitive body, because the arrangement of the parts of the sensitive body that receive the parts of the form, as well as the arrangement of the receptive power in the parts of the receiving body, is uniform throughout the vitreous humor and the whole of the subtle matter pervading the hollow of the nerve. Since this is the case, when the form reaches a given point on the surface of the vitreous [humor], it will run along a continuous line, and it will not change its [relative] position in the hollow of the nerve through which the sensitive body extends. And all the lines along which all the points in the form run will be uniformly arranged with respect to one another, and all these lines will bend at the bend of the nerve, and at the point of bending all will be arranged as they were before bending, and afterward as well, because of the sensitive quality of this body. Accordingly, the form will reach the common nerve properly arranged, and it is not possible for the forms of visible objects to extend to the final sensor in any way other than this, for it is not possible for forms to reach the common nerve properly arranged unless their passage occurs in this way.⁑

2.16 ◉ Et cum forme extenduntur secundum istam ordinationem, oportet ut forma perveniens in quolibet puncto superficiei glacialis semper extendatur super eandem verticationem ad idem punctum loci nervi communis ad quod pervenit forma. Sed tamen forma perveniens ad quodlibet punctum superficiei glacialis pervenit semper ad idem punctum superficiei vitrei. Et sequitur ex hoc ut omnia duo puncta consimilis situs in respectu duorum oculorum ab eis extendantur due forme ad idem punctum in nervo communi.

2.16 ◉ And since forms extend according to this arrangement, the form reaching any point on the surface of the glacialis must always extend along the same line to the same point at the common nerve where the form [as a whole] reaches. But the form reaching any given point on the surface of the glacialis also invariably reaches the same point on the surface of the vitreous [humor]. From this it follows that from any two points that are correspondingly situated on [each of] the two eyes two forms extend to the same point in the common nerve.⁑

2.17 ◉ Et etiam sequitur ut sit corpus sentiens quod est in concavo nervi aliquantulum diafonum ut appareant in eo forme lucis et coloris, et sequitur etiam ut sit eius diafonitas similis diafonitati humoris vitrei ut non obliquantur forme apud perventum earum ad ultimam superficiem vitrei vicinantem concavo nervi, quoniam quando diafonitas duorum corporum fuerit consimilis, non obliquabuntur forme. Et non est possibile ut forme obliquantur apud istam superficiem, quoniam ista superficies est sperica, et est ex spera. Si autem forme obliquarentur ab ista superficie, non elongarentur ab ea nisi modicum, et fierent statim monstruose. Obliquatio ergo formarum non potest esse apud istam superficiem.

2.17 ◉ It also follows that the sensitive body pervading the hollow of the nerve should be somewhat transparent so the forms of light and color can appear in it, and it follows, as well, that its transparency should be like the transparency of the vitreous humor so that the forms are not refracted when they reach the posterior surface of the vitreous humor at the hollow of the nerve, for when the transparency of two bodies is identical, the forms will not refract. And it is not possible for the forms to be refracted at this surface, because this surface is spherical and is formed from a sphere. However, if the forms were to refract at this surface, they would not get very far from it before they were distorted.⁑ So there can be no refraction of forms at this surface.

2.18 ◉ Et cum diafonitas corporis sentientis quod est in concavo nervi non est diversa a diafonitate humoris vitrei, nec faciet contingere ista diversitas aliquam diversitatem in forma. Et quamvis forma extendatur cum extensione sensus, diafonitas corporis sentientis quod est in concavo nervi non est diversa a diafonitate corporis vitrei. Diafonitas autem ista istius corporis non est nisi ut extendantur forme in eo secundum verticationes quas exigat diafonitas. Et diafonitas eius non est nisi ut recipiat formas lucis et coloris et ut appareant in eo forme, quoniam corpus non recipit lucem et colorem, nec pertranseunt in eo forme lucis et coloris nisi sit diafonum aut fuerit in eo aliquid diafonitatis. Et non apparet lux et color in corpore diafono nisi sit cum eo in diafonitate aliquid spissitudinis, et propter hoc non est glacialis in fine diafonitatis nec in fine spissitudinis. Corpus ergo sentiens quod est in concavo nervi est diafonum, et in eo est cum hoc aliquid spissitudinis. Forma autem pertransit in isto corpore cum eo quod est in eo de diafonitate, et apparent forme in eo virtuti sensitive cum eo quod est in eo de spissitudine. Et sentiens ultimum non comprehendit formas lucis et coloris nisi ex formis pervenientibus ad istud corpus apud perventum eorum ad nervum communem, et comprehendit lucem ex illuminatione istius corporis et colorem ex coloratione. Secundum ergo hunc modum erit perventus formarum ad ultimum sentiens et comprehensio ultimi sentientis quoad illas.

2.18 ◉ If the transparency of the sensitive body pervading the hollow of the nerve is no different from the transparency of the vitreous humor, there will be no variation [in transparency] to cause a variation in the form. And although the form extends in tandem with sensation, the transparency of the sensitive body that pervades the hollow of the nerve is no different from the transparency of the vitreous body. However, the transparency of this body is intended only to let forms extend through it along the lines that transparency requires. So it is transparent only so that it can receive the forms of light and color and so that those forms can appear in it, for a body does not receive light and color, nor do the forms of light and color pass through it, unless it is [completely] transparent or there is some transparency in it. And light and color do not appear in a transparent body unless there is some opacity to go along with its transparency, and for this reason the glacialis is neither exquisitely transparent nor inordinately opaque. Hence, the sensitive body that pervades the hollow of the nerve is transparent, but along with that there is some opacity in it. So the form passes through this body on account of the transparency it possesses, and forms are revealed to the sensitive power in it on account of the opacity it possesses. And the final sensor perceives the forms of light and color only from the forms reaching through this body when they arrive at the common nerve, and it perceives light from the illumination of this body and color from its coloring.⁑ This, then, is how forms will reach the final sensor and how the final sensor will perceive them.

2.19 ◉ Et postquam declaratum est quod forme obliquantur apud superficiem vitrei, dicamus quod axis piramidis radialis non potest esse declinans super istam superficiem, nec potest esse alia linea perpendicularis super ipsam. Quoniam axis si fuerit declinans super istam superficiem, quando forme pervenirent ad istam superficiem, diversificarentur in ordinatione et mutarentur sue dispositiones. Forme autem non possunt pervenire in superficie vitrei secundum suum esse nisi fuerit axis piramidis super istam superficiem perpendicularis. Quoniam quando visus fuerit oppositus alicui rei vise et pervenerit axis radialis super superficiem illius rei vise, perveniet forma illius rei vise in superficie glacialis ordinata secundum ordinationem partium superficiei rei vise, et perveniet forma puncti quod est apud extremitatem axis superficiei rei vise ad punctum quod est super axem in superficie glacialis. Et pervenient forme omnium punctorum superficiei rei vise quorum remotio a puncto quod est apud extremitatem axis est equalis ad puncta formarum que sunt in superficie glacialis quorum remotio a puncto quod est super axem est equalis, quoniam omnia puncta pervenientia ad superficiem glacialis sunt super lineas radiales extensas a centro visus ad superficiem visus, et axis radialis est perpendicularis super superficiem glacialis. Omnes ergo superficies plane exeuntes ab axe et secantes superficiem glacialis erunt perpendiculares super istam superficiem.

2.19 ◉ Having shown that forms are refracted at the surface of the vitreous [humor], we should add that the axis of the cone of radiation cannot be obliquely incident upon this surface, nor can any other line be perpendicular to that surface.⁑ For if the [visual] axis were to intersect this surface obliquely, then, when forms arrived at this surface, they would vary in arrangement and would change their orientations. But forms can reach the surface of the vitreous humor properly arranged only when the axis of the cone is perpendicular to this surface. For when the eye faces some visible object and the visual axis reaches the surface of that visible object, the form of that visible object will reach the surface of the glacialis arranged according to the actual arrangement of the parts on the surface of the visible object, and the form of the point on the surface of the visible object at the extremity of the [visual] axis will reach the point on the surface of the glacialis intersected by that axis. Furthermore, the forms of all the points on the surface of the visible object that are equidistant from the point at the extremity of the [visual] axis will extend to points of the forms on the surface of the glacialis that are equidistant from the point where the [visual] axis intersects it, for all of the points reaching the surface of the glacialis lie on radial lines extending from the center of the eye to the surface of the eye, and the visual axis is perpendicular to the surface of the glacialis. Therefore, all the planes containing the [visual] axis and intersecting the surface of the glacialis will be perpendicular to its surface.

2.20 ◉ Et iam declaratum est quod superficies humoris vitrei aut est plana aut est sperica, et centrum eius non est centrum visus. Si ergo axis radialis est declinans super istam superficiem et non est perpendicularis super ipsam, non exibit ab axe superficies plana perpendicularis super istam superficiem nisi una superficies tantum, et omnes superficies residue exeuntes ab axe erunt declinantes super ipsam, quoniam hec est proprietas linearum declinantium super superficies planas et spericas. Ymaginemur ergo superficiem exeuntem ab axe et perpendicularem super superficiem vitrei extendi ab axe. Secabit ergo superficiem vitrei et superficiem glacialis, et signabit in eis duas differentias communes. Et ymaginemur super differentiam communem que est communis huic superficiei et superficiei glacialis inter istam superficiem et superficiem glacialis duo puncta, et sint remota a puncto quod est super axem equaliter. Et ymaginemur duas lineas exeuntes a centro glacialis usque ad ista duo puncta. Erunt ergo due linee cum axe in superficie communi perpendiculari super superficiem vitrei, quoniam duo puncta et punctum centri ista tria sunt in ista superficie. Et erunt duo anguli qui fient ex istis duabus lineis et axe equales, et erunt iste due linee secantes differentiam communem que est in superficie vitrei super puncta duo. Et similiter axis secabit communem differentiam istam et super punctum medium inter illa duo puncta. Si ergo superficies vitrei est plana, erit differentia communis linea recta. Et si axis fuerit declinans super superficiem vitrei, et fuerit superficies que fecit differentiam communem perpendicularis super istam superficiem, erit axis declinans super communem differentiam, scilicet super istam lineam. Et erunt laterum duo anguli inequales, quoniam si axis esset perpendicularis super istam differentiam communem, esset perpendicularis super superficiem. Et cum duo predicti anguli sint inequales, et duo anguli qui sunt apud centrum glacialis quod est extremitas axis sunt equales, erunt due partes linee que est differentia communis inequales. Ergo erunt duo puncta extremitatum diverse distantie a puncto quod est super axem existenti in ista linea. Et ista duo puncta sunt illa ad que perveniunt forme duorum punctorum superficiei glacialis que sunt equaliter distantia ab axe, quoniam sunt apud duas extremitates duarum linearum radialium transeuntium per ista duo puncta. Et punctus qui est super axem ex superficie vitrei est ille ad quem pervenit forma puncti quod est super axem ex superficie glacialis. Et cum axis fuerit declinans super superficiem vitrei, et superficies vitrei fuerit plana, duo puncta forme pervenientis in superficie glacialis quorum distantia a puncto quod est super axem est equalis que sunt in superficie perpendiculari super superficiem vitrei, quando pervenerint ad superficiem vitrei, erit distantia eorum a puncto pervenienti super axem distantia inequalis.

2.20 ◉ And it has already been shown that the surface of the vitreous humor is either plane or spherical and that its center is not the center of the eye. Therefore, if the visual axis intersects that surface obliquely rather than orthogonally, only one of the planes containing the [visual] axis will be perpendicular to that surface, so all the remaining planes containing the [visual] axis will be oblique to it, for such is a property of lines that are oblique to plane and spherical surfaces. Let us then imagine a plane containing the [visual] axis and perpendicular to the surface of the vitreous humor [and let it be] extended beyond the [visual] axis. It will therefore intersect the surface of the vitreous [humor] and the surface of the glacialis and will describe two different common sections in them. Then let us imagine two points on the common section of this plane and the surface of the glacialis, and let them be equidistant from the point where the [visual] axis intersects the glacialis. Let us also imagine two lines extending from the center of the glacialis to these two points. Therefore, the two lines will lie along with the [visual] axis in the same plane that is perpendicular to the surface of the vitreous humor, for, along with the centerpoint, the two points form three points on this surface. Moreover, the two angles formed by these two lines with the [visual] axis will be equal, and these two lines will intersect the common section on the surface of the vitreous [humor] at two points. Likewise, the [visual] axis will intersect this common section at the point midway between these two points. Therefore, if the surface of the vitreous [humor] is plane, the common section will be a straight line.⁑ But if the [visual] axis is oblique to the surface of the vitreous [humor], and the plane forming the common section is perpendicular to this surface, then the [visual] axis will be oblique to the common section [of the two planes], i.e. to this line. So the sides of the two angles will be unequal, because, if the [visual] axis were perpendicular to this common section, it would be perpendicular to the surface. But since the two aforementioned angles are unequal while the two angles at the center of the glacialis, which is the endpoint of the [visual] axis, are equal, then the two segments of the line forming the common section will be unequal. Thus, the two points at the end [of those segments] will lie at different distances from the point on the [visual] axis that intersects this line.⁑ But it is to these two points that the forms of the two points that are equidistant from the [visual] axis on the surface of the glacialis reach, for they lie at the endpoints of the two radial lines passing through these two points. Now the point lying on the [visual] axis at the surface of the vitreous [humor] is the one to which the form of the point on the [visual] axis at the surface of the glacialis extends. Granted that the [visual] axis is oblique to the surface of the vitreous [humor], granted that the surface of the vitreous [humor] is plane, granted that the two points of the form that reaches the surface of the glacialis are equidistant from the point reached by the [visual] axis, and granted that these two points lie on a plane that is perpendicular to the surface of the vitreous [humor], then, when they extend onward to the surface of the vitreous [humor], they will lie at unequal distances from the point reaching along the [visual] axis.⁑

2.21 ◉ Et quando axis fuerit declinans super superficiem vitrei, et fuerit superficies vitrei plana, erit differentia communis que sit a qualibet superficie exeunti ab axe et secante superficiem vitrei continens cum axe duos angulos inequales, preter unam superficiem tantum, et est illa que secat superficiem perpendicularem super vitreum, quoniam differentia communis eius continebit cum axe duos angulos rectos. Et erit axis declinans super differentias communes omnium superficierum residuarum. Et cum duo anguli predicti fuerint inequales, et fuerint duo anguli respicientes duas partes differentie communis, scilicet anguli qui sunt apud centrum superficiei glacialis, equales, erunt due partes differentie communis que est in superficie vitrei inequales, et erunt duo puncta que sunt extremitates istius differentie communis diverse distantie a puncto quod est super axem. Due autem partes differentie communis que sunt in superficie glacialis erunt equales, et erunt duo puncta que sunt in extremitate istius differentie communis equalis distantie a puncto qui est super axem in superficie glacialis. Et cum ita est, quando forma pervenerit a superficie glacialis ad superficiem vitrei, erit ordinatio eius non secundum suum esse in superficie glacialis nec secundum suum esse in superficie rei vise.

2.21 ◉ If the axis is oblique to the surface of the vitreous [humor] and the surface of the vitreous [humor] is plane, the common section of any plane containing the [visual] axis and intersecting the surface of the vitreous [humor] will form two unequal angles with the [visual] axis, except for a single plane, and that is the plane that intersects the surface of the vitreous [humor] orthogonally, for the common section formed by it will subtend two right angles with the [visual] axis. But the [visual] axis will be oblique to the common sections of every other [intersecting] plane. And if the two aforesaid angles are unequal while the two angles opposite the two portions of the common section—i.e., the angles at the center of the surface of the glacialis—are equal, then the two portions of the common section on the surface of the [vitreous] humor will be unequal, and the two endpoints of this common section will lie at different distances from the point on the [visual] axis. However, the two portions of the common section on the surface of the glacialis will be equal, and the two endpoints of this common section will be equidistant from the point where the [visual] axis intersects the surface of the glacialis. This being the case, when the form passes from the surface of the glacialis to the surface of the vitreous [humor], its arrangement will not be the same as it is on the surface of the glacialis or as it is on the surface of the visible object.

2.22 ◉ Et similiter etiam declarabitur quando superficies vitrea fuerit sperica, et fuerit axis declinans super ipsam, quoniam puncta que sunt in superficie glacialis quorum distantia ab axe est equalis quando pervenerint ad superficiem vitrei, erit distantia eorum a puncto axis inequalis. Quoniam quando axis non fuerit perpendicularis super superficiem vitrei, et superficies vitrei fuerit sperica, non pertransibit axis iste per centrum vitrei, et ipse pertransit per centrum superficiei glacialis. Linee ergo que exeunt a centro glacialis ad puncta quorum distantia a puncto axis in superficie glacialis est equalis continent cum axe apud centrum glacialis angulos equales. Et cum ita est, et centrum glacialis non est centrum vitrei, iste linee distinguent ex superficie vitrei arcus inequales. Et nulle linee continentes cum axe angulos rectos et existentes cum axe in eadem superficie distinguunt ex superficie vitrei duos arcus equales nisi due linee tantum, et sunt ille que sunt in superficie secante superficiem perpendicularem super superficiem vitrei. Cum ergo axis fuerit declinans super superficiem vitrei, forme pervenientes in superficie vitrei erunt diverse ordinationis, sive sit ista superficies plana sive sperica.

2.22 ◉ The same will also hold when the vitreous surface is spherical and the [visual] axis strikes it obliquely, for when the points on the surface of the glacialis that lie equidistant from the [visual] axis reach the surface of the vitreous [humor], their distance from the axial point will be unequal. For when the [visual] axis is not perpendicular to the surface of the vitreous [humor], and when the surface of the vitreous [humor] is spherical, this axis will not pass through the center of [the sphere that defines the surface of] the vitreous [humor], but it will pass through the center of [the sphere that defines] the surface of the glacialis. Therefore, the lines that extend from the center of the glacialis to points that are equidistant from the point of [intersection of] the [visual] axis on the surface of the glacialis subtend equal angles with the axis at the center of the glacialis. And if this is so, but the center of the glacialis is not the center of the vitreous [humor], then these lines will demarcate unequal arcs on the surface of the vitreous humor.⁑ And only two lines lying in the same plane as the [visual] axis and subtending right angles with it mark off equal arcs on the surface of the vitreous [humor], and those are lines that lie on a plane that intersects the surface of the vitreous [humor] orthogonally. Thus, if the [visual] axis is oblique to the surface of the vitreous [humor], the forms that reach the surface of the vitreous [humor] will be improperly arranged, whether that surface is plane or spherical.

2.23 ◉ Et cum axis fuerit perpendicularis super superficiem vitrei, erit perpendicularis super omnes differentias communes, et erunt quelibet due linee exeuntes a centro glacialis, quod est punctus in axe, continentes cum axe angulos rectos et distinguentes ex differentia communi que est in superficie vitrei duas partes equales. Et erit distantia duorum punctorum que sunt extremitates duarum partium equalium a puncto qui est super axem in superficie vitrei equalis, sive sit superficies vitrei plana sive sperica. Secundum ergo omnes dispositiones non pervenit forma ad superficiem vitrei et situs partium eius secundum esse suum in superficie visus nisi axis perpendicularis sit super superficiem vitrei. Et sentiens non sentit formam nisi secundum suum esse apud perventum eius ad ipsum, et sentiens comprehendit ordinationem partium rei vise secundum suum esse in superficie rei vise. Non est ergo possibile ut forme perveniant in superficie vitrei nisi sit ordinatio partium earum secundum suum esse. Ergo non est possibile ut axis radialis sit declinans super superficiem vitrei; erit igitur perpendicularis. Omnes ergo linee radiales residue erunt obliquate super istam superficiem, sive sit plana sive sit sperica, quoniam secant axem super centrum glacialis. Nulla autem linearum istarum transit per centrum superficiei vitrei, si fuerit sperica, nisi axis tantum, quoniam est perpendicularis super ipsam et quia centrum superficiei glacialis non est centrum superficiei vitrei. Et cum declaratum est quod forme pervenientes in superficie glacialis non perveniunt ad concavum nervi nisi postquam fuerint oblique reflexe, et non est reflexio earum nisi apud superficiem vitrei, et axis est perpendicularis super istam superficiem, et omnes linee radiales residue sunt obliquate super istam superficiem, quando forme pervenient ad superficiem vitrei, obliquabuntur omnia puncta que sunt in ea preter punctum axis, quoniam iste punctus extenditur secundum rectitudinem axis quousque perveniat ad locum girationis concavi nervi. Nulla ergo forma perveniens ad superficiem glacialis extenditur ad concavum nervi secundum rectitudinem nisi punctus tantum axis, et omnia puncta residua perveniunt ad concavum nervi secundum lineas obliquatas.

2.23 ◉ But if the axis is perpendicular to the surface of the vitreous [humor], it will be perpendicular to all the common sections [on it], and any two lines that extend from the center of the glacialis, which is a point on the [visual] axis, will subtend right angles with the [visual] axis and will mark off two equal segments on the common section on the surface of the vitreous [humor]. Moreover, the two endpoints of the two equal segments will be equidistant from the point of [intersection of] the [visual] axis on the surface of the vitreous [humor], whether the surface of the vitreous [humor] is plane or spherical. Under all circumstances, then, the form reaches the surface of the vitreous with its parts arranged as they are on the surface of the eye only when the [visual] axis is perpendicular to the surface of the vitreous [humor]. Moreover, the [final] sensor only senses the form as it actually is when that form reaches it, and the [final] sensor perceives the arrangement of the parts of the visible object as it really exists on the surface of the visible object. It is therefore not possible for the forms to reach the surface of the vitreous [humor] without having their parts arranged as they really are [on the surface of the visible object]. It is not possible, then, for the visual axis to be oblique to the surface of the vitreous [humor]; so it will be perpendicular. Thus, all the remaining radial lines will be oblique to this surface, whether it is plane or spherical, because they intersect the [visual] axis at the center of the glacialis. However, none of these lines, except the [visual] axis, passes through the center of the surface of the vitreous [humor], assuming it is spherical, because it is perpendicular to this surface, but the center of the surface of the glacialis is not the [same as the] center of the surface of the vitreous humor. And since it has been shown that forms reaching the surface of the glacialis only reach the hollow of the nerve after having been refracted along oblique lines, and since their refraction happens only at the surface of the vitreous [humor], and since the [visual] axis is perpendicular to this surface while all the remaining radial lines are oblique to this surface, then, when the forms reach the surface of the vitreous [humor], all of the points on them except for the axial point will be diverted, for this point extends straight along the [visual] axis until it reaches the bend in the hollow of the nerve. Therefore, no form other than [that of] the point on the [visual] axis that reaches the surface of the glacialis extends to the hollow of the nerve along a straight line; all the rest of the [forms of the] points reach the hollow of the nerve along oblique lines.

2.24 ◉ Cum ergo visus comprehenderit rem visam, et illa res visa fuerit opposita medio visus, et fuerit axis intra piramidem radialem continentem illam rem visam, forma illius rei vise perveniet ad superficiem glacialem secundum rectitudinem linearum radialium. Deinde extenduntur forme ab ista superficie secundum rectitudinem linearum radialium etiam quousque perveniant ad superficiem vitrei. Deinde punctus axis extendetur ab ista superficie secundum rectitudinem axis quousque perveniat ad locum girationis concavi nervi. Et omnia puncta residua obliquantur secundum lineas secantes lineas radiales et consimilis ordinationis quousque perveniant ad locum girationis concavi nervi. Perveniet ergo forma in isto loco ordinata secundum suum ordinem in superficie glacialis et secundum suam ordinationem in superficie rei vise. Sed dispositio formarum obliquatarum non est sicut dispositio formarum extensarum recte, quoniam obliquatio necessario alterabit ipsas aliqua alteratione. Sequitur ergo de ista dispositione ut sit punctus perveniens ad locum girationis concavi nervi qui extendebatur secundum rectitudinem axis magis verificatus omnibus punctis formarum.

2.24 ◉ Thus, when the eye perceives a visible object that faces the middle of the eye, and since the [visual] axis lies inside the cone of radiation that encompasses that visible object, the form of that visible object will reach the surface of the glacialis along straight radial lines. From this surface forms then extend along straight, radial lines as well, until they reach the surface of the vitreous [humor]. Then, from this surface the [form of the] axial point will reach straight along the axial line until it reaches the place where the hollow of the nerve bends. Meantime, all the remaining points are refracted along lines that intersect the [original] radial lines, and they maintain the same arrangement until they reach the place where the hollow of the nerve bends. Thus, the form will arrive at this place arranged according to its order on the surface of the glacialis as well as its order on the surface of the visible object [itself]. However, the disposition of refracted forms is not like the disposition of forms that pass straight on, for refraction will necessarily change them is some way.⁑ Therefore, it follows from this circumstance that the point extending straight along the [visual] axis to the place where the hollow of the nerve bends is more clearly perceived than all the [other] points of [such] forms.⁑

2.25 ◉ Et etiam obliquatio punctorum pervenientium in superficie obliquationis propinquiorum puncto axis magis est minor et remotiorum maior, quoniam obliquatio non est nisi secundum angulos qui fiunt ex lineis super quas forme veniunt et ex perpendicularibus que sunt super superficiem obliquationis. Et linee continentes cum perpendicularibus angulos minores erit obliquatio earum secundum angulos minores, et linee continentes cum perpendicularibus angulos maiores erit obliquatio earum secundum angulos maiores. Et linee radiales propinquiores axi minus declinant super superficiem obliquationis, et sic continent cum perpendicularibus que sunt super superficiem obliquationis angulos minores. Et ille que sunt remotiores ab axe magis declinant super superficiem obliquationis, et sic continent cum perpendicularibus angulos maiores. Et forme quarum obliquatio est minor magis manifestantur, et forme quarum obliquatio est maior minus. Punctus ergo qui est super axem perveniens ad locum girationis concavi nervi est manifestior omnibus punctis residuis, et quod est propinquius illi est manifestius remotiori ab illo.

2.25 ◉ Also, the refraction of points reaching the surface of refraction nearer the axial point is less, and [that of those reaching it] farther [from that point] is greater, for refraction depends entirely upon the angles that are formed by the [radial] lines along which the forms arrive and the normals to the surface of refraction. And refraction of lines forming smaller angles with the normals will occur at smaller angles, whereas refraction of lines forming greater angles with the normals will occur at greater angles. But radial lines that are nearer the [visual] axis are less oblique to the surface of refraction, so they form smaller angles with the normals to the surface of refraction. Those, on the other hand, that are farther from the [visual] axis are more oblique to the surface of refraction, so they form greater angles with the normals. And forms that suffer less refraction are clearer [to sight], whereas forms that suffer greater refraction are less so.⁑ Thus, the point on the [visual] axis [whose form] reaches the place where the hollow of the nerve bends is more clear[ly seen] than all the rest of the points, and whatever point is nearer it is more clear[ly seen] than one lying farther from it.

2.26 ◉ Et iste forme sunt ille que extenduntur ad nervum communem, et ex illis comprehendit ultimum sentiens formam rei vise. Et cum ista forma perveniens ad locum girationis concavi nervi est diverse dispositionis—scilicet quod punctus axis est manifestior omnibus punctis residuis, et quod est propinquius illi est magis manifestum post—forma perveniens in nervo communi ex qua comprehendit virtus sensitiva formam rei vise erit diverse dispositionis. Et punctus eius respondens puncto axis in superficie rei vise est manifestior omnibus punctis residuis forme, et ei propinquius manifestius.

2.26 ◉ Now these forms are the ones that extend to the common nerve, and it is from these that the final sensor perceives the form of the visible object. And since this form arrives at the place where the hollow of the nerve bends with varying dispositions—i.e., in such a way that its axial point is clearer than all the remaining points and that whatever point lies nearer it is clearer than one farther from it—the form that reaches the common nerve [and] on the basis of which the sensitive faculty perceives the form of the visible object will vary in disposition. So the point on it that corresponds to the axial point on the surface of the visible object is clearer than all the other points of the form, and the nearer to it any point lies, the clearer it is.

2.27 ◉ Et cum inducantur dispositiones rerum visarum, et distinguatur qualitas comprehensionis visus a rebus visis quas comprehendit visus in simul et qualitas comprehensionis visus a partibus unius rei vise, invenientur convenientes huic quod determinavimus. Quoniam aspiciens quando in eodem tempore fuerit oppositus multis rebus visibilibus, et visus eius fuerit quietus, et non moverit ipsum, inveniet rem visam oppositam medio sui visus manifestiorem illis que sunt a parte laterum illius medii, et quod est propinquius medio erit manifestius. Et similiter quando inspiciens inspexerit rem visam magnam, et visus eius fuerit oppositus medio illius rei vise, et fuerit quietus, comprehendet medium illius rei vise manifestius illius rei extremitatibus. Et hoc manifestabitur bene quando fuerint multa visibilia sibi propinqua, et aspiciens fuerit oppositus uni illorum quod erit medium inter illa visibilia, visu quieto, quoniam tunc comprehendet comprehensione manifesta illud medium; et cum hoc etiam comprehendet illa que sunt in lateribus illius, sed non manifeste. Et hoc manifestatur magis quando spatium super quod sunt illa visibilia fuerit longum, quoniam tunc erit inter comprehensionem medii et comprehensionem extremitatum magna diversitas.

2.27 ◉ And when the dispositions of visible objects are examined, and when the way sight perceives [several] visible objects at the same time is determined along with how it perceives the parts of a single visible object, the results will be found to agree with what we have shown. For when a viewer faces several visible objects at the same time, and when his eye remains steady, and he does not shift it, he will find that the visible object directly along his central line-of-sight is clearer than those to the side of it, and [he will find] that what lies nearer his central line-of-sight will be clearer. By the same token, when the viewer looks at a large visible object, and his line-of-sight is aimed directly at the midpoint of that visible object and remains steady, he will perceive the middle of that visible object more clearly than he will the outer edges of that object. This will become eminently clear when several visible objects are adjacent to one another, and the viewer faces one of the objects that is in the midst of the rest, for in that case, if his focus remains steady, he will perceive that middle object with clarity; and along with that he will also perceive those that surround it, but not clearly. This is especially obvious when those visible objects occupy considerable space, for then there will be a significant difference between the perception of the middle object and the perception of the outer ones.

2.28 ◉ Deinde si hec species motus moverit suum visum in aspiciente et fuerit oppositus alii rei vise preter illam rem visam que ante erat opposita, comprehendet istam secundam comprehensione manifesta. Primam autem comprehendet comprehensione debili. Et si fuerit oppositus extremitati et intueatur ipsam, comprehendet ipsam comprehensione manifestiori quam in comprehensione prime dispositionis secundum eius remotionem ab eo, et cum hoc comprehendet medium comprehensione debili, quamvis sit propinquius. Et erit inter comprehensionem medii apud oppositionem eius extremitati et inter comprehensionem medii apud oppositionem eius ipsi medio illius diversitas sensibili.

2.28 ◉ Subsequently, if he shifts his viewpoint under these conditions so that he looks directly at an object other than the visible object he faced before, he will perceive this second object more clearly. The first one, however, he will perceive more dimly. And if he faces the one at the end and focuses on it, he will perceive it more clearly than he did under the original condition because of its distance from his line-of-sight [at that time], and at the same time he will perceive the middle object more dimly, even though it is nearer to him. Moreover, there will be a significant difference [in clarity] between his perception of the middle object when he focuses on the object at the end and his perception of the middle object when he focuses on it.

2.30 ◉ Manifestabitur ergo ex hac experimentatione quod visio per medium visus et per axem quem distinximus est manifestior visione per extremitates visus et per lineas continentes axem. Declaratum est ergo quod visio erit per axem piramidis radialis manifestior quam visio per omnes lineas radiales et quod visio per illud quod propinquius est axi est manifestior quam per illud quod est remotior.

2.30 ◉ From this experiment it will therefore be clear that vision [taking place] through the center of the eye, along the [visual] axis as defined by us, is clearer than vision at the edge of the eye, along lines surrounding the [visual] axis. It has therefore been shown that vision [taking place] along the axis of the visual cone will be clearer than vision [taking place] along all [the other] radial lines and, moreover, that vision [taking place] along a line nearer the [visual] axis is clearer than [vision taking place] along a line that is farther [from the visual axis].

◉[Capitulum 3]

◉[Chapter 3]

3.1 ◉ Sensus quidem visus nichil comprehendit de rebus visibilibus nisi in corpore. In corpore autem multe res congregantur et accidunt ei multe res, et visus comprehendit de corporibus multas res que sunt in eis et que accidunt illis. Et color est unum eorum que accidunt corporibus, et similiter lux, et sensus visus comprehendit utrumque istorum in corporibus. Et comprehendit etiam alias res preter istas duas, sicut figuram, et situs, et magnitudinem, et motum, et alia que nos distinguemus post. Et comprehendit etiam consimilitudinem colorum et diversitatem eorum, et consimilitudinem lucis et diversitatem eius. Et similiter etiam comprehendit consimilitudinem figurarum, et situum, et motuum.

3.1 ◉ The sense of sight, in fact, perceives none of the visible properties unless they are embodied.⁑ Moreover, many inherent properties, as well as many accidental properties combine together in a body, and sight perceives many of the inherent and accidental properties possessed by bodies.⁑ Color is one of those properties that occur in bodies, and light as well, and the sense of sight perceives both of these in bodies. It also perceives other properties besides these two, e.g., shape, spatial disposition, size, motion, and other properties that we shall specify later.⁑ It also perceives similarities and differences among colors, as well as similarities and differences among lights. So too, it perceives similarities among shapes, and spatial dispositions, and motions.

3.2 ◉ Et comprehensio omnium istorum non est secundum unum modum, nec comprehensio cuiuslibet istorum est sensu solo. Quoniam visus quando comprehendit duo individua in eodem tempore, et fuerint consimilia in forma, comprehendet individua, et comprehendet que sunt similia. Sed consimilitudo duarum formarum individuorum duorum non est ipse forme nec una illarum.

3.2 ◉ Furthermore, these properties are not all perceived in the same way, nor is it through brute sensation that every one of them is perceived.⁑ For, when the eye perceives two individuals at the same time, and when they are similar in structure, it will perceive [that they are] individuals, and it will perceive that they are similar. But the similarity of the two forms of the two individuals is neither the [two] forms themselves nor either one of them.

3.3 ◉ Et cum visus comprehendit individua ex formis pervenientibus ad ipsum visum ex duobus individuis, ipse ergo comprehendit consimilitudinem duorum individuorum ex similitudine duarum formarum pervenientium a forma ad visum. Et consimilitudo duarum formarum non est ipse forme nec tertia forma propria consimilitudini.

3.3 ◉ But since sight perceives the individuals by means of forms coming to the eye from the two individuals, it therefore perceives the similarity of the two individuals on the basis of the similarity of the two forms reaching from the form [of each of those individuals]⁑ to the eye. But the similarity of the two forms is neither the forms themselves nor a third form pertaining to similarity.

3.4 ◉ Et etiam consimilitudo duarum formarum est convenientia illarum in aliquo. Non ergo comprehendetur duarum formarum similitudo nisi ex comparatione unius ad alteram et ex comprehensione istius in quo sunt consimiles. Et cum visus comprehendit similitudinem, et non est in eo tertia forma ex qua comprehendit similitudinem, visus ergo non comprehendit similitudinem duarum formarum nisi ex comparatione unius ad alteram.

3.4 ◉ But yet the similarity of the two forms consists in their agreement in some respect. Therefore, the similarity of the two forms will only be perceived through a comparison of one to the other and from a perception of what it is in virtue of which they are similar. And since sight perceives similarity, but there is no third form in it by which it perceives similarity, sight cannot perceive the similarity of the two forms unless it compares one to the other.

3.5 ◉ Et similiter comprehendit visus diversitatem duarum formarum diversarum ex comparatione unius ad alteram.

3.5 ◉ Likewise, sight perceives the difference between two different forms by a comparison of one to the other.⁑

3.7 ◉ Et cum ita est, comprehensio ergo sensus visus a similitudine formarum et diversitate illarum non est per solum sensum sed per comparationem formarum adinvicem.

3.7 ◉ And since that is the case, the visual sense does not perceive similarity and difference among forms through brute sensation but through a comparison of forms among each other.

3.8 ◉ Et etiam quando visus comprehendit duos colores unius generis, et fuerit unus illorum fortior altero, sicut viride mirti et viride fistici, comprehendet que sunt viridia, et comprehendet etiam quod alterum illorum est fortioris viriditatis. Et distinguet inter duas viriditates, et comprehendet consimilitudinem eorum in viriditate et diversitatem illorum in fortitudine et debilitate.

3.8 ◉ In addition, when sight perceives two colors of the same kind, but one of them is more vivid⁑ than the other, e.g., myrtle-green and pistachio-green, it will perceive that they are green, but it will also perceive that one of them is of a more vivid green. So it will differentiate between two greens, and it will perceive their similarity in greenness as well as their difference in vividness or dullness.

3.9 ◉ Sed distinctio inter duas viriditates non est ipse sensus viriditatis, quoniam sensus viriditatis est ex viridificatione visus et ex viridificatione visus ab utraque viriditate, et comprehendet quod sunt unius generis. Comprehensio ergo visus quod altera viriditas est fortior altera et quod due sunt unius generis est distinctio colorationis que est in visu, non ipse sensus coloris.

3.9 ◉ Nonetheless, differentiation between two greens is not the actual sensation of green, for the sensation of green arises from the [general] »greening« of sight as well as from the [specific] »greening« of sight by both greens, so it will perceive that they are of the same kind.⁑ Therefore, the perception by sight that one green is more vivid than the other and [yet] that the two are of the same genus represents a differentiation of the coloring that occurs in sight, not the actual sensation of color.

3.10 ◉ Et similiter, quando duo colores sunt consimiles in fortitudine et fuerint unius generis, quoniam visus comprehendit duos colores, et comprehendit quod unius generis sunt et quod sunt consimiles in fortitudine.

3.10 ◉ The same also holds when two colors are similar in vividness and are of the same kind, for sight perceives the two colors, and it perceives that they are of the same kind and that they are similar in vividness.

3.11 ◉ Et similiter est dispositio lucis apud visum, quoniam visus comprehendit lucem et distinguit inter lucem fortem et debilem.

3.11 ◉ And the same holds for the effect of light on sight, for sight perceives the light and differentiates between strong and weak light.

3.12 ◉ Comprehensio ergo visus quoad consimilitudinem colorum et diversitatem eorum, et consimilitudinem lucis et diversitatem eius, et consimilitudinem lineationum formarum rerum visibilium, et figure et situs earum, et diversitates illarum non est nisi ex comparatione illorum adinvicem, non solo sensu.

3.12 ◉ Thus, the perception by sight of similarity and difference among colors, of similarity and difference in light, and of similarity in the outlines, shapes, and spatial dispositions of the forms of visible objects, as well as of differences among them, arises only from comparing them to one another, not from brute sensation.

3.13 ◉ Et etiam sensus visus comprehendit diafonitatem corporum diafonorum et diafonitatem corporum que non sunt in fine diafonitatis, sed non comprehendit diafonitatem talem ratione nisi per comparationem. Quoniam lapides diafoni quorum diafonitas est modica non comprehenduntur a visu esse diafoni nisi postquam fuerint oppositi luci, et comprehendetur lux a posteriori eorum, et comprehendetur quod sunt diafona. Et similiter diafonitas cuiuslibet corporis diafoni non comprehendetur a visu nisi postquam comprehendetur corpus aut lux que est a posteriori eius, et comprehendetur cum hoc per distinctionem quod illud quod appareat a posteriori est diversum a corpore diafono.

3.13 ◉ In addition, the sense of sight perceives the transparency of [completely] transparent bodies as well as the transparency of bodies that are not absolutely transparent, but it does not perceive such transparency through any other procedure than comparison. For transparent stones of slight transparency are not perceived by sight to be transparent until after they are placed against the light; then the light will be perceived behind them, and it will [thereby] be perceived that they are transparent. Likewise, the transparency of no transparent body will be perceived by sight until after a body or light that lies behind it is perceived, and along with that it will be perceived through differentiation that what appears from behind is different from the transparent body [through which it appears].

3.14 ◉ Comprehensio autem eius quod illud quod est a posteriori corporis diafoni est diversum ab illo corpore non est comprehensio solo sensu, sed est comprehensio per rationem. Et cum diafonitas non comprehendetur nisi per signationem, ergo non comprehendetur nisi distinctione et ratione.

3.14 ◉ However, the perception that what lies behind the transparent body is different from that [transparent] body is not [arrived at] by brute sensation; rather, it is a perception [arrived at] by judgment.⁑ And since transparency will only be perceived [indirectly], by implication, it will be perceived only through differentiation⁑ and judgment.

3.15 ◉ Et etiam scriptura non comprehendetur nisi ex distinctione formarum litterarum, et compositione illarum, et comparatione illarum ex sibi similibus que sunt note scriptori ante. Et similiter multe res visibiles quando considerabitur qualitas comprehensionis illarum, invenietur quod non comprehenduntur solo sensu sed ratione et distinctione.

3.15 ◉ Writing, as well, will be deciphered only by [the reader’s] discerning the forms of the letters, along with their combinations, and by comparing them to similar ones already known to the writer.⁑ And by the same token, when the way many visible characteristics are perceived is examined, it will be found that they are not perceived through brute sensation, but through judgment and differentiation.

3.16 ◉ Et cum ita est, non ergo omne quod comprehenditur a visu comprehenditur solo sensu; sed multe visibiles intentiones comprehendentur per rationem et distinctionem cum sensu forme vise.

3.16 ◉ And since this is the case, not everything that is perceived by sight is perceived through brute sensation; instead, many visible characteristics will be perceived through judgment and differentiation in conjunction with the sensation of the form that is seen.

3.17 ◉ Visus autem non habet virtutem distinguendi, sed virtus distinctiva distinguit istas res. Sed distinctio virtutis distinctive in istis rebus visibilibus non est nisi mediante visu.

3.17 ◉ However, sight does not possess the power to differentiate; the faculty of discrimination⁑ differentiates these properties. Nonetheless, the differentiation of these visible characteristics that is carried out by the faculty of discrimination cannot take place without the mediation of sight.

3.18 ◉ Et etiam visus comprehendit multas res visas per cognitionem, et cognoscit hominem esse hominem, et equum equum, et Socratem esse Socratem quando viderit ipsum prius. Et cognoscit animalia sibi assueta, et arbores, et plantas, et lapides, quando prius vidit ipsa et sibi consimilia. Et cognoscit omnes intentiones sibi assuetas in rebus visibilibus.

3.18 ◉ Sight also perceives many things by means of recognition, so it recognizes that a human is a human, that a horse is a horse, and that Socrates is Socrates when it has seen the same thing before. And it recognizes familiar animals, trees, shrubs, and stones when it has seen them or their like before. Moreover, it recognizes all familiar characteristics⁑ that are in visible objects.

3.19 ◉ Et non comprehendit visus quiditatem alicuius rei vise nisi per cognitionem. Cognitio autem non est comprehensio solo sensu, quoniam visus non cognoscit omne quod videt prius. Et cum visus comprehenderit aliquod individuum, et postea separabitur ab illo longo tempore, et post viderit ip sum, et non fuerit rememorans ipsius, non cognoscit ipsum, quoniam non cognoscit illud quod cognovit nisi quando fuerit rememorans. Si ergo cognitio esset comprehensio solo sensu, oporteret quando visus videret aliquod individuum quod prius vidit quod statim cognosceret ipsum in secunda visione secundum omnes dispositiones, sed non ita est.

3.19 ◉ Sight perceives what kind of thing⁑ a visible object is through recognition exclusively. But recognition is not perception by brute sensation, for sight does not recognize everything it has seen before. And when sight perceives some particular individual and is later removed from it for a long time, then sees that individual again but does not remember it, it does not recognize that individual, for it does not recognize what it knew before unless it remembers. Therefore, if recognition were perception by brute sensation, it would follow that, when sight saw some individual that it had seen before, it would immediately recognize it on seeing it again under all conditions, but such is not the case.

3.20 ◉ Et cum cognitio non est nisi per rememorationem, cognitio ergo non est comprehensio solo sensu. Comprehensio autem per cognitionem est comprehensio per aliquem modorum rationis, quoniam cognitio est comprehensio consimilitudinis duarum formarumscilicet forme quam comprehendit visus apud cognitionem et forme quam comprehendebat illius rei vise, vel sibi similis, in prima vice vel prioribus vicibus. Et propter hoc non erit cognitio nisi per rememorationem, quoniam si prima forma non fuerit presens memorie, non comprehendet visus similitudinem duarum formarum, et sic non cognoscet rem visam.

3.20 ◉ And since recognition occurs only through remembering, recognition is not perception by brute sensation. Perception through recognition does, however, entail perceiving by some means of judgment, for recognition is the perception of similarity between two forms—i.e., of the form sight perceives at the moment of recognition and the form of that visible object, or its like, that it has perceived one or more times before. Accordingly, there will be no recognition without remembering, for if the original form is not present in memory, sight will not perceive the similarity of the two forms, and so it will not recognize the visible object.⁑

3.21 ◉ Cognitio autem est forme alicuius rei individue et forme speciei. Cognitio ergo individui est ex assimulatione forme individui quam comprehendit visus apud cognitionem individui alii forme quam prius comprehendebat. Et cognitio speciei est ex assimulatione forme rei vise ad alias formas sibi similes in individuis sue speciei que prius comprehendebat.

3.21 ◉ Recognition, moreover, entails recognition of the form of some individual object or of the form of its kind. Therefore, the recognition of an individual arises from the assimilation of the form of an individual at the time sight perceives that individual to another form that it has perceived before. Recognition of kind arises from an assimilation of the form of a visible object to other forms resembling it among individuals of its kind that it has perceived earlier.

3.22 ◉ Et comprehensio similitudinis est comprehensio per rationem, quoniam non est nisi ex comparatione unius formarum ad alteram. Cognitio ergo non est nisi modus rationis; sed ista ratio distinguitur ab omnibus rationibus, quoniam cognitio non erit per inductionem omnium intentionum que sunt in forma, sed erit per signa. Cum ergo visus comprehendit aliquam intentionum que sunt in forma, et fuerit memorans prime forme, statim cognoscet formam. Et non est ita omne quod comprehenditur per rationem, quoniam plura eorum que comprehenduntur per rationem non comprehenduntur nisi post inductionem omnium intentionum que sunt in eis.

3.22 ◉ But perception of similarity entails judgment, for it only occurs by means of comparing one form to another. Therefore, recognition is merely a form of judgment; yet this form of judgment is distinct from other [forms of] judging, because, rather than involving an evaluation of all the characteristics of a form, recognition will occur through defining features.⁑ Thus, when sight perceives a certain characteristic in a form and remembers an earlier form [with that characteristic], it will immediately recognize the form. But this is not the case with everything that is perceived through judgment, for various things that are perceived through judgment are perceived only after a scrutiny of all the characteristics they possess.

3.23 ◉ Quoniam scriptor, quando momento aspexerit formam ABCD, statim comprehendet quod est ABCD. Ex comprehensione ergo eius quod A est precedens et D est ultimum, comprehendet quod est ABCD. Et similiter, si viderit DOMINUS scriptum, statim comprehendet ipsum per cognitionem et consuetudinem. Et similiter omnes dictiones sibi assuetas; quando scriptor viderit ipsas, statim comprehendet sine indigentia distinctionis unius ab altera. Et non est ita si scriptor inspexerit dictionem extraneam scriptam quam ante non vidit, quoniam scriptor non comprehendet istam dictionem nisi postquam distinxerit eius litteras, et post comprehendet dictionem. Omnis ergo forma quam prius non vidit visus nec similem sibi, quando comprehendetur a visu, non comprehendet visus quid est illa forma nisi postquam distinxerit omnes illas intentiones illius forme aut plures illarum.

3.23 ◉ For instance, at the very moment a writer sees the combination »ABCD,« he will immediately grasp that it is »ABCD«. Therefore, from his perception that »A« comes first and that »D« comes last, he will grasp that it is »ABCD«. Likewise, if he sees »DOMINUS« written, he will immediately grasp it through recognition and habit. And the same holds for all words familiar to him; when the writer sees them, he will immediately grasp them without having to differentiate one from the other. But such is not the case when the writer sees an unfamiliar written word that he has not seen before, for the writer will not recognize this word until after he has differentiated its letters, and [only] afterwards will he recognize the word. Thus, when any form, or its like, that has not been seen before is perceived by sight, sight will not perceive what that form represents until after it has differentiated all or several of the characteristics of that form.

3.24 ◉ Forma autem consueta comprehendetur a visu statim comprehensione quarumdam intentionum que sunt in illa forma. Illud ergo quod comprehenditur per cognitionem comprehendetur per signum, et non omne quod comprehenditur per rationem comprehendetur per signum. Et plures intentiones visibilium non comprehenduntur nisi per cognitionem, et non comprehendetur quiditas alicuius rei vise nec alicuius rei sensibilis alio sensu nisi per cognitionem. Et virtus cognitionis est coniuncta virtuti sensus, et non completur comprehensio sensibilium nisi per cognitionem.

3.24 ◉ On the other hand, a familiar form will be perceived immediately by sight through a perception of certain of the characteristics possessed by that form. Therefore, whatever is perceived through recognition will be perceived by means of a defining feature, but not everything that is perceived through judgment will be perceived by means of a defining feature. Still, several characteristics of visible objects are perceived only through recognition, and the perception of what kind of thing a given visible object is, or what kind of thing a given object perceived by another sense is, will occur only through recognition. And the faculty of recognition is allied with the faculty of sensation, so the perception of sensible characteristics is fully achieved only through recognition.

3.25 ◉ Cognitio autem non est solo sensu. Intentiones ergo que comprehenduntur sensu visu quedam comprehenduntur solo sensu, et quedam per cognitionem, et quedam per rationem et distinctionem.

3.25 ◉ However, recognition does not occur through brute sensation. Therefore, of [all] the characteristics that are perceived by visual sensation, some are perceived through brute sensation, some through recognition, and some through judgment and differentiation.

3.26 ◉ Et etiam plures intentiones visibilium que comprehenduntur per rationem et distinctionem comprehenduntur in tempore valde parvo, et non apparet quod comprehensio earum sit per rationem et distinctionem propter velocitatem rationis per quam comprehenduntur iste intentiones. Quoniam figura, et magnitudo, et diafonitas corporis, et sibi similia ex intentionibus que sunt in rebus visibilibus, comprehenduntur in maiori parte comprehensione valde veloci. Et non comprehenditur tunc quod comprehensio earum sit per rationem. Et cum comprehensio istarum intentionum est per rationem, non est nisi propter manifestationem positionum illarum et per consuetudinem virtutis distinctive ad istas intentiones. Apud ergo istum eventum istius forme, comprehendit omnes intentiones que sunt in ea, et sic distinguentur ab eo apud comprehensionem.

3.26 ◉ Also, several of the visible characteristics that are perceived through judgment and differentiation are perceived in an extraordinarily short time, and it is not apparent that their perception involves judgment and differentiation because of the speed of the inferential process through which these characteristics are perceived. For shape, size, transparency, and similar characteristics that are possessed by visible objects are generally perceived by means of an extremely quick perception. But there is no perception at that time that their perception involves judgment. Since the perception of these characteristics does involve judgment, however, it is only because of the obviousness of their interrelationships and the faculty of discrimination’s familiarity with such characteristics [that the process of judgment goes unnoticed by the perceiver]. Accordingly, as soon as this form reaches [the eye], sight perceives all the characteristics it possesses, and so they will be differentiated by it at the moment of perception.

3.27 ◉ Et similiter argumentatio et omnes rationes quarum propositiones sunt universales et manifeste; non indiget virtus distinctiva aliquanto tempore etiam in comprehendendo suas conclusiones, sed apud intellectum statim propositionis intelligetur conclusio.

3.27 ◉ And the same applies to logical argument and all forms of reasoning when the premises are evident and general; the faculty of discrimination does not require much time to reach the conclusions entailed by them but, instead, will understand the conclusion immediately after grasping the premises.

3.28 ◉ Et causa in hoc est quod virtus distinctiva non arguit per compositionem et ordinationem propositionum, sicut componitur argumentatio per vocabula, quoniam argumentum quod concludit non erit argumentum secundum verbum nec secundum ordinationem propositionum. Argumentum autem virtutis distinctive non est ita, quoniam virtus distinctiva comprehendit conclusionem sine indigentia in verbis et sine indigentia ordinationis propositionum et ordinationis verborum.

3.28 ◉ The reason is that the faculty of discrimination does not proceed by juxtaposing and ordering premises in the way that an argument based on terms does, for its conclusions will not be based on words or on the arrangement of premises.⁑ The procedure followed by the faculty of discrimination is not like this, because the faculty of discrimination grasps the conclusion without needing words and without needing an arrangement of premises or an arrangement of words.

3.29 ◉ Quoniam ordinatio verborum argumenti non est nisi modus qualitatis comprehensionis virtutis distinctive a conclusione, sed comprehensio virtutis distinctive ad conclusionem non indiget modo qualitatis nec ordinatione qualitatis comprehensionis.

3.29 ◉ For the arrangement of words in an argument is only one way in which the faculty of discrimination reaches a conclusion, but to reach a perceptual conclusion the faculty of discrimination does not need [this particular] mode of reasoning or [this particular] arrangement of [premises leading to] a perceptual conclusion.

3.30 ◉ Intentiones ergo visibiles que comprehenduntur ratione comprehenduntur pluries valde velociter, et non apparet in maiori parte si comprehensio earum sit in ratione. Et etiam intentiones visibiles que comprehenduntur per rationem et distinctionem, quoniam multotiens comprehenduntur per rationem, et intellexerit virtus distinctiva intentiones earum, si post viderit ipsas, comprehendet eas per cognitionem sine indigentia distinctionis omnium intentionum que sunt in secundis, sed per signa tantum. Et distinguet illam conclusionem per cognitionem sine indigentia argumentationis alicuius iterande, et est exemplum in eo scriptore qui primo videt verbum extraneum.

3.30 ◉ Therefore, the visible properties that are perceived through judgment are generally perceived very quickly, and for the most part it does not seem as if their perception is arrived at through judgment. Even in the case of visible properties that are perceived through judgment and differentiation, since they are frequently perceived through judgment, and since the faculty of discrimination [already] knows these characteristics if it sees them later, it will perceive them through recognition without having to differentiate all the properties in objects seen later, and it will do so through defining features alone. Moreover, it will reach its conclusion by means of recognition without having to go through the steps of argumentation, as happens, for example, with the writer who sees an unfamiliar word for the first time.

3.31 ◉ Et similiter omnes intentiones que comprehenduntur per rationem quando propositiones earum fuerint manifeste et conclusiones fuerint vere; quoniam quando anima intellexerit conclusionem esse veram, deinde multotiens venerit anime, erit conclusio quasi propositio manifesta. Et sic quando anima viderit propositionem, statim intelliget conclusionem sine indigentia argumentationis iterande.

3.31 ◉ And the same holds for all deductions that are made through judgment when their premises are evident and their conclusions true; for when the soul⁑ realizes that the conclusion is true and reaches that conclusion frequently afterward, the conclusion will be transformed into an evident premise. Thus, when the soul sees the premise, it will immediately reach the conclusion without having to go through the steps of argumentation.

3.32 ◉ Et plures intentiones quas non comprehendit virtus distinctiva quod sint vere nisi per rationem putatur quod sint propositiones prime, et quod non comprehendantur nisi per naturam et intellectum, non per rationem. Verbi gratia, quod totum sit maius parte, et putatur quod natura intellectus iudicet quod sit verum, et quod comprehensio veritatis ipsius non est per rationem. Sed totum esse maius parte non comprehendetur nisi per rationem, quoniam distinctio non habet viam ad comprehendendum quod totum est maius sua parte nisi postquam intellexerit intentionem totius, et partis, et intentionem maioritatis. Quoniam si non intellexerit intentionem partium, non intelliget intentionem totius. Intentio autem totius non est nisi omnitas, et intentio partis non est nisi aliquiditas, et maioritas est relatio ad alterum, et intentio maioris est illud quod est equale alii et plus. Et probatio quod omne totum est maius sua parte est quod refertur ei cum quadam equivalentia et addit super ipsam cum residuo. Et ex convenientia intentionis maioris cum intentione totius in augmentatione, apparet quod totum sit maius parte. Et cum comprehensio eius quod totum sit maius parte non est nisi per istam viam, comprehensio ergo eius non est nisi per rationem, non per naturam intellectus. Et illud quod est in natura intellectus non est nisi comprehensio convenientie intentionis totius et intentionis maioris in augmentatione tantum.

3.32 ◉ Moreover, several deductions whose truth the faculty of discrimination knows only through judgment are deemed to be first principles and are thought to be grasped naturally through pure understanding alone, not by means of judgment. For example, it is assumed that [the proposition] »the whole is greater than the part« will be judged naturally by the understanding to be true and that the perception of its truth does not involve judgment. But the fact that the whole is greater than the part will only be understood through judgment, for there is no way for the differentiating [faculty] to grasp that the whole is greater than its part without first knowing the meaning of »whole« and »part« and the meaning of »greater.« For if it does not know the meaning of »parts,« it will not know the meaning of »whole.« But the meaning of »whole« is simply »totality,« whereas to be a »part« means simply to be »something,« and »greatness« is a relation [of something] to something else, so to be »greater« than something else means to be more than equal to it. So the test of whether every whole is greater than its part is whether the former is somehow equal to the latter yet exceeds it by some amount. From the conjunction of the meaning of »greater« with the meaning of »whole« in [terms of] additional amount, it becomes apparent that the whole is greater than the part. And since the conclusion that the whole is greater than the part is reached only in this way, its realization occurs by judgment alone, not by natural understanding. So what occurs by nature in the understanding is merely the perception of the conjunction of the meaning of »whole« and the meaning of »greater« in [terms of] additional amount.⁑

3.33 ◉ Et ordinatio istius sillogismi est ita: omne totum addit super partem; et omne addens super aliud est maius ipso; ergo omne totum est maius sua parte. Et velocitas comprehensionis virtutis distinctive circa conclusionem non est nisi quia propositio universalis est manifesta. Sed comprehensio virtutis distinctive quod totum est maius sua parte est per rationem, et quia propositio universalis est ei manifesta, comprehendet conclusionem apud eventum propositionis minoris particularis, et propositio particularis est additio intentionis totius super partem. Et quia veritas conclusionis istius sillogismi est certissima in anima et presens in memoria, quando veniet propositio ad ipsum, recipit ipsam intellectus sine indigentia argumentationis iterande, sed per cognitionem tantum.

3.33 ◉ Now the arrangement of this syllogism is as follows: (1) Every whole exceeds the part. (2) Everything that exceeds something else is greater than it. (3) Therefore, every whole is greater than its part. But the speed with which the faculty of discrimination reaches the conclusion is due only to the fact that the major premise is evident.⁑ Nonetheless, the realization by the faculty of discrimination that the whole is greater than its part occurs through judgment, and since the major premise is obvious to it, it will realize the conclusion as soon as the specific minor premise occurs to it, and that specific premise involves the meaning of »whole« as exceeding the part. And since the truth of the conclusion of this syllogism is absolutely certain in the soul and exists in memory, when the proposition occurs to it, the understanding accepts it without having to go through the steps of argumentation, so it realizes it by means of recognition alone.

3.34 ◉ Et omne quod est istius generis vocatur ab hominibus propositio prima. Et putatur quod comprehendetur solo intellectu et quod non indigeatur in comprehensione veritatis circa ipsum nisi solo intellectu. Et causa illius est quod comprehenduntur statim.

3.34 ◉ Everything of this kind is called a »first principle« by mankind. And it is supposed that such will be grasped by pure understanding so that there is no need of anything but pure understanding to realize its truth.⁑ And the reason for this is that such propositions are grasped immediately.

3.35 ◉ Sillogismi ergo quorum propositiones sunt universales et manifeste comprehenduntur in tempore insensibili. Deinde quando sillogisatur multotiens, comprehendet ita quod veritas conclusionis confitetur vel certificetur in anima; tunc efficietur conclusio quasi propositio manifesta. Et secundum hunc modum erit comprehensio virtutis distinctive ad plures intentiones que comprehenduntur ratione in tempore insensibili sine indigentia argumentationis iterande.

3.35 ◉ Therefore, syllogisms whose premises are universal and obvious are grasped in an imperceptible amount of time. Then, if the syllogism is frequently reiterated, the intellect will grasp it in such a way that the truth of its conclusion will be assimilated or certified in the soul, at which time the conclusion will become an evident premise.⁑ In this way the faculty of discrimination will grasp numerous deductions that are reached by means of judgment in an imperceptible amount of time without having to go through the steps of argumentation.

3.36 ◉ Et etiam multotiens non apparet qualitas comprehensionis intentionum visibilium que comprehendentur ratione et cognitione, quoniam comprehensio earum erit valde velociter et quia comprehensio qualitatis comprehensionis non erit nisi per secundum argumentum post primum argumentum per quod fuit visio. Virtus autem distinctiva non utitur isto argumento secundo in tempore in quo comprehendit aliquam intentionem visibilem, nec distinguit qualiter comprehendit illam intentionem, nec potest propter velocitatem comprehensionis eius ad intentiones comprehensas per cognitionem et per argumentum cuius propositiones sunt manifeste et certe in anima. Et propter hoc non sentitur qualitas comprehensionis veritatis plurium propositionum verarum que comprehenduntur per cognitionem, et radix affirmationis veritatis earum est per rationem apud earum eventum. Quoniam quando iste propositiones evenerint virtuti distinctive, statim iudicat quod sint vere per cognitionem, sed apud cognitionem non inquirit qualiter affirmata fuerit prius veritas, nec inquirit qualiter comprehendit quod sunt vere apud eventum earum.

3.36 ◉ Furthermore, how visible characteristics will be perceived by judgment and recognition is often not apparent, for their perception will occur very quickly, and the perception of how they are perceived will occur only through a second deductive process that follows the initial deductive process through which the visual perception was realized. However, the faculty of discrimination does not use this second deductive process at the time it perceives a given visible characteristic, nor does it discern how it perceives that characteristic, nor can it because of the speed with which it perceives characteristics by means of recognition and by deduction whose premises are evident and indubitable to the soul. For this reason it does not notice how it grasps the truth of various true propositions that are perceived by means of recognition, and their truth is affirmed on the basis of a judgment made when they are realized. For when these propositions occur to the faculty of discrimination, it immediately judges that they are true by means of recognition, but at the point of recognition it does not investigate how that truth was verified before, nor does it investigate how it perceives that the propositions are true when they occur to it.

3.37 ◉ Et etiam secundum argumentum per quod comprehendit virtus distinctiva qualitatem comprehensionis eius ad illud quod comprehendit non est argumentum in fine velocitatis, sed indiget consideratione. Quoniam comprehensiones diversantur; et quedam sunt per naturam intellectus, et quedam per cognitionem, et quedam per considerationem et distinctionem. Comprehensio ergo qualitatis comprehensionis et que comprehensio eiusmodi comprehensionis est non est nisi per argumentum et distinctionem non velocem. Et propter hoc non apparet multotiens qualitas comprehensionis rerum visibilium que comprehenduntur ratione apud comprehensionem.

3.37 ◉ Furthermore, the second deductive process through which the faculty of discrimination perceives how it perceives what it perceives is not a process that occurs terribly quickly; instead, it requires deliberation. For perceptions differ; some occur naturally to the understanding,⁑ some occur through recognition, and some occur through deliberation and discernment. Therefore, the perception of how the perception occurs and that it is of such-and-such a kind is reached only through a deductive procedure and a differentiation that is not swift. Accordingly, at the instant of perception, how the visible properties perceived through judgment are [themselves] perceived is usually not evident.

3.38 ◉ Et etiam est homo natus ad distinguendum et ad arguendum sine difficultate et labore, et non percipit quod ipse arguit nisi quando arguit cum difficultate. Quando vero non utitur difficultate et cognitione, non percipit quod arguit. Argumenta ergo assueta quorum propositiones sunt manifeste et non indigent difficultate sunt in homine naturaliter, et propter hoc non percipit quando comprehendit conclusiones earum quod comprehendit ipsas per argumentum. Et significatio quod homo natus est ad arguendum, et quod ipse arguit et non percipit quod arguit, est quod apparet in pueris in primo cremento. Quoniam ipse comprehendit plures res sicut homo perfectus distinguens, et utitur multis operationibus per distinctionem. Verbi gratia quia puer, quando ei demonstrantur duo ex eodem genere, sicut duo poma, et fuerit unum pulcrius alio, accipiet pulcrius et dimittet alterum. Sed electio rei pulcrioris non est nisi per comparationem alterius ad alterum. Et comprehensio pulcri quod sit pulcrum, et fedi quod sit fedum —et similiter, quando elegerit pulcrius alio pulcro minoris pulcritudinis—significat quod non elegit ipsum nisi post comparationem unius ad alterum, et comprehensionem forme cuiuslibet illorum, et comprehensionem argumenti pulcritudinis pulcrioris super minus pulcrum. Et electio pulcrioris non est nisi per propositionem universalem dicentem quod est pulcrius est melius, et quod est melius est dignius ad eligendum. Ipse ergo utitur hac propositione, et non percipit quod utitur ea.

3.38 ◉ Moreover, man is inherently apt to differentiate and deduce without difficulty or effort, and he does not perceive that he is deducing unless he deduces with difficulty. For when he does not exert effort and thought, he does not perceive that he is engaged in deduction. Therefore, customary deductions whose premises are evident and that do not demand effort are natural to man, and because of this he does not perceive that, when he is grasping such conclusions, he is grasping them through deduction. Evidence that man is inherently apt to deduce and that he engages in deduction without perceiving that he is deducing is found in children at an early stage in their growth. For a child grasps many things that a grown man discerns, and he uses many procedures for differentiation. For instance, when two things of the same kind, such as two fruits, are shown to a child, and when one is more attractive than the other, he will accept the more attractive one and reject the other. But the choice of the more attractive object is based exclusively upon a comparison of one to the other. So the child’s perception that the attractive one is attractive and that the ugly one is ugly—and, likewise, his choosing the more attractive over the less attractive one—indicates that he chooses it only after comparing one to the other, perceiving the form of each of them, and perceiving by deduction the attractiveness of the more over the less attractive one. But the choice of the more attractive is based entirely upon a major premise that asserts that what is more attractive is better, and what is better is more worthy of being chosen. The child therefore uses this premise, but he does not perceive that he is using it.

3.39 ◉ Et cum ita est, puer ergo arguit et distinguit. Et non est dubium quod puer nescit quid sit argumentum, nec percipit, quando arguit, utrum arguat aut non. Et si quis etiam intenderet ipsum instruere quid esset arguere, non intelligeret. Et cum puer arguit et nescit quid est argumentum, anima ergo humana est nata ad arguendum sine difficultate et labore, et non percipit homo apud comprehensionem rei quod sit huiusmodi quod sit per argumentum. Sed intentiones que comprehenduntur ratione non sunt nisi intentiones manifeste quarum propositiones sunt valde manifeste; intentiones vero quarum propositiones non sunt valde manifeste et quarum argumenta indigent difficultate, quando comprehenduntur ab homine, forte percipit quod comprehendit ipsas per rationem quando fuerint ille vere distinctionis.

3.39 ◉ And since this is the case, the child deduces and differentiates. But there is no doubt that the child does not know what a deduction is and does not perceive whether he is deducing or not when he does. Moreover, if one were to try to teach him what deduction is, he would not understand. Yet, since the child does deduce yet has no idea what a deduction is, it follows that the human soul is inherently apt to engage in deduction without difficulty or effort, yet when a man perceives that something is of such-and-such a kind, he does not perceive that he achieves this perception through deduction. It is only obvious conclusions whose premises are exceedingly obvious that are drawn through judgment, though; when conclusions whose premises are not particularly obvious and which entail difficulty are drawn by a man, he may well perceive that he makes them through judgment when they really are a matter of differentiation.

3.40 ◉ Iam ergo declaratum est ex omni quod diximus quod quedam intentiones que comprehenduntur per visum comprehenduntur solo sensu, et quedam per cognitionem, et quedam per distinctionem, et argumentum, et rationem, et positionem, et quod qualitas comprehensionis intentionum particularium per visum non apparet in maiori parte propter velocitatem istius quod comprehenditur per cognitionem et propter velocitatem argumenti per quod comprehenduntur intentiones visibiles, et quia virtus distinctiva est nata ad arguendum sine labore et difficultate, sed natura et consuetudine.

3.40 ◉ From everything we have said, then, it has been shown that some characteristics that are perceived by sight are perceived through brute sensation, others through recognition, and others yet through differentiation, deduction, judgment, and syllogism; and [it has also been shown] that the manner in which particular characteristics are perceived by sight is usually not evident because of the speed with which it perceives through recognition, and because of the speed with which it grasps visible properties through deduction, and also because the faculty of discrimination is inherently apt to deduce without effort or difficulty, doing so instead naturally and customarily.

3.41 ◉ Et non indiget argumentatione iteranda illa virtus in comprehensione alicuius intentionum particularium que multotiens fuerint vise.

3.41 ◉ Furthermore, that faculty does not need to go through the deductive steps to perceive any of the particular characteristics that are frequently seen.

3.42 ◉ Et comprehenduntur etiam intentiones que multotiens fuerint vise ratione et distinctione que sunt in anima ita quod homo non percipit quietem illarum; nec quies illarum habet principium sensibile, quoniam habet ex pueritia quod comprehendit visibilia, et ex pueritia est in eo quedam distinctio, et precipue distinctio per quam comprehenduntur distinctiones sensibiles. Ipse ergo comprehendit intentiones sensibiles ratione et distinctione, et adquirit cognitionem intentionum sensibilium, et multotiens reduntur ipse intentiones sensibiles illi successive quousque quiescant in eius anima ita etiam quod non percipit quietem earum. Et sic, quando venerit ipsa intentio particularis que quievit in anima eius, comprehendet etiam apud eius eventum per cognitionem. Et cum hoc non percipit qualitatem comprehensionis, nec qualitatem cognitionis, nec qualiter quieverit cognitio ipsius intentionis in anima eius. Omnes ergo intentiones particulares que comprehenduntur ratione et distinctione et multotiens reduntur iam comprehensa sunt ab homine in preterito tempore, et quieverunt in anima, et facta est forma universalis quiescens ex qualibet intentione particularium. Comprehenduntur ergo iste intentiones sine aliqua argumentatione iteranda quam primo fecit, et sine ratione per quam comprehensa fuit veritas illius intentionis, et sine comprehensione qualitatis comprehensionis ipsius apud comprehensionem, et sine comprehensione qualitatis cognitionis apud comprehensionem. Et nichil remanet indigens argumentatione iteranda nisi intentiones particulares que sunt in individuis particularibus, sicut figura in re individua (scilicet in re visa signata), aut situs rei vise individue, aut magnitudo rei vise individue, aut comparatio coloris alicuius rei vise individue cum colore alterius rei vise, et sibi similis. Et secundum istos modos erit comprehensio omnium intentionum particularium que sunt in rebus visibilibus.

3.42 ◉ Moreover, characteristics that are frequently seen and are perceived through judgment and differentiation exist in the soul in such a way that mankind does not perceive that they are ensconced there;⁑ nor does their being ensconced there have a perceptible beginning, for it is from childhood that man perceives visible objects, and it is from childhood that some differentiation occurs in him, especially the differentiation through which sensible distinctions are perceived. Thus, he perceives sensible characteristics by judgment and differentiation and gains a knowledge of sensible characteristics, and these sensible characteristics are continually presented to him until they are ensconced in his soul in such a way that he does not even perceive their being ensconced. Hence, when a particular characteristic that is [already] ensconced in his soul is presented to him, he will perceive it through recognition the moment it is presented. But in the process he does not perceive how he perceives it, or how he recognizes it, or how the knowledge of that characteristic has come to be ensconced in his soul. Accordingly, all of the particular characteristics that are perceived through judgment and differentiation and that are frequently re-presented [to him] have already been grasped by man at an earlier time and have become ensconced in the soul so that a universal form of some particular property is created and ensconced in the soul.⁑ As a result, such properties are perceived without [the soul’s] having to go through the deductive steps it went through initially, and without having to undergo the process of judging through which the veracity of that characteristic is grasped,⁑ and without perceiving how the perception of that property arises when it arises, and without perceiving how recognition occurs at the moment of perception. So there is no lingering need to retrace the steps of deduction except in the case of particular characteristics possessed by particular individuals, such as the shape of a particular thing (i.e., in an individuated object), or the spatial disposition of an individual visible object, or the size of an individual visible object, or a comparison of the color of one individual visible object with the color of another visible object, and the like. In these ways the perception of all particular properties of visible objects will take place.

3.43 ◉ Et cum declarata sint omnia ista, incipiemus modo ad declarandum qualitates comprehensionis cuiuslibet intentionum particularium que comprehenduntur per visum et qualitates argumentationum per que adquirit virtus distinctiva intentiones comprehensas sensu visus.

3.43 ◉ And now that all of these points have been explained, we shall begin to explain how each of the particular visible properties is perceived by sight and the kinds of deductive processes the faculty of discrimination employs in grasping the properties perceived by the sense of sight.

3.44 ◉ Intentiones particulares que comprehenduntur visu sunt multe, sed generaliter dividuntur in 22, et sunt: lux, color, remotio, situs, corporeitas, figura, magnitudo, continuatio, discretio vel separatio, numerus, motus, quies, asperitas, lenitas, diafonitas; item, spissitudo, umbra, obscuritas, pulcritudo, turpitudo, et consimilitudo et diversitas in omnibus intentionibus particularibus et in omnibus formis compositis ex intentionibus particularibus. Ista sunt ergo omnia que comprehenduntur per sensum visus. Et si aliqua intentio visibilis est preter istas, collocabitur sub aliqua istarum: sicut ordinatio, que collocabitur sub situ; et scriptura et pictura, que collocantur sub figura et ordinatione; et sicut rectitudo, et curvitas, et concavitas, et convexio, que collocantur sub figura; et multitudo et paucitas, que collocantur in numero; et sicut equalitas et augmentum, que collocantur sub similitudine et diversitate; et alacritas, et risus, et tristitia, que comprehenduntur ex figura forme faciei (collocantur ergo sub figura); et sicut fletus, qui comprehenditur ex figura faciei cum motu lacrimarum (collocatur ergo sub figura et motu); et sicut humiditas et siccitas que collocantur sub motu et quiete, quoniam humiditas comprehenditur sensu visu, sed non sensu visu comprehenditur nisi ex liquiditate corporis humidi et ex motu unius partis illius ante aliam, et siccitas comprehenditur visu, sed non comprehenditur visu nisi ex retentione partium corporis sicci et ex privatione motus liquiditatis. Et similiter quelibet intentio particularis comprehensa a visu collocatur sub partibus quas prediximus, et omnes intentiones visibiles sunt sicut superius diximus.

3.44 ◉ The particular properties that are perceived by sight are numerous, but they are generally reduced to twenty-two, namely: light, color, distance,⁑ spatial disposition,⁑ corporeity,⁑ shape, size, continuity, discontinuity or separation, number, motion, rest, roughness, smoothness, transparency; likewise: opacity, shadow, darkness, beauty, ugliness, similarity, and difference among all particular characteristics as well as among all the forms composed of particular characteristics. These, then, are all of the things that are perceived by the sense of sight. If there is any visible characteristic besides these, it will be subsumed under one of them: e.g., arrangement, which will be subsumed under spatial disposition; writing and drawing, which are subsumed under shape and arrangement; straightness, curvature, concavity, and convexity, which are subsumed under shape; multitude and dearth, which are subsumed under number; equality and excess, which are subsumed under similarity and difference; joy, laughter, and sadness, which are included in the shape of the face (and are therefore subsumed under shape); weeping, which is included in the shape of the face along with the streaming of tears (so it is subsumed under shape and motion); moistness and dryness, which are subsumed under motion and rest, for moistness is perceived by the sense of sight only from the fluidity of the moist body and from the motion of one of its parts with respect to another, whereas dryness is perceived by sight only through the rigidity of the parts of the dry body as well as through the lack of motion in fluidity. And likewise, every particular property perceived by sight is subsumed under the headings that we described earlier, and all of the visible properties are as we have claimed above.⁑

3.45 ◉ Et cum ita est, distinctio et argumentatio virtutis distinctive, et cognitio formarum et signorum eorum, non erunt nisi ex distinctione virtutis distinctive ex formis pervenientibus intra concavum nervi communis apud comprehensiones ultimi sentientis illas et ex cognitione signorum formarum istarum.

3.45 ◉ This being the case, moreover, the differentiation and deduction carried out by the faculty of discrimination, as well as the recognition of forms and their defining features, will occur only through the faculty of discrimination’s differentiation of the forms reaching into the hollow of the common nerve when the final sensor perceives them and through recognition of the defining features of those forms.

3.46 ◉ Et etiam corpus sentiens extensum a superficie membri sentientis usque ad concavum nervi communis—scilicet spiritus visibilis—est sentiens per totum, quoniam virtus sensitiva est per totum istius corporis. Cum ergo extenditur forma a superficie membri sentientis usque ad concavum nervi communis, quelibet pars corporis sentientis sentiet formam. Et cum pervenerit forma in concavum nervi communis, comprehendetur ab ultimo sentiente, et tunc erit distinctio et argumentatio. Virtus ergo sensitiva sentit formam rei vise ex toto corpore sentiente extensa a superficie membri sentientis usque ad concavum nervi communis, et virtus distinctiva distinguit intentiones que sunt in forma apud comprehensionem ultimi sentientis circa formam. Secundum ergo hunc modum erit comprehensio formarum rerum visibilium a virtute sensitiva, et ab ultimo sentiente, et a virtute distinctiva. Et declarabitur ex ista dispositione quod virtus sensitiva sentit locum membri sentientis in quo pervenit forma, quoniam non sentit formam nisi ex loco in quo pervenit forma.

3.46 ◉ Furthermore, the sensitive body reaching from the surface of the sensitive organ to the hollow of the common nerve—i.e., the visual spirit—is sensitive throughout, for the sensitive power extends through the whole of this body. Therefore, when the form reaches from the surface of the sensitive organ to the hollow of the common nerve, every part of the sensitive body will sense the form. And when the form arrives at the hollow of the common nerve, it will be perceived by the final sensor, and at that time differentiation and deduction will take place. Thus, the sensitive power senses the form of the visible object throughout the entire sensitive body that extends from the surface of the sensitive organ to the hollow of the common nerve, and the faculty of discrimination discerns the properties that the form possesses at the moment the final sensor perceives the form. This, then, is the way in which the forms of visible objects will be perceived by the sensitive power, as well as by the final sensor and the faculty of discrimination.⁑ On this basis, moreover, it will be shown that the sensitive power senses the place on the sensitive organ where the form reaches, for it only senses the form according to the place where the form arrives.

3.47 ◉ Et etiam declaratum est in capitulo precedenti quod a quolibet puncto superficiei glacialis extenditur forma secundum unam verticationem continuam cum eo quod est in ea de obliquatione et incurvatione quousque perveniat ad unum punctum loci in quod pervenit forma in concavo nervi communis. Et cum ita est, forma ergo perveniens in parte superficiei glacialis extenditur ab illa parte ad aliam partem concavi nervi communis. Et vise res diverse que comprehenduntur simul in eodem tempore extenditur forma cuiuslibet illarum ad locum certum concavi nervi communis, et perveniunt forme omnium illarum rerum visarum ad concavum nervi communis, et erit ordinatio formarum illarum adinvicem in concavo nervi communis sicut ordinatio ipsarum rerum visarum adinvicem. Cum ergo fuerit visus oppositus alicui rei vise, forma lucis et coloris illius rei vise pervenit in superficie visus et in superficie glacialis, et extenditur super verticationes determinatas quas diximus secundum suam ordinationem, et figuram, et formam quousque perveniat ad concavum nervi communis. Et comprehendetur a virtute sensitiva apud proventum eius in corpore glacialis et apud proventum eius in toto corpore sentiente. Deinde apud proventum eius in concavo nervi communis comprehenditur ab ultimo sentiente, et virtus distinctiva distinguit omnes intentiones que sunt in ea. Et forma coloris et forma lucis non perveniunt ad concavum nervi nisi quia corpus sentiens extensum in concavo nervi coloratur a forma lucis et coloris, et illuminatur a forma lucis. Et pervenit forma ad concavum nervi communis, et erit pars corporis sentientis quod est in concavo nervi communis ad quem pervenit forma rei vise colorata colore illius rei vise et illuminata luce que est in illa re visa. Et si res visa habuerit unum colorem, erit illa pars corporis sentientis unius coloris, et si partes rei vise fuerint diversi coloris, erunt partes illius partis corporis sentientis quod est in concavo nervi communis diversi coloris. Et ultimum sentiens comprehendit colorem rei vise ex coloratione quam invenit in illa parte, et comprehendit lucem rei vise ex illuminatione quam invenit in illa parte. Et virtus distinctiva comprehendit plures intentiones particulares que sunt in re visa ex distinctione intentionum que sunt in illa forma ab ea—scilicet ex ordinatione partium forme, et ex figuratione illius quod continet formam, et ex figuratione partium eius, et diversitate colorum, et situum, et ordinationum que sunt in partibus illius forme, et ex consimilitudine et diversitate earum.

3.47 ◉ It has also been shown in the preceding chapter that a form extends from any given point on the surface of the glacialis along a single, continuous line, following whatever bends or curves are in it, until it reaches a single point at the place where the form enters the hollow of the common nerve.⁑ And since that is the case, the form arriving at an area on the surface of the glacialis extends from there to another area in the hollow of the common nerve. Moreover, the form of each of the different visible objects that are perceived together at the same time extends to a specific place in the hollow of the common nerve, and the forms of all of those visible objects reach the hollow of the common nerve, and the relative arrangement of those forms in the hollow of the common nerve will be the same as the relative arrangement of the visible objects themselves.⁑ Thus, when the eye faces some visible object, the form of the light and color on that visible object reaches the surface of the eye and the surface of the glacialis, and it extends along the determinate paths that we described [earlier], preserving its proper arrangement, shape, and structure until it reaches the hollow of the common nerve. And it will be perceived by the sensitive power when it arrives at the body of the glacialis to pass through the whole of the sensitive body. Then, when it reaches the hollow of the common nerve, it is perceived by the final sensor, and the faculty of discrimination differentiates all the [visible] properties it possesses. But the form of color and the form of light reach the hollow of the nerve only because the sensitive body that pervades the hollow of the nerve is colored by the form of light and color and is illuminated by the form of light. So the form reaches the hollow of the common nerve, and the portion of the sensitive body that is in the hollow of the common nerve where the form of the visible object extends will be colored by the color of that visible object and illuminated by the light that is in that visible object. And if the visible object possesses one color, that portion of the sensitive body will be of one color, whereas if the parts of the visible object are of different colors, the parts of that portion of the sensitive body in the hollow of the common nerve will be of different colors. The final sensor, moreover, perceives the color of the visible object from the coloring that it encounters in that portion [of the sensitive body], and it perceives the light of the visible object from the illumination it encounters in that [same] portion. Meanwhile, the faculty of discrimination perceives various particular properties that are in the visible object by discerning the properties that are in that form at that spot—i.e., from the arrangement of the parts of the form, from the configuration of what surrounds that form, from the configuration of that form’s parts, from the different colors, spatial dispositions, and arrangements of the parts of that form, and from their similarity and difference.⁑

3.48 ◉ Et etiam lux veniens a re visa colorata ad visum non venit per se sine colore, et forma coloris veniens a re visa colorata ad visum non venit sine luce sola, et non venit forma lucis et coloris que sunt in re visa nisi admixte, nec comprehendit eas ultimum sentiens nisi admixtas. Tamen cum hoc sentiens comprehendit rem visam illuminatam, et comprehendit quod lux apparens in re vise est diversa a colore, et ista comprehensio est distinctio. Distinctio autem non est nisi virtutis distinctive, non sensitive. Tamen cum comprehensione istius intentionis a virtute distinctiva, ista intentio quiescit in anima, et non indiget argumentatione iteranda apud eventum cuiuslibet forme, sed quiescit in anima. Sed quod lux que est in ea est diversa a colore qui est in ea et comprehensio virtutis distinctive quod lux accidentalis que est in re visa colorata est diversa a colore qui est in ea est quia super unam rem visam diversatur lux, et aliquando augmentatur, et aliquando diminuitur. Et cum hoc est, remanet color eius idem; quamvis diversetur scintillatio coloris secudum diversitatem lucis, tamen genus coloris non diversatur. Et etiam lux accidentalis forte pervenit ad rem visam ex foramine, et cum fuerit opilatum illud foramen, obscurabitur illa res visa. Ex comprehensione ergo virtutis distinctive circa diversitatem lucis super res visas, et ex comprehensione eius circa illuminationem rei vise aliquando et privationem lucis ab ea aliquando comprehendit quod colores qui sunt in rebus visis sunt diversi a luce que accidit in eis. Forma ergo quam comprehendit sentiens ex re visa colorata est forma admixta ex forma lucis et coloris que sunt in re visa, et virtus distinctiva comprehendit quod color qui est in eo est diversus a luce que est in ea. Et ista comprehensio est comprehensio secundum cognitionem apud eventum forme in sentienti, quoniam iam quiescunt in anima quod lux cuiuslibet forme admixte ex luce et colore est diversa a colore qui est in ea.

3.48 ◉ Furthermore, the light reaching from the colored visible object to the eye does not arrive on its own without color, nor does the form of the color reaching from the colored visible object to the eye arrive on its own without light, so the form of the light and color in the visible object arrives only as a mixture, and the final sensor perceives such forms only as mixtures. Notwithstanding this fact, the [final] sensor perceives the illuminated visible object and perceives that the light appearing in the visible object is distinct from the color, and this perception constitutes differentiation. [The capacity of] differentiation, however, belongs to the faculty of discrimination alone, not to the sensitive faculty. Yet when it is perceived by the discriminative faculty, this property becomes ensconced in the soul, so there is no need for repeating the deductive steps when every [such form] reaches it [afterward]; instead it remains ensconced in the soul. The faculty of discrimination’s perception that the light in the object is distinct from the color in it, as well as its perception that the accidental light in the colored visible object is distinct from the color in it, is due to the fact that the light shining on any given visible object can vary, sometimes increasing and sometimes decreasing. Yet, despite these variations, its color remains the same; even though the brightness of the color may vary according to the variation in light, the color does not vary in kind. Moreover, accidental light may shine on a visible object through an aperture, but when that aperture is blocked, that visible object will be darkened. Hence, from the faculty of discrimination’s perception of the variation in light shining on visible objects, and from its perception of the visible object’s being illuminated at times and lacking light at others, it perceives that the colors possessed by visible objects are distinct from the light that shines on them. Therefore, the form of the colored visible object that the sensitive faculty perceives is a form mixed from the form of the light and color that are in the visible object, and the faculty of discrimination perceives that the color that is in it is distinct from the light that is in it. But this perception takes place according to recognition at the moment the form reaches the [final] sensor, for already ensconced in the soul is the notion that the light in every form that is a mixture of light and color is distinct from the color in that form.⁑

3.49 ◉ Et primum quod comprehendit virtus distinctiva ex intentionibus que appropriantur forme est quiditas coloris. Quiditas autem coloris non comprehendetur a virtute distinctiva nisi per cognitionem quando color rei vise fuerit ex coloribus assuetis, et comprehensio quiditatis coloris a virtute distinctiva secundum cognitionem non est nisi ex comparatione forme coloris ad formas quas comprehendebat ante, ex formis scilicet similibus illi colori. Quoniam visus, quando comprehenderit colorem rubeum, et comprehendit quod sit rubeus, non comprehendet quod sit rubeus nisi quia cognoscit ipsum, et ista cognitio non est nisi ex assimilatione eius ad res quas comprehendebat prius. Si autem visus nunquam comprehendisset rubeum colorem nisi modo, nesciret apud comprehensionem rubei quod sit rubeus. Cum ergo color fuerit ex coloribus assuetis, cognoscetur a visu secundum cognitionem, et si fuerit ex coloribus extraneis ita quod visus nunquam comprehenderit talem ante, non comprehendetur a visu ut cognoscat ipsum; sed assimilabit ipsum coloribus propinquis illis, scilicet quos cognoscebat. Radix ergo comprehensionis coloris est solo sensu; deinde quando multotiens redierit super visum, comprehendetur per cognitionem, scilicet cuiusmodi fuerit coloris.

3.49 ◉ Among the properties belonging to the form, the first one that the faculty of discrimination perceives is the kind of color [it possesses]. But what kind of color [the form possesses] will be perceived by the faculty of discrimination only through recognition, if the color of the visible object is among those colors familiar to it, so the faculty of discrimination’s perception of what kind of color [the form possesses], which occurs through recognition, arises exclusively from a comparison of the form of its color to forms that it has perceived before, that is, from forms resembling [the form of] that color.⁑ For, when it perceives a red color and perceives that it is red, sight will not perceive that it is red unless it recognizes it, and this recognition is due only to an assimilation⁑ of it to things it has perceived before. If, however, sight had never perceived a red color until this time, it would not know that the red it perceives is red. Thus, when the color is one of the familiar colors, it will be known to sight through recognition, but if it is among colors that are unfamiliar to it, such that sight has never perceived such a color before, it will not be perceived by sight so as to be recognized by it; rather sight will assimilate it to colors that are near it, ones that it has already apprehended. Thus, brute sensation provides the basis for perceiving a color; then, when [that color] is transmitted to the eye over and over again, it will be perceived through recognition, specifically, of what kind of color it is.

3.50 ◉ Et quiditas lucis etiam non comprehendetur a visu nisi per cognitionem, quoniam visus cognoscit lumen solis et distinguit inter ipsum et lucem lune et ignis, et sic cognoscit lucem lune et lucem ignis. Comprehensio ergo quiditatis cuiuslibet istarum lucium a visu non est nisi per cognitionem.

3.50 ◉ What kind of light [is being seen] will also be perceived by sight through recognition alone, for sight recognizes sunlight and differentiates it from moonlight and firelight, and thus it recognizes moonlight and firelight. Therefore, the perception by sight of what kind of light each of these is occurs only through recognition.

3.52 ◉ Deinde omne quod comprehenditur per sensum visus post lucem et colorem non comprehendetur solo sensu, sed comprehendetur per distinctionem et argumentationem cum sensu. Quoniam omne quod comprehenditur per distinctionem et argumentationem non comprehendetur nisi ex distinctione intentionum que sunt in forma sensibili, et similiter omne quod comprehenditur per cognitionem non comprehenditur nisi ex comprehensione signorum que sunt in forma sensibili. Et intentiones que comprehenduntur per distinctionem, et argumentationem, et cognitionem non comprehenduntur nisi cum sensu forme. Lux autem que est in corpore illuminato per se comprehenditur a visu secundum suum esse, et per se, et ex ipso sensu; et lux et color que sunt in corpore colorato illuminato lumine accidentali comprehenduntur a visu in simul et admixta, et solo sensu. Lux ergo essentialis comprehenditur a sentiente ex illuminatione corporis sentientis, et color comprehenditur a sentiente ex alteratione corporis sentientis et eius coloratione. Et cum huiusmodi comprehensione lucis a corpore sentienti per lumen accidentale admixtum cum illo colore sentiens ergo comprehendit ex corpore apud perventum forme coloris ad ipsum lucem coloratam, et comprehendit ex eo apud perventum forme lucis essentialis in eo lucem solam. Ista ergo duo tantum comprehenduntur a visu solo sensu.

3.52 ◉ Everything perceived by the sense of sight after light and color will therefore not be perceived through brute sensation but will be perceived through differentiation and deduction along with sensation. For everything that is perceived through differentiation and deduction will be perceived only by distinguishing the properties possessed by the sensible form, and likewise, everything that is perceived through recognition is perceived solely through a perception of the defining features conveyed by the sensible form. But the properties perceived through differentiation, deduction, and recognition are only perceived with the sensation of the form. The light in an intrinsically luminous body, however, is perceived by sight on its own, as it actually exists, on the basis of the sensation itself; and the light and color in a colored body illuminated by accidental light are perceived by sight mixed together, and [they are thus perceived] through brute sensation. Therefore, essential light is perceived by the sensitive faculty from the illumination of the sensitive body, and color is perceived by the sensitive faculty from an alteration and a coloring that occurs in the sensitive body. And along with this sort of perception of light by the sensitive body on the basis of accidental light mixed with that color, the sensitive faculty thus perceives the colored light of the body when the form of color reaches it, but it only perceives its light when the form of essential light reaches it.⁑ So these are the only two visible properties that are perceived by sight through brute sensation.

3.53 ◉ Et etiam dicemus quod comprehensio coloris in eo quod est color est ante comprehensionem quiditatis coloris: scilicet quod visus comprehendit colorem et sentit quod est color antequam sentiat cuiusmodi sit coloris. Quoniam apud perventum forme in visu coloratur visus, et cum coloratur visus, sentit quod sit coloratus, et sic sentit colorem. Deinde ex distinctione coloris et comparatione ipsius ad colores notos visui comprehendit quiditatem coloris. Comprehensio ergo coloris in eo quod est color erit ante comprehensionem quiditatis coloris, et erit comprehensio quiditatis coloris per cognitionem. Et significatio quod visus comprehendit colorem in eo quod est color antequam comprehendat cuiusmodi sit ratio coloris est quia visibilia quorum colores sunt fortes, sicut viriditas profunda, et fuscitas, et sibi similia, quando fuerint in loco obscuro non valde, non comprehenduntur a visu in illo loco nisi quasi color tantum. Tamen sentit quod sint colores, et non distinguit cuiusmodi sint colores in principio comprehensionis. Et quando locus non fuerit valde obscurus, et fuerit visus multum intuens, comprehendet cuiusmodi sint coloris, aut si lux augmentetur et intendatur in illo loco. Declarabitur ergo ex ista experimentatione quod visus comprehendit colorem in eo quod est color antequam comprehendat cuiusmodi sit coloris.

3.53 ◉ We shall say, further, that the perception of color, insofar as it is color, precedes the perception of what kind of color it is: that is, sight perceives color and senses that it is color before it senses what kind of color it is. For as soon as the form reaches the eye, the eye is colored, and when the eye is colored, it senses that it is colored, and thus it senses the color [itself]. Then, by differentiating the color and comparing it to colors already known to sight, it perceives what kind of color it is. Therefore, the perception of color, insofar as it is color, will occur before the perception of what kind of color it is, and the perception of what kind of color it is will occur through recognition. Evidence that sight perceives color, insofar as it is color, before it perceives what kind of color it is [can be found] in the fact that, when visible objects whose colors are strong—e.g., deep green, brown, and the like—are in a location that is not too dark, those colors are only perceived by sight in that location as color [in the generic sense].⁑ Still, it senses that they are colors, but it does not discern what kind of colors they are at the beginning of perception. When the location is not too dark, however, and when sight scrutinizes [the colors] closely, it will perceive what kind of colors they are, or [it will do so] if the light increases and intensifies in that location. From this experiment it will therefore be clear that sight perceives color, insofar as it is color, before it perceives what kind of color it is.

3.54 ◉ Et illud quod comprehendit visus ex colore in principio sui proventus ad visum est coloratio, et coloratio est quasi obscuritas aut umbra quando color fuerit subtilis. Et si res visa fuerit diversorum colorum, comprehendet visus in principio ex forma illius rei vise obscuritatem partium diverse qualitatis secundum fortitudinem et debilitatem, aut quasi umbras diversas in fortitudine et debilitate. Primum ergo quod comprehendit visus ex forma coloris est mutatio membri sentientis et coloratio eius que est obscuritas, aut similitudo obscuritati. Deinde sentiens distinguet illam colorationem. Et si res visa fuerit illuminata, distinguetur ille color a visu et comprehendetur eius quiditas quando fuerit ex coloribus quos multotiens comprehendebat. Et si fuerit ex coloribus quos fere semper comprehendebat, comprehendetur in minimo tempore, et in instanti secundo inter quod et primum in quo comprehendit colorem in quantum est color non est sensibile tempus. Si autem fuerit ex coloribus non manifestis quos visus non comprehendit ante nisi raro, aut fuerit in loco obscuro debilis lucis, non comprehendetur a visu quiditas eius nisi in tempore sensibili. Et si res visa fuerit obscura, et non fuerit in ea nisi modica lux, sicut illud quod comprehenditur nocte et in locis valde obscuris, non distinguetur a sentiente ex ea nisi obscuritas tantum. Declaratum est ergo ex comprehensione colorum in locis obscuris quod comprehensio coloris in eo quod est color est ante comprehensionem quiditatis eius.

3.54 ◉ What sight perceives about color at the very moment it reaches the eye is its coloring-effect, and coloring is a sort of darkening or shading when the color is subtle. And if the visible object is of various colors, sight will first perceive the gradations in darkness of the various parts of the form of that visible object, or [it will perceive them] as various gradations of shadow. So the first thing that sight perceives from the form of color is a change in the sensitive organ and a coloring in it that consists of darkness or something resembling darkness. Then the sensitive faculty will differentiate that coloring. And if the visible object is illuminated, that color will be differentiated by sight, and what kind of color it is will be perceived when it belongs to the set of colors that sight has frequently perceived. Moreover, if it is one of the colors that sight has almost constantly perceived, [what kind of color it is] will be perceived in minimal time, so that there is no perceptible time between the instant when the color is recognized and the instant when it was first perceived as mere color. However, if it belongs to the set of colors that are not clear and that have only been perceived rarely by sight, or if the color lies in a dark, dimly lit place, what kind of color it is will be perceived by sight only after a perceptible interval of time. Furthermore, if the visible object is dark, so that there is only a little illumination in it, as is the case with what is perceived at night or in places that are extremely dark, only its darkness will be discerned by the sensitive faculty. From the perception of colors in dark places, therefore, it is clear that the perception of color, insofar as it is color, precedes the perception of what kind of color it is.

3.55 ◉ Et significatio etiam quod visus comprehendit colorem in eo quod est color antequam comprehendat cuiusmodi sit coloris est quia visus, cum comprehenderit colorem extraneum quem nunquam vidit ante, comprehendet quod est color, et cum hoc nesciet cuiusmodi sit coloris. Et cum fuerit multum circa ipsum, assimilabit ipsum propinquiori colori simili ipsi.

3.55 ◉ A further indication that sight perceives color, insofar as it is color, before it perceives what kind of color it is can be found in the fact that, when sight perceives an unfamiliar color that it has never seen before, it will perceive that it is a color, yet it will nonetheless have no idea of what kind of color it is. But when it scrutinizes that color closely, sight will assimilate it to the nearest color resembling it.

3.56 ◉ Ex istis ergo experimentationibus declaratur declaratione manifesta quod comprehensio coloris in eo quod est color erit ante comprehensionem quiditatis coloris. Et declaratum est etiam ex istis experimentationibus quod comprehensio quiditatis coloris non erit nisi per distinctionem. Illud ergo quod comprehendit visus solo sensu non est nisi color in eo quod est color, et lux in eo quod lux, et preter ista non comprehendit solo sensu nisi per distinctionem, et argumentationem, et cognitionem.

3.56 ◉ From these experiments, then, it is eminently clear that the perception of color, insofar as it is color, will precede the perception of what kind of color it is. And it has also been shown on the basis of these experiments that the perception of what kind of color it is will be based only on differentiation. Hence, what sight perceives through brute sensation is only [the fact of] color, insofar as it is color, as well as [the fact of] light, insofar as it is light, but other than this brute sensation perceives nothing without differentiation, deduction, and recognition.

3.57 ◉ Et etiam dicamus quod comprehensio quiditatis coloris non est nisi in tempore, quoniam comprehensio quiditatis coloris non est nisi per distinctionem et assimilationem. Sed distinctio non est nisi in tempore; ergo comprehensio quiditatis coloris non est nisi in tempore. Significatio autem manifesta quod comprehensio quiditatis coloris non est nisi in tempore est illud quod apparet in troco apud motum eius, quoniam quando in troco fuerint tincture diverse, et ille tincture fuerint linee extense ex medio superficiei eius manifeste et ex parte colli eius usque ad finem sue circumferentie, quoniam quando trocus fuerit circumgiratus motu forti, et aspexerit ipsum quis, comprehendet omnes eius colores quasi unum diversum ab omnibus coloribus qui sunt in eo, quasi esset color compositus ex omnibus coloribus illarum linearum. Et non comprehendet lineationem nec diversitatem colorum. Et cum hoc comprehendet ipsum quasi quietum quando motus eius fuerit valde fortis, quoniam quodlibet punctum non figitur in eodem loco tempore sensibili, sed in quam minimo tempore girat circumferentiam totam super quam revolvitur. Pervenit ergo forma puncti in visu super circumferentiam circuli in visu, et visus non comprehendit colorem illius puncti in minimo tempore nisi ex tota circumferentia circuli pervenientis in visu. Comprehendit ergo colorem illius puncti in minimo tempore circumgiratum. Et similiter omnia puncta que sunt in superficie troci; scilicet quod visus comprehendit colorem cuiuslibet illorum super totam circumferentiam circuli super quam movetur ille punctus in minimo tempore, et omnia puncta quorum remotio a centro est equalis moventur apud circumgirationem troci super eandem circuli unius circumferentiam. Et accidit ergo ex hoc ut appareat color cuiuslibet puncti illorum punctorum quorum remotio a centro est equalis super circumferentiam eiusdem circuli in minimo tempore quod erit tempus revolutionis, quare apparebunt colores omnium punctorum in tota circumferentia illius circuli admixti. Et propter hoc comprehenditur color superficiei troci quasi unus color admixtus ex omnibus coloribus qui sunt in sua superficie.

3.57 ◉ We should also point out that the perception of what kind of color it is invariably takes time, for the perception of what kind of color it is occurs only through differentiation and assimilation. But differentiation can only occur over time; therefore, the perception of what kind of color it is invariably takes time. There is clear evidence, moreover, that the perception of what kind of color it is invariably takes time in what is seen to happen in the motion of a top,⁑ for if lines of various colors are painted on the outer surface of that top so as to extend from its center, on the side of its axle, to its outer edge, then, when the top is spun vigorously while one looks at it, he will perceive all of its colors as a single color different from all the colors on it, that color appearing to be composed of all the colors of those lines. So he will not perceive the lines or the differences among the colors.⁑ Moreover, while this is going on, he will perceive the top to be still when its spin is extremely swift, for none of its points remains fixed in the same spot for any perceptible time, but instead every point spins through the entire circumference along which it revolves in minimal time. Accordingly, the form of the point radiates to the eye to [delineate] the circumference of a circle on [the surface of] the eye, so, in the minimal time [of the top’s rotation] sight only perceives the color of that point according to the entire circumference of the circle as it is configured in the eye. Hence, in [this] minimal time, sight perceives the color of that point according to its entire path of revolution. And the same holds for all of the points on the surface of the top; sight perceives the color of each of them according to the entire circumference of the circle along which that point moves in minimal time, and every point lying the same distance from the center moves along the same circular circumference as the top spins. On this account, then, it happens that the color of every point among those that are equidistant from the center will appear on the circumference of the same circle during the minimal time that one revolution takes, so the colors of all the points on the entire circumference of that circle will appear mixed. Accordingly, the color of the surface of the top is perceived as a single color mixed from all of the colors that are on its surface.

3.58 ◉ Si ergo visus comprehendisset quiditatem coloris in uno instanti, et non indiguisset ad comprehendendum quiditatem eius tempore, comprehendisset in uno instanti et in quolibet instantium temporis in quo movetur trocus quiditates omnium colorum qui sunt in troco distincti apud motum. Quoniam si non indiguerit tempore ad comprehendendum quiditates eorum, comprehendet illos in parte temporis revolutionis et in quolibet instantium temporis revolutionis apud motum eorum sicut comprehendet quiditatem eorum apud eorum quietem, quoniam quiditas omnium colorum visibilium assuetorum in quiete et in motu sunt uniusmodi non mutate. In quolibet ergo instantium in quibus movetur res visa non mutatur color eius. Et cum visus non comprehendit quiditates colorum qui sunt in superficie troci quando trocus movebitur motu veloci, et comprehendit ipsos quando trocus fuerit quiescens vel in motu tardo, et cum ita est, visus ergo non comprehendit quiditatem coloris nisi sit color fixus in eodem loco tempore sensibili, vel fuerit in motu tempore sensibili in spatio cuius quantitas non operatur in situ illius coloris a visu operatione extranea.

3.58 ◉ Thus, if sight were to perceive what kind of color it is in an instant, and if it needed no time to arrive at the perception of what kind of color it is, then at any given instant of the top’s rotation it would perceive individually what kind of color all of the colors on the top are while it was moving. For if it needs no time to perceive what kinds of colors they are, then, in a portion of the time of revolution and at any instant during the time of revolution as the top spins, sight will perceive those colors in the same way that it will perceive what kinds of colors they are when they are motionless, for all the colors of familiar visible objects remain the same in kind whether they are in motion or at rest. At any instant, therefore, that the visible object moves, its color does not change. But since sight does not perceive what kinds of colors are on the surface of the top when the top spins vigorously, and since it does perceive what kind of colors they are when the top is immobile or spins slowly, then, that being the case, sight does not perceive what hue a given color is unless it remains fixed in the same spot for a perceptible amount of time, or unless it takes a perceptible amount of time to move a distance that is not so untoward as to distort the spatial relationship between that [spot of] color and the eye.⁑

3.59 ◉ Declarabitur ergo ex ista dispositione quod comprehensio quiditatis coloris non erit nisi in tempore, et declarabitur ex ista dispositione quod comprehensio quiditatis omnium visibilium non erit nisi in tempore. Quoniam quando visus non comprehendit quiditatem coloris qui comprehenditur solo sensu nisi in tempore, maxime indiget comprehensione in tempore in intentionibus visibilibus que comprehenduntur per distinctionem et argumentationem. Comprehensio ergo quiditatis visibilium, et comprehensio per cognitionem, et comprehensio per distinctionem et argumentationem non erit nisi in tempore, sed multotiens erit in minimo tempore.

3.59 ◉ It will therefore be obvious from this case that the perception of what kind of color it is will invariably take time, and it will be obvious from this case that the perception of what kinds of things all visible objects are will invariably take time. For, since sight requires time to perceive what kind of color it is that it perceives through brute sensation, it requires all the more time to perceive the visible properties that are grasped through differentiation and deduction.⁑ Therefore, the perception of what kinds of things visible objects are, as well as perception through recognition and perception through differentiation and deduction, will invariably take time, but more often than not it will take minimal time.

3.60 ◉ Et etiam dicemus quod color in eo quod est color et lux in eo quod est lux non comprehendetur visu nisi in tempore, scilicet quod instans apud quod erit comprehensio coloris in eo quod est color et comprehensio lucis in eo quod est lux est diversum ab instanti quod est primum instans in quo contingit superficiem visus aer deferens formam. Quoniam color in eo quod est color et lux in eo quod est lux non comprehenduntur a sentiente nisi post proventum forme in corpore sensibili, et non comprehenduntur ab ultimo sentienti nisi post proventum forme ad concavum nervi communis. Sed proventus forme ad concavum nervi communis non est nisi sicut proventus lucis a foraminibus per que intrat lux ad corpora opposita illis foraminibus, et proventus lucis a foramine ad corpus oppositum foramini non erit nisi in tempore, quamvis lateat sensum. Quoniam proventus lucis a foramine ad corpus oppositum foramini non potest evadere ab altero duorum modorum, scilicet quod: aut lux perveniet in parte aeris vicinantis foramini antequam perveniat in partem aliam sequentem, deinde perveniet ad illam partem, deinde ad aliam quousque perveniat ad corpus oppositum foramini; aut lux perveniet in toto aere medio inter foramen et corpus oppositum foramini et in ipso corpore opposito foramini simul. Si ergo aer recipit lucem successive, non pervenit lux ad corpus oppositum foramini nisi per motum, sed motus non erit nisi in tempore. Si autem totus aer recipit lucem simul, proventus lucis etiam in aere postquam non erat in eo non erit nisi in tempore, quamvis lateat sensum. Quoniam quando foramen per quod intrat lux fuerit opilatum, et deinde fuerit ablatum opilans, instans in quo fuerit ablatum opilans a prima parte foraminis et in quo fuerit discoopertus aer qui est in foramine ad partem lucis est diversum ab instanti apud quod pervenit lux in aere contingenti illam partem que est intra foramen et in aere continuato cum illo aere secundum omnes dispositiones. Quoniam lux non pervenit in aliqua parte aeris que est intra foramen quod est coopertum circa lucem nisi postquam fuerit discooperta aliqua pars foraminis circa lucem, et nulla pars foraminis discooperitur in minori uno instanti, sed instans non dividitur. Nichil ergo ex luce pervenit in interius foraminis in illo instanti in quo fuerit discooperta illa pars foraminis, quoniam illud quod est discoopertum ex foramine in uno instanti non discooperitur successive, nec illud quod discooperitur ex foramine in uno instanti est pars alicuius quantitatis. Quoniam non discooperitur in uno instanti nisi punctus carens quantitate aut linea carens latitudine, quoniam non auferetur cooperiens ab habenti longitudinem et latitudinem nisi successive—igitur per motum. Sed motus non erit nisi in tempore, et illud quod discooperitur ex foramine in uno instanti caret latitudine.

3.60 ◉ We shall also point out that color, insofar as it is color, and light, insofar as it is light, will invariably take time to be perceived, i.e., that the instant when color will be perceived as color, insofar as it is color, and when light will be perceived as light, insofar as it is light, is different from the instant when the air transmitting the form makes initial contact with the surface of the eye. For color, insofar as it is color, and light, insofar as it is light, are only perceived by the sensitive faculty after the form arrives in the sensitive body, and they are not perceived by the final sensor until after the form reaches the hollow of the common nerve. But the way the form reaches the hollow of the common nerve is just the same as the way light extends from apertures through which it passes to bodies facing those apertures,⁑ and light invariably takes time to pass from an aperture to a body facing the aperture, even though the time-interval is imperceptible. For there is only one of two ways in which light can extend from an aperture to a body facing the aperture: either the light will reach a portion of the air abutting on the aperture before it reaches a subsequent portion, after which it will pass to that portion, then on to another until it reaches the body that faces the aperture; or else the light will reach through the whole of the air between the aperture and the body facing the aperture, and it will reach that same body facing the aperture, all at the same instant. If the air receives the light in successive intervals, then light can only reach the body facing the aperture by moving, but motion will only occur in time. On the other hand, if the air as a whole receives the light all at once, the light’s reaching the air after it was not there will happen only in time, even though it may be imperceptible. For when the aperture through which the light enters is blocked, and then the obstruction is removed, the instant when the obstruction is removed from the first portion of the aperture and when the air in the aperture on the side of the light is exposed is different from the instant when the light reaches the air contiguous with that portion inside the aperture and continuous with that air at all times. For light does not reach any portion of the air inside the aperture when it is blocked from light until after some portion of the aperture is exposed to the light, but no portion of the aperture is exposed in less than an instant. An instant is indivisible, though. Hence, no light reaches the inside of the aperture at the instant when that portion of the aperture is exposed, for the portion of the aperture that is exposed in an instant is not exposed in successive intervals, nor is that portion of the aperture that is exposed in a single instant a quantifiable portion. For only a point, which lacks dimension, or a line, which lacks breadth, is exposed in an instant, because it is only by being uncovered in successive intervals—and therefore by being moved—that an obstruction possessing length and breadth will be removed. Motion, however, will only occur in time, and the portion of the aperture that is exposed in a single instant lacks breadth.

3.61 ◉ Est ergo punctus aut linea, sed punctus carens quantitate et linea carens latitudine non est pars aeris. Punctus ergo carens quantitate et linea carens latitudine quod est punctum quod discooperitur ex foramine in instanti non est nisi finis alicuius partium aeris qui est intra foramen, non pars aeris. Et punctus carens quantitate non recipit lucem nec linea carens latitudine, quoniam non recipit lucem nisi corpus. Et cum ita est, nichil pervenit ex luce in aerem qui est intra foramen in instanti in quo discooperitur primum quod discooperitur ex foramine. Instans ergo quod est punctum instans apud quod pervenit lux in aere qui est intra foramen aut in parte eius est diversum ab instanti in quo discooperitur primum quod discooperitur ex foramine. Sed inter quelibet duo instantia est tempus. Lux ergo non pervenit ex aere qui est extra foramen ad aerem qui est intra foramen nisi in tempore, sed istud tempus valde latet sensum propter velocitatem receptionis formarum lucis ab aere.

3.61 ◉ Thus, it consists of a point or a line, but neither a point, which lacks dimension, nor a line, which lacks breadth, constitutes a [quantifiable] portion of air. Therefore, a point, which lacks dimension, or a line, which lacks breadth, constitutes the point of the aperture that is exposed in an instant, and it represents nothing but the limit of some portion of the air inside the aperture, not an [actual] portion of the air. So a point, which lacks dimension, does not receive light, nor does a line, which lacks breadth, for only a body receives light. And since this is the case, none of the light reaches the air inside the aperture at the very instant the initial portion of the aperture is opened. Thus, the instant, or point in time, at which the light reaches the air inside the aperture, or a portion of that air, is different from the instant at which the initial portion of the aperture is opened. And between each of these two instants there is [an interval of] time. Therefore, light passes from the air outside the aperture to the air inside the aperture only over time, but this time is absolutely imperceptible because of the speed with which air receives the forms of light.⁑

3.62 ◉ Et similiter visus quando fuerit oppositus rei vise postquam non erat ita, et fuerit aer deferens formam rei vise contingens superficiem visus postquam nichil fuerit ex aere contingens ipsum, non perveniet forma ex aere deferente formam ad interius concavi nervi communis nisi in tempore. Sed sensus caret via comprehensionis istius temporis propter parvitatem eius, et errorem eius, et debilitatem eius ad comprehendendum id quod est in fine parvitatis. Istud ergo tempus respectu sensus est sicut instans in respectu.

3.62 ◉ Likewise, when the eye faces a visible object after having not faced it, and when the air transmitting the form of the visible object makes contact with the surface of the eye after not having touched it, the form will pass from the air transmitting the form to the interior of the hollow of the common nerve only over time.⁑ But the sense lacks a means of perceiving this time because it is so short and because the sense lacks adequate precision, being too weak to perceive whatever is exceptionally small. Thus, with respect to the sense, this time-interval amounts to an instant.

3.63 ◉ Et etiam membrum sentiens non sentit formas venientes ad ipsum nisi postquam patitur ab illis. Non sentit ergo colorem in eo quod est color nec lucem in eo quod est lux nisi postquam patitur a forma lucis et coloris. Sed passio membri sentientis a forma coloris et forma lucis est aliquantula alteratio, sed nulla alteratio est nisi in tempore. Visus ergo non comprehendit colorem in eo quod est color nec lucem in eo quod est lux nisi in tempore. Et in tempore in quo extenditur forma a superficie membri sentientis ad concavum nervi communis erit comprehensio coloris in eo quod est color et lucis in eo quod est lux a virtute sentiente que est in toto corpore sentiente, et apud proventum forme in concavum nervi communis erit comprehensio coloris in eo quod est color et lucis in eo quod est lux ab ultimo sentiente. Comprehensio ergo coloris in eo quod est color et lucis in eo quod est lux est in tempore sequenti tempus in quo pervenit forma a superficie membri sentientis ad concavum nervi communis.

3.63 ◉ In addition, the sensitive organ does not sense the forms reaching it until it undergoes their effect. Therefore, it does not sense color, insofar as it is color, or light, insofar as it is light, until after it has undergone the effect of the form of light and color. But the effect of the form of color and the form of light on the sensitive organ constitutes something of an alteration, and alteration only occurs over time. Therefore, sight does not perceive color, insofar as it is color, or light, insofar as it is light, except over time. Moreover, during the time that the form reaches from the surface of the sensitive organ to the hollow of the common nerve, the sensitive power that pervades the entire sensitive body will perceive the color, insofar as it is color, and the light, insofar as it is light, and when the form reaches the hollow of the common nerve, the final sensor will perceive the color, insofar as it is color, and the light, insofar as it is light. Hence, the perception of color, insofar as it is color, and light, insofar as it is light, occurs at a time following the time when the form reaches from the surface of the sensitive organ to the hollow of the common nerve.⁑

3.64 ◉ Et etiam est instans quod est primum apud quod pervenerit forma in superficie visus diversum ab instanti quod est primum instans in quo aer deferens formam contingit primum punctum superficiei visus quando visus fuerit oppositus rei vise postquam non fuerit ita et postquam oculus apperuerit palpebras postquam fuerint clause. Quoniam quando ita fuerit, primum quod contingit superficiem visus ex aere deferente formam illius rei vise est unus punctus aut linea carens latitudine; deinde pars post aliam quousque fiat aer deferens formam contingens partem superficiei visus in quam pervenit forma. Et apud contactum illius puncti carentis quantitate aut linee carentis latitudine superficiei visus ad punctum carens quantitate aut ad lineam carentem quantitate superficiei aeris deferentis formam nichil pervenit ex forma lucis et coloris in superficie visus, quoniam minimum ex superficie in quod pervenit lux aut forma coloris non erit nisi superficies. In instanti ergo in quo contingit punctus superficiei visus primum punctum aeris deferentis formam nichil pervenit ex forma in superficie visus. Instans ergo quod est primum instans apud quod pervenit forma in superficie visus est diversum ab instanti quod est primum instans apud quod contingit aer deferens formam superficiei visus quando visus fuerit oppositus rei vise et apperuerit palpebras eius postquam fuerint clause.

3.64 ◉ Furthermore, the first instant at which the form reaches the surface of the eye is different from the first instant at which the air transmitting the form makes contact with the first point on the surface of the eye when the eye faces a visible object after having not faced it or after the eyelids are opened after having been closed. For when this happens, the first point on the surface of the eye touched by the air transmitting the form of that visible object forms a single point or a line, which lacks breadth; then [it continues] bit-by-bit until the air transmitting the form touches the [whole] area on the surface of the eye where the form reaches. But when a point, which lacks dimension, or a line, which lacks breadth, makes contact on the surface of the eye with a point, which lacks dimension, or a line, which lacks breadth, on the surface of the air transmitting the form, none of the form of light and color reaches the surface of the eye, because the smallest portion of the surface to which light or the form of color can reach will be nothing but a surface [itself]. Therefore, at the instant the first point of the air transmitting the form makes contact with a point on the surface of the eye, none of the form reaches the surface of the eye. Therefore, when the eye faces the visible object or the eyelids are opened after having been closed, the first instant at which the form reaches the surface of the eye is different from the first instant at which the air transmitting the form makes contact with the surface of the eye.

3.65 ◉ Et cum ita est, non pervenit forma lucis aut coloris in aliqua parte membri sentientis nec in superficie visus nisi in tempore. Non comprehendit ergo sentiens colorem in eo quod est color nec lucem in eo quod est lux nisi in tempore; scilicet quod instans apud quod cadit sensus coloris in eo quod est color et lucis in eo quod est lux est diversum ab instanti quod est primum instans apud quod contingit aer deferens formam superficiem visus.

3.65 ◉ Since this is the case, the form of light or color does not reach any portion of the sensitive organ or of the surface of the eye except over time. Therefore, the sensitive faculty does not perceive color, insofar as it is color, or light, insofar as it is light, except over time; that is, the instant at which the sensation of color, insofar as it is color, and light, insofar as it is light, occurs is different from the first instant at which the air transmitting the form makes contact with the surface of the eye.

3.66 ◉ Iam ergo declaratum est ex omnibus que diximus quomodo comprehendit visus lucem in eo quod est lux, et quomodo comprehendit colorem in eo quod est color, et quomodo comprehendit quiditatem coloris et lucis, et quomodo comprehendit qualitatem lucis.

3.66 ◉ From everything we have said, then, it is evident how sight perceives light, insofar as it is light, how it perceives color, insofar as it is color, how it perceives what kind of color or light it is, and how it perceives the quality of light.⁑

3.67 ◉ Sed remotio rei vise a visu non comprehendetur a visu solo sensu, nec comprehensio remotionis rei vise est comprehensio loci rei vise, nec comprehensio rei vise in suo loco est ex comprehensione remotionis eius tantum, nec comprehensio loci rei vise est ex comprehensione remotionis eius tantum. Quoniam locus rei vise sit ex tribus intentionibus, scilicet ex remotione, et ex parte, et ex quantitate remotionis.

3.67 ◉ Now the distance of a visible object from the eye will not be perceived by sight through brute sensation, nor is the perception of the distance of the visible object a perception of the object’s location, nor is the perception of the visible object in its location due solely to the perception of its distance, nor is the perception of the visible object’s location due solely to a perception of its distance. For the location of the visible object depends upon three things, namely, distance, direction, and the magnitude of the distance.

3.68 ◉ Quantitas ergo remotionis est diversa ab intentione remotionis in eo quod est remotio, quoniam intentio remotionis inter duo corpora est privatio contactus, et privatio contactus est esse aliquod spatium inter illa duo corpora. Et quantitas remotionis est quantitas illius spatii. Intentio ergo remotionis in eo quod est remotio est ex situ; non est ergo quantitas remotionis. Comprehensio ergo intentionis remotionis, que est privatio contactus, est diversa a comprehensione quantitatis spatii, que est mensura remotionis.

3.68 ◉ Hence, the magnitude of the distance is different from the fact of distance, insofar as it is distance, because distance [per se] means an absence of contact between two bodies, and an absence of contact means that there is some space between those two bodies. The magnitude of the distance, on the other hand, is the extent of that space. The fact of distance, insofar as it is distance, is thus a matter of spatial disposition; so it is not the magnitude of the distance. Accordingly, perception of the fact of distance [per se], which is an absence of contact, is different from perception of the extent of the spatial separation, which is the measure of the distance.⁑

3.69 ◉ Et comprehensio quantitatis remotionis est ex comprehensione magnitudinis, et comprehensio remotionis rei vise et comprehensio partis eius ambo sunt ex comprehensione situs loci. Et qualitas comprehensionis utriusque istorum est diversa a qualitate comprehensionis alterius, quoniam privatio contactus est diversa a parte. Comprehensio ergo loci rei vise non est comprehensio remotionis rei vise.

3.69 ◉ Now the perception of the magnitude of a distance follows from the perception of magnitude, whereas the perception of the visible object’s distance and the perception of its direction both follow from a perception of the spatial disposition of its location. Furthermore, the way in which either of these is perceived is different from the way in which the other is perceived, for the absence of contact is different from direction. Thus, the perception of a visible object’s location is not [the same as] the perception of a visible object’s distance.

3.70 ◉ Et comprehensio rei vise in suo loco consistit in comprehensione quinque rerum: scilicet ex comprehensione lucis que est in ea, et comprehensione coloris eius, et comprehensione remotionis eius, et comprehensione partis eius, et comprehensione quantitatis remotionis eius. Et nullum istorum comprehenditur per se solum, nec comprehenditur unum post aliud; sed omnia comprehenduntur simul, quoniam comprehenduntur per cognitionem, non per argumentationem iterandam.

3.70 ◉ The perception of a visible object in its place consists in the perception of five things: namely, perception of the light that is in it, perception of its color, perception of its distance, perception of its direction, and perception of the magnitude of its distance. None of these, moreover, is perceived by itself, nor is any one of them perceived after another; instead, all of them are perceived together, because they are perceived through recognition rather than through a process of deduction.

3.71 ◉ Et ex comprehensione rei vise in suo loco opinati sunt ponentes radios quod visio erit per radios exeuntes a visu et pervenientes ad rem visam, et quod visio erit per extremitatem radii. Et ratiocinati sunt contra naturales dicentes, cum visio fuerit per formam venientem a re visa ad visum, et illa forma pervenit ad interius visus, quare comprehenditur res visa in suo loco qui est extra visum, et forma eius iam pervenit ad interius visus? Et non sciverunt isti quod visio non completur solo sensu tantum, et quod visio non completur nisi per distinctionem et cognitionem antecedentem, et si cognitio et distinctio antecedens non esset, non compleretur in visu visio, et non comprehendet visus quid est res visa apud visionem. Quoniam quid est res visa non comprehenditur solo sensu nisi per distinctionem aut cognitionem aut argumentationem iterandam apud visionem. Si ergo visio esset solo sensu tantum, et omnia que comprehenduntur ex intentionibus que sunt in rebus visibilibus non comprehendentur nisi solo sensu, non comprehendetur res visa in suo loco nisi postquam pervenisset aliquid ad ipsum quod contingeret et sentiret eam. Cum autem visio non completur solo sensu, sed per distinctionem, et argumentationem, et cognitionem, non indigetur in comprehensione rei in suo loco sentiente extenso ad ipsam.

3.71 ◉ On the basis of the perception of a visible object in its place, the proponents of [visual] rays have supposed that vision will take place through rays that are emitted from the eye and extend out to the visible object, so that vision will occur at the endpoint of the ray. And they have argued against the natural philosophers⁑ by asking [the following question]: If vision occurs by means of a form reaching from the visible object to the eye, and if that form arrives inside the eye, then how is the visible object perceived in its place outside the eye when its form is now extended into the eye? But these theorists have failed to realize that vision is not achieved through brute sensation alone, but that vision is only fully realized through differentiation or previous knowledge, so, if there were no previous knowledge or differentiation, vision would not be realized in the eye, nor would sight perceive what the visible object is when it is seen. For what a visible object is is perceived not through brute sensation but through differentiation, recognition, or a process of deduction that occurs when seeing takes place. Therefore, if vision were a matter of brute sensation alone, and if all the properties of visible objects that are perceived [by sight] were perceived through brute sensation alone, the visible object would not be perceived in its place until after something extended out to it to make contact with it and feel it. However, since vision is not achieved through brute sensation, but through differentiation, deduction, and recognition, there is no need for the sensitive agent to reach out to the visible object in order to perceive it in its place.⁑

3.72 ◉ Redeamus ergo ad narrandum qualitatem comprehensionis visionis, et dicamus quod remotio rei vise non comprehenditur per se nisi per distinctionem. Et cum hoc ista intentio est ex intentionibus que quiescunt in anima secundum tempora pertransita, ita quod non est percepta ab anima propter nimiam frequentationem et iterationem eius super virtutem distinctivam, quare non indigetur in comprehensione eius argumentatione iteranda apud comprehensionem cuiuslibet rei vise. Nec querit etiam virtus distinctiva etiam apud comprehensionem cuiuslibet rei vise quomodo quievit intentio remotionis rei vise in ea, quoniam non distinguit qualitatem comprehensionis apud comprehensionem cuiuslibet rei vise. Et non comprehendit remotionem nisi cum aliis intentionibus que sunt in re visa, et comprehendit illam apud comprehensionem rei vise per cognitionem antecedentem.

3.72 ◉ So let us return to our discussion of how visual perception occurs, and let us say that the distance of a visible object is perceived, as such, only through differentiation. In addition, the [resulting] notion is one of those notions that becomes ensconced in the soul over time in such a way that the fact that it is ensconced there is not perceived by the soul because of the extraordinary frequency with which it recurs to the faculty of discrimination; thus, there is no need for that faculty to repeat the process of perceptual deduction when it perceives each visible object. Nor at the moment of perceiving each visible object does the faculty of discrimination analyze how the notion of a visible object’s distance has come to be ensconced in it, for it does not discern how it perceives each visible object when it perceives it. But it perceives distance only in conjunction with other properties possessed by the visible object, and, when it perceives the visible object, it perceives that property by means of previous knowledge.

3.73 ◉ Quomodo virtus distinctiva comprehendit remotionem per distinctionem est secundum quod narrabo. Quando est visus oppositus rei vise postquam non fuit oppositus, comprehendit rem visam, et quando auferetur ab oppositione, destruetur comprehensio. Et similiter, quando visus apperuerit palpebras postquam fuerint clause, et fuerit oppositus alicui rei vise, comprehendet illam rem visam, et cum clauserit palpebras, destruetur comprehensio. Et in natura intellectus est quod illud quod accidit in visu apud aliquem situm et destruetur apud eius ablationem non est fixum intra visum, nec operans ipsum est intra visum. Et in natura intellectus est etiam quod illud quod apparet apud apertionem palpebrarum et destruitur apud clausionem earum non est fixum intra visum, nec faciens ipsum accidere est intra visum. Et cum virtus distinctiva comprehenderit quod illud quod accidit in visu ex quo visus comprehendit rem visam nec est res fixa intra visum, nec operans ipsum est intra visum, statim comprehendit quod illud quod accidit in visu est veniens ex extrinseco, et operans ipsum est extra visum. Et cum visio destruitur apud clausionem palpebrarum et apud ablationem ab oppositione, et sic apud apertionem palpebrarum et apud oppositionem, virtus distinctiva comprehendit quod illud quod videtur in visu non est applicatum ad visum. Et cum virtus distinctiva comprehendit quod illud quod videtur non est intra visum nec est applicatum cum visu, statim comprehendit quod inter ipsum et visum est remotio. Quoniam in natura intellectus est, aut in fine manifestationis distinctionis, quod omne quod non est in corpore nec est applicatum cum ipso quod sit inter ea remotio, et hec est qualitas comprehensionis remotionis rei vise in eo quod est remotio.

3.73 ◉ How the faculty of discrimination perceives distance through differentiation is as follows. When the eye faces a visible object after having not faced it, it perceives the visible object, but when it is removed from its facing position, the perception will disappear. Likewise, when the eyelids are opened after having been closed, and when the eye faces some visible object, it will perceive that visible object, but when the eyelids are closed, the perception will disappear. Now it is intuitively obvious that what affects the eye in a given situation but disappears when it is removed is not fixed in the eye, nor is what creates the effect in the eye. It is also intuitively obvious that what appears when the eyelids are opened and disappears when they are closed is not fixed in the eye, nor does the thing creating this effect lie within the eye. Now when the faculty of discrimination perceives that the effect occurring in the eye, which provides the basis for its perception of the visible object, is not something fixed within the eye, nor is the thing creating that effect within the eye, then it immediately perceives that what occurs in the eye comes from outside, so the thing creating the effect lies outside the eye. Moreover, since vision ceases as soon as the eyelids are closed or as soon as the eye is removed from a facing position yet returns as soon as the eyelids are opened or the eye is restored to a facing position, the faculty of discrimination perceives that what is seen in the eye is not placed directly upon the eye. And when the faculty of discrimination perceives that what is seen neither lies within the eye nor is placed directly upon the eye, it immediately perceives that there is distance between that thing and the eye. For it is intuitively obvious, or at least nearly so, to the faculty of discrimination, that, if something is not actually in a body or placed directly upon it, there must be distance between them, and this is how the distance of a visible object, insofar as it is distance, is perceived.

3.74 ◉ Sed virtus distinctiva non indiget in comprehensione remotionis rei vise ad dividendum ea que divisimus, quoniam non fecimus hoc nisi gratia declarandi. Et virtus distinctiva comprehendit conclusionem istius distinctionis apud visionem sine indigentia illius divisionis. Ex comprehensione ergo rei vise apud oppositionem et apertionem palpebrarum, et ex destructione eius apud ablationem oppositionis et apud clausionem palpebrarum, comprehendit virtus distinctiva quod res visa est extra visum et quod non est applicata cum visu. Et secundum istum modum comprehendit virtus distinctiva quod inter visum et rem visam sit remotio. Deinde propter frequentationem istius intentionis et iterationem eius quievit in anima, ita quod non percipit quietem eius nec qualitatem quietis eius, scilicet quod omnia visibilia sunt extra visum et quod inter quamlibet rem visam et visum est remotio. Remotio ergo rei vise a visu non comprehenditur nisi per modicam distinctionem, scilicet quod virtus distinctiva comprehendit quod visio est propter intentionem extrinsecam a visu. Et cum hoc, quando fuerit quiescens in anima, intelliget virtus distinctiva quod quelibet res visa comprehensa a visu est extra visum, et inter ipsum et visum est remotio.

3.74 ◉ However, in perceiving the distance of a visible object, the faculty of discrimination does not need to go through the analytic procedure we detailed, for we have done this only for the sake of illustration. Rather, the faculty of discrimination reaches its perceptual conclusion as soon as sight occurs without relying on such an analytic procedure. Therefore, from the perception of the visible object when the eye faces it or when the eyelids are opened, and from its disappearance when the facing position is changed or when the eyelids are closed, the faculty of discrimination perceives that the visible object lies outside the eye rather than being placed directly upon it. And this is how the faculty of discrimination perceives that there is distance between the eye and the visible object. Then, given the frequent recurrence of this notion, i.e., that all visible objects lie outside the eye and that there is distance between every visible object and the eye, it becomes ensconced in the soul in such a way that the soul does not perceive that it has become ensconced there or how it has become ensconced there. Thus, to perceive the distance of a visible object from the eye requires some differentiation, namely, for the faculty of discrimination to perceive that vision is due to something that operates from outside the eye. And, in addition, when this notion becomes ensconced in the soul, the faculty of discrimination will realize that every visible object that is perceived by sight lies outside the eye and that there is some distance between that object and the eye.⁑

3.75 ◉ Et cum hoc, sicut diximus superius, non comprehenditur remotio nisi cum aliis. Et apud nostrum sermonem de qualitate comprehensionis situs declarabitur quomodo comprehendetur remotio cum situ, et quomodo comprehendetur res visa in suo loco.

3.75 ◉ As we claimed above, moreover, distance is only perceived in conjunction with other properties. But how distance will be perceived in conjunction with spatial disposition and how the visible object will be perceived in its place will be explained in our discussion of how spatial disposition is perceived.⁑

3.76 ◉ Comprehensio vero quantitatis remotionis a visu diversatur, quoniam quedam comprehenduntur per sensum visus et certificatur earum quantitas, et quedam comprehenduntur quorum quantitas non certificatur. Remotio rei vise a visu comprehenditur in qualibet re visa, et certificatur in qualibet re visa. Quantitas autem remotionis non certificatur a visu in qualibet re visa, quoniam inter quedam visibilia et visum sunt corpora ordinata continuata, et inter quedam vero et visum non sunt corpora ordinata continuata, nec remotio eorum respicit corpora ordinata continuata. Illa ergo quorum remotio respicit corpora ordinata continuata, quando visus comprehenderit corpora ordinata que respiciunt remotionem eorum, scilicet visibilium, comprehendet quantitates illorum corporum. Et cum comprehenderit mensuras illorum corporum, comprehendet quantitates spatiorum que sunt inter extremitates illorum. Et spatium quod est inter duas extremitates corporis visi quod respicit remotionem que est inter visum et rem visam quarum altera est in parte rei vise et altera in parte aspicientis est remotio rei vise a visu, quoniam respicit spatium quod est inter visum et rem visam. Cum ergo visus comprehenderit mensuram istius spatii, comprehendet mensuram remotionis rei vise. Visus ergo comprehendit quantitatem remotionum rerum visibilium quarum remotio respicit corpora ordinata continuata ex comprehensione mensurarum corporum ordinatorum respicientium remotiones earum.

3.76 ◉ The perception of the magnitude of a distance from the eye varies, for some distances are perceived by the sense of sight, and their magnitudes are accurately determined, but others are perceived without having their magnitudes accurately determined.⁑ That a visible object is distant from the eye is perceived for every visible object, and it is grasped with certainty for every visible object. However, the magnitude of the distance is not accurately determined by sight for every visible object, for between some visible objects and the eye there are objects arranged in successive, continuous order, whereas between other visible objects and the eye there are no objects arranged in successive, continuous order, so their distances are not spanned by a continuous, ordered range of bodies. Thus, when sight perceives a continuous, ordered range of bodies, i.e., of visible objects, that spans a given distance, it will perceive the sizes of those bodies. And when it perceives the sizes of those bodies, it will perceive the sizes of the spaces that lie between their extremities. Now the space that lies between the two extremities of a visible body that spans the distance between the eye and a visible object, one of those extremities lying on the side of the visible object, the other on the side of the viewer, represents the distance of the visible object from the eye, for it corresponds to the space between the eye and the visible object.⁑ Thus, when sight perceives the measure of this space, it will perceive the measure of the visible object’s distance. Therefore, sight perceives the magnitude of the distances of visible objects whose distance is spanned by a continuous, ordered range of bodies by perceiving the measures of the bodies ranged in order along those distances.

3.77 ◉ Et remotio quarumdam rerum istarum visibilium est mediocris, et remotio quarumdam est extra mediocritatem. Remotio ergo visibilium quorum remotio est mediocris comprehenditur a visu vera comprehensione certificata, quoniam visibilia quorum remotio est mediocris, et inter ipsa et visum sunt corpora ordinata continuata, comprehenduntur a visu vera comprehensione. Et cum visus comprehendit ista visibilia vera comprehensione, comprehendet corpora ordinata interiacentia ipsum et ipsa visibilia vera comprehensione. Et cum comprehendit ista corpora vera comprehensione, comprehendet spatia interiacentia extremitates eorum vera comprehensione. Et cum comprehenderit spatia vera comprehensione, comprehendet mensuras remotionum visibilium respicientium ista spatia vera comprehensione certificata. Visibilia ergo quorum remotio est respiciens corpora ordinata continuata et quorum remotio a visu est mediocris, visus comprehendit mensuras remotionum eorum vera comprehensione et certa—et est dicere certa in ultimitate in qua poterit sensus comprehendere.

3.77 ◉ Now the distance of some of these visible objects is moderate, whereas the distance of others is inordinate.⁑ Therefore, the distance of visible objects that lie at a moderate distance is perceived by sight according to a correct and definite perception, because, when visible objects lie at a moderate distance, and there is a continuous, ordered range of bodies between them and the eye, these objects are perceived by sight correctly. And if sight perceives these visible objects correctly, it will correctly perceive the bodies ranged in order between itself and them. Moreover, if sight perceives these bodies correctly, it will perceive the spaces between their extremities correctly. Finally, if it perceives those spaces correctly, it will perceive correctly and with precision the measures of the distances of the visible bodies ranged along those spaces. Therefore, when the distance of visible objects from the eye is spanned by a continuous, ordered range of bodies, and when that distance is moderate, sight perceives the measure of their distances correctly and precisely—which is to say with as much precision as sense can achieve in perception.⁑

3.78 ◉ Mensure vero remotionum visibilium quorum remotio est extra mediocritatem et quorum remotio respicit corpora ordinata continuata, et cum hoc sunt comprehensa a visu, non comprehendentur a visu vera comprehensione certificata, quoniam visibilia quorum remotio est extra mediocritatem non comprehenduntur a visu vera comprehensione. Et cum inter visum et ista visibilia fuerint corpora ordinata continuata, non comprehendentur a visu omnia ista visibilia vera comprehensione propter extraneitatem remotionum extremitatum suarum et exitus eorum a mediocritate per quam visus certificat visibilia. Et cum visus non comprehendet ista corpora vera comprehensione, non comprehendet spatia interiacentia extremitates vera comprehensione. Non comprehendet ergo remotiones que sunt interiacentes ipsum et visibilia que sunt apud extremitates istorum corporum vera comprehensione. Quantitates ergo remotionum visibilium quorum remotio est extra mediocritatem, et inter ipsam et visum sunt corpora ordinata continuata, non comprehenduntur a visu vera comprehensione.

3.78 ◉ On the other hand, when visible objects lie at inordinate distances and those distances are spanned by a continuous, ordered range of bodies, even though the bodies along that range are perceived by sight, the measures of the distances of the visible objects will not be perceived correctly and precisely by sight, because visible objects whose distance is untoward are not correctly perceived by sight.⁑ And when there are bodies arranged in continuous, successive order between the eye and those visible objects, not all of those [intervening] visible bodies will be correctly perceived by sight because of the excessive distance between their extremities and because they lie beyond the threshold at which sight perceives visible objects with accuracy. And if sight will not perceive those bodies correctly, it will not perceive the spaces between their extremities correctly. Therefore, it will not correctly perceive the distances between itself and the visible objects that lie at the extremities of those bodies. When the distances of visible objects are untoward, then, and when there are bodies in continuous, successive order between them and the eye, the magnitudes of their distances are not correctly perceived by sight.

3.79 ◉ Remotiones autem visibilium quorum remotio non respicit corpora ordinata continuata non comprehenduntur quidem a visu vera comprehensione, quare visus, quando comprehenderit nubes in plano et in locis carentibus montibus, existimabit quod sint magne remotionis in respectu corporum celestium. Et cum nubes fuerint inter montes et fuerint continuate, forte cooperientur cacumina montium a nubibus, et cum nubes fuerint distantes, forte apparebunt cacumina montium superiora nubibus, et forte comprehendet visus partes nubium applicatas cum ventre montium, et forte erit hoc in montibus non valde altis. Ex ista ergo experimentatione videtur quod remotio nubium non est extranea, et quod plures illarum sunt propinquiores terre cacuminibus montium, et quod illud quod existimatur de extraneitate remotionis illarum est error. Et declarabitur inde quod visus non comprehendit mensuram remotionis nubium in plano, et quod mensura remotionis nubium comprehendetur a visu quando fuerint inter montes, et apparuerint cacumina montium superius.

3.79 ◉ Furthermore, the distances of visible objects whose distance is not spanned by a continuous, ordered range of bodies are certainly not perceived correctly by sight; accordingly, when it perceives clouds over a plain or in places without mountains, sight will conclude that they lie far away [at a distance] comparable to [that of] celestial objects.⁑ If, moreover, the clouds lie among mountains but are continuous, the peaks of the mountains may be hidden by the clouds, whereas if the clouds are separated, the peaks of the mountains may appear above them, and sight may perceive portions of the clouds lying against the shoulder of those mountains, and this may happen in the case of mountains that are not very high. From this [sort of] experience, then, it seems that the distance of the clouds is not inordinate, and the majority of them lie closer to the ground than mountain peaks, so the conclusion that they lie exceedingly far away is erroneous. Hence, it will be evident that sight does not [correctly] perceive the measure of the distance of clouds when they lie above a plain, but the measure of the distance of clouds will be [correctly] perceived by sight when they lie among mountains, and the peaks of those mountains appear above them.

3.80 ◉ Et hoc invenitur etiam in pluribus visibilibus que sunt super faciem terre, scilicet quod mensure remotionum non respicientes corpora ordinata continuata non comprehendentur a visu. Ex illis ergo ex quibus manifestatur hoc, scilicet quod visus non comprehendit quantitatem remotionis rei vise nisi quando remotio eius fuerit respiciens corpora ordinata continuata, et comprehenderit visus illa corpora, et certificaverit mensuras eorum, est ut paret experimentator domum in qua non intret ante horam experimentationis. Et sit in quibusdam parietibus illius domus strictum foramen, et sit post illud foramen vacuitas quam ante illam horam non vidit. Et sint in illa vacuitate duo parietes quorum unus sit propinquior foramini alio, et sit inter illos duos parietes distantia alicuius quantitatis. Et sit paries propinquior cooperiens quandam partem parietis remotioris, et sit quedam pars parietis remotioris apparens. Et sit foramen elevatum a terra ita quod, quando aspiciens aspexerit per ipsum, non videat faciem terre que est post parietem in quo foramen est. Experimentator quidem, quando intraverit istum locum et inspexerit istud foramen, videbit duos parietes in simul, et non comprehendet remotionem que est inter ipsos. Si vero remotio primi parietis fuerit magna remotio extranea a foramine, comprehendet duos parietes quasi se contingentes, et forte existimabit quod sint unus continuus quando color eorum fuerit unus. Et si paries primus fuerit remotus a foramine mediocriter, et percipiatur quod sint duo parietes, existimabitur quod sunt duo propinqui sibi aut se contingentes, et non certificabitur remotio que est inter ipsos. Et cum comprehenderit primum parietem visus, quando remotio eius fuerit mediocris, quasi esset propinquus, et non certificabit remotionem eius etiam. Et non certificabitur remotio que est inter ista duo corpora huiusmodi per sensum visus quando ante illam horam non vidit illum locum nec illos duos parietes. Et forte comprehendit visus illa duo corpora quasi se contingentia, quamvis ante sciverit distantiam que est inter ea.

3.80 ◉ This phenomenon is also encountered in various visible objects that are situated at ground-level; that is, the measure of their distances, when they are not spanned by a continuous, ordered range of bodies, will not be [correctly] perceived by sight. From such examples, then, it is evident that sight does not perceive the magnitude of the distance of a visible object unless its distance is spanned by a continuous, ordered range of bodies, and unless sight perceives those bodies and determines their measures accurately. For instance, let anyone who wants to conduct the experiment set up a room that he will not enter before the time of the experiment. And let there be a narrow aperture in any of the walls of that room, and let there be a space behind this aperture that has not been seen before that time. Then, within that space let two walls be set up, one nearer the aperture than the other, and let there be some determinate distance between those two walls. Then, let the nearer wall block a portion of the farther wall, but let some portion of that farther wall show. Let the aperture be high enough above the ground that, when the viewer looks through it, he cannot see the ground behind the wall with the aperture in it.⁑ When the experimenter enters this place and looks through the aperture, he will definitely see the two walls together, but he will not perceive the distance between them. Indeed, if the first wall lies an inordinate distance from the aperture, he will perceive the two walls as contiguous, and he will perhaps conclude that they are continuous, forming a single wall, when their color is the same.⁑ If, however, the first wall lies a moderate distance from the aperture, and if it is perceived that there are two walls, it will be judged that the two are near to, or contiguous with, one another; so the distance between them will not be accurately determined. Furthermore, when it perceives the first wall, given that its distance is moderate, sight [will judge its distance] as if it were near, and it will not determine its distance accurately. So the distance between two bodies of this sort will not be accurately determined by the sense of sight when the experimenter has not seen that location or those two walls before.⁑ And sight might perceive those two walls as contiguous, even when it has already determined the distance between them.

3.81 ◉ Et cum visus non comprehendit remotionem que est inter duo corpora huiusmodi, non comprehendet quantitatem remotionis ultimi corporis, et cum hoc comprehendit formam eius. Et cum non comprehendit quantitatem remotionis istius corporis, quamvis comprehendat istud corpus, non comprehendet corpora continuata respicientia remotionem eius, et non comprehendet visus quantitatem remotionis rei vise certe ex comprehensione forme rei vise. Et non comprehendit visus quantitatem remotionis rei vise nisi per argumentationem. Visus autem non arguit super aliquam mensuram nisi per comparationem illius mensure ad aliam mensuram iam comprehensam a visu vel ad mensuram tunc comprehensam cum ea; et nichil est per quod visus potest mensurare remotionem rei vise et comparare ad ipsum ita quod comprehendat mensuram eius vere nisi corpora ordinata respicientia remotionem rei vise. Si autem mensuraverit visus remotionem per alia quam per ista corpora, erit mensuratio qualiscumque, non certa. Non igitur comprehenditur quantitas remotionis rei vise a sensu visu nisi sit remotio eius respiciens corpora ordinata continuata, et comprehendit visus illa corpora et mensuras illorum.

3.81 ◉ Since sight does not perceive the distance between two bodies of this sort, it will not perceive the magnitude of the distance of the farther body, even though it perceives its form. And if it does not perceive the magnitude of the distance of this body, even though it perceives the body [itself], then sight will not perceive a continuous range of bodies spanning that distance, so, on the basis of its perception of the form of the visible object, sight will not perceive the magnitude of the distance of that visible object properly. Now sight perceives the magnitude of the distance of a visible object only through deduction. And sight deduces any measure only by comparing that measure to another measure already known to sight or to some measure perceived at the same time; but without an ordered range of bodies spanning the distance of a visible object, sight has no means of measuring the distance of the visible object or of subjecting it to comparison in order to perceive its measure correctly. Moreover, if sight measures the distance by anything other than those bodies, the measure will be arbitrary rather than accurate. Therefore, the magnitude of the distance of a visible object is not perceived by the sense of sight unless its distance is spanned by a continuous, ordered range of bodies, and sight perceives those bodies as well as their measures.

3.82 ◉ Et ista experimentatio quam diximus habet multa similia ex visibilibus, sicut ex duabus arboribus erectis secundum modum quem diximus in parietibus, aut ligno ex transverso posito foramini secundum modum quem diximus de pariete primo.

3.82 ◉ The experiment that we have described provides the same results for a variety of visible objects, such as two trees standing in the relationship described for the walls, or a stick placed crosswise to the aperture in the same position as we described for the first wall.

3.85 ◉ Remotiones autem visibilium distantium adinvicem comprehenduntur a visu ex comprehensione divisionis que est inter visibilia. Dispositiones autem quantitatis remotionum visibilium adinvicem sunt apud visum sicut dispositiones remotionum visibilium a visu. Quoniam due res vise atque distincte, si inter eas fuerint corpora continuata et ordinata, et comprehenderit visus illa corpora et mensuras eorum, comprehendet quantitatem remotionis que est inter illas res duas visas; si autem non, non comprehendet quantitatem distantie que est inter illas vere. Et similiter, si inter illas duas res visas fuerint corpora ordinata continuata, et fuerint valde extranee remotionis ita quod visus non poterit certificare mensuras illorum corporum, non certificabitur mensura que est inter illa duo corpora.

3.85 ◉ Furthermore, the distances of visible objects that stand apart from one other are perceived by sight through a perception of the separation between the visible objects.⁑ Moreover, the magnitude of the distances between visible objects is handled by sight in the same way as the [magnitude of the] distances of visible objects from the eye. For, when there is a continuous, ordered range of bodies between two separate visible objects, and when sight perceives those bodies and their measures, it will [correctly] perceive the magnitude of the distance between those two visible objects; if [there is] not [such a range of bodies], however, sight will not correctly perceive the magnitude of the distance between them. Likewise, if there is a continuous, ordered range of bodies between the two visible objects, but if those bodies lie at such a remote distance that sight cannot determine their measures accurately, the measure [of the distance] between those two objects will not be determined accurately.

3.86 ◉ Remotiones ergo visibilium a visu non comprehenduntur nisi ex comprehensione virtutis distinctive, quoniam illud quod accidit in visu apud visionem non accidit nisi per aliquid extrinsecum. Et nulla quantitas remotionis visibilium comprehenditur per sensum visum vera comprehensione nisi remotiones visibilium quorum remotio respicit corpora ordinata et continuata et quorum remotio cum hoc est mediocris, et visus cum hoc etiam comprehendit corpora ordinata respicientia remotiones eorum et certificat mensuras illorum corporum, ut se sequuntur. Mensure autem remotionum preter huiusmodi non certificantur a visu. Visibilia autem quorum mensure remotionum earum non certificantur a visu quedam remotiones eorum sunt respicientes corpora ordinata continuata, et visus cum hoc comprehendit illa corpora, et sunt illa quorum extremitatum remotio est extranea. Et quedam remotiones eorum sunt respicientes corpora ordinata continuata, sed visus non comprehendit illa corpora, sive sint remotiones eorum extranee sive mediocres. Et quedam remotiones eorum non respiciunt corpora ordinata continuata, et sunt illa visibilia que sunt valde elevata a terra que sunt extranee remotionis et que non habent prope ipsam remotionem nec parietem respicientem remotionem eorum. Et omnia visibilia dividuntur in istas partes.

3.86 ◉ Therefore the distances of visible objects from the eye are perceived only through a perception carried out by the faculty of discrimination, for what occurs in the eye at the time of sight occurs only through something outside [the eye]. Moreover, the magnitude of the distance of visible objects is not correctly perceived by the sense of sight unless the distances of the visible objects are spanned by a continuous, ordered range of bodies, provided that [any such] distance is moderate and, in addition to this, that sight also perceives those bodies ranged in continuous order and accurately determines their measures according to their succession. The measures of distances that do not meet these requirements are not accurately determined by sight. Moreover, of visible objects whose distances are not accurately determined by sight, some lie at distances that are spanned by a range of continuous, ordered bodies, so that, although sight perceives those bodies, their extremities lie an inordinate distance away. Others lie at distances that are spanned by a continuous, ordered range of bodies, but sight does not [correctly] perceive those bodies, whether their distances are inordinate or moderate. Others still lie at distances that are not spanned by a continuous, ordered range of bodies, and these include visible objects that are so high above the earth that they lie an inordinate distance away and have no other [comparable] distance near them or a wall spanning their distance.⁑ All visible objects fall under these categories.

3.87 ◉ Et quando visus comprehendit visibilia quorum remotionum quantitates non certificantur a visu, distinctiva virtus statim cognoscit mensuras remotionis eorum secundum estimationem, non secundum rectitudinem. Et comparat remotionem earum ad remotionem sibi similium ex visibilibus comprehensis a visu ante, et sustentat se in argumentatione super formam rei vise, et comparat formam rei vise ad formam visibilium similium quas visus comprehendit ante et quorum quantitates remotionum iam certificantur a virtute distinctiva. Et sic comparat remotionem rei vise cuius quantitatem remotionis non certificat ad remotionem visibilium sibi similium quas comprehendit visus ante et quorum remotionum mensure certificantur iam a virtute distinctiva. Cum ergo virtus distinctiva non certificaverit lineationes forme rei vise, comparabit quantitatem totius forme eius ad mensuras formarum visibilium equalium illis formis in mensura quarum quantitates remotionum iam certificate sunt, et assimilabit remotionem rei vise cuius quantitas remotionis non certificatur ab eo ad remotionem visibilium equalium vise in mensura quorum remotiones iam sunt certificate.

3.87 ◉ When sight perceives visible objects the magnitudes of whose distances are not accurately determined by sight, the faculty of discrimination immediately apprehends the measures of their distance according to estimation rather than true reckoning. And it compares their distance to the distance of similar visible objects that have been perceived before by sight, and it depends upon the form of the visible object in making its judgment, and it compares the form of the visible object to the form of similar visible objects that sight has perceived before, the magnitude of their distances having already been accurately determined by the faculty of discrimination. And thus it compares the distance of a visible object the magnitude of whose distance it cannot accurately determine with the distance of similar visible objects that have been perceived by sight before, the measure of their distances having already been accurately determined by the faculty of discrimination. Thus, if the faculty of discrimination cannot accurately determine the lineaments of the form of the visible object, it will compare the magnitude of its entire form to the magnitudes of forms of visible objects that are equal in size, the magnitudes of their distances having already been accurately determined, and it will assimilate the distance of a visible object whose distance it cannot accurately determine to the distance of visible objects that are the same size whose distances have already been accurately determined.⁑

3.88 ◉ Et hoc est maximum super quod potest virtus distinctiva in comprehendendo mensuras remotionum visibilium. Forte ergo inveniet per istam argumentationem certitudinem in comprehendendo remotionem illius quod est huiusmodi, et forte errabit. Et in illis in quibus invenit certitudinem non certificatur utrum invenit certitudinem an non. Et ista argumentatio erit argumentatio in fine velocitatis propter assuetudinem virtutis distinctive in comprehendendo remotionem visibilium per argumentationem et certificationem.

3.88 ◉ And this is the best that the faculty of discrimination can do in perceiving the measures of the distances of visible objects. Thus, in perceiving the distance of an object of this sort, it may reach an accurate determination by following such a deductive process, or it may err. But in those instances in which it does reach an accurate determination, it cannot be sure whether it has reached an accurate determination or not. Moreover, this deductive process will be carried out extremely quickly because the faculty of discrimination is accustomed to perceiving the distance of visible objects through deduction or accurate determination.

3.89 ◉ Et forte existimabit virtus distinctiva mensuram remotionis rei vise, si fuerit remotio eius respiciens corpora ordinata, et fuerit ex remotionibus mediocribus, propter assuetudinem virtutis distinctive in existimando vel arguendo remotiones visibilium et propter velocitatem cum sue estimationis argumentatione. Et cum remotio rei vise fuerit mediocris, non erit inter estimationem remotionum et inter veram remotionem magna diversitas.

3.89 ◉ Furthermore, the faculty of discrimination may estimate the measure of the distance of a visible object if it is spanned by an ordered range of bodies and is moderate, [and it will do so] because the faculty of discrimination is accustomed to estimating or deducing the distances of visible objects and because of the speed with which it arrives at its estimate. And if the distance of the visible object is moderate, there will not be much discrepancy between the estimate of the distances and the true distance.

3.90 ◉ Cum ergo visus comprehenderit aliquam rem visam, statim virtus distinctiva comprehendet remotionem eius et mensuram remotionis eius secundum quod poterit comprehendere—scilicet aut per certitudinem aut estimationem—et statim remotio eius habebit in anima mensuram ymaginatam. Mensura ergo remotionis rei vise comprehensa a visu cuius forma est ymaginata in anima, quando illa remotio fuerit respiciens corpora ordinata continuata, et cum hoc fuerit illa remotio mediocris, et cum hoc comprehenderit visus illa corpora ordinata respicientia eius remotionem, et cum hoc iam virtus distinctiva cognoverit ipsa et certificaverit mensuras eorum, tunc mensura certificata est.

3.90 ◉ Therefore, when sight perceives any visible object, the faculty of discrimination will immediately perceive its distance, as well as the measure of its distance, to the best of its ability—i.e., through accurate determination or through estimation—and its distance will immediately have an imagined measure in the soul. Thus, given a visible object perceived by sight and having its form imagined in the soul, when its distance is spanned by a continuous, ordered range of objects, that distance being moderate, and when sight perceives those bodies ranged in continuous order over its distance, and when the faculty of discrimination has already apprehended these bodies and accurately determined their measures, then the measure of the distance [of that visible object] is accurately determined.

3.91 ◉ Si autem eius remotio non fuerit respiciens corpora ordinata continuata, aut fuerit respiciens corpora ordinata continuata, et comprehenderit visus illa corpora, et fuerit cum hoc remotio extranea ita quod visus non potest certificare mensuras illorum corporum, aut fuerit visus respiciens corpora continuata ordinata, et non comprehenderit visus illa corpora nec certificaverit mensuras eorum, aut poterit comprehendere illa corpora, sed non aspexerit illa tunc nec mensuraverit quantitates eorum, sive sint remotiones illorum visibilium extranee sive mediocres, erit tunc mensura eius que est ymaginata in anima non certificata nec verificata.

3.91 ◉ On the other hand, if the distance is not spanned by a continuous, ordered range of bodies, or if it is spanned by a continuous, ordered range of bodies that are perceived by sight but whose distances are so inordinate that sight cannot accurately determine the sizes of those bodies, or if the eye faces a continuous, ordered range of bodies but sight does not [correctly] perceive those bodies or does not accurately determine their sizes, or if the eye could perceive those bodies but does not notice them and therefore does not determine their sizes, whether those bodies lie at an inordinate or at a moderate distance, then the measure of that distance imagined in the soul will not be accurately determined or verified.

3.92 ◉ Et remotiones que sunt inter visibilia distincta non comprehenduntur nisi ex comprehensione divisionis que est inter visibilia, et quedam quantitates remotionum que sunt inter visibilia divisa comprehenduntur vera comprehensione, et quedam comprehenduntur per estimationem. Mensura ergo remotionis que est inter duo visibilia inter que sunt corpora ordinata continuata, et visus comprehenderit illa corpora et certificaverit mensuras eorum, est mensura certificata. Mensura autem remotionis que est inter duo visibilia inter que non sunt corpora continuata ordinata, aut inter que sunt corpora continuata ordinata, sed visus non certificat mensuras illorum corporum aut non comprehendet illa corpora, est mensura non certificata. Secundum ergo istos modos erit comprehensio remotionum visibilium per sensum visus.

3.92 ◉ Now the distances between disjoined visible objects are perceived only through the perception of the separation that exists between them, and some of the magnitudes of the distances between disjoined visible objects are correctly perceived, whereas others are perceived through estimation. Thus, the measure of the distance between two visible objects that have a continuous, ordered range of bodies between them is accurately determined as long as sight perceives those bodies and determines their sizes. On the other hand, if two visible objects do not have a continuous, ordered range of bodies between them, or if they have a continuous, ordered range of bodies between them but sight does not accurately determine the sizes of those bodies or will not perceive those bodies, then the measure of the distance between the two visible objects is not accurately determined. It is therefore in these ways that the sense of sight will perceive the distances of visible objects.

3.93 ◉ Et etiam corpora respicientia remotiones visibilium assuetorum que sunt in remotionibus assuetis que assuete comprehenduntur a visu comprehenduntur a visu, et certificantur mensure eorum propter frequentationem eorum a visu ita quod visus propter hoc comprehendit mensuras remotionum eorum per cognitionem. Quoniam visus, quando comprehenderit aliquod visibile assuetum, et fuerit in remotione assueta, cognoscet ipsum, et cognoscet eius remotionem, et existimabit quantitatem remotionis eius. Quando ergo existimaverit quantitatem remotionis huiusmodi visibilium, erit estimatio eorum prope verum, et non erit inter estimationem eius et inter veritatem magna diversitas. Quantitates ergo remotionum visibilium assuetorum que sunt in remotionibus assuetis comprehenduntur a visu per cognitionem et estimationem quantitatum eorum. Et plures remotiones visibilium comprehenduntur secundum modum huiusmodi.

3.93 ◉ Furthermore, when bodies span the distances of familiar objects lying at familiar distances, which sight is used to perceiving, those bodies are perceived by sight and their sizes are accurately determined because they recur to sight so often that sight perceives the measures of their distances through recognition. For, when it perceives any familiar visible object that lies at a familiar distance, sight will recognize it and will recognize its distance, so it will estimate the magnitude of its distance. Therefore, when it estimates the magnitude of the distance of such bodies, the estimate of their distance will be almost exact, so there will not be much discrepancy between the estimated and actual distance. The magnitudes of the distances of familiar objects that lie at familiar distances are therefore perceived by sight through recognition and through an estimate of their sizes. The majority of the distances of visible objects, moreover, are perceived in this manner.

3.94 ◉ Situs vero quem visus comprehendit ex visibilibus dividitur in tres modos quorum unus est situs totius rei vise apud visum aut situs cuiusdam partium rei vise apud visum. Et iste modus est oppositio. Secundus est situs superficiei rei vise opposite visui apud visum, et situs superficierum rei vise oppositarum visui apud visum quando res visa fuerit multarum superficierum, et fuerit illud quod apparet ex eis visui multe superficies, et situs terminorum superficierum visibilium apud visum, et situs linearum et spatia que sunt inter quelibet duo puncta aut inter quelibet duo visibilia que simul comprehenduntur a visu apud visum. Modus tertius est situs partium rei vise adinvicem, et situs terminorum rei vise superficiei adinvicem, et situs partium terminorum rei vise superficiei adinvicem. Et iste modus est ordinatio. Et similiter situs visibilium diversorum adinvicem collocatur sub hoc modo. Omnes ergo situs qui comprehenduntur a visu dividuntur in istos tres modos.

3.94 ◉ Now spatial disposition, which sight perceives among visible objects, can be subdivided into three kinds, the first of which involves the spatial disposition of the entire visible object vis-à-vis the eye or the spatial disposition of any of the visible object’s parts vis-à-vis the eye. This kind of spatial disposition is [called] »opposition.«⁑ The second kind involves the spatial disposition of the surface of a facing visible object vis-à-vis the eye; this includes the spatial disposition of the surfaces of a visible object facing the eye when it has several surfaces and many of those surfaces are exposed to view; it also includes the spatial disposition of the boundaries of the surfaces of the visible objects vis-à-vis the eye, as well as the spatial disposition vis-à-vis the eye of the lines or the spaces between any two points or between any two visible objects that are perceived at the same time by sight.⁑ The third kind involves the spatial disposition of the parts of the visible object in relation each another; it also involves the spatial disposition of the boundaries of the surface of the visible object in relation to each other, as well as the spatial disposition of the parts of the boundaries of the surface of the visible object with respect to each other. This kind of spatial disposition is [called] »arrangement.« Likewise, the spatial disposition of various visible objects in relation to one another is a subtype of this. Therefore, all spatial dispositions perceived by sight can be subdivided into these three kinds.

3.95 ◉ Et situs cuiuslibet habentis situm apud alium componitur ex remotione illius habentis situm ab illo alio et ex situ illius habentis situm respectu illius alterius. Oppositio ergo rei vise visui componitur ex remotione rei vise a visu et ex parte in qua est res visa respectu visus. Comprehensio autem remotionis rei vise iam declaratum est quod est intentio quiescens in anima. Verus autem locus rei vise comprehenditur ex situ rei vise apud visionem, quoniam visus non comprehendit rem visam nisi ex oppositione. Et loca que comprehenduntur a sensu comprehenduntur a distinctione, et sensus et distinctio distinguit inter loca, quamvis in eis nichil sit ex visibilibus. Et distinguit distinctio inter locum obiectum visui et locum propinquum ei, et virtus distinctiva comprehendit omnia loca per ymaginationem. Cum ergo visus fuerit oppositus alicui loco et comprehendit aliquod visibile, et visus postea fuerit ablatus ab illo loco et fuerit oppositus alii loco, destruetur visio illius rei vise. Et cum revertetur iterum ad oppositionem illius loci, revertetur illius rei vise visio.

3.95 ◉ The spatial disposition of one thing with respect to another is a function of the distance of one of the things from the other and the spatial orientation of the one with respect to the other. Therefore, the opposition of a visible object vis-à-vis the eye depends on the distance of the visible object from the eye and the direction of the visible object vis-à-vis the eye. Now it has already been shown that the perceptual notion of a visible object’s distance is ensconced in the soul.⁑ The true location of the visible object, however, is perceived from the spatial disposition of the visible object vis-à-vis the eye, for the eye only perceives a visible object from a facing position. Furthermore, the locations perceived by sense are perceived by differentiation, so both sense and [the faculty of] discrimination distinguish among locations, even when there are no visible objects filling them. But [the faculty of] discrimination makes the distinction between a location right in front of the eye and a location near it, and the faculty of discrimination perceives all locations through imagination. Therefore, when the eye faces some location and perceives a visible object [in it], if the eye then shifts its focus from that location to face another location, the original visible object will disappear from view. But when the eye returns its focus to face that [original] location, the original visible object will come back into view.

3.96 ◉ Et cum visus comprehenderit rem visam apud oppositionem illius in loco in quo est res visa, et comprehenderit virtus distinctiva locum oppositum visui apud comprehensionem illius rei vise, et quando visus est ablatus ab oppositione illius loci destruetur visio illius rei vise, tunc ergo virtus distinctiva comprehendet quod res visa non est nisi in parte opposita visui apud visionem illius rei vise.

3.96 ◉ Now if sight perceives the visible object facing it in the location where the visible object is, and if the faculty of discrimination perceives the location facing the eye when that visible object is perceived, and if, when the eye shifts its focus so that it no longer faces that place, the object disappears from view, then the faculty of discrimination will perceive that the visible object only exists in the direction that the eye faces when that visible object is seen.

3.97 ◉ Et etiam declaratum est quod visus recipit formas proprie ex verticationibus linearum radialium et quod ipse non patitur a formis nisi ex verticationibus istarum linearum tantum. Et etiam est declaratum quod forma extenditur in corpore visus secundum rectitudinem linearum radialium. Cum ergo forma rei vise pervenerit in visum, statim sentiens sentiet formam, et sentiet partem visus in quam pervenit forma, et sentiet verticationem per quam extendetur forma in corpore membri sentientis. Cum ergo comprehenderit visus locum forme in visu et comprehenderit verticationem per quam extendebatur forma, statim virtus distinctiva comprehendet locum in quem ex quo per quem extendebatur illa verticatio. Locus autem per quem ex quo extenditur illa verticatio est locus in quo est illa res visa. Ex comprehensione ergo partis visus in qua pervenit forma rei vise, et ex comprehensione verticationis per quam extendebatur forma et ex qua patitur visus a forma comprehendit virtus distinctiva verticationem per quam extendebatur forma rei vise secundum veritatem. Et secundum hunc modum distinguuntur loca visibilium, quoniam visibilia distincta non distinguuntur a visu nisi ex distinctione locorum in superficie distinctorum membri sentientis ad que perveniunt forme visibilium distinctorum.

3.97 ◉ It has also been shown that sight receives forms properly along radial lines and that it is affected by forms only along such lines.⁑ It has also been shown that the form extends through the body of the eye along straight, radial lines.⁑ Therefore, when the form of the visible object reaches the eye, the sensitive faculty will immediately sense the form, and it will sense the area on the eye where the form reaches, and it will sense the direction [of the radial line]⁑ along which the form will extend through the body of the sensitive organ. Therefore, when sight perceives the location of the form on the eye and also perceives the direction [of the radial line] along which the form has extended [to the eye], the faculty of discrimination will immediately perceive the location to which, from which, and along which that [radial] line has extended. But the location along which and from which that [radial] line extends is where the visible object is situated. Therefore, it is on the basis of the perception of the area on the eye where the form reaches, along with the perception of the direction [of the radial line] along which the form has extended and according to which sight is affected by the form, that the faculty of discrimination perceives the actual direction from which the form of the visible object has reached [the eye]. This is how the locations of visible objects are differentiated, for visible objects that are separated from one another are discerned by sight [as separated] only through a differentiation of the distinct places on the surface of the sensitive organ where the forms of the individual visible objects reach.⁑

3.98 ◉ Et comprehensio loci rei vise secundum hunc modum habet simile in auditu, quoniam sentiens comprehendit vocem per sensum auditus, et comprehendit locum a quo venit vox, et distinguit inter vocem venientem a dextra et vocem venientem a sinistra, et ab ante et retro. Immo distinguit etiam inter loca vocum distinctione subtiliori ista, et distinguit inter locum vocis venientis a loco sibi opposito faciliter et locum vocis venientis a loco obliquo a verticatione oppositionis. Et non distinguuntur a sentienti loca ex quibus veniunt voces respectu auditus nisi per verticationes super quas veniunt voces ad auditum. Sensus ergo auditus comprehendit voces, et comprehendit verticationes ex quibus veniunt voces, et ex comprehensione verticationum super quas veniunt voces ad auditum et super quarum rectitudinem percutit vox auditum comprehendit virtus distinctiva locum a quo venit vox. Sicut ergo loca vocum comprehenduntur a sensu auditus, deinde a virtute distinctiva mediante auditu, ita loca visibilium comprehenduntur a virtute distinctiva per sensum visus.

3.98 ◉ Perceiving the location of a visible object in this manner has a parallel in hearing, for the sensitive faculty perceives sound through the sense of hearing, and it also perceives the place from which the sound comes, so it differentiates between a sound coming from the right and a sound coming from the left, as well as [one coming] from in front and [one coming] from behind. Indeed, it differentiates the locations of sounds even more subtly than this, so it distinguishes the location of a sound reaching it from straight ahead more easily than it does the location of a sound reaching it from a location off to the side. But the places from which sounds originate are distinguished by the sensitive faculty by means exclusively of the direction from which the sounds come to the hearing. Thus, the sense of hearing perceives sounds, and it also perceives the direction from which the sounds come, and it is from perceiving the direction from which the sounds reach the hearing, that [direction] being according to the straight lines along which the sound strikes the hearing, that the faculty of discrimination perceives the location from which the sound comes. Consequently, just as the locations of sounds are perceived by the sense of hearing and subsequently by the faculty of discrimination through hearing, so are the locations of visible objects perceived by the faculty of discrimination through visual sensation.

3.99 ◉ Et ex illis ex quibus declaratur quod sentiens comprehendit verticationem secundum quam patitur visus a forma rei vise est illud quod comprehenditur in speculis secundum reflexionem, quoniam res visa quam quidem comprehendit visus secundum reflexionem non comprehenditur a visu nisi in oppositione et cum est opposita illi. Sed forma eius pervenit ad visum secundum linearum rectarum verticationes que sunt linee radiales extense a visu in partem oppositionis. Cum ergo visus senserit formam ex verticationibus linearum radialium, existimabit rem visam esse apud extremitates illarum linearum, quoniam nichil comprehendet ex visibilibus assuetis que semper comprehendit nisi apud extremitates linearum ymaginatarum inter visum et rem visam, que sunt linee radiales. Ex comprehensione ergo rei vise a visu secundum conversionem in visus oppositionem et secundum rectitudinem verticationum super quas forme reflexe perveniunt ad visum, videbitur quod sentiens sentit verticationem per quam venit forma et ex qua patitur visus a forma. Et cum sentiens sentit verticationem ex qua patitur a forma, comprehendit virtus distinctiva locum in quo extenditur illa verticatio, et comprehendet locum rei vise. Locus ergo rei vise comprehenditur a sentiente comprehensione larga ex comprehensione situs apud visionem, et comprehendetur a virtute distinctiva larga comprehensione ex comprehensione situs rei vise apud visionem, et comprehenditur vera comprehensione certificata ex comprehensione verticationis ex qua patitur visus a forma rei vise. Remotio autem rei vise est intentio que iam quievit in anima. Igitur apud perventum rei vise ad visum comprehendit virtus distinctiva locum rei vise cum quiete intentionis remotionis apud ipsam. Et adiunctio remotionis et loci est oppositio. Cum ergo virtus distinctiva comprehenderit locum rei vise et suam remotionem in simul, comprehendet eius oppositionem. Comprehensio ergo oppositionis est ex comprehensione loci rei vise et comprehensione remotionis rei vise in simul, et comprehensio loci erit secundum modum quem diximus. Cum ergo forma rei vise pervenerit in visum, sentiet sentiens locum membri sentientis in quem pervenit forma, et comprehendit virtus distinctiva locum rei vise ex verticatione per quam extenditur forma. Et intentio remotionis iam quieta est apud ipsam. Ipsa ergo comprehendit locum et remotionem in simul apud comprehensionem forme a sentienti. Igitur apud comprehensionem forme a sentienti comprehendet virtus distinctiva oppositionem. Secundum ergo hunc modum dictum erit comprehensio oppositionis.

3.99 ◉ Furthermore, among those things demonstrating that the sensitive faculty perceives the direction [of the radial line] along which sight is affected by the form of a visible object, what is perceived in mirrors according to reflection provides support, for the visible object that sight perceives through reflection can only be perceived by sight directly opposite, as if [the object were actually] facing it. And its form reaches the eye along the straight lines that constitute radial lines extended directly outward from the eye. Thus, since sight senses the form along radial lines, it will judge the visible object to lie at the endpoints of those lines, for it will perceive no familiar object that it regularly perceives except at the endpoints of the lines that are imagined [to extend] between the center of the eye and the visible object, and these are radial lines. Hence, from the fact that sight perceives the visible object, after reflection, as if it faced the eye directly along the straight [radial] lines according to which the reflected forms reach the eye [from the mirror], it will be apparent that the sensitive faculty senses the direction [of the radial line] along which the form arrives and along which sight is affected by the form. And when the sensitive faculty senses the direction from which it is affected by the form, the faculty of discrimination perceives the location from which that line extends, so it will perceive the location of the visible object. Thus, the location of a visible object is perceived grosso modo by the sensitive faculty from a perception of its spatial disposition at the moment it is seen, so it will be perceived grosso modo by the faculty of discrimination from a perception of the spatial disposition of the visible object at the moment it is seen, but it is correctly perceived and accurately determined on the basis of a perception of the direction from which sight is affected by the form of the visible object. However, the notion of the distance of the visible object has already become ensconced in the soul. Thus, as soon as the [form of] the visible object reaches the eye, the faculty of discrimination perceives the location of the visible object along with the ensconced notion of its distance. But the combination of distance and location yields opposition. Therefore, when the faculty of discrimination perceives the location and distance of the visible object together, it will perceive its opposition. Perception of opposition thus arises from a perception of the visible object’s location together with a perception of the visible object’s distance, and perception of location will be according to the manner we described. Therefore, when the form of the visible object reaches the eye, the sensitive faculty will sense the location on the sensitive organ where the form arrives, and the faculty of discrimination perceives the location of the visible object from the direction [of the radial line] along which the form extends. Moreover, the notion of distance is already established for it. So it perceives location and distance together at the time the form is perceived by the sensitive faculty. Therefore, as soon as the sensitive faculty perceives the form, the faculty of discrimination will perceive the [visible object’s] opposition. So the perception of opposition will occur in the way just described.

3.100 ◉ Et iam declaratum est quomodo visus comprehendit formam rei vise solo sensu. Apud ergo proventum forme rei vise in visu comprehendet sentiens colorem rei vise, et lucem eius, et locum visus qui colorabatur et illuminabatur ab illa forma. Et comprehendet virtus distinctiva locum eius, et remotionem apud comprehensionem lucis et coloris eius a sentiente. Et sic comprehenduntur lux et color, locus et remotio simul, scilicet in minimo tempore. Sed locus et remotio sunt oppositio, et lux et color sunt forma rei vise, et ex comprehensione forme cum comprehensione oppositionis sustentatur comprehensio rei vise in oppositione visus. Ergo comprehensio rei vise in oppositione visus non est nisi quia forma et oppositio comprehenduntur simul. Deinde propter frequentationem istius intentionis et multitudinem iterationis eius est facta forma signum sensui et virtuti distinctive. Apud ergo forme proventum in visu comprehenditur a sentiente, et comprehendit virtus distinctiva oppositionem, et efficitur ex hoc ab ipso sentiente quidem comprehensio rei vise in suo loco. Secundum ergo hunc modum erit comprehensio rei vise in suo loco, et similiter de qualibet partium rei vise.

3.100 ◉ Now it has already been shown how sight perceives the form of a visible object by brute sensation. Accordingly, when the form of the visible object reaches the eye, the sensitive faculty will perceive the color of the visible object, and its light, and the location on the eye that has been colored and illuminated by that form. Meanwhile, the faculty of discrimination will perceive both its location and its distance when its light and color are perceived by the sensitive faculty. Hence, light and color, as well as location and distance, are perceived at the same time, i.e., in minimal time. But location and distance yield opposition, and light and color yield the form of the visible object, so it is on the basis of the perception of the form along with the perception of opposition that the visible object is perceived to be in opposition to the eye. Thus, the perception that the visible object faces the eye results solely from the fact that the form and [the fact of] opposition are perceived together. Then, given the frequent recurrence of this perception, the form is transformed into a sign⁑ for the sense and for the faculty of discrimination. Thus, when the form reaches the eye, it is perceived by the sensitive faculty, and the faculty of discrimination perceives its opposition, and from this the sensitive faculty forms the perception of the visible object in its [true] location. In this way, therefore, the perception of the visible object in its [true] location will ensue, and the same holds for any of the parts of the visible object.

3.101 ◉ Cum ergo remotio rei vise fuerit ex remotionibus mediocribus certificate quantitatis, erit locus rei vise in quo comprehenditur a visu locus verus. Et si remotio rei vise non fuerit ex remotionibus certificate mensure, erit comprehensio rei vise in oppositione certificata secundum oppositiones, quoniam oppositio componitur ex ubi et remotione in eo quod remotio. Sed locus rei vise in quo comprehenditur a visu est estimatus, non certificatus, quoniam locus certificatus non comprehenditur nisi ex certificatione quantitatis remotionis.

3.101 ◉ When, therefore, the distance of the visible object is moderate and is accurately determined in magnitude, the location where the visible object is perceived by sight will be the true location.⁑ And [even] if the distance of the visible object is not accurately determined in magnitude, the perception of the visible object’s being in opposition will be accurately determined, because opposition, as such, consists of place and distance, in the generic sense. But the location where the visible object is perceived by sight is estimated, not precisely determined, because a determinate location is perceived on the basis, solely, of an accurate determination of the magnitude of the distance.

3.102 ◉ Situs vero superficierum visibilium apud visum dividuntur in duo: scilicet in directam oppositionem et obliquationem. Superficies autem directa opposita visui est illa que, quando comprehenditur a visu apud rectam oppositionem, occurret axis radialis alicui puncto ex ea, et cum hoc erit axis elevata super superficiem elevatione equali. Et superficies obliquata est illa que, quando comprehenditur a visu apud obliquationem et occurrerit axis radialis alicui puncto ex ea, erit obliquata super superficiem non elevata super ipsam elevatione equali secundum omnes diversitates modorum obliquationis.

3.102 ◉ Now the spatial disposition of the surfaces of visible objects vis-à-vis the eye is subdivided into two: directly facing and obliquely facing. A surface [is said] to face the eye directly when it is perceived by sight straight ahead and when the visual axis touches some point on it so as to form equal [i.e., right] angles with it. A surface [is said] to face the eye obliquely when it is perceived by sight at a slant and when the visual axis touches every point on it at an inclination so as to form unequal angles with it, striking that surface everywhere at different inclinations.

3.103 ◉ Termini vero superficierum visibilium, et linee que sunt in rebus, et spatia que sunt inter visibilia et inter partes visibilium dividuntur in duo quorum alterum est linee et spatia secantia lineas radiales et alterum est linee et spatia equidistantia lineis radialibus respicientia ipsas. Et linee et spatia secantia lineas radiales dividuntur secundum situm in duo, in obliquationem et directionem secundum divisionem situum et superficierum in ista duo. Linea autem directa est illa ad cuius aliquod punctum perveniet axis radialis, et erit perpendicularis super ipsam, et linea obliquata est illa que, quando axis radialis venerit ad aliquod punctum eius, erit obliquatus super ipsum, non perpendicularis.

3.103 ◉ Now the boundaries of the surfaces of visible objects, as well as the lines in objects and the gaps between visible objects and between the parts of visible objects fall into two categories: first, lines and gaps⁑ intersecting the radial lines, and second, lines and gaps parallel to the radial lines they correspond to. As far as spatial disposition is concerned, lines and gaps that intersect the radial lines are subdivided into oblique and directly facing according to the twofold division of spatial dispositions and surfaces. A directly facing line is one to which the visual axis will fall orthogonally at some point, whereas an oblique line is one to which the visual axis, will [invariably] fall obliquely rather than orthogonally, no matter where it is dropped.

3.104 ◉ Visus autem comprehendit obliquationem superficierum et linearum, et directionem earum, ex comprehensione diversitatis remotionum extremitatum superficierum et linearum et equalitatis earum. Quoniam quando visus comprehenderit superficiem rei vise, et comprehenderit remotiones extremitatum eius, et senserit equalitatem remotionum terminorum superficiei ab eo, aut equalitatem remotionum duorum locorum oppositorum equalis remotionis a loco superficiei ad quam intuetur quis, comprehendet superficiem esse directe oppositam, et iudicabit virtus distinctiva quod sit directa. Et cum visus comprehenderit superficiem rei vise, et comprehenderit remotionum extremitatum eius diversitatem, et non invenerit in superficie duo loca equalis remotionis a loco superficiei ad quam intuetur quorum remotio ab eo fuerit equalis, comprehendet superficiem obliquatam in respectu eius, et iudicabit virtus distinctiva quod sit obliquata.

3.104 ◉ Now sight perceives the fact that surfaces and lines are oblique, or that they are directly facing, by perceiving difference or equality among the distances of the extremities of the surfaces or lines [from the center of sight⁑]. For when it perceives the surface of a visible object and perceives the distances of its edges, if it senses the equality of the distances of the edges of the surface from the center of sight, or if it senses the equality of the distances [from the center of sight] of two locations lying equidistant from the spot on the surface where the viewer is directing his focus, sight will perceive that the surface is directly facing, and the faculty of discrimination will judge it to be directly facing. On the other hand, when it perceives the surface of the visible object, but perceives that the distances of its extremities [from the center of sight] are different and does not find two locations on that surface that are the same distance [from the center of sight] and equidistant from the spot on the surface to which the viewer directs his focus, sight will perceive that the surface is oblique with respect to itself, and the faculty of discrimination will judge it to be oblique.⁑

3.105 ◉ Et similiter de sitibus linearum et spatiorum directorum et obliquatorum; scilicet quod visus comprehendit directionem linee et spatii quando senserit quod due remotiones duarum extremitatum linee aut spatii ab eo sunt equales, aut quod due remotiones duorum punctorum linee aut spatii quorum remotio a puncto ad quem intuetur quis (puncto scilicet linee aut spatii) est equalis ab eo sunt equales. Et comprehendit obliquationem linee aut spatii quando senserit quod due remotiones duarum extremitatum linee aut spatii ab eo, aut quod due remotiones duorum punctorum equalis remotionis a puncto ad quem intuetur quis linee aut spatii sunt diverse. Et ista equalitas et diversitas multotiens comprehenduntur a sentiente per estimationem et per signa. Secundum ergo hunc modum erit obliquationis comprehensio et directionis a visu.

3.105 ◉ And the same holds for the spatial dispositions of lines and gaps that are directly facing or oblique; when it perceives that the distances of the two endpoints of the line or gap [from the center of sight] are equal, or when it perceives that two points on the line or surface that are equidistant from the point to which the viewer directs his focus (a point, that is, on the line or gap) are also equidistant from the center of sight, sight perceives that the line or gap is directly facing. On the other hand, sight perceives the line or gap as oblique when it senses that the distances of the two endpoints of the line or gap from the center of sight are different, or when it senses that the distances [from the center of sight] of the two points equidistant from the point to which the viewer is directing his focus are different. And this equality or difference is often perceived by the sensitive faculty by means of estimation and signs. It is therefore in this way that oblique and directly facing [dispositions] will be perceived by sight.

3.106 ◉ Et cum superficies tota aut linea tota fuerit directa visui, non erit quelibet pars eius per se directe opposita visui. Immo nulla pars eius est directe opposita visui per se nisi pars supra quam est axis apud directam oppositionem. Cum ergo movetur axis radialis super superficiem directam aut super lineam directam, quelibet pars per quam transit axis erit axis obliquatus super ipsam preter primam partem in qua est punctus super quem fuit axis perpendicularis. Et sic erit quelibet pars superficiei directe opposite et linee directe opposite quando fuerit sumpta per se obliquata preter partem predictam. Et quando accipietur tota superficies aut tota linea, erit tota directa. Et cum punctus apud quem erit axis perpendicularis super superficiem aut lineam fuerit in medio superficiei aut linee, erit superficies aut linea in fine directe oppositionis visui. Si autem punctus non fuerit in medio, erit superficies aut linea directa, sed non in fine directionis; et quanto magis punctus ad quem axis fuerit perpendicularis super superficiem aut lineam fuerit medio superficiei propinquior aut linee, tanto magis erit superficies aut linea maioris directe oppositionis.

3.106 ◉ Moreover, if the entire surface or entire line faces the eye directly, then no part of it will face the eye directly on its own. Or, rather, no part of it faces the eye directly on its own except for the part directly opposite the [visual] axis. Therefore, when the visual axis scans a surface or line that faces [the eye] directly, the axis will fall obliquely to any part, other than the original point to which the visual axis fell orthogonally. Hence, aside from the aforementioned part, any part on a surface or line that faces [the eye] directly will be oblique, when taken by itself. Yet when the surface or line is taken as a whole, it will be directly facing as a whole. Furthermore, when the point on the surface or line to which the [visual] axis will be perpendicular is the midpoint of that surface or line, the surface or line will be [in a] perfectly facing [disposition] vis-à-vis the eye. On the other hand, if that point is not the midpoint, then the surface or line will be [in a] directly facing [disposition], but not a perfectly facing one; and the closer the point on the surface or line to which the [visual] axis falls orthogonally is to the midpoint of the surface or line, the closer that surface or line will be to a perfectly facing disposition.

3.107 ◉ Situs autem linearum et spatiorum equidistantium radialibus lineis comprehenduntur a visu ex comprehensione oppositionis. Quoniam quando visus comprehenderit extremitates linearum aut spatiorum que sequuntur et vicinantur visibilia opposita illi et extremitates eorum propinquas que sequuntur eundem visum, comprehendet situs eorum, et comprehendet extensionem eorum in verticatione oppositionis.

3.107 ◉ Now the spatial dispositions of lines and gaps that are parallel to the radial lines are perceived by sight on the basis of the perception of opposition. For when sight perceives the endpoints of the lines or gaps that are right next to or near visible objects that face it with their own near extremities right next to the eye, it will perceive their spatial disposition, and it will perceive their extension in the line of opposition.⁑

3.108 ◉ Secundum ergo istos modos erit comprehensio situum superficierum linearum et spatiorum a visu respectu illius.

3.108 ◉ It is therefore in these ways that the perception of the spatial dispositions of surfaces, lines, and gaps with respect to the eye will occur to sight.

3.109 ◉ Quedam autem superficies, et linee, et spatia secantia lineas radiales sunt valde magne obliquationis super radiales lineas, et quedam sunt modice, et quedam sunt perpendiculares super lineas radiales, et sunt superficies et linee et spatia directe opposita visui. Extremitas autem remotior cuiuslibet superficierum et linearum et spatiorum maxime obliquationis super lineas radiales sequitur partem remotam a visu, scilicet partem sequentem extremitates linearum radialium. Et extremitas propinquior sequitur partem propinquam visui, scilicet partem sequentem visum. Et quando visus comprehenderit aliquam lineam vel aliquod spatium, statim comprehendet duo ubi sequentia extremitates illius linee aut illius spatii. Et similiter, quando visus comprehenderit aliquam superficiem, comprehendet ubitates sequentes extremitates illius superficiei ex comprehensione extensionis illius superficiei in longitudine et latitudine. Cum ergo visus comprehenderit superficiem obliquam super lineas radiales, et fuerit illa superficies maxime declinationis, comprehendet ubitatem visus sequentem extremitatem remotiorem apud comprehensionem superficiei, et comprehendet ipsam esse sequentem extremitates linearum radialium, et comprehendet ubitatem sequentem extremitatem propinquiorem, et comprehendet ipsam esse sequentem illud quod est prope visum; et similiter de linea et spatio maxime obliquationis. Et cum visus perceperit quod una duarum extremitatum superficiei, aut linee, aut spatii sequitur ubitatem remotam a visu, et quod altera extremitas sequitur ubitatem propinquam visui, statim percipiet remotionem unius duarum extremitatum illius superficiei, aut linee, aut spatii, et appropinquationem alterius. Et cum perceperit remotionem unius duarum extremitatum, aut linee, aut spatii, aut superficiei, et appropinquationem alterius, statim percipiet obliquationem situs illius superficiei, aut linee aut spatii. Obliquatio ergo superficierum, et linearum, et spatiorum obliquatorum super lineas radiales extranee obliquationis comprehenditur a visu ex comprehensione duarum ubitatum extremitatum eorum.

3.109 ◉ Now some surfaces, lines, and gaps that intersect radial lines are extremely oblique with respect to those radial lines, some are slightly oblique, and some are perpendicular to the radial lines, these latter surfaces, lines, and gaps facing the eye directly. Moreover, for surfaces, lines, and gaps that are extremely oblique with respect to the radial lines, the farther extremity of any of them lies away from the eye, i.e., at the [farther] extremities of the radial lines. The nearer extremity, for its part, lies toward the eye, i.e., near the center of sight. So when sight perceives any line or any gap, it will immediately perceive the two places occupied by the endpoints of that line or that gap. Similarly, when sight perceives any surface, it will perceive where the edges of that surface are by perceiving the extension of that surface according to length and breadth. Thus, when it perceives a surface that is not only oblique, but extremely oblique to the radial lines, sight will perceive where the farther edge is when it perceives the surface, and it will perceive that it lies at the [farther] extremities of the radial lines; it will also perceive where the nearer edge is, and it will perceive that it lies near the center of sight; and the same holds for a line or gap that is extremely oblique. Furthermore, when sight perceives that one of the two extremities of the surface, line, or gap lies away from the eye, and when it also perceives that the other extremity lies toward the eye, it will immediately perceive the remoteness of one of the extremities of that surface, line, or gap and the nearness of the other. Moreover, when it perceives the remoteness of one of the two extremities of the line, gap, or surface and the nearness of the other, it will immediately perceive the oblique disposition of that surface, line, or gap. Therefore, in the case of surfaces, lines, and gaps that are exceedingly oblique with respect to the radial lines, sight perceives their obliquity by perceiving where their two extremities are.

3.110 ◉ Declinatio autem et directa oppositio linearum, et superficierum, et spatiorum modice obliquationis et directorum visui non comprehenduntur a visu vera comprehensione certificata nisi remotio eorum sit mediocris et respiciens corpora ordinata comprehensa a visu. Et comprehenderit ex mensuris eorum corporum mensuras remotionum extremitatum illarum superficierum, et linearum, et spatiorum, et comprehenderit equalitatem duarum remotionum duarum extremitatum superficiei, aut linee, aut spatii aut inequalitatem earum. Quoniam nulla ubitatum sequentium extremitates superficierum, et linearum, et spatiorum directe oppositorum aut declinantium modica declinatione est sequens visum; sed extremitates eorum opposite sequuntur ubitates dextras et sinistras, aut superiores, aut inferiores. Si ergo visus non comprehenderit mensuras remotionum illius quod est huiusmodi a visu, non comprehendet diversitatem et inequalitatem remotionum extremitatum eorum oppositorum aut equalitatem eorum. Et cum hoc non comprehenderit, non comprehendet obliquationem eorum nec directionem. Cum ergo superficies, et linee, et spatia fuerint maxime remotionis, et fuerit obliquatio eorum modica, non poterit visus comprehendere eorum obliquationem, nec poterit distinguere inter obliquum et rectum, quoniam quantitates remotionum superficierum, et linearum, et spatiorum quorum remotio est maxima non certificantur a visu, sed existimantur. Et quando remotio eorum fuerit magna, et fuerit cum hoc obliquationis modice, erit differentia que est inter remotiones extremitatum eorum oppositorum valde modica, fere carens quantitate respectu quantitatum remotionum eorum. Et cum visus non certificaverit quantitates remotionum extremitatum eorum, non comprehendet diversitatem que est inter remotionem extremitatum eorum. Et cum non comprehenderit diversitatem que est inter remotiones extremitatum superficiei, et linee, et spatii, existimabit remotiones illas esse equales, et non comprehendet obliquationem illius superficiei, aut linee, aut spatii. Et cum non comprehenderit obliquationem illius superficiei, aut linee, aut spatii, existimabit ipsum esse directum. Et obliquatio superficierum, et linearum, et spatiorum quorum remotio est maxima non comprehendetur a visu quando fuerit modica. Visus ergo comprehendit omnes superficies, et lineas, et spatia que sunt maxime remotionis et minime obliquationis quasi directe oppositas, et non certificat situs eorum nec distinguit inter obliquum et directe oppositum, sed comprehendit obliquum et directum secundum unum modum.

3.110 ◉ Neither the slant of slightly inclined surfaces, lines, or gaps, nor the directly facing [disposition] of surfaces, lines, or gaps that face the eye directly is correctly perceived or accurately determined by sight unless they lie at a moderate distance spanned by an ordered range of bodies that are perceived by sight. From the measures of these bodies it perceives the measures of the distances of the extremities of those surfaces, lines, and gaps, and it [thereby] perceives the equality or inequality of the distances of the two extremities of the surface, line, or gap. For none of the places occupied by the extremities of surfaces, lines, or gaps that face [the eye] directly or that are slightly inclined [to it] lie toward the center of sight [in any discernible way]; instead, their opposite extremities occupy places that are [perceived according to] right and left, or up and down. Therefore, since sight does not perceive the measures of the [appropriate] distances for objects disposed toward the eye in this manner, it will not perceive the difference or inequality, or the equality of the distances of their opposite extremities. And since it does not perceive this, it will perceive neither their obliquity nor their directly facing [disposition]. Thus, if the surfaces, lines, or gaps lie exceedingly far away, and if their obliquity is slight, sight will not be able to perceive their obliquity, nor will it be able to differentiate between oblique and directly facing [dispositions], for the magnitudes of the distances of surfaces, lines, and gaps that lie exceedingly far away are estimated rather than accurately determined by sight. Furthermore, when they lie extremely far away, and when their obliquity is slight, the difference between the distances of their opposite extremities will be [so] tiny [as to] dwindle to nothing compared to the [overall] distances of the extremities [from the eye]. And since sight cannot accurately determine the magnitude of the distances of their extremities, it will not perceive the difference in the distances of their surfaces, lines, or gaps [from the center of sight]. And since it cannot perceive the difference in the distances of the extremities of the surface, line, or gap, it will judge those distances to be the same, and it will not perceive the obliquity of that surface, line, or gap. And since it cannot perceive the obliquity of that surface, line, or gap, it will judge it to face [the eye] directly. So the obliquity of surfaces, lines, or gaps that lie extremely far away will not be perceived by sight when it is slight. Therefore, sight perceives all surfaces, lines, or gaps that lie extremely far away and that are barely inclined as if they were directly facing, so it neither determines their spatial disposition accurately nor differentiates between oblique and directly facing [dispositions] but, rather, perceives oblique and directly facing [dispositions] in the same way.

3.111 ◉ Et similiter situs superficierum et linearum et spatiorum quorum remotio est mediocris, quando non fuerit respiciens corpora ordinata, aut visus non comprehenderit corpora respicientia remotiones eorum, et non certificaverit quantitates remotionum eorum, tunc situs, scilicet, non certificatur a visu. Nec distinguit visus inter obliquum eorum et directum, sed accipit situm eorum estimatione, et fortasse existimabit illud quod est huiusmodi esse directum, quamvis sit obliquum. Et cum superficies, et linee, et spatia fuerint in remotione mediocri, et remotiones eorum fuerint respicientes corpora ordinata, et comprehenderit visus illa corpora et quantitates eorum, comprehendet quantitates remotionum extremitatum illarum superficierum, et linearum, et spatiorum. Et comprehendet equalitatem remotionum extremitatum eorum oppositorum, si fuerint extremitates ille equales, et inequalitatem eorum, si fuerint inequales. Et cum comprehenderit equalitatem remotionum extremitatum superficiei, aut linee, aut spatii, aut inequalitatem eorum, comprehendet directionem illius superficiei, aut linee, aut spatii, aut eorum obliquationem certificata comprehensione.

3.111 ◉ Likewise, when the distance of surfaces, lines, or gaps is moderate but is not spanned by a range of ordered bodies, or if sight does not perceive the bodies spanning their distances or does not determine the magnitudes of their distances accurately, then the spatial disposition of those surfaces, lines, or gaps is not accurately determined by sight. So sight does not discern whether they are oblique or directly facing but determines their spatial disposition through estimation, and sight may well judge something of this sort to be directly facing when, in fact, it is oblique. On the other hand, if the surfaces, lines, or gaps lie at a moderate distance that is spanned by an ordered range of bodies, and if sight perceives those bodies and their magnitudes, it will perceive the magnitudes of the distances of the extremities of those surfaces, lines, or gaps [from the center of sight]. It will also perceive the equality of the distances of their opposite extremities [from the center of sight], if those extremities are equidistant [from the center of sight], or their inequality, if they are not equidistant [from the center of sight]. And when it perceives the equality of the distances of the extremities of the surface, line, or gap [from the center of sight], or when it perceives their inequality, it will perceive the directly facing [disposition] or the obliquity of that surface, line, or gap with accuracy.

3.112 ◉ Et similiter obliquatio linearum, aut superficierum, aut spatiorum que sunt maxime obliquationis non comprehenditur a visu nisi sint in remotione mediocri respectu magnitudinis eorum. Nam visus non comprehendit ubitates sequentes extremitates superficiei, aut linee, aut spatii nisi quando comprehenderit qualitatem extensionis illius superficiei, aut linee, aut spatii. Sed visus non comprehendit qualitatem extensionis superficiei, aut linee, aut spatii nisi quando fuerit in remotione mediocri respectu quantitatis illius superficiei, aut linee, aut spatii. Declinatio ergo superficiei, aut linee, aut spatii secantium lineas radiales, quando fuerit maxima, comprehendetur a visu ex comprehensione ubitatum extremitatum eius. Et si fuerit modice obliquationis aut directe oppositionis, comprehendetur a visu esse obliquum aut esse directum ex comprehensione quantitatum remotionum extremitatum eorum oppositorum. Et visus non certificat qualitatem situum superficierum, et linearum, et spatiorum que sunt maxime obliquationis nisi quando certificaverit qualitatem extensionis eorum, et non certificat situm superficierum, et linearum, et spatiorum que sunt modice obliquationis aut directe oppositorum nisi quando certificaverit quantitates remotionum extremitatum eorum, et comprehenderit inequalitatem remotionum extremitatum eorum oppositorum aut equalitatem earum. Sed visus raro certificat situs visibilium. Et plura que comprehendit visus ex sitibus visibilium non comprehendit nisi per estimationem. Sustenatio ergo visus in comprehensione situum visibilium non est nisi secundum estimationem. Cum ergo aspiciens aspexerit et voluerit certificare situm alicuius superficiei, aut situm alicuius linearum que sunt in visibilibus, aut situm alicuius spatiorum que sunt in superficiebus visibilium, intuebitur formam illius rei vise et qualitatem extensionis illius superficiei, aut linee, aut spatii. Si ergo forma illius rei vise in qua est illa superficies, aut linea, aut spatium fuerit manifesta certificata, et fuerit obliquatio illius superficiei, aut linee, aut spatii maxima, comprehendet visus obliquationem eius vere ex comprehensione qualitatis extensionis eius et ex comprehensione duarum ubitatum extremitatum eius oppositorum. Et si forma illius rei vise fuerit manifesta, et non fuerit maxime obliquationis, et remotio eius fuerit respiciens corpora ordinata, videbit corpora respicientia remotiones extremitatum eius, et considerabit quantitatem eorum, et comprehendet remotionem illius superficiei, aut linee, aut spatii et quantitatem obliquationis eius aut directionem eius ex comprehensione quantitatum remotionum extremitatum eius.

3.112 ◉ In the same vein, the obliquity of lines, surfaces, or gaps that are exceedingly oblique are perceived by sight only when their distance is moderate in comparison to their size. For sight does not perceive where the extremities of the surface, line, or gap are unless it perceives how that surface, line, or gap extends. But sight does not perceive how the surface, line, or gap extends unless it lies at a moderate distance in comparison to the size of that surface, line, or gap. Thus, the slant of a surface, line, or gap that cuts the radial lines at an extreme angle will be perceived by sight according to a perception of where its extremities are. And if the slant is slight, or if the [surface, line, or gap] faces [the eye] directly, it will be perceived by sight as oblique or directly facing on the basis of the perception of the magnitudes of the distances of its opposite extremities [from the center of sight]. But sight does not accurately determine the spatial disposition of extremely oblique surfaces, lines, or gaps unless it accurately determines how they are extended, and it does not accurately determine the spatial disposition of surfaces, lines, or gaps that are slightly oblique or directly facing unless it accurately determines the magnitudes of the distances of their extremities and perceives the inequality or equality of the distances of their opposite extremities [from the center of sight]. But sight rarely determines the spatial disposition of visible objects with accuracy. The majority of spatial dispositions that sight perceives among visible objects are perceived by sight only through estimation. Hence, estimation provides the only basis for visual perception of the spatial dispositions of visible objects. Accordingly, when a viewer wishes to determine accurately the spatial disposition of some surface, or of one of the lines on visible objects, or of one of the gaps on the surfaces of visible objects, he will inspect the form of that visible object and examine how its surface, or the line [on its surface], or the gap [on its surface] extends. Hence, if the form of that visible object on which that surface, line, or gap lies is accurately determined, and if the slant of that surface, line, or gap is extreme, sight will perceive its obliquity correctly by perceiving how it extends and by perceiving where its two opposite extremities are. Moreover, if the form of that visible object is clear[ly perceived], if its obliquity is not extreme, and if its distance is spanned by an ordered range of bodies, sight will see the bodies spanning the distances of its extremities and will scrutinize their magnitudes, and then, on the basis of the perception of the magnitudes of the distances of its extremities [from the center of sight], it will perceive the distance of that surface, line, or gap, as well as the degree of its obliquity or the fact that it faces [the eye] directly.

3.113 ◉ Et si forma rei vise non fuerit manifesta, aut fuerit manifesta sed obliquatio non fuerit maxima, et remotio non fuerit respiciens corpora ordinata, non comprehendet visus certitudinem situs huiusmodi superficiei, aut linee, aut spatii. Et cum hoc, quando visus comprehenderit formam non manifestam, et non invenerit remotiones eius esse respicientes corpora ordinata, statim percipiet quod situs illius superficiei, aut linee, aut spatii non certificatur.

3.113 ◉ If, however, the form of the visible object is not clear[ly perceived], or if it is clear[ly perceived] and its obliquity is not extreme, but its distance is not spanned by an ordered range of bodies, sight will not accurately perceive the spatial disposition of a surface, line, or gap of this kind. In addition, when sight does not perceive a form clearly and does not find its distance spanned by an ordered range of bodies, it will immediately perceive that the spatial disposition of that surface, line, or space is not accurately determined.

3.114 ◉ Secundum ergo istos modos comprehendit visus situs superficierum visibilium et situs linearum et spatiorum que sunt in superficiebus visibilium, scilicet que omnes sunt secantes lineas radiales.

3.114 ◉ It is therefore in these ways that sight perceives the spatial disposition of the surfaces of visible objects, or the spatial disposition of lines or gaps in the surfaces of visible objects, assuming that they all intersect the radial lines.

3.115 ◉ Quod vero est ex spatiis que sunt inter visibilia distincta in rebus remotioribus maximis—scilicet quando fuerit remotio utriusque visibilium que sunt apud duas extremitates spatii remotio maxima—comprehendetur ergo a visu tunc quasi directe oppositum, quamvis sit obliquum, quoniam non comprehendit diversitatem que est inter remotiones extremitatum eius. Et si alterum duorum visibilium que sunt apud extremitates duas spatii fuerit propinquius altero, et senserit visus appropinquationem eius, comprehendit spatium quod est inter ea esse obliquum secundum quod comprehendit ex appropinquatione propinquioris illorum duorum visibilium et ex remotione remotioris illorum. Et si alterum duorum visibilium fuerit propinquius, sed non visus comprehenderit appropinquationem eius, non sentiet obliquationem spatii quod est inter ea. Situs ergo superficierum, et linearum, et spatiorum secantium lineas radiales non certificatur a visu nisi sit remotio eorum mediocris, et cum hoc certificat visus equalitatem aut inequalitatem remotionum extremitatum eorum. Si autem visus non certificaverit equalitatem remotionis extremitatum eorum, aut inequalitatem, non poterit certificare situm illorum.

3.115 ◉ When the gap between two disjoined visible objects is extremely far away—i.e., when each of the visible objects at the extremities of the gap lies an inordinate distance [from the center of sight]—that gap will then be perceived by sight as directly facing, even if it is oblique, because it does not perceive the difference in distance [from the center of sight] of [the visible objects forming] its extremities. Yet if one of the two visible objects forming the two extremities of the gap is nearer than the other, and if sight perceives the fact that it is nearer, it perceives the gap between them as oblique insofar as it perceives the nearness of the nearer of the two visible objects and the remoteness of the farther of the two. On the other hand, if one of the two visible objects is nearer, but sight does not perceive its nearness, then it will not sense the obliquity of the gap between them. Thus, the spatial disposition of surfaces, lines, and gaps that intersect the radial lines is not accurately determined by sight unless they lie at a moderate distance and, in addition, unless sight accurately determines the inequality or equality of the distances of their extremities [from the center of sight]. If sight does not accurately determine the equality or inequality of the distance of their extremities [from the center of sight], though, it will be unable to determine their spatial disposition accurately.

3.116 ◉ Et plura illorum que comprehenduntur a visu ex sitibus visibilium non comprehenduntur nisi per estimationem. Si ergo fuerint in remotione mediocri, non erit magna diversitas inter situm comprehensum a visu per estimationem et verum situm, et si fuerint in remotione maxima, non distinguet inter obliquum et directum. Quoniam visus, quando non comprehenderit inequalitatem duarum remotionum duarum extremitatum rei vise, comprehendet ipsas esse equales, et sic iudicabit ipsam rem visam esse directam.

3.116 ◉ Furthermore, the majority of the spatial dispositions of visible objects that are perceived by sight are perceived only through estimation. Therefore, if they lie at a moderate distance, there will not be much discrepancy between the spatial disposition perceived by sight through estimation and the true spatial disposition, whereas if they lie extremely far away, sight will not differentiate between oblique and directly facing [disposition]. For, if sight does not perceive the inequality of the distances of the two extremities of the visible object [from the center of sight], it will perceive them to be equal, and so it will judge the visible object itself to be directly facing.

3.117 ◉ Secundum ergo istos modos erit comprehensio situum superficierum, et linearum, et spatiorum per sensum visus.

3.117 ◉ It is therefore in these ways that the sense of sight will perceive the spatial dispositions of surfaces, lines, and gaps.

3.118 ◉ Situs vero partium rei vise adinvicem, et situs terminorum superficiei rei vise aut superficierum eius adinvicem, et situs visibilium distinctorum adinvicem (que collocantur sub ordinatione) comprehenduntur a visu ex comprehensione locorum visus ad que perveniunt forme partium et ex comprehensione ordinationis partium forme que perveniunt ad visum a virtute distinctiva. Quoniam forma cuiuslibet partium superficiei rei vise pervenit in aliquam partem partis superficiei membri sentientis in quam pervenit forma totius. Et cum superficies rei vise fuerit diversorum colorum, et fuerint inter partes eius differentie per quas distinguuntur partes adinvicem, erit forma perveniens in visum diversorum colorum, et erunt partes eius distincte secundum distinctionem partium superficiei rei vise. Et sentiens sentit formam, et sentit quamlibet partium forme ex sensu colorum illarum partium et lucis que est in eis, et sentit loca formarum partium in visu ex sensu colorum partium illarum et lucis illarum, et virtus distinctiva comprehendit ordinationem illorum locorum ex comprehensione diversitatis colorum partium forme et ex comprehensione differentiarum partium. Et sic comprehendit dextrum et sinistrum, superius et inferius ex comparatione illorum adinvicem, et comprehendit contiguum et separatum.

3.118 ◉ The spatial disposition of the parts of the visible object with respect to one another, the spatial disposition of the edges of the surface or surfaces of the visible object with respect to one another, and the spatial disposition of separate visible objects with respect to one another (all of these cases falling under the head of arrangement) are perceived by sight through the perception of the locations on the eye to which the forms of the parts extend and through the perception by the faculty of discrimination of the arrangement of the parts of the form that extend to the eye. For the form of each of the parts of the surface of the visible object reaches a particular spot on the area of the surface of the sensitive organ to which the form of the whole object extends. And if the surface of the visible object is of various colors, and if there are differences among the parts of the visible object according to which those parts are differentiated from one another, the form reaching the eye will consist of different colors, and its parts will be differentiated according to the way the parts of the visible object’s surface are differentiated. So the sensitive faculty senses the form while sensing each of the parts of the form by means of a sensation of the colors of those parts, as well as of the light in them, and it senses the locations of the forms of the parts in the eye by sensing the colors and light of those parts, and the faculty of discrimination perceives the arrangement of those locations by perceiving the difference among the colors of the parts of the form and by perceiving the distinctions among the parts. And so it perceives right and left, as well as above or below, by comparing those parts to one another, and it also perceives contiguity and separation.

3.119 ◉ Situs vero partium rei vise adinvicem secundum accessionem et remotionem—scilicet secundum prominentiam et fundationem—comprehenduntur a visu ex comprehensione quantitatis remotionum partium ab eo et comprehensione diversitatis remotionum partium secundum magis et minus. Situs vero partium rei vise, quando fuerit in remotione mediocri, adinvicem secundum accessionem et remotionem comprehenduntur a visu, et hoc cum comprehenderit visus quantitatem illius remotionis, et comprehenderit quantitates remotionum partium eius, et comprehenderit inequalitatem que est inter remotiones partium ab eo et equalitatem. Si autem visus non certificaverit quantitates remotionis eius et quantitatem remotionum partium eius, non comprehendet visus ordinationem partium eius secundum accessionem et remotionem apud visionem. Si autem fuerit ex visibilibus assuetis que cognoscuntur a visu, comprehendet ordinationem partium eius secundum preminentiam et profundationem, et figuram superficiei eius per cognitionem, non sola visione. Et si fuerit ex visibilibus extraneis que visus non cognoscit, comprehendet superficiem eius quasi planam quando non certificaverit quantitates remotionum partium eius. Et ista intentio apparet quando visus aspexerit aliquod corpus convexum aut concavum et fuerit in remotione maxima, quoniam tunc visus non comprehendet concavitatem aut convexitatem, sed comprehendet ipsum quasi planum.

3.119 ◉ Now, along the line-of-sight—i.e., according to outward or inward projection [vis-à-vis the center of sight]—the relative spatial dispositions of the parts of a visible object are perceived by sight through perception of the magnitude of the distances of the parts from the center of sight and through perception of the difference among the distances of the parts [from the center of sight] according to relative extent. Indeed, when the visible object lies at a moderate distance, the relative spatial dispositions of its parts along the line-of-sight are perceived by sight, but only if it perceives the magnitude of the visible object’s [overall] distance [from the center of sight] while perceiving the magnitudes of the distances of its parts [from the center of sight] and while perceiving the inequality or equality among the distances of the parts from the center of sight. However, if sight does not accurately determine the magnitudes of its distance and the magnitude of the distances of its parts [from the center of sight], it will not perceive the arrangement of its parts along the line-of-sight. On the other hand, if the visible object is one of those that are routinely perceived by sight, it will perceive the arrangement of its parts, as well as the shape of its surface, according to outward or inward projection, but [it will do so] through recognition rather than through vision per se. If the visible object is among unfamiliar objects that sight does not recognize, though, it will perceive its surface as flat when it cannot accurately determine the magnitudes of the distances of its parts [from the center of sight]. And this perception arises when sight looks at any convex or concave body that lies extremely far away, for in that case sight will not perceive its concavity or convexity but will perceive the object as flat.⁑

3.120 ◉ Et situs partium superficiei rei vise adinvicem in diversitate ubitatum et in separatione et in continuatione non comprehenduntur a visu nisi ex comprehensione partium forme pervenientium in visu, et ex comprehensione diversitatum colorum et differentiarum per que distinguuntur partes, et ex comprehensione ordinationis partium forme a virtute distinctiva. Et situs partium rei vise superficiei adinvicem in accessione, et etiam secundum remotionem respectu visus, non comprehenduntur a visu nisi ex comprehensione quantitatis remotionis partium et ex comprehensione inequalitatis et equalitatis quantitatum remotionum eorum. Ordinatio ergo partium secundum accessionem et remotionem illius cuius quantitates remotionum partium certificantur a visu comprehenditur a visu. Ordinatio autem partium illius remotionum partium cuius quantitates non certificantur a visu non comprehenduntur a visu. Ordinatio autem partium rei vise distinctarum comprehenditur a visu ex comprehensione locorum visus in que perveniunt forme illarum partium et ex comprehensione distinctionis in visu a virtute distinctiva; et similiter de visibilibus distinctis. Termini autem superficiei rei vise aut superficierum eius et ordinatio eorum comprehenduntur a visu ex comprehensione partis superficiei eius in quam pervenit color illius superficiei et lux eius a visu et ex comprehensione terminorum illius partis et ordinationis circumferentie illius partis a virtute distinctiva. Secundum ergo istos modos comprehendit visus situs partium visibilium, et situs partium superficierum visibilium adinvicem, et situs terminorum superficierum, et situs partium distinctarum visibilium adinvicem, et situs visibilium distinctorum adinvicem.

3.120 ◉ As far as differences in location, discontinuity, and continuity are concerned, the relative spatial disposition of the parts of a visible object’s surface are not perceived by sight except through a perception of the parts of the form that reach the eye, as well as through a perception of the various colors and differences that distinguish the parts from one another and a perception of the arrangement of the parts of the form by the faculty of discrimination. Neither the relative spatial dispositions nor the relative distances from the eye of the parts of the visible object’s surface are perceived by sight along the line-of-sight except through a perception of the magnitude of the distance of the parts and through a perception of the inequality or equality of the magnitudes of their distances. Therefore, the arrangement of the parts along the line-of-sight is [properly] perceived by sight when the magnitudes of their distances [from the center of sight] are accurately determined. On the other hand, the arrangement of the parts is not [properly] perceived when the magnitudes of the distances of its parts are not accurately determined by sight. Furthermore, the arrangement of the individual parts of a visible object is perceived by sight through a perception of the locations on the eye where the forms of those parts extend, as well as through a perception of [their] distinct interpositions on the eye by the faculty of discrimination; and the same holds for individual visible objects. The boundaries of the surface or surfaces of the visible object are perceived by the eye, along with their arrangement, through a perception of the spot on its surface where the color and light of that surface reach the eye and through a perception of the boundaries of that part and the arrangement of the circumference of that part by the faculty of discrimination. In these ways, then, sight perceives the spatial dispositions of the parts of visible objects, the relative spatial dispositions of the surfaces of visible objects, the spatial dispositions of the boundaries of their surfaces, the relative spatial dispositions of the individual parts of visible objects, and the relative spatial dispositions of individual visible objects.

3.121 ◉ Corporeitas vero, que est extensio corporis secundum trinam dimensionem, comprehenditur a visu in quibusdam corporibus et in quibusdam non. Tamen homo distinguens iam quietum est apud ipsum quod non comprehenditur sensu visu nisi corpus, et sic, quando ipse comprehendit visibile, sciet statim quod est corpus, quamvis non comprehendat extensionem eius secundum trinam dimensionem. Et visus comprehendit in omnibus corporibus extensionem eorum secundum longitudinem et latitudinem ex comprehensione superficierum corporum oppositorum illi. Cum ergo comprehenderit superficiem corporis, sciendo quod illud visibile est corpus, comprehendet statim extensionem illius corporis secundum longitudinem et latitudinem. Et non remanet nisi dimensio tertia. Et quedam corpora continentur a superficiebus planis secantibus se oblique adinvicem, et quedam continentur a superficiebus concavis aut convexis, et quedam continentur a superficiebus diversarum figurarum secantibus se oblique adinvicem, et quedam continentur ab una superficie rotunda. Corpus ergo quod continetur a superficiebus secantibus se cuius una superficies est plana, quando comprehenditur a visu, et fuerit superficies eius plana opposita visui et directa ei, et fuerint superficies residue secantes superficiem directe oppositam perpendiculares super superficiem directe oppositam aut oblique super ipsam ad partem strictam ex parte posteriori superficiei directe opposite, non apparebit visui ex eo nisi superficies directe opposita tantum. Ergo ex huiusmodi corporibus non comprehendit visus nisi longitudinem et latitudinem tantum; ergo non sentit corporeitatem corporum huiusmodi. Corpus autem quod continetur a superficiebus secantibus se, quando superficies eius fuerit opposita visui, sed non secundum directam oppositionem, et fuerit sectio istius superficiei cum alia superficie illius corporis comprehensa a visu ita quod poterit comprehendere duas superficies in simul, comprehendetur a visu tunc eius corporeitas. Quoniam comprehendet obliquationem superficiei corporis ad eius profunditatem, quare comprehendet extensionem corporis secundum profunditatem. Et comprehendet ex superficie obliqua extensionem in longum et latum, et sic comprehendet corporeitatem huiusmodi corporum.

3.121 ◉ Now corporeity, which consists in the extension of a body in three dimensions, is perceived by sight in some bodies and not in others. Still, according to human judgment, it is an absolute given that only a body can be perceived by sense, and so, when someone perceives a visible object, he will immediately realize that it is a body, even though he may not perceive its extension according to three dimensions. But sight perceives the extension of all bodies according to length and breadth on the basis of the perception of the surfaces of bodies that face it. Therefore, when it perceives the surface of a body, thereby realizing that this visible object is a body, it will immediately perceive the extension of that body according to length and breadth. So only the third dimension is left. Now some bodies are enveloped by plane surfaces that intersect each other to form corners, some are enveloped by concave or convex surfaces, some are enveloped by surfaces of various shapes that intersect one another to form corners, and some are enveloped by one [continuous] curved surface. Therefore, if one of the intersecting surfaces that envelop a body is plane, and if that surface faces the eye directly, and if the remaining surfaces that intersect this plane surface that faces the eye directly are perpendicular to that surface or are oblique to it so as to converge on one another behind it, then, when sight perceives that body, only the surface that faces the eye directly will be seen by it. Of such bodies, then, sight perceives only the length and breadth, so it does not sense the corporeity of such bodies. On the other hand, if one of the intersecting surfaces that envelopes the body faces the eye but not directly, and if the intersection of this surface with another surface on that body is perceived by sight so that it can perceive both surfaces at once, then the corporeity of that body will be perceived by sight. For it will perceive the slope of the surface of the body in terms of its depth, whereby it will perceive the extension of the body according to depth. But it will also perceive the extension of that sloping surface in length and breadth, and so it will perceive the corporeity of such a body.

3.122 ◉ Et similiter, quando una superficierum corporis fuerit directe opposita visui, et fuerint superficies secantes illam superficiem aut una illarum obliqua super superficiem directe oppositam ad amplum ex parte posteriori superficiei directe opposite, quoniam visus comprehendet in tali corpore superficiem directe oppositam et superficiem oblique secantem superficiem directe oppositam. Et comprehendet etiam sectionem istarum superficierum, et sic, sicut diximus, comprehendet corporeitatem illius corporis. Et generaliter dico quod quodlibet corpus in quo visus potest comprehendere duas superficies secantes se comprehendet corporeitatem in illo.

3.122 ◉ And the same holds if one of the surfaces of the body faces the eye directly, and one or more of the surfaces intersect that surface obliquely so as to diverge outward behind the surface that faces the eye, for in such a body sight will perceive both the surface that faces the eye directly and the surface that intersects it obliquely. And it will also perceive the intersection of these surfaces, and thus, as we said, it will perceive the corporeity of that body. And I say that, in general, whenever sight can perceive two surfaces intersecting one another in a given body, it will perceive its corporeity.

3.123 ◉ Corpora autem in quibus est superficies convexa comprehensa a visu, et fuerit illud quod continet ipsum una superficies aut multe superficies, visus poterit comprehendere corporeitatem eius ex comprehensione veritatis eius, quoniam quando superficies convexa fuerit opposita visui, erunt remotiones partium eius a visu inequales, et erit medium eius propinquius extremitatibus visui. Et cum visus comprehenderit convexitatem eius, comprehendet quod medium eius est sibi propinquius extremitatibus. Et cum senserit quod medium eius est propinquius illi et quod extremitates sunt remotiores, sentiet statim quod superficies est exiens apud ipsum ab ultimis tendentibus ad posterius, et sic sentiet extensionem corporis in profunditate respectu superficiei directe opposite. Et ipse comprehendet extensionem illius corporis secundum longitudinem et latitudinem ex comprehensione extensionis superficiei convexe secundum longitudinem et latitudinem. Et similiter, si alia superficies corporis preter superficiem directe oppositam fuerit convexa, et comprehenderit visus convexitatem eius, quoniam visus etiam comprehendet extensionem eius secundum trinam dimensionem.

3.123 ◉ In the case of bodies with a convex surface that is perceived by sight, whether those bodies consist of one or more surfaces, sight will be able to perceive their corporeity through a perception of their actual [shape], for when a convex surface faces the eye directly, the distances of its parts from the eye will be unequal, and its midpoint will lie nearer the eye than its outer edge.⁑ So when sight perceives its convexity, it will perceive that its midpoint is nearer to it than its extremities. And when it senses that the object’s midpoint lies nearer to it, whereas the object’s outer edge lies farther away, it will immediately sense that the surface curves away from it toward the back, and so it will sense the extension of the body in depth with respect to the surface directly facing it. But it will also perceive the extension of that body according to length and breadth through the perception of the extension of the convex surface according to length and breadth. And the same holds if, in addition to the surface that faces the eye directly, the other surfaces of the body are convex, and if sight perceives their convexity, for sight will also perceive their extension according to three dimensions.

3.124 ◉ Corpus autem in quo est superficies concava comprehensa a visu, quando visus senserit aliam superficiem illius corporis et senserit sectionem eius cum superficie concava, tunc sentiet obliquationem illius corporis superficiei, et cum senserit obliquationem illius superficiei, statim sentiet corporeitatem eius. Si autem superficies eius concava fuerit comprehensa a visu, et non apparuerit visui alia superficierum residuarum, non comprehendet visus corporeitatem huiusmodi corporis, nec visus comprehendet ex huiusmodi corporibus nisi extensiones eius secundum duas dimensiones corporis tantum. Visus autem non sentiet corporeitatem huiusmodi corporum nisi per scientiam precedentem tantum, non per sensum trium dimensionum illius corporis. Et superficies concava extenditur etiam in profunditate propter propinquitatem extremitatum eius visui et remotionem medii, sed non comprehenditur ex extensione profunditatis nisi extensio vacuitatis, non extensio corporis visi cuius superficies est illa superficies concava.

3.124 ◉ In the case of a body containing a concave surface that is perceived by sight, if sight senses another surface on that body and senses the intersection of that surface with the concave one, it will then sense the slope of the [other surface] of that body, and when it senses the slope of that surface, it will immediately sense the body’s corporeity. On the other hand, if its concave surface is perceived by sight, but none of the remaining surfaces is exposed to view, sight will not perceive the corporeity of such a body, nor will sight perceive anything about such bodies beyond their extension in two physical dimensions.⁑ Moreover, sight will sense the corporeity of such bodies only through previous knowledge, not through a sensation of the three dimensions of the body. But a concave surface also extends in depth according to the propinquity of its outer edge and the remoteness of its midpoint with respect to the eye, but, as far as perception of depth is concerned, only the extension of the [side’s] hollow is perceived, not the extension of the body [itself] that contains that concave surface.

3.125 ◉ Comprehensio ergo corporeitatis a visu non est nisi ex comprehensione obliquationum superficierum corporum. Et obliquationes superficierum corporum per quas significatur visui quod corpora sint corpora non comprehenduntur a visu nisi in corporibus quorum remotio est mediocris. In corporibus autem maxime remotionis quorum remotio non certificatur a visu non comprehendit visus obliquationes superficierum. Et sic non comprehendit corporeitatem eius per sensum visus, quoniam in talibus corporibus non comprehendit visus situs partium superficierum eorum adinvicem, nec comprehendit ipsas nisi planas. Et sic non comprehendit obliquationes superficierum, et sic non comprehendit corporeitatem. Visus ergo non comprehendit corporeitatem corporis maxime remotionis cuius remotio non certificatur illi.

3.125 ◉ Thus, the perception of corporeity by sight depends exclusively on a perception of the way the surfaces of bodies slope [toward one another]. But the slopes of the surfaces of bodies according to which sight is alerted to the fact that bodies are bodies are perceived by sight only in the case of bodies that lie at a moderate distance. In the case of bodies that lie extremely far away, however, when their distance is not accurately determined by sight, sight does not perceive the slopes of the surfaces. And thus it does not perceive its corporeity by the sense of sight, for in such bodies sight does not perceive the relative spatial disposition of the parts of their surfaces, so it only perceives them as flat. It does not, therefore, perceive the slopes of the surfaces, and so it does not perceive the body’s corporeity. Thus, sight does not perceive the corporeity of a body that lies extremely far away and whose distance is not accurately determined by it.

3.126 ◉ Et ipse comprehendit corporeitatem corporum ex comprehensione obliquationum superficierum corporum, et obliquationes superficierum corporum non comprehenduntur a visu nisi in visibilibus mediocris remotionis quorum situs partium superficierum adinvicem comprehenduntur a visu. Et preter ista visibilia non comprehendit corporeitatem eius visus, et non comprehendit corporeitatem eius nisi per scientiam antecedentem tantum.

3.126 ◉ But sight perceives the corporeity of bodies by perceiving the slopes of the surfaces of [those] bodies, and the slopes of the surfaces of [those] bodies are only perceived by sight in the case of visible objects that lie at a moderate distance when the relative spatial disposition of the parts of their surfaces are perceived by sight. And, except for these visible objects, sight does not perceive the corporeity of bodies, or else it perceives their corporeity through previous knowledge alone.⁑

3.127 ◉ Figura autem rei vise dividitur in duo quorum alterum est figura circumferentie superficiei rei vise aut circumferentie alicuius partis rei vise. Secundum autem est figura corporeitatis rei vise aut figura corporeitatis alicuius partis rei vise—et iste modus est forma superficiei rei vise cuius corporeitas comprehenditur per sensum visus aut forma partis superficiei rei vise cuius corporeitas comprehenditur. Et omne quod visus comprehendit ex figuris visibilibus dividitur in istos modos.

3.127 ◉ The shape of a visible object is subdivided into two kinds, the first being the shape of the circumference of the surface of the visible object or the [shape of the] circumference of some part of the visible object.⁑ The second kind is the shape of the body of the visible object, or the shape of the body of some part of the visible body—which is to say the form of the surface of the visible object whose corporeity is perceived by the sense of sight or the form of a part of the surface of the visible object whose corporeity is perceived [by the sense of sight].⁑ Everything that sight perceives in the way of the shapes of visible objects falls under these heads.

3.128 ◉ Figura vero circumferentie superficiei rei vise comprehenditur a sentiente ex comprehensione circumferentie forme que pervenit in concavum nervi communis et ex comprehensione circumferentie partis superficiei membri sentientis in quam pervenit forma rei vise, quoniam in utroque istorum locorum figuratur circumferentia superficiei rei vise. Quem ergo istorum locorum averterit sentiens poterit comprehendere in eo figuram circumferentie rei vise. Et similiter figura circumferentie cuiuslibet partium superficiei rei vise comprehenditur a sentiente ex sensu ordinationis partium terminorum partis forme. Et cum sentiens voluerit certificare figuram circumferentie superficiei rei vise aut figuram circumferentie alicuius partis rei vise, movebit axem radialem super circumferentiam rei vise. Et sic per motum certificabit situm partium terminorum forme superficiei aut partis superficiei que est in superficie membri sentientis et que est in concavo nervi communis, quare comprehendet ex certificatione situum terminorum forme figuram circumferentie superficiei. Secundum ergo hunc modum erit comprehensio figure circumferentie rei vise et figure circumferentie cuiuslibet partis superficiei rei vise per sensum visus.

3.128 ◉ The shape of the circumference of a visible object’s surface is perceived by the sensitive faculty through the perception of the circumference of the form that reaches the hollow of the common nerve and through the perception of the circumference of the area on the surface of the sensitive organ where the form of the visible object reaches, for the circumference of the surface of the visible object is delineated in both of these places. Therefore, whichever of these places the sensitive faculty examines, it will be able to perceive the shape of the circumference of the visible object [delineated] in it. Likewise, the shape of the circumference of any part of the surface of the visible object is perceived by the sensitive faculty through its sensation of the arrangement of the parts of the boundaries of the form of the part. And if the sensitive faculty wants to accurately determine the shape of the circumference of the surface of the visible object or the shape of the circumference of some part of the visible object, it will move the visual axis over the circumference of the visible object. Through [such] a scanning-process, then, it will accurately determine the spatial disposition of the parts of the boundaries of the form of the surface or the part of the surface that lies on the surface of the sensitive organ as well as in the hollow of the common nerve, so it will perceive the shape of the circumference of the surface on the basis of its accurate determination of the spatial dispositions of the boundaries of the form. It is in this way, then, that the shape of the circumference of the visible object, or the shape of the circumference of some part of the surface of the visible object, will be perceived by the sense of sight.

3.129 ◉ Forma autem superficiei rei vise non comprehenditur a visu nisi ex comprehensione situum partium superficiei rei vise et ex dissimilitudine situum partium superficiei rei vise et consimilitudine eorumdem. Et certificatur forma superficiei ex comprehensione diversitatis inequalitatis remotionum partium superficiei rei vise et equalitatis earum, aut inequalitatis elevationum partium superficiei et equalitatis earum. Quoniam convexitas superficiei non comprehenditur a visu nisi ex comprehensione propinquitatis partium mediarum in superficie et remotionis partium in terminis, aut ex inequalitate elevationum partium eius quando superficies superior corporis fuerit convexa. Et similiter convexitas termini superficiei non comprehenditur a visu nisi ex comprehensione propinquitatis medii et remotionis extremitatum quando convexitas eius opponitur visui, aut ex inequalitate elevationum partium eius quando gibbositas eius fuerit inferius aut superius, aut ex inequalitate dextri partium eius aut sinistri eius quando gibbositas eius fuerit dextra aut sinistra.

3.129 ◉ Now the form of the surface of a visible object is not perceived by sight except through the perception of the spatial dispositions of the parts of the visible object’s surface and through the dissimilarity or similarity of the spatial dispositions of the parts of the surface of the visible object.⁑ And the form of the surface is accurately determined through the perception of the inequality or equality of the distances of the parts of the surface of the visible object [with respect to the eye] or [through the perception] of the inequality or equality of the heights of the parts of the surface. For the convexity of the surface is only perceived by sight through the perception of the nearness of the central parts on the surface and the remoteness of the parts at the extremity, or else through the inequality of the heights of its parts when the upper surface of the body is convex. By the same token, the convexity of the outer edge of the surface is only perceived by sight through the perception of the nearness of the midpoint and the remoteness of the outer edge when its convexity faces the eye, or through the inequality of the heights of its parts when its bulge points down or up, or else through the inequality of its right-hand or left-hand parts when its bulge points toward the right or left.

3.130 ◉ Concavitas autem superficiei, quando opponitur visui, comprehenditur a visu ex comprehensione remotionis partium mediarum et appropinquatione extremitatum terminorum. Et similiter est de concavitate terminorum superficiei quando opponitur visui. Et visus non comprehendit concavitatem superficiei quando concavitas fuerit opposita superius, aut inferius, aut apud latus nisi quando superficies concava fuerit in parte abscisa et apparuerit arcualitas termini eius que est versus visum.

3.130 ◉ When a concave surface faces the eye, however, its concavity is perceived by sight through the perception of the remoteness of the central parts and the proximity of the outer edges. And the same holds for the concavity of the outer edges of the surface when it faces the eye. But sight does not perceive the concavity of the surface when the concavity faces upward or downward, or toward the side, unless the concave surface is cut in such a way that the curvature of its edge facing the eye is apparent.

3.131 ◉ Planities autem superficiei comprehenditur a visu ex comprehensione equalitatis remotionis partium et consimilitudinis ordinationis eorum, et similiter rectitudo termini superficiei quando terminus opponetur visui. Rectitudo termini autem superficiei, et arcuitas et curvitas eius quando superficies fuerit opposita visui, et fuerint termini continentes ipsam, comprehendentur a visu ex ordinatione partium eius adinvicem.

3.131 ◉ A surface is perceived by sight as flat through the perception of the equality of the distance of its parts and its uniform arrangement throughout, and the same holds for the straightness of the edge of a surface when that edge faces the eye. However, when a surface faces the eye and several edges enclose that surface, the straightness, bend, or curvature of [any] edge of the surface will be perceived by sight through the arrangement of its parts among one another.

3.132 ◉ Convexitas autem superficiei rei vise que opponetur visui, et concavitas eius, et planities eius comprehenduntur a visu ex comprehensione diversitatis remotionum partium superficiei, aut elevationum earum, aut latitudinum earum, et equalitatis earum, et ex quantitatibus excessus remotionis partium, aut elevationum, aut latitudinum earum adinvicem. Et similiter convexitas et concavitas eius, et planities cuiuslibet partis rei vise comprehenditur a visu ex comprehensione excessus remotionum partium illius partis, aut excessus elevationum aut latitudinum eorum, aut equalitatis earum. Et propter istam causam non comprehendet visus concavitatem et convexitatem nisi in visibilibus quorum remotio est mediocris. Visus autem comprehendit propinquitatem quarumdam partium superficiei et remotionem quarumdam per corpora intervenientia ipsi et superficiei et per corpora respicientia remotiones partium quorum appropinquatio et remotio certificantur a visu. Et cum quedam partes superficiei fuerint prominentes et quedam profunde, comprehendit visus prominentiam et profunditatem illarum per obliquationes superficierum partium, et sectiones partium, et curvitates earum in locis profunditatis, et per situs superficierum partium adinvicem. Et hoc erit quando visus non comprehenderit illam superficiem ante, nec aliquam huiusmodi generis. Si autem illa res visa fuerit ex visibilibus assuetis, comprehendet visus formam eius et formam superficiei per cognitionem antecedentem. Forma autem rei vise que continetur ex superficiebus secantibus se et diversorum situum comprehenditur a visu ex comprehensione sectionis superficierum eius, et ex comprehensione situs cuiuslibet superficierum eius, et ex comprehensione forme cuiuslibet superficierum eius.

3.132 ◉ The convexity, concavity, or flatness of the surface of a visible object facing the eye is perceived by sight through the perception of the difference in, or the equality of, the distances, or heights, or breadths of the parts of the surface [from the center of sight], as well as through the [perception of] how much the distances, or heights, or breadths of the parts exceed one another. Likewise, the convexity, concavity, or flatness of any part of the visible object is perceived by sight through a perception that the distances, or heights, or breadths of the parts of that part vary in magnitude or are equal among one another. It is for this reason that sight will not perceive concavity or convexity except in visible objects that lie at a moderate distance. Sight, moreover, perceives the nearness of certain parts of the surface and the remoteness of others by means of bodies that lie between it and the surface or by means of bodies spanning the distances of the parts, when the nearness or remoteness of those bodies are accurately determined by sight. And if some parts of the surface protrude, and others are indented, then sight perceives their protrusion and indentation through the slopes of the surfaces of the parts, and the intersections of the parts, and their curvatures at the points of indentation, and [it also perceives them] through the relative spatial disposition of the surfaces of the parts. This will be the case when sight has not perceived that surface, or anything like it, before. If, however, that visible object is familiar, sight will perceive its form as well as the form of its surface through previous acquaintance.⁑ The form of a visible object that is enveloped by surfaces that intersect one another and that have various spatial dispositions is perceived by sight from the perception of the intersection of its surfaces, and from the perception of the spatial disposition of each of its surfaces, and from the perception of the shape of each of its surfaces.

3.133 ◉ Forme ergo figurarum rerum visarum quarum corporeitas comprehenditur a visu comprehenduntur ex comprehensione formarum superficierum earum et ex comprehensione situum superficierum earum adinvicem. Et forme superficierum visibilium quarum partes sunt diversi situs comprehenduntur a visu ex comprehensione convexitatis, et concavitatis, et planitiei partium superficierum eorum visibilium, et preminentie et profunditatis partium superficiei. Secundum ergo hunc modum erit comprehensio formarum superficierum visibilium et figurarum earum. Et cum sentiens voluerit certificare formam superficiei rei vise aut formam alicuius partis rei vise, movebit visum in oppositione eius, et faciet transire axem radialem super omnes partes eius donec sentiet remotiones partium eius, et situs cuiuslibet illarum apud visum, et situm illarum adinvicem. Et cum sentiens comprehenderit remotiones partium superficiei et situs earum, et comprehenderit preminentiam et profunditatem illarum, comprehendet formam illius superficiei rei vise, et certificabit figuram eius. Et multotiens errat visus in eo quod comprehendit ex formis superficierum visibilium et formis figurarum visibilium, et non percipit errorem. Quoniam convexitas parva, et concavitas parva, et prominentia, et profunditas parva non bene comprehenduntur secundum accessum ad visum, quamvis eorum remotio sit mediocris, nisi sit propinqua valde visui.

3.133 ◉ Hence, the forms of the shapes of visible objects whose corporeity is perceived by sight are perceived through the perception of the forms of their surfaces and through the perception of the relative spatial dispositions of their surfaces. Moreover, the forms of visible surfaces whose parts have various spatial dispositions are perceived by sight through the perception of the convexity, concavity, or flatness of the parts of their visible surfaces, or from the height or depth of the parts of the surface. This, therefore, is how the forms and shapes⁑ of visible surfaces will be perceived. Moreover, when the sensitive faculty wants to accurately determine the form of a visible object’s surface, or the form of any part of the visible object, it will shift its focus straight ahead and will make the visual axis scan all the parts of that object until it will sense the distances of its parts, the spatial dispositions of each of its parts vis-à-vis the eye, and the spatial disposition of all of the parts with respect to one another. And when the sensitive faculty perceives the distances and spatial dispositions of the parts of the surface, and when it perceives the height and depth of those parts, it will perceive the form of that surface of the visible object, and it will accurately determine its shape. But sight frequently errs in its perception of the forms of the surfaces of visible objects and the forms of the shapes of visible objects, but it does not perceive its error. For a slight convexity, or a slight concavity, or a slight protrusion or indentation is poorly perceived by sight along the line-of-sight, even when its distance is moderate, unless it lies very near the eye.

3.134 ◉ Visibilia ergo quorum forme comprehenduntur a visu sunt illa quorum quantitates partium superficierum comprehenduntur a visu et quorum excessus et equalitas remotionum partium comprehenduntur a visu, et visibilia quorum forme certificantur a visu sunt illa quorum quantitates remotionum partium et quorum quantitates excessus remotionis partium certificantur a visu. Et similiter figure circumferentiarum superficierum visibilium et figure circumferentiarum partium superficierum visibilium non certificantur a visu nisi sint in remotionibus mediocribus, et certificaverit visus ordinationem terminorum earum et situum partium terminorum earum adinvicem, et certificaverit angulos earum. Et quorum situs terminorum non certificantur a visu nec anguli eorum, si habuerint angulos, non certificabit visus figuras eorum. Omnes ergo figure visibilium comprehenduntur a visu secundum modos quos declaravimus.

3.134 ◉ Hence, sight perceives the forms of visible objects when the sizes of the parts of their surfaces are perceived by sight and when the inequality or equality of the distances of their parts [from the center of sight] are perceived by sight, whereas sight accurately determines the forms of visible objects when the magnitudes of the distances of their parts [from the center of sight] and the amounts by which the distances of the parts [from the center of sight] differ among each other are accurately determined by sight. Likewise, the shapes of the circumferences of the surfaces of visible objects and the shapes of the circumferences of the parts of the surfaces of visible objects are not accurately determined by sight unless they lie at a moderate distance, and unless sight accurately determines the arrangement of their extremities and the relative spatial dispositions of their parts, and unless it accurately determines their angles of juncture. If neither the spatial disposition of their extremities nor their angles of juncture, assuming they have such, are accurately determined by sight, sight will not accurately determine their shapes. Therefore, all the shapes of visible objects are perceived by sight in the ways that we have described.

3.135 ◉ Magnitudo vero et quantitas rei vise comprehenduntur a visu, sed qualitas comprehensionis eius est ex intentionibus dubitabilibus in qualitate comprehensionis magnitudinis. Et plures illorum opinantur quod quantitas magnitudinis rei vise non comprehenditur a visu nisi ex quantitate anguli qui fit apud centrum visus quem continet superficies piramidis radialis cuius basis continet rem visam, et quod visus comparat quantitates rerum visarum ad quantitates angulorum qui fiunt a radiis qui continent res visas apud centrum visus. Et non sustentatur in comprehensione magnitudinis nisi super angulos tantum. Et quidam illorum opinantur quod comprehensio magnitudinis non completur in comparatione ad angulos tantum, sed per considerationem remotionis rei vise et situs eius cum comparatione ad angulos.

3.135 ◉ The magnitude or size of a visible object is perceived by sight, but the way it is perceived is a matter of debate as far as the perception of magnitude is concerned. Several of those [authorities who have tried to explain this] believe that a visible object’s size is perceived by sight only through the size of the angle formed at the center of sight, that angle also containing the surface of the visual cone whose base encompasses the visible object, [and they further believe] that sight correlates the sizes of visible objects to the sizes of the angles formed by the rays that comprehend the visible objects at the center of sight. So the perception of magnitude depends solely upon those angles.⁑ Certain other [authorities] believe that the perception of size is not achieved through a correlation of the angles alone, but also through an evaluation of the distance and spatial disposition of the visible object along with a correlation of the angles.⁑

3.136 ◉ Et veritas est quod non est possibile ut sit comprehensio quantitatum rerum visarum a visu ex comparatione ad angulos quos res vise respiciunt apud centrum visus tantum, quoniam eadem res visa non diversatur in quantitate apud visum, quamvis remotiones eius diversentur diversitate non magna. Quoniam quando res visa fuerit prope visum, et comprehenderit visus quantitatem eius, et postea fuerit elongata a visu, non multum diminuetur eius quantitas apud visum quando remotio secunda fuerit mediocris. Et nunquam diversatur quantitas alicuius rei vise assuete apud visum quando remotiones eius diversantur et cum fuerint ex remotionibus mediocribus.

3.136 ◉ Actually, it is not possible for the perception of the sizes of visible objects by sight to depend solely upon a correlation of angles subtended by visible objects at the center of sight, for, as far as sight is concerned, the same visible object may not differ in size, even though it lies at distances that vary to a moderate extent.⁑ For when a visible object is near the eye so that sight perceives its size, and then it is moved some distance away from the eye, its size will not diminish much as far as sight is concerned, provided that the second distance is moderate. Moreover, as far as sight is concerned, the size of no familiar visible object will ever change as its distances change, assuming that those distances are moderate.

3.137 ◉ Et similiter corpora equalia diversarum remotionum, quando remotio remotissimi illorum fuerit mediocris, comprehendentur a visu equalia. Sed anguli quos respicit una eadem res visa in remotionibus diversis mediocribus diversantur diversitate alicuius quantitatis. Quoniam, quando res visa fuerit remota a visu per unum cubitum, deinde si elongetur a visu donec fuerit eius remotio per duos cubitos, erit inter duos angulos qui fiunt apud visum ab illa re visa magnus excessus. Et tamen non comprehendit visus rem visam in remotione duorum cubitorum minorem quam in remotione unius cubiti. Et similiter, si elongetur a visu per tres cubitos aut quattuor, non videbitur minor, quamvis anguli qui fiunt apud visum diversentur diversitate extranea.

3.137 ◉ Likewise, when bodies of equal size lie at different distances, and the farther distance is moderate, they will be perceived as equal in size by sight. Nevertheless, the angles subtended by the same visible object at various moderate distances differ by some amount. For when a visible object lies one cubit from the eye and is then moved farther away from the eye until it lies two cubits from it, there will be a significant difference in the two angles subtended by that object at the center of sight. Still, sight does not perceive the object lying two cubits away as any smaller than the object lying one cubit away. By the same token, if it is moved three or four cubits away from the eye, it will not appear smaller, even though the angles formed at the center of sight will differ by a considerable amount.⁑

3.138 ◉ Et etiam iterum, si in superficie alicuius corporis signetur figura quadrata equalium laterum et rectorum angulorum, et elevetur illud corpus donec eius superficies in qua est quadratio sit prope equidistantiam visus et ita quod visus cum hoc comprehendat figuram quadratam, comprehendet visus figuram quadratam equalium laterum, et cum hoc anguli quos respiciunt latera quadrata apud centrum visus erunt inequales quando centrum visus fuerit prope superficiem in qua est quadratio. Et tamen visus comprehendet latera quadrati equalia.

3.138 ◉ So too, if a square is drawn on the surface of some body, and if that body is raised until the surface on which the square is drawn is almost parallel to the line-of-sight so that the eye can still make out the square, sight will perceive the square as having equal sides, although the angles subtended by the sides of the square at the center of sight will be unequal when the center of sight lies near the surface on which the square is drawn. Nevertheless, sight will perceive the sides of the square as equal.

3.139 ◉ Et similiter, quando in circulo extrahuntur dyametri diversorum situum, deinde elevetur superficies in qua est circulus donec sit prope equidistantiam visus, erunt anguli quos respiciunt dyametri circuli apud centrum visus diversi magna diversitate secundum diversitatem situs dyametrorum. Et tamen visus non comprehendit dyametros circuli nisi equales quando remotio eorum fuerit mediocris.

3.139 ◉ Likewise, when diameters are drawn in a circle at various angles to one another, and the surface on which the circle is drawn is raised until it is nearly parallel to the line-of-sight, the angles subtended by the circle’s diameters at the center of sight will vary significantly according to the orientation of the diameters. Nevertheless, sight invariably perceives the diameters of the circle to be equal, as long as they lie at a moderate distance.⁑

3.140 ◉ Si ergo comprehensio rerum visarum esset ex comparatione ad angulos tantum qui fuerint ex visibilibus apud centrum visus, non comprehenderentur latera quadrati equalia, nec comprehendentur dyametri circuli equales, nec circulus comprehendetur rotundus, nec comprehendetur una res visa in remotionibus diversis unius quantitatis. Ex experimentatione ergo istarum intentionum, patet quod comprehensio quantitatum rerum visarum non est ex comparatione ad angulos tantum.

3.140 ◉ If the perception of [the size of] visible objects depended solely on a correlation of the angles subtended by visible objects at the center of sight, then, the sides of the square would not be perceived as equal, nor would the diameters of the circle be perceived as equal, nor would the circle be perceived as circular, nor would any single visible object be perceived to be of the same size at various distances. Therefore, on the basis of such experiments, it is clear that the perception of the sizes of visible objects does not depend solely on a correlation of angles.

3.141 ◉ Et cum hoc declaratum est, modo certificemus qualitatem comprehensionis magnitudinis. Et iam declaratum est quod sustentatio in comprehensione plurium sensibilium non est nisi super argumentationem et distinctionem. Magnitudo autem est una intentionum que comprehenduntur ratione et argumentatione, et radix super quam sustentatur virtus distinctiva in distinctione quantitatis magnitudinis rei vise est quantitas partis visus in qua pervenit forma rei vise. Et pars in qua pervenit forma rei vise determinatur et mensuratur per angulum qui est apud centrum visus quem continet piramis radialis continens rem visam et partem visus in qua pervenit forma rei vise. Pars ergo visus in qua pervenit forma rei vise et angulus quem continet piramis radialis continens illam partem sunt radix quam non possunt sensus et distinctio vitare in comprehensione magnitudinis rei vise.

3.141 ◉ Now that this has been shown, let us determine precisely how magnitude is perceived. It has already been shown that the perception of various sensible properties depends entirely upon deduction and differentiation.⁑ Magnitude is one of those properties that is perceived through judgment and deduction, and the basis upon which the faculty of discrimination determines the size of the visible object is the size of the area on the eye upon which the form of the visible object is projected. And the area upon which the form of the visible object is projected is determined and measured by the angle at the center of sight that contains the visual cone, which encompasses [both] the visible object and the area on the eye upon which the form of the visible object is projected. Therefore, the area on the eye upon which the form of the visible object is projected and the angle containing the visual cone that encompasses that area are factors that the sensitive faculty and faculty of discrimination cannot do without in perceiving the magnitude of the visible object.

3.142 ◉ Sed tamen non sufficit virtuti distinctive in comprehensione magnitudinis consideratio anguli tantum, aut consideratio partis visus respicientis angulum tantum, quoniam una res visa, quando comprehenditur a visu, et est prope ipsum, comprehendet sentiens locum visus in quem pervenit forma rei vise, et comprehendet quantitatem illius loci. Deinde, quando illa res visa elongabitur a visu, comprehendetur etiam a visu, et comprehendet sentiens locum visus in quem pervenit forma eius secundo, et comprehendet quantitatem loci. Et manifestum est quod locus visus in quem pervenit forma eius primo et locus visus in quem pervenit forma eius secundo diversantur secundum quantitatem, quoniam locus forme in visu erit secundum quantitates anguli quem respicit illa res visa apud centrum visus. Et quanto magis elongabitur res visa, tanto magis strictificabitur piramis continens ipsam, et eius angulus, et locus visus in quem pervenit forma. Et cum sentiens comprehenderit locum in quem pervenit forma rei vise, et comprehendit quantitatem loci, comprehendet diminutionem loci apud remotionem rei vise a visu.

3.142 ◉ Still and yet, neither an evaluation of the angle by itself, nor an evaluation of the area on the eye subtending that angle, suffices on its own for the faculty of discrimination to perceive size, for, when a single visible object lying near the eye is perceived by sight, the sensitive faculty will perceive the location on the eye upon which the visible object’s form is projected, and it will perceive the size of that location. Then, if that visible object is drawn farther away from the eye, it will still be perceived by sight, and the sensitive faculty will perceive the location on the eye upon which the form is projected the second time, and it will perceive the size of that location. And it is clear that the location of the eye upon which the form is projected in the first place and the location of the eye upon which the form is projected afterward differ in size, for the [size of the] location of the form on the eye will depend upon the sizes of the angles encompassing the visible object at the center of sight. The farther away the visible object gets, the narrower the [visual] cone encompassing it will get, and [the narrower that cone gets, the narrower] its angle [will get], and [the narrower that angle gets, the narrower] the location on the eye upon which the form is projected [will get]. So when the sensitive faculty perceives the location upon which the form of the visible object is projected, and when it perceives the size of that location, it will perceive the decrease in size of that location according to the distance of the visible object from the eye.

3.143 ◉ Et ista intentio multotiens et sepe revertitur ad visum, scilicet quod visibilia semper elongantur a visu, et visus ab eis, et appropinquant visui, et visus illis, et visus comprehendit ipsa, et comprehendit diminutionem locorum formarum illorum in visu apud remotionem, et comprehendit augmentationem locorum formarum illorum in visu apud appropinquationem. Ex frequentia ergo istius intentionis quievit in anima apud virtutem distinctivam quod, quanto magis res visa elongatur a visu, tanto diminuitur locus forme eius in visu et angulus quem respicit res visa apud centrum. Et cum hoc est, est quietum in distinctione quod locus in quem pervenit forma rei vise, et angulus quem respicit res visa apud centrum visus, non erit nisi secundum remotionem rei vise a visu. Et cum hoc quietum est in anima, quando virtus distinctiva distinxerit quantitatem rei vise, non considerabit angulum tantum, sed considerabit angulum et remotionem in simul, quoniam quietum est apud ipsam quod angulus non erit nisi secundum remotionem. Quantitates ergo visibilium non comprehenduntur nisi per distinctionem et comparationem. Comparatio autem per quam comprehenditur quantitas rei vise est comparatio basis piramidis radialis, que est superficies rei vise, ad angulum piramidis et ad quantitatem longitudinis piramidis, que est remotio rei vise a visu. Et consideratio virtutis distinctive non est nisi in parte superficiei membri sentientis in quem pervenit forma rei vise cum consideratione remotionis rei vise a superficie visus, quoniam quantitas partis in quam pervenit forma nunquam erit nisi secundum quantitatem anguli quem respicit illa pars apud centrum visus. Et non est inter remotionem rei vise a superficie visus et remotionem eius a centro visus in maiori parte diversitas operans in remotionem.

3.143 ◉ This situation occurs over and over again for sight; that is, visible objects continually recede from the eye, or the eye recedes from them, or they continually approach the eye, or the eye approaches them, and sight perceives them, and it perceives the decrease in the size of the locations of their forms on the eye with the increase in distance, and it also perceives the increase in the size of the locations of their forms on the eye with the decrease in distance. On the basis, therefore, of such repeated experience, it becomes ensconced in the soul that, as far as the faculty of discrimination is concerned, the farther the visible object recedes from the eye, the smaller the location of its form on the eye becomes, and [the smaller that location becomes, the smaller] the angle at the center of sight encompassing the visible object [becomes]. When this happens, it is established in the faculty of discrimination that [the size of] the area upon which the visible object’s form is projected, as well as the angle at the center of sight encompassing the visible object, depends entirely on the distance of the visible object from the eye. And when this fact is ensconced in the soul, then, if the faculty of discrimination determines the size of a visible object, it will not evaluate the angle alone but will evaluate the angle and the distance together, for it has been established for it that the angle will depend entirely upon the distance. Thus, the sizes of visible objects will be perceived only through differentiation and correlation. But the correlation through which the size of the visible object is perceived involves a correlation of the base of the visual cone, which is the surface of the visible object, to the angle of the cone as well as to the magnitude of the length of the cone, which is the distance of the visible object from the eye. Furthermore, the evaluation [carried out] by the faculty of discrimination invariably includes [an evaluation of] the area on the surface of the sensitive organ upon which the form of the visible object is projected along with an evaluation of the distance of the visible object from the surface of the eye, for the size of the area upon which the form is projected will invariably depend on the size of the angle encompassing that area at the center of sight. For the most part, moreover, the difference between the distance of the visible object from the surface of the eye and its distance from the center of sight has no effect [on the perception of] distance.

3.144 ◉ Et etiam iam declaratum est quod sentiens comprehendit verticationes que sunt inter centrum visus et rem visam, que sunt verticationes linearum radialium, et comprehendit verticationum ordinationem, et ordinationem visibilium, et ordinationem partium rei vise. Et cum sentiens comprehendit hoc, virtus distinctiva comprehendit quod iste verticationes, quanto magis elongantur a visu tanto, magis ampliabuntur spatia que sunt inter earum extremitates. Et ista intentio iam etiam quieta est in anima, et cum hoc quietum est etiam in anima quod linee radiales, quanto magis elongabuntur a visu, tanto magis erit res visa que est apud earum extremitates maior. Cum ergo visus comprehenderit aliquam rem visam, et comprehenderit terminos eius, comprehendet verticationes ex quibus comprehendit terminos illius rei vise. Et verticationes ex quibus comprehenderit terminos rei vise sunt linee continentes angulum qui est apud centrum visus quem respicit illa res visa, et sunt linee continentes locum visus in quem pervenit forma rei vise. Cum ergo visus comprehenderit verticationes, ymaginabit virtus distinctiva extensionem istarum linearum a centro visus usque ad terminos rei vise. Et quando cum hoc comprehenderit quantitatem remotionis rei vise, ymaginabit quantitatem longitudinum istarum linearum et quantitatem spatii quod est inter extremitates earum, et spatia que sunt inter extremitates istarum linearum sunt dyametri rei vise. Et quando virtus distinctiva ymaginabit quantitatem anguli, et quantitatem longitudinum linearum radialium, et quantitatem spatiorum que sunt inter extremitates earum, comprehendet quantitatem rei vise secundum suum esse.

3.144 ◉ It has also been shown that the sensitive faculty perceives the lines extending between the center of sight and the visible object, these lines representing radial lines, and it perceives the arrangement of these lines, as well as the arrangement of visible objects and the arrangement of the parts of any visible object.⁑ When the sensitive faculty perceives this [set of arrangements], the faculty of discrimination perceives that the farther these [radial] lines extend from the center of sight, the larger the intervals between their extremities will get. But this fact is already ensconced in the soul, and along with it there is also ensconced in the soul the fact that, the farther the radial lines get from the center of sight, the larger the visible object at their extremities will be. Thus, when sight perceives a visible object and perceives its boundaries, it will perceive the [radial] lines along which it perceives the boundaries of that visible object. But the [radial] lines along which it perceives the boundaries of the visible object form the angle at the center of sight that encompasses that visible object, and they are also the [radial] lines encompassing the location on the eye upon which the form of the visible object is projected. Thus, when sight perceives those [radial] lines, the faculty of discrimination will imagine the extension of those [radial] lines from the center of sight to the boundaries of the visible object. And when, on that basis, it perceives the magnitude of the visible object’s distance, it will imagine the magnitude of the length of those lines, as well as the extent of the interval between their endpoints, but the intervals between the endpoints of these lines form cross-sections of the visible object. So when the faculty of discrimination imagines the size of the angle, the magnitude of the lengths of the radial lines, and the extent of the intervals between their endpoints, it will perceive the actual size of the visible object.

3.145 ◉ Verticationes autem que extenduntur inter centrum visus et terminos cuiuslibet rei vise comprehense a visu comprehenduntur a sentiente et a virtute distinctiva, et sentiens et virtus distinctiva comprehendunt quantitatem partis visus in qua pervenit forma illius rei vise. Et cum virtus distinctiva comprehenderit verticationes linearum radialium, comprehendet situs eorum adinvicem, et comprehendet appropinquationem et remotionem earum adinvicem, et comprehendet qualitatem extensionis earum. Et nichil remanet quo completur comprehensio magnitudinis rei vise nisi quantitas remotionis rei vise.

3.145 ◉ Now the [radial] lines that extend between the center of sight and the boundaries of any visible object perceived by sight are perceived by the sensitive faculty and the faculty of discrimination, and the sensitive faculty and the faculty of discrimination perceive the size of the area on the eye upon which the form of that visible object is projected. And when the faculty of discrimination perceives the radial lines, it will perceive their relative spatial disposition, and it will perceive their convergence or divergence, and it will perceive how they extend. To complete the perception of the visible object’s size, then, nothing remains but [to determine] the magnitude of the visible object’s distance.

3.146 ◉ Et iam declaratum est in qualitate comprehensionis remotionis rei vise quod cuiuslibet rei vise remotio comprehenditur a visu aut certe aut estimatione. Et cum virtus distinctiva comprehenderit situs linearum radialium continentium terminos rei vise, et quantitatem partis que est inter ipsas et superficiem membri sentientis, que est quantitas anguli, et ymaginaverit cum hoc quantitatem remotionis rei vise, statim ymaginabit quantitatem anguli et remotionis in simul. Et cum ymaginaverit quantitatem anguli et quantitatem remotionis in simul, comprehendet quantitatem rei vise secundum quantitatem anguli et secundum quantitatem remotionis in simul. Et virtus distinctiva ymaginat quantitatem remotionis cuiuslibet rei vise comprehense a visu, et ymaginat verticationes continentes terminos eius, et per istam ymaginationem perveniet apud ipsam forma piramidis continentis rem visam et quantitas basis eius que est res visa. Et sic perveniet illi quantitas rei vise.

3.146 ◉ It has already been shown in [the discussion of] how the distance of a visible object is perceived that the distance of any visible object is perceived by sight either precisely or by estimation.⁑ So when the faculty of discrimination perceives the spatial disposition of the radial lines encompassing the boundaries of the visible object, and when it perceives the size of the area they demarcate on the surface of the sensitive organ, which is [a function of] the size of the angle, and when it also imagines the magnitude of the visible object’s distance, then it will immediately imagine the size of the angle and that of the distance together. And when it imagines the size of the angle and the magnitude of the distance together, it will perceive the size of the visible object according to the size of the angle and the magnitude of the distance together. So the faculty of discrimination imagines the magnitude of the distance of any visible object perceived by sight, and it imagines the [radial] lines encompassing its boundaries, and by means of this conceptual process, the form of the visual cone that encompasses the visible object will occur to it along with the size of the cone’s base, which is formed by the visible object.⁑ And so the size of the visible object will occur to it.

3.147 ◉ Et significatio quod comprehensio magnitudinis rei vise erit per comparationem magnitudinis ad remotionem rei vise est quia visus, quando comprehenderit duo visibilia diverse remotionis et respicientia eundem angulum apud centrum visus—scilicet ut radii transeuntes per extrema primi illorum perveniant ad extrema secundi—et primum illorum non cooperuerit totum secundum, et comprehenderit visus remotionem cuiuslibet illorum comprehensione certificata, semper visibile remotius comprehendetur a visu visibili propinquiori maius. Et quanto magis visibile remotius elongabitur, et visus certificaverit quantitatem remotionis eius, tanto magis comprehendetur maius. Verbi gratia, quod quando visus aspexerit parietem remotum a visu remotione mediocri, et certificaverit visus remotionem illius parietis et quantitatem eius, et certificaverit quantitatem latitudinis eius, deinde apposuerit aspiciens manum uni visui inter visum et parietem et clauserit alterum oculum, inveniet tunc quod manus eius cooperiet portionem magnam illius parietis. Et comprehendet quantitatem manus eius in illa dispositione, et comprehendet quod quantitas cooperta a manu ex pariete est multo maior quantitate manus eius, et visus comprehendet verticationes linearum radialium, et comprehendet angulum quem continent linee radiales. Tunc ergo visus comprehendit quod angulus quem respiciunt manus et paries est idem angulus, et tunc etiam comprehendit quod pars cooperta manu eius est multo maior manu. Et cum ita est, virtus distinctiva in illa comprehensione comprehendit quod remotius duorum visibilium diverse remotionis respicientium unum angulum est maioris quantitatis.

3.147 ◉ Evidence that the perception of a visible object’s size will occur through a correlation of the object’s [apparent] size to its distance is found in the fact that, when sight perceives two visible objects that lie at different distances but subtend the same angle at the center of sight—i.e., such that the rays passing through the endpoints of the first of those objects extend to the endpoints of the second—and if the first of those objects does not block the second one entirely, and if sight accurately perceives the distance of each of them, the farther visible object will always appear larger to sight than the nearer one. Moreover, the greater the distance of the farther visible object becomes, the larger it will be perceived to be, as long as sight accurately determines the magnitude of its distance. For instance, if an observer looks at a wall that lies at a moderate distance from the eye, and if he accurately determines the distance and size of that wall, and if he accurately determines the magnitude of its breadth, then, if the observer places his hand in front of one of his eyes between the center of sight and the wall and closes the other eye, he will find that his hand will cover a considerable portion of that wall. Yet he will perceive the size of his hand in that situation, and he will perceive that the size [of the portion] of the wall covered by his hand is much larger than the size of his hand, and sight will perceive the radial lines and will perceive the angle formed by these radial lines. In this case, then, sight perceives that the angle subtended by the hand and by the wall is the same angle, and it also perceives that the portion covered by the hand is much larger than the hand. And since this is so, the faculty of discrimination, in arriving at this perception, perceives that the farther of the two visible objects lying at different distances and subtending the same angle is larger.

3.148 ◉ Deinde, quando visus in illa dispositione auferetur, et aspexerit alium parietem remotiorem illo pariete, et opposuerit manum eius inter visum et illum parietem, inveniet quod illud quod cooperitur ex secundo pariete est maius illo quod cooperitur ex primo. Et cum tunc aspexerit celum, inveniet quod manus eius cooperiet medium illius quod apparet de celo aut magnam portionem illius. Tamen aspiciens non dubitabit quin manus eius nichil sit respectu eius quod cooperitur de celo secundum sensum. Declaratum est ergo ex ista experimentatione quod visus non comprehendit quantitatem magnitudinis rei vise nisi ex comparatione magnitudinis rei vise ad quantitatem remotionis eius cum comparatione ad angulum, non ex comparatione ad angulum tantum. Et si comprehensio quantitatis magnitudinis esset secundum angulum tantum, opporteret ut duo visibilia diverse remotionis respicientia unum angulum apud centrum visus viderentur equalia, et non est ita. Quantitas ergo magnitudinis rei vise non comprehenditur per distinctionem nisi ex ymaginatione piramidis continentis rem visam a virtute distinctiva, et ex ymaginatione quantitatis anguli piramidis cum ymaginatione longitudinis piramidis, et ex comparatione basis piramidis ad quantitatem anguli eius et ad quantitatem longitudinis eius in simul. Et hec est qualitas comprehensionis magnitudinis.

3.148 ◉ Afterward, if the eye is shifted in this situation, and the observer looks at another wall farther away than that [first] wall, and if he places his hand between the eye and that [second] wall, he will find that the portion of the second wall covered [by his hand] is larger than the portion of the first wall covered [by his hand]. And if he then looks at the sky, he will find that his hand will cover half of what appears of it, or at least a large portion of it. Nonetheless, the observer will not doubt that, as far as sensation is concerned, his hand is nothing in comparison to the portion of the sky that is covered by it. It has therefore been shown on the basis of this experiment that sight does not perceive a visible object’s size through a correlation of angles alone, but through a correlation of the visible object’s [apparent] size to the magnitude of its distance, as well as through a correlation of angles. Moreover, if perception of the size of a magnitude were determined by angle alone, two visible objects lying at different distances and subtending the same angle at the center of sight would have to appear equal, but such is not the case. Therefore, the size of a visible object is perceived by [the faculty of discrimination] only through its imagining the cone that encompasses the visible object, while imagining the size of the angle of the cone and the length of the cone, and then correlating the [size of the] base of the cone to the size of its angle and its length, all at the same time. This is how size is perceived.

3.149 ◉ Et propter multitudinem consuetudinis visus in distinctione remotionum visibilium, quando senserit formam et remotionem rei vise, statim ymaginabit quantitatem loci forme et quantitatem remotionis, et comprehendet ex congregatione duarum istarum intentionum magnitudinem rei vise. Sed tamen quantitates remotionum visibilium sunt collocate sub magnitudinibus que comprehenduntur a visu. Et iam predictum est quod quedam quantitates remotionum visibilium comprehenduntur certe et quedam estimative, et quod illa que comprehenduntur estimative comprehenduntur assimilatione remotionis rei vise ad remotiones sibi similium ex visibilibus certificate remotionis, et quod remotiones certificate quantitatis sunt ille que respiciunt corpora ordinata et continuata. Et ex comprehensione corporum ordinatorum continuatorum respicientium ipsas a visu et ex certificatione quantitatum illorum corporum erit certificatio quantitatum remotionum visibilium que sunt apud extremitates eorum. Remanet ergo ad declarandum quomodo visus comprehendet quantitates remotionum visibilium respicientium corpora ordinata continuata et quomodo certificat quantitates corporum ordinatorum continuatorum respicientium remotiones visibilium.

3.149 ◉ Sight is so accustomed to determining the distances of visible objects that, when it senses both the form and the distance of the visible object, it will immediately imagine the size of the location of the form and the magnitude of [the object’s] distance, and, by combining these two notions, it will perceive the size of the visible object. Nevertheless, the magnitudes of the distances of visible objects form part of the set of magnitudes that are perceived by sight. And it has already been pointed out that the magnitudes of some distances of visible objects are perceived accurately, whereas others are perceived through estimation,⁑ and [it has been pointed out] that those magnitudes that are perceived through estimation are perceived by assimilating the distance of the visible object to distances like it among visible objects whose distances are accurately determined,⁑ and [it has also been pointed out] that distances that are precisely determined are ones that are spanned by a continuous, ordered range of bodies.⁑ So it is through perception by sight of the continuous, ordered bodies spanning their distances, as well as from the accurate determination of the sizes of those bodies, that the magnitudes of the distances of the visible objects flanking those bodies will be perceived. It remains, therefore, to explain how sight will perceive the magnitudes of the distances of visible objects that are spanned by a continuous and ordered range of bodies and how it accurately determines the sizes of the continuous and ordered bodies that span the distances of visible objects.

3.150 ◉ Corpora ergo ordinata continuata respicientia remotiones visibilium sunt in maiori parte partes terre. Et visibilia assueta que semper comprehenduntur a visu et frequentius sunt superficies terre, et corpus terre interiacet ipsa et corpus hominis aspicientis. Et quantitates partium terre interiacentium aspicientem et visibilia que sunt super faciem terre respicientium remotionem istorum visibilium a visu semper comprehenduntur a visu. Et comprehensio quantitatum partium terre interiacentium aspicientem et visibilia que sunt super faciem terre non est nisi ex mensuratione illarum adinvicem a visu et ex mensuratione partium terre remotarum ab eo ad partes terre propinquas illi quarum quantitates sunt certificantes. Deinde ex frequentatione comprehensionis partium terre ab eo et ex frequentatione mensurationis illarum ab eo comprehendet quantitates partium terre que sunt apud pedes per cognitionem et per assimilationem illarum ad eis similes iam prius comprehensas. Visus ergo, quando aspexerit partem terre interiacentem ipsum et rem visam, cognoscet quantitatem eius propter frequentationem comprehensionis similium illi parti terre. Et ista intentio est ex intentionibus quas sentiens adquirit a principio crescentie. Et sic pervenient quantitates remotionum visibilium assuetorum figurate in ymaginatione et quiete in anima ita quod homo non percipit qualitatem quiescentie earum.

3.150 ◉ For the most part, the bodies that are ranged in continuous order over the distances of visible objects consist of portions of the ground. And the familiar visible objects that are continually perceived by sight stand on the earth’s surface, and the ground lies between them and the body of the person who is observing. And the magnitudes of the portions of the ground that lie between the viewer and visible objects standing on the face of the earth and that span the distances between those visible objects and the eye are continually perceived by sight. Moreover, the magnitudes of the portions of the ground that lie between the viewer and visible objects standing on the face of the earth are perceived only if sight measures them against one another and measures the portions of the ground far away from the center of sight against portions of the ground that are near it and have had their magnitudes accurately determined. Then, given how often sight perceives [such] portions of ground and how often it measures them, it will perceive the magnitudes of the portions of the ground that are at [the viewer’s] feet by recognizing them and by assimilating them to ones like them that have already been perceived. Thus, when sight looks at the portion of the ground lying between it and a visible object, it will realize its magnitude because of how often it perceives portions of ground similar to that one. And this perception is among those that the sensitive faculty acquires from the very beginning of [a person’s] development. And so [notions of] the magnitudes of the distances of familiar objects will become impressed in the imagination and ensconced in the soul so that a person does not notice how they have become ensconced there.

3.151 ◉ Quomodo vero est principium comprehensionis partium terre inter ipsum et visibilia est secundum quod narrabo. Principium earum cuius quantitas certificabatur a visu est illud quod est apud pedes, quoniam quantitas illius quod est apud pedes comprehenditur a visu et a virtute distinctiva. Et virtus certificat ipsam per mensuram corporis hominis, quoniam illud quod est apud pedes semper mensuratur ab homine sine intentione per pedes eius, quando ambulat super ipsum, et per brachium eius, quando extenditur manus ad ipsum. Et omne quod est prope hominem ex terra semper mensuratur per corpus hominis, et sine intentione, et visus comprehendit istam mensurationem et sentit ipsam. Et virtus distinctiva comprehendit istam mensurationem, et intelligit ipsam, et certificat ex ea quantitates partium terre continuatarum cum corpore hominis. Quantitates ergo partium terre propinquarum homini iam sunt intellecte apud sentientem et apud virtutem distinctivam, et iam forme earum sunt ymaginate apud virtutem distinctivam et quiete in anima. Et visus comprehendit istas partes terre semper, et sentiens sentit verticationes que extenduntur a visu ad extremitates istarum partium apud comprehensionem illarum a visu et apud considerationem corporis terre a visu, et comprehendit partes superficiei membri sentientis in quas perveniunt forme istarum partium terre, et comprehendit quantitates partium visus et quantitatem angulorum quos respiciunt iste partes visus. Anguli ergo quos respiciunt partes terre propinque homini intelliguntur apud sentientem secundum transitum temporis, et forme eorum sunt ymaginate in anima. Et quantitates longitudinum linearum radialium que extenduntur a centro visus ad extremitates partium terre propinquarum homini comprehenduntur a sentiente et a virtute distinctiva, et certificantur ab ea, quoniam longitudines istarum verticationum semper mensurantur per corpus hominis sine intentione. Si ergo homo fuerit erectus et aspexerit terram apud pedes eius, erunt longitudines linearum radialium secundum quantitatem erectionis hominis, et virtus distinctiva intelliget certe quod remotio interiacens visum et partem terre est quantitas erectionis hominis.

3.151 ◉ Now the way in which the portions of the ground between the viewer and visible objects are initially perceived is as follows: the very first portion to have had its magnitude accurately determined by sight is the one at the [viewer’s] feet, for the magnitude of the portion at the [viewer’s] feet is perceived by sight and by the faculty of discrimination. But that faculty determines [its size] on the basis of the measure of the human body, for what lies at the feet is always measured unconsciously by a person according to his feet when he paces over it, or according to his arm, when he extends his hand to it. So everything on earth that is near a person is invariably measured unconsciously in terms of the human body, and sight perceives this measure and senses it. The faculty of discrimination, meanwhile, perceives this measure and understands it, and on that basis it accurately determines the magnitudes of the portions of the ground immediately surrounding the human body. Thus, the magnitudes of the portions of ground near any person have already been grasped by the sensitive faculty as well as by the faculty of discrimination, and their forms have already been imagined by the faculty of discrimination and ensconced in the soul. But sight perceives these portions of ground continually, and the sensitive faculty senses the [radial] lines that extend from the eye to the extremities of these portions when sight perceives them and when it examines the whole of the ground [before it]; it also perceives the areas on the surface of the sensitive organ where the forms of those portions of ground are projected, and it perceives the magnitudes of those areas on the eye as well as the size of the angles subtended by those areas on the eye. Thus, the angles subtended by the portions of the ground near any person are realized by the sensitive faculty over the course of time, and their forms are imagined in the soul. Also, the lengths of the radial lines extending from the center of sight to the extremities of the portions of the ground near any person are perceived by the sensitive faculty and by the faculty of discrimination, and they are accurately determined by them, for the lengths of those [radial] lines are always measured unconsciously in terms of the human body. Therefore, when a person stands upright and looks toward the ground at his feet, the lengths of the radial lines will depend on the height of the standing person, and the faculty of discrimination will realize with certainty that the distance between the eye and that portion of the ground is the height of the standing person.

3.152 ◉ Et longitudines locorum terre continuatorum cum corpore hominis sunt intellecte et percepte quantitates apud virtutem distinctivam, et forme earum sunt quiete in anima. Cum ergo visus aspexerit partem que est apud pedes, statim sentiens comprehendet verticationes pervenientes ad extremitates illius partis, et ymaginabit virtus distinctiva quantitates longitudinum verticationum pervenientium ad extremitates earum et quantitates angulorum quos continent ille verticationes. Et cum virtus distinctiva ymaginaverit quantitates longitudinum verticationum et quantitates angulorum quos continent verticationes, comprehendet quantitatem spatii que est inter extremitates illarum verticationum certa comprehensione. Secundum ergo hunc modum certificantur quantitates partium terre continentium aliquam partium terre per sensum visus.

3.152 ◉ So the extent of the areas on the ground immediately surrounding the human body is realized and perceived by the faculty of discrimination, and their forms are ensconced in the soul. When sight looks at a portion [of the ground] at the [viewer’s] feet, then, the sensitive faculty will immediately perceive the [radial] lines extending out to the extremities of that part, and the faculty of discrimination will imagine the lengths of the [radial] lines extending out to its extremities as well as the sizes of the angles formed by those [radial] lines. And when the faculty of discrimination imagines the lengths of those [radial] lines and the sizes of the angles formed by those [radial] lines, it will accurately perceive the magnitude of the space between the endpoints of those [radial] lines. It is in this way, then, that the magnitudes of the parts of earth encompassing some portion of the ground⁑ are accurately determined by the sense of sight.

3.153 ◉ Deinde quantitates partium terre sequentium istas partes in remotione comprehenduntur a visu ex comparatione quantitatum partium linearum radialium que extenduntur ad extremitates earum ad quantitates radialium que extenduntur ad primas partes que sequuntur hominem. Et sic comparat virtus distinctiva lineas radiales tertio loco venientes ad radios secundos communes prime parti et secunde, et percipit quantitatem augmentationis tertii radii super secundum. Et cum hoc senserit, sentiet quantitatem tertii radii, et ipse comprehendet quantitatem secundi radii certa comprehensione. Erunt ergo duo radii continentes partem secundam terre note quantitatis apud virtutem distinctivam, et similiter erit situs eorum notus apud ipsam. Et cum comprehenderit longitudinem duorum radiorum et situm eorum, comprehendet spatium quod est inter extremitates eorum certa comprehensione. Secundum ergo hunc modum comprehendet virtus distinctiva etiam quantitates partium terre sequentium partes continentes pedes.

3.153 ◉ Subsequently, the magnitudes of the portions of ground at the next remove from these portions are perceived by sight through a comparison of the lengths of the radial line-segments that extend to their extremities to the lengths of the rays that extend to the initial portions [of ground] immediately surrounding the person. And thus the faculty of discrimination compares the radial lines reaching a third location to the second rays that mark the dividing-line between the first and second portions [of ground], and it perceives the increase in length of the third ray over that of the second one. And when it senses this, it will sense the length of the third ray, and it will accurately perceive the length of the second ray. The length of the two rays comprehending the second portion of ground will thus have been accurately determined by the faculty of discrimination, and their spatial disposition will have also been accurately determined by it. And when it perceives the length and spatial disposition of the two rays, it will accurately perceive the [magnitude of the] interval between their endpoints.⁑ It is in this way, therefore, that the faculty of discrimination will also perceive the extent of the portions of ground at the next remove from those at the [viewer’s] feet.

3.154 ◉ Et etiam partes sequentes partes continentes pedes semper etiam mensurantur per corpus hominis. Quoniam, quando homo ambulaverit super terram, mensurabitur terra super quam ambulat per pedes eius et passus, et comprehendet virtus distinctiva quantitatem eius. Et cum homo pertransierit locum in quo fuit et partes continuatas cum pedibus eius, et pervenerit ad illas partes sequentes, mensurabuntur etiam iste partes sicut mensurabantur etiam priores, et comprehendet etiam sequentes sicut comprehendebat priores. Et ista comprehensio erit certificata sine dubio, et sic certificabitur ab eo per comprehensionem istam secundam prima comprehensio. Si ergo quantitas eius non fuerit primo certificata, certificabitur secundo. Et ista commensuratio comprehenditur a sentiente semper, et utitur ipsa sine intentione sollicita, sed aspecta aliqua partium terre a visu, comprehendit sentiens et virtus distinctiva istam mensurationem per viam accidentalem sine intentione. Deinde propter frequentationem istius intentionis sunt iam certificate quantitates partium terre sequentium pedes et quantitates eorum que sequuntur ipsas. Secundum ergo hunc modum adquirit sentiens et virtus distinctiva quantitates partium terre continentium hominem interiacentium visum et visibilia, et ista adquisitio est in principio crescentie hominis. Deinde adquiescunt quantitates remotionum visibilium assuetorum que sunt super faciem terre apud sentientem et apud virtutem distinctivam. Erit ergo comprehensio remotionum visibilium assuetorum que sunt super faciem terre per cognitionem et assimilationem eorum adinvicem.

3.154 ◉ Moreover, the portions of ground at the next remove from those at the [viewer’s] feet are invariably measured in terms of the human body. For when a person paces over the ground, he will measure the ground over which he paces according to [the measure of] his feet and his pace, and the faculty of discrimination will perceive its extent. And when a person traverses the location where he was and continues to pace over successive portions [of ground] with his feet, when he comes to those successive portions of ground, he will measure them in the same way he measured the previous ones, and he will perceive those successive portions of grounds in the same way he did the previous ones. And this perception will be absolutely determinate, and so his first perceptual determination will be corroborated by this second perceptual determination. Hence, if its extent was not accurately determined by the first perceptual pass, it will be accurately determined by the second. And this comparative measurement is invariably perceived by the sensitive faculty, and it avails itself of such measurement without any conscious effort, and when some portion of ground is scanned by sight, the sensitive faculty and the faculty of discrimination perceive its measure automatically rather than through conscious effort. Then, because of the continual recurrence of this process, the extent of the portions of ground passed over by the feet is accurately determined, as is the extent of the portions next in order. In this way, then, the sensitive faculty and the faculty of discrimination grasp the magnitudes of the portions of ground immediately surrounding a person and lying between his eye and visible objects, and this grasp occurs at the very beginning of a person’s development. Subsequently, through their sensitive and discriminative faculties, people grasp the magnitudes of the distances of familiar visible objects standing on the face of the earth. Thus, the perception of the distances of familiar visible objects standing on the face of the earth will be due to recognition and the assimilation of those distances to one another.⁑

3.155 ◉ Et est dicere comprehensionem quantitatum remotionum visibilium per adquisitionem a sentiente et a virtute distinctiva non quod ista comprehendit quot cubiti sunt in qualibet remotione; sed adquirit ex qualibet remotione et ex qualibet parte terre quantitatem ymaginatam et determinatam, et ad illas quantitates determinatas comparat quantitates remotionum visibilium quas comprehendit post. Et similiter adquirit ex cubito, et palma, et a qualibet quantitate mensurata quantitatem determinatam. Quando ergo aspiciens comprehenderit aliquod spatium et voluerit scire quot cubiti fuerint in eo, comparabit formam adquisitam ex ymaginatione ex illo spatio ad formam adquisitam in ymaginatione ex cubito, et comprehendet per istam comparationem spatii quantitatem respectu cubiti.

3.155 ◉ Now this is not to say that the perception of the magnitudes of the distances of visible objects, which is carried out by the sensitive faculty and the faculty of discrimination, is a matter of perceiving the number of cubits that a given distance is; rather, the viewer derives a determinate, imagined magnitude from some given distance and some given portion of ground, and he compares such determinate magnitudes to the magnitudes of the distances he perceives later. Likewise, it is from the cubit, or the palm’s-breadth, or some other measured magnitude that he derives a determinate magnitude. Thus, when a viewer perceives some space and wants to know how many cubits it spans, he will compare the form of that space that has been derived by the imagination to the form of a cubit that has been acquired by the imagination, and, on the basis of this comparison, he will perceive the magnitude of the space in terms of cubits.⁑

3.156 ◉ Et etiam ex assuetudine hominis est quod, quando voluerit certificare aliquam intentionem, frequentabit aspectum eius, et distinguet intentiones eius, et considerabit tempus, et per illud comprehendet illam intentionem secundum veritatem. Aspiciens ergo quando comprehenderit aliquam rem visam super faciem terre et voluerit certificare remotionem eius, intuebitur partem terre continuatam interiacentem ipsum et rem visam, et movebitur visus in longitudine ipsius. Et sic movebitur axis radialis super illam partem, et mensurabit ipsam, et comprehendet ipsam secundum singulares partes, et sentiet partes eius parvas quando remotio illius ultimi spatii fuerit mediocris. Et quando visus comprehenderit partes terre et comprehenderit partes parvas, comprehendet virtus distinctiva quantitatem totius spatii, quoniam per motum axis radialis super spatium certificabit virtus distinctiva quantitatem partis visus in quam pervenit forma illius spatii, et quantitatem anguli quem respicit illud spatium, et quantitatem longitudinis radii qui extenditur ad ultimum spatii. Et cum iste due intentiones certificabuntur a virtute distinctiva, certificabitur quantitas partis terre vise. Et similiter quantitates longitudinum corporum elevatorum a terra extensorum in parte remota, sicut parietum et montium, comprehenduntur a visu sicut comprehenduntur quantitates partium terre, et comprehendet remotiones visibilium respicientium ipsas ex comprehensione quantitatum longitudinum earum. Secundum ergo hunc modum certificat visus quantitates remotionum visibilium que fuerint in remotionibus mediocribus et fuerint respicientia corpora ordinata continuata.

3.156 ◉ It is also normal for a person, when he wants to determine some property accurately, to look at it repeatedly, to differentiate its particular characteristics, and to take his time examining it, and thus he will perceive that property as it actually exists. Therefore, when the viewer perceives any visible object on the ground and wants to determine its distance accurately, he will scrutinize the portion of ground lying directly between him and the visible object, and he will move his line-of-sight along it. And so he will move his visual axis over that portion of ground, and he will measure it, and he will perceive it according to its individual parts, and he will sense its small parts when the distance of the outer limit of this space is moderate. And when sight perceives the portions of the ground and perceives their small parts, the faculty of discrimination will perceive the magnitude of the entire space, for, by passing the visual axis over that space, the faculty of discrimination will accurately determine the size of the area on the eye upon which the form of that space is projected, the size of the angle subtended by that area,⁑ and the length of the ray that extends to the outer limit of that space. When these last two characteristics are accurately determined by the faculty of discrimination, it will accurately determine the magnitude of the portion of ground that is seen. So too, the distances of objects, such as walls and mountains, that stand above the earth’s surface and lie far away [from the viewer] are perceived by sight in the same way as the magnitudes of the portions of the earth are, and sight will perceive the distances of visible objects ranged along them by perceiving the magnitudes of their lengths. This, then, is how sight accurately determines the magnitudes of the distances of visible objects that lie at moderate distances, those distances being spanned by a range of continuous, ordered bodies.

3.157 ◉ Quedam autem visibilia que sunt super faciem terre habent remotionem mediocrem, et quantitates partium terre interiacentium visum et ipsa sunt quantitates mediocres. Et quedam sunt quorum remotio est maxima et extra mediocritatem, et quantitates partium terre interiacentium visum et ipsa sunt extranee magnitudinis. Et quantitates partium terre comprehenduntur a visu secundum modos quos narravimus. Illud ergo eorum quod est propinquum et mediocris quantitatis comprehenditur et certificatur a visu, et quod est ex eis extranee remotionis non certificatur a visu quantitas eius. Quoniam visus, quando consideravit spatia, comprehendit quantitates eorum dum senserit augmentationem longitudinis radii, et dum senserit angulos quos respiciunt partes parve partium spatii apud motum axis super spatium. Et certificabit quantitatem spatii dum senserit parvam augmentationem in longitudine radii et augmentationem parvam in angulo quem respicit spatium. Et cum remotio fuerit maxima, non sentiet augmentationem parvam in longitudine radii, nec sentiet motum radii super parvam partem spatii cuius remotio est maxima, nec sentiet angulum quem respicit parva pars remotionis maxime, nec certificabit longitudinem radii pervenientis ad extremum spatii, nec certificabit quantitatem anguli quem respicit spatium illud. Et cum non certificaverit longitudinem radii pervenientis ad extremum spatii, nec certificavit quantitatem anguli quem respicit spatium, non certificabit quantitatem spatii.

3.157 ◉ Now some visible objects that stand on the ground lie at moderate distances, and the portions of ground lying between them and the center of sight are of moderate extent. But some lie at extreme and inordinate distances, and the portions of ground lying between them and the center of sight are of inordinate extent. But the extent of portions of ground is perceived by sight in the ways we have described. Accordingly, the extent of any of them that lies near [the viewer] and is of moderate size is perceived and accurately determined by sight, whereas the extent of any of them that lies at an inordinate distance is not accurately determined by sight. For when it examines intervals, sight perceives their extent as long as it senses the increase in the length of the rays, and as long as it senses the angles subtended by the small parts of the portions of space as the visual axis scans the space. And it will accurately determine the extent of the space as long as it senses a slight increase in the length of the ray and a slight increase in the angle subtended by the given space. But when the distance is extreme, sight will not sense the slight increase in the length of the ray, nor will it sense the motion of the ray over a small portion of a space that lies extremely far away, nor will it sense the angle subtended by a small portion [of ground] that lies extremely far away, nor will it accurately determine the length of the ray extending to the outer limit of the space, nor will it accurately determine the size of the angle subtended by that space. And since it does not accurately determine the length of the ray extending to the outer limit of that space, and since it has not accurately determined the size of the angle subtended by the space, it will not accurately determine the extent of the space.

3.158 ◉ Et etiam, quando remotio fuerit maxima, partes parve que sunt in ultimo spatii non comprehenduntur a visu nec distinguuntur ab eo, quoniam parva quantitas in remotione maxima latet visum. Cum ergo axis radialis movebitur super spatium remotum maximum et perveniet ad remotionem maximam, transibit partem parvam spatii, et non sentiet sentiens motum eius, quoniam pars parva in remotione maxima non facit angulum sensibilem apud centrum visus. Cum ergo axis radialis movebitur super spatium remotum, et senserit visus quod ipse iam transierit partem aliquam spatii, quantitas illius partis quam transivit non erit quantitas quam comprehendit per sensum, sed erit maior. Et quanto magis augmentabitur remotio spatii, tanto magis erunt partes latentes visum apud ultimum spatii, et super quas latet motus radii visus, erunt scilicet maiores. Quantitates ergo remotionum maximarum que sunt super faciem terre non certificantur a visu, quoniam non certificat quantitatem longitudinis radii pervenientis ad ultimum earum nec quantitatem anguli quem respicit spatium illud.

3.158 ◉ In addition, when the distance is extreme, the small portions [of ground] that lie at the outer limit of the space are not perceived or distinguished by sight, for a small magnitude disappears from sight at an extreme distance. Thus, when the visual axis is moved over a space that is inordinately far away, and when it reaches the outer limit of that space, it will pass over a small portion of the space, so the sensitive faculty will not sense its motion, because a small portion [of ground] at an extreme distance does not subtend a perceptible angle at the center of sight. So if the visual axis moves over a distant space, and if sight senses that it has just passed over some portion of that space, then the extent of the portion it has passed over will not be the extent perceived through sense; rather, it will be larger.⁑ And as the space extends out farther, the portions [of ground] toward the outer limit of the space that disappear from sight will become larger, as will the portions over which the motion of the rays is not sensed. Thus, the extent of extreme distances on the ground are not accurately determined by sight, because it cannot accurately determine the length of the ray[s] extending to their outer limit, nor can it accurately determine the size of the angle subtended by that space.

3.159 ◉ Et etiam sentiens sentit certificationem quantitatis spatii, quoniam visibile propinquum visui in remotione mediocri est magis certe visionis, scilicet, quia forme eorum sunt manifestiores et comprehenduntur a visu manifestiori comprehensione. Et color et lux eorum sunt manifestiores, et situs superficierum eorum apud visum, et situs partium eorum, et forma partium eorum et partium superficierum sunt manifestiores visui. Et si in eis fuerit lineatio aut pictura aut partes parve, apparebunt visui manifestius. Et non est ita de visibilibus maxime remotionis. Quoniam res visa, quando fuerit in remotione maxima, non certificabit visus formam eius secundum suum esse, et dubitabit in colore, et luce, et forma superficierum eius, et nichil apparebit in ea ex subtilibus intentionibus et ex partibus parvis. Et ista intentio est manifesta sensui. Cum ergo visus comprehenderit aliquod spatium super faciem terre, statim postquam viderit ultimum eius et quedam visibilia in ultimo eius, sentiet quod illud spatium est ex spatiis mediocribus aut ex spatiis maxime remotionis. Si vero certificaverit formam ultimi eius aut formam rei vise que est apud ultimum eius manifeste, et distinxerit cum hoc quantitatem illius spatii secundum modum predictum, tunc virtus distinctiva cum hoc comprehendet quod quantitas illius spatii est certificata ex comprehensione manifestationis forme ultimi eius aut forme rei vise que est apud ultimum eius. Si autem non certificaverit formam ultimi eius aut formam etiam rei vise que est apud ultimum eius, non certificabit quantitatem illius spatii. Et cum hoc virtus distinctiva apud considerationem illius spatii comprehendit quod etiam illud spatium non est certificate quantitatis propter latentiam forme ultimi eius aut forme rei vise que est apud ultimum eius.

3.159 ◉ Furthermore, the sensitive faculty senses the fact that the magnitude of the space has been determined, for a visible object that lies near the eye at a moderate distance is seen more clearly [than one lying farther away] precisely because the forms of such [objects] are clearer and are more clearly perceived by sight. Moreover, their color and illumination are clearer to sight, as are the spatial dispositions of their surfaces and the spatial dispositions of their parts, and the form of their parts and the parts of their surfaces are clearer to sight.⁑ Also, if there is some design or picture [in them], or [if they have] small subdivisions, those designs or subdivisions will appear more clearly to sight. But such is not the case for visible objects lying extremely far away. For when a visible object lies extremely far away, sight will not determine its form as it actually is but will be uncertain about its color, its luminosity, and the form of its surfaces, and none of the subtle characteristics or small subdivisions in it will appear. And this fact is evident to sense. Therefore, when sight perceives some space on the ground and immediately afterward sees its outer limit along with some visible objects at its outer limit, it will sense that the space lies at a moderate distance or lies inordinately far away. On the one hand, if it accurately determines the form of its outer limit or the form of a visible object at its outer limit with perfect clarity, and if, in addition, it distinguishes the extent of that space in the way previously described, then on that basis the faculty of discrimination will perceive that the extent of that space is accurately determined by perceiving the clarity of the form of its outer limit or the form of the visible object at its outer limit. On the other hand, if it does not accurately determine the form of its outer limit or the form of a visible object at its outer limit [with clarity], then it will not accurately determine the extent of that space. In addition to this, after having examined this space, the faculty of discrimination perceives that the extent of this space is not accurately determined because of the indefiniteness of the form of its outer limit or the form of the visible object at its outer limit.

3.160 ◉ Quantitates ergo remotionum visibilium distinguentur a visu, et qualitas comprehensionis quantitatum earum certificatur apud intuitionem, et quando aspiciens voluerit certificare quantitatem rei vise et certificare quantitatem remotionis rei vise, intuebitur remotionem et distinguet ipsam, et sic distinguetur ab eo remotio certificata a remotione non certificata. Et nichil est ergo ex remotionibus visibilium cuius quantitas sit certificata nisi remotiones respicientes corpora ordinata continuata, et cum hoc sunt remotiones mediocres. Quantitates ergo huiusmodi remotionum comprehenduntur a visu secundum modum quem declaravimus, et preter ista non certificantur a visu; sed existimantur et assimilantur, scilicet quia visus assimilat remotionem rei vise remotioni sibi similium ex visibilibus assuetis quorum quantitas remotionis est certificata iam ab eo. Et cum visus senserit iam latentiam forme rei vise propter remotionem, dubitabit in quantitate remotionis eius. Et remotio mediocris cuius quantitas certificatur a visu est remotio apud cuius ultimum non latet visum pars habens proportionem sensibilem ad totam remotionem. Et remotio mediocris respectu rei vise in qua visus comprehendit unam quantitatem rei vise est remotio mediocris apud cuius ultimum non latet pars illius rei vise habens proportionem sensibilem ad quantitatem rei vise quando visus intuebitur illam partem per se. Omne ergo spatium cuiuslibet partis longitudo, scilicet habens proportionem sensibilem ad quantitatem longitudinis spatii, comprehenditur a visu, et non latet visum ex partibus spatii que sunt apud ultimum eius nisi illud quod caret proportione sensibili ad longitudinem illius spatii, et tale omne spatium est ex remotionibus mediocribus. Remotio autem que est extra mediocritatem in magnitudine est illa apud cuius ultimum latet quantitas habens proportionem sensibilem ad totam illam remotionem. Et remotio que est extra mediocritatem respectu visus est illa in qua latet quantitas aliqua ex illa re visa habens proportionem sensibilem ad totam illam rem visam, aut latet aliqua intentio illius rei vise cuius latentia operatur in latentiam quiditatis illius rei vise.

3.160 ◉ Therefore, the magnitudes of the distances of visible objects will be distinguished by sight while the way in which their magnitudes are perceived is accurately determined at the moment of perception, and if the viewer wants to accurately determine the size of a visible object or to accurately determine the magnitude of the distance of a visible object, he will scrutinize the distance and define it, and thus a determinate distance will be distinguished by him from an indeterminate one. Thus, the only distances of visible objects that are of a determinate size are those distances that are spanned by a continuous, ordered range of bodies and, moreover, that are moderate. The magnitudes of these sorts of distances are therefore perceived by sight in the way we have shown, and no others are accurately determined by sight; instead they are estimated and assimilated—i.e., sight assimilates the distance of a visible object to ones similar to it among familiar visible objects whose distances have already been accurately determined by it. But the moment sight senses the indefiniteness of the form of a visible object that is due to [extreme] distance, it will be uncertain about how far away it is. Now a distance whose magnitude is accurately determined by sight is [considered] moderate when a portion of it that is of a perceptible size in relation to the whole and that lies at its outer limit does not disappear from sight. Moreover, with regard to a visible object whose size is [correctly] perceived by sight, a distance is [considered] moderate when, at its outer limit, a portion of that object that is of a perceptible size in relation to the whole does not disappear from sight if sight focuses on that part by itself. Thus, any space is [considered to be] of moderate extent if, in forming part of a length, it has a perceptible size in relation to the length as a whole, and if it is perceived by sight, so that no portion of the space, except one that has no perceptible size in relation to the length of that space, disappears from sight. A distance that is of inordinate extent, however, is one in which a [quantifiable] portion at its outer limit lacks perceptible size in relation to the length as a whole. And a distance that is inordinate with respect to sight is one in which any magnitude contained by it that has a perceptible size in relation to the whole disappears from sight, or when some characteristic of the visible object [at that distance] is invisible, that invisibility preventing the visual perception of precisely what that visible object is.

3.161 ◉ Et etiam sentiens comprehendet quantitatem remotionis rei vise ex quantitate anguli quem respicit res visa. Quoniam, quando visus comprehenderit visibilia assueta que sunt in remotionibus assuetis, statim apud comprehensionem cognoscet ipsa visus, et quando visus cognoverit ipsa, cognoscet quantitates magnitudinum eorum, quoniam quantitates magnitudinum eorum iam fuerunt certificate propter frequentationem comprehensionis cuiuslibet visibilium assuetorum, et iam sunt quiete in ymaginatione. Et visus, statim cum comprehendit rem visam assuetam, comprehendit partem visus in qua pervenit forma illius rei vise quam respicit illa pars. Et cum sentiens comprehenderit illam quantitatem magnitudinis rei vise per cognitionem, et comprehenderit angulum quem tunc respicit illa res visa, comprehendet quantitatem remotionis illius rei vise in illa dispositione, quoniam angulus quem respicit illa res visa non erit nisi secundum quantitatem remotionis. Et sicut sentiens recipit significationem super quantitatem magnitudinis et remotionem cum illo angulo, ita accipit significationem super quantitatem remotionis ex quantitate magnitudinis cognite apud ipsam cum illo angulo. Quoniam illa magnitudo non respicit illum angulum nisi ex illa eadem remotione aut ex remotione equali illi, non ex omnibus remotionibus. Et cum sentiens comprehenderit quantitatem remotionis illius rei vise assuete multotiens et frequenter in horis in quibus illa res visa respicit apud centrum visus simile illi angulo, et multotiens acceperat significationem super quantitatem magnitudinis illius rei vise ex quantitate remotionis illius rei vise cum quantitate anguli qui est equalis illi angulo, virtus distinctiva intelliget quantitatem remotionis in qua comprehendit magnitudinem illius rei vise respectu illius anguli. Et cum virtus distinctiva intellexerit quantitatem remotionis illius rei vise respectu illius anguli, et comprehenderit in ista remotione magnitudinem illius rei vise respectu illius eiusdem anguli quando virtus distinctiva cognoverit illam rem visam, et cognoverit quantitatem magnitudinis eius quam ante comprehenderit, et comprehenderit statim quantitatem anguli quam tunc respicit illa res visa, cognoscet quantitatem remotionis secundum quam illa remotio respicit illum angulum. Sentiens ergo comprehendit quantitatem remotionum visibilium assuetorum ex comparatione anguli ad magnitudinem rei vise. Deinde propter frequentationem comprehendet sentiens remotionem rei vise assuete per cognitionem. Et erit quantitas anguli quem respicit res visa assueta apud comprehensionem eius cum cognitione illius rei vise signum super quantitatem remotionis illius rei vise, et plures remotionum visibilium assuetorum comprehenduntur secundum hunc modum. Et ista comprehensio non est in fine certificationis, tamen inter istam remotionem et remotionem certificatam non est maxima diversitas, et ex ista comprehensione opinati sunt mathematici quod magnitudo rei vise comprehenditur per angulum. Visibilia ergo assueta que sunt in remotionibus assuetis, quando visus comprehenderit ipsa et cognoverit quantitates remotionum istorum secundum istam viam, inveniet veritatem rei in maiori parte in quantitatibus remotionum eorum, aut non erit inter illud quod comprehendit ex quantitatibus remotionum eorum et inter remotiones veras magna diversitas.

3.161 ◉ The sensitive faculty will also perceive the magnitude of a visible object’s distance according to the size of the [visual] angle subtended by the visible object. For, when it perceives familiar objects that lie at familiar distances, sight will immediately recognize them at the moment of perception, and when sight recognizes them, it will recognize their sizes, for their sizes will already have been accurately determined on account of the frequency with which any of the familiar visible objects has been perceived, so they [will] have become ensconced in the imagination. Moreover, as soon as it perceives a familiar visible object, sight perceives the area on the eye upon which the form of that visible object is projected and which corresponds to that form. Then, when the sensitive faculty perceives the size of the visible object through recognition, and when it perceives the angle subtended by that visible object at this time, it will perceive the magnitude of the distance of the visible object in that situation, for the angle subtended by that visible object will depend entirely on the magnitude of the distance.⁑ And just as the sensitive faculty gets an indication of the size and distance [of the object] from that angle, so too it gets an indication of the magnitude of its distance from the size that is recognized by it along with the angle. For that magnitude subtends that angle at that particular distance alone, or at one equal to it, not at every distance. And since the sensitive faculty perceives the magnitude of the distance of that familiar visible object with great frequency, during which times that visible object subtends a similar angle at the center of sight, and since it will have gotten continual indications of the size of that visible object from the magnitude of the distance of that visible object along with the size of an angle equal to that [currently perceived] angle, the faculty of discrimination will apprehend the magnitude of the distance at which it perceives the size of that visible object in relation to that angle. And when the faculty of discrimination apprehends the magnitude of the distance of that visible object in relation to that angle, and when at that distance it perceives the size of that visible object with respect to that same angle at the time the faculty of discrimination recognizes that visible object, and when it recognizes its size, having perceived it before, and when it immediately perceives the size of that angle subtended by that visible object at this time, it will perceive the magnitude of the distance according to which that particular distance corresponds to that particular angle. Thus, the sensitive faculty perceives the magnitude of the distances of familiar visible objects by correlating the angle to the size of the visible object. Then, from continual reiteration, the sensitive faculty will perceive the distance of a familiar visible object through recognition. At the time the angle is perceived and the familiar visible object is recognized, the size of the angle subtended by the visible object will serve as an indication of the magnitude of the distance of that visible object, and the majority of the distances of familiar visible objects are perceived in this way. But this perception is not particularly accurate, although there is no significant discrepancy between the distance [derived in this way] and the correctly determined distance, so it is from this [type of ] perceptual process that the mathematicians have supposed that the size of any visible object is perceived through the angle.⁑ Thus, when sight perceives familiar visible objects that lie at familiar distances, and when it recognizes the magnitudes of their distances in this way, it will, for the most part, arrive at the truth of the matter in regard to the magnitudes of their distances, or there will be no significant discrepancy between the magnitudes of their distances as perceived by it and the true magnitudes of their distances.

3.162 ◉ In illo autem quod visus comprehendit ex quantitatibus remotionum visibilium extraneorum que non frequenter comprehendit, visus erratur in maiori parte, et cum hoc forte inveniet aliquando in eo quod comprehendit ex quantitatibus earum secundum hunc modum. Secundum ergo istos modos quos declaravimus comprehenduntur quantitates remotionum visibilium per sensum visus.

3.162 ◉ In the case, however, of the magnitudes of the distances of unfamiliar visible objects that it does not perceive with frequency, sight generally errs, although sometimes it may find itself reckoning their sizes [correctly] in this way. According to the ways we have described, then, the magnitudes of the distances of visible objects are perceived by the sense of sight.

3.163 ◉ Et postquam declarata est qualitas comprehensionis quantitatum remotionum visibilium, et distincte sunt remotiones visibilium, distinguemus modo magnitudines visibilium que comprehenduntur a visu, et distinguemus comprehensionem illorum a visu. Dicamus ergo quod magnitudines quas comprehendit visus apud oppositionem sunt quantitates superficierum visibilium, et quantitates partium superficierum visibilium, et quantitates terminorum superficierum visibilium, et quantitates terminorum partium superficierum visibilium, et quantitates spatiorum que sunt inter terminos partium superficierum visibilium, et quantitates spatiorum que sunt inter visibilia distincta. Et isti sunt omnes modi quantitatum quas comprehendit visus apud oppositionem rei vise. Quantitas autem corporis rei vise non comprehenditur a visu apud oppositionem, quoniam visus non comprehendit totam superficiem corporis apud oppositionem; et non comprehendit nisi illud quod sibi opponitur ex superficie corporis eius, quamvis corpus sit parvum. Et si visus comprehenderit corporeitatem corporis, non comprehendet quantitatem corporis eius, sed figuram corporeitatis tantum. Si ergo corpus fuerit motum, aut visus moveatur ita quod visus comprehendat totam superficiem corporis per sensum aut per significationem, tunc virtus distinctiva comprehendet quantitates corporeitatis eius per secundam argumentationem preter argumentationem qua usa est apud visionem. Et similiter virtus distinctiva, cum comprehendet quantitatem corporeitatis cuiuslibet partium corporis, non comprehendet ipsam nisi per argumentationem secundam preter argumentationem que est apud visionem. Quantitates ergo quas visus comprehendit apud oppositionem non sunt nisi quantitates superficierum et linearum quas determinavimus tantum.

3.163 ◉ Having shown how the magnitudes of the distances of visible objects are perceived, and having analyzed the distances of visible objects, we shall now analyze the [kinds of] magnitudes of visible objects that are perceived by sight as well as analyzing their perception by sight. Accordingly, we should say that the [kinds of] magnitudes that sight perceives from a facing position are the magnitudes of visible surface, the magnitudes of the parts of visible surfaces, the magnitudes of the boundaries of visible surface, the magnitudes of the boundaries of the parts of visible surfaces, the magnitudes of the intervals between the boundaries of the parts of visible surfaces, and the magnitudes of the intervals between individual visible objects. These are the only kinds of magnitudes that sight perceives from a facing position. Now the size of the body of a visible object is not perceived by sight from a facing position, for sight does not perceive the entire surface of a body from a facing position; it perceives only that portion of its surface that faces it, even if the body is small. And if sight does perceive the mass of the body, it will perceive not the size of its body but, rather, the shape of its mass. Thus, if the body is moved, or if the eye moves so that sight perceives the body’s entire surface [directly] by sensation or through defining features, then the faculty of discrimination will perceive the sizes of its mass by means of a secondary deduction beyond the deduction that is used during the visual process itself. Likewise, when it perceives the size of the mass of any part of the body, the faculty of discrimination will only perceive it by means of a secondary deduction beyond the deduction that is used during the visual process itself. Thus, the magnitudes that sight perceives from a facing position are only the sizes of the surfaces or lines that we have specified.

3.164 ◉ Et iam declaratum est quod comprehensio magnitudinis non est nisi ex comparatione basis piramidis radialis continentis magnitudinem ad angulum piramidis qui est apud centrum visus et longitudinem piramidis, que est remotio magnitudinis rei vise. Et iam declaratum est quod quedam remotiones visibilium sunt certificate, et quedam estimate. Magnitudines autem visibilium quorum est remotio certificata comprehenduntur a visu ex comparatione magnitudinum earum ad angulos quos respiciunt ille magnitudines apud centrum visus et ad remotiones eorum certificatas. Comprehensio ergo quantitatum remotionum huiusmodi visibilium erit comprehensio certificata. Quantitates autem remotionum visibilium quorum remotio est estimata et non certificata comprehenduntur a visu ex comparatione magnitudinis eorum ad angulos quos respiciunt ille magnitudines apud centrum visus et ad remotiones earum estimatas et non certificatas. Comprehensio ergo quantitatum remotionum huiusmodi visibilium erit comprehensio non certificata. Cum ergo sentiens voluerit certificare quantitatem magnitudinis alicuius rei vise, movebit visum super suos dyametros, et sic movebitur axis radialis super omnes partes rei vise. Si ergo remotio rei vise fuerit ex remotionibus maximis, statim apparebit sensui latentia forme eius, et manifestabitur sentienti quod quantitas eius non est certificata. Et si remotio rei vise fuerit ex remotionibus mediocribus, statim apparebit sensui verificatio visionis eius. Si ergo axis radialis moveatur super illud quod est huiusmodi visibilium, mensurabit ipsum vera mensuratione, et comprehendet partes eius, et certificabit quantitates partium eius. Et per motum certificabit quantitates partium superficiei membri sentientis in qua pervenit forma illius rei vise et quantitatem anguli piramidis quem respicit illa pars. Et cum voluerit certificare remotionem eius super corpus respiciens remotionem eius, et per motum certificabit quantitatem corporis respicientis remotionem eius que est equalis secundum sensum longitudinibus linearum radialium. Et cum sentiens certificaverit quantitatem remotionis rei vise et quantitatem anguli quem continet piramis continens rem visam, certificabit quantitatem illius rei vise.

3.164 ◉ It has already been shown that the perception of size is due only to a correlation of the base of the visual cone encompassing the size to the angle of the cone at the center of sight and to the length of the cone, which represents the magnitude of the distance of the visible object.⁑ It has also been shown that certain distances of visible objects are accurately determined, and certain of them are estimated.⁑ The sizes of visible objects whose distance is accurately determined are perceived by sight through a correlation of their sizes to the angles subtended by those magnitudes at the center of sight, as well as to their determinate distances. Thus, the perception of the magnitudes of the distances of such visible objects will be a determinate perception. The magnitudes of the distances of visible objects whose distance is estimated, not determinate, however, are perceived by sight through a correlation of their size to the angles subtended by those magnitudes at the center of sight, as well as to their estimated, not determinate, distances. Accordingly, the perception of the magnitudes of the distances of such visible objects will not be accurately determined. When the sensitive faculty wants to determine the size of any visible object with accuracy, then, it will move the line-of-sight over its cross-sections, and so it will move the visual axis over all portions of the visible object. Hence, if the distance of the visible object is extreme, the indefiniteness of its form will be immediately revealed to the sense, and it will be obvious to the sensitive faculty that its size is not accurately determined. But if the distance of the visible object is moderate, then the determinate nature of its visual perception will be immediately revealed to the sense. Accordingly, if the visual axis is moved over a visible object of this sort, sight will measure it correctly, and it will perceive its parts, and it will accurately determine the sizes of its parts. And through [such] motion sight will accurately determine the sizes of the areas on the surface of the sensitive organ upon which the form of the visible object is projected as well as the size of the angle of the visual cone subtended by that part. Then, if it wishes to accurately determine the distance of that object on the basis of some intervening entity, sight will accurately determine the extent of that entity by the [axial] motion [just described], the [overall] extent [of that entity] being virtually equal to the lengths of the radial lines.⁑ So when the sensitive faculty accurately determines the magnitude of the visible object’s distance and the size of the angle forming the cone that encompasses the visible object, it will accurately determine the size of that visible object.

3.165 ◉ Motus autem axis super partes rei vise non erit per girationem axis a loco centri et per motum eius per se super partes rei vise, quoniam iam declaratum est quod ista linea semper est extensa recte usque ad locum girationis nervi super quem componitur oculus. Et cum situs eius a visu non mutatur, sed totus oculus movetur in oppositione rei vise, et medium loci, qui est locus sensus visus, opponitur cuilibet parti partium rei vise, et cum totus visus movebitur in oppositione rei vise, axis transibit per quamlibet partium rei vise. Et tunc forma cuiuslibet partium rei vise extenditur ad visum apud perventum axis ad ipsam super rectitudinem axis. Et cum hoc erit axis fixus in suo situ, et non mutabitur a suo loco respectu omnium partium totius oculi. Et erit giratio eius in ista dispositione apud motum totius visus in loco nervi qui est apud concavum ossis tantum.

3.165 ◉ Now the motion of the [visual] axis over the parts of the visible object will not be due to a rotation of the axis from the center of the eye, or through its independent motion over the parts of the visible object, for it has already been shown that this line always extends directly to the place where the nerve to which the eye is attached flexes.⁑ And since its situation does not change with respect to the [center of] the eye, but, rather, the entire eye moves in opposition to the visible object while the central location, which is the center of the sense of sight, faces any part of the visible object, and since the entire eye will move in opposition to the visible object, the [visual] axis will pass over every part of the visible object. And so the form of any part of the visible object extends to the eye straight along the [visual] axis when the axis reaches it. Still, the [visual] axis will remain fixed in its situation, so it will not change its situation with respect to any part of the eye as a whole. And, under this condition, its rotation will be due solely to the motion of the entire eye at the place in the eyesocket where the nerve [flexes].

3.166 ◉ Et cum visus voluerit intueri rem visam et inceperit intueri in extremitatem rei vise, erit tunc extremum axis super partem extremam rei vise. Erit ergo in ista dispositione maior pars totius rei vise in parte superficiei visus declinante aut obliqua ab axe ad aliquam partem preter partem super quam est axis, quoniam forma extremitatis eius erit in medio eius et in loco axis in visu, et erit residuum forme obliquum ad aliam partem ab axe. Deinde, quando visus movebitur post istam dispositionem super aliam dyametrum rei vise, transferetur axis ad partem sequentem illam partem illius, et erit forma prime partis declinans ad alterum ubi oppositum ubitati ad quam movetur axis. Iam deinde non cessabit forma declinare dum axis movetur super illum dyametrum quousque axis perveniat ad ultimum illius dyametri rei vise et ad partem extremam rei vise oppositam prime partis. Erit ergo forma totius rei vise in ista dispositione obliqua ad ubi oppositum ubitati ad quam prius fuit obliqua preter quam ultima pars extrema que erat super axem et in medio visus. Et axis in toto isto motu erit fixus in suo situ, et erit iste motus valde velox, et in maiori parte est insensibilis propter velocitatem. Axis autem non superponitur in suo motu terminis anguli quem respicit res visa apud centrum visus, nec secat latitudinem anguli quem respicit aliquis dyametrorum rei vise, quoniam hoc non erit nisi quando axis fuerit motus per se et totus oculus quiescens, quod est impossibile. Sed totus oculus movetur apud intuitionem, et axis movetur per motum eius. Sentiens autem non comprehendit quantitatem anguli quem respicit res visa apud centrum visus nisi ex comprehensione quantitatis partis superficiei visus in qua figuratur forma rei vise et ex ymaginatione anguli quem respicit illa pars apud centrum visus.

3.166 ◉ So when sight wishes to inspect a visible object and begins to examine it at the extremity of the visible object, the endpoint of the [visual] axis will then lie upon the outer edge of the visible object. In that case, then, the majority of the [form representing the] whole visible object will lie on an area of the surface of the eye that is inclined to, or to the side of, the [visual] axis away from where the axis lies, for the form of the object’s edge will be in the middle of the eye where the [visual] axis lies, so the rest of the form will be inclined to, or to the side of, the [visual] axis. Afterward, as sight moves beyond this position over [one or] another cross-section of the visible object, the [visual] axis will be shifted to a part next to that [original] part of the visible object, and the form of the first part will be inclined to the [new] place to which the [visual] axis is moved. Nor at any time after will that form stop inclining away as long as the [visual] axis moves along that cross-section until the axis reaches the endpoint of that cross-section of the visible object and to the opposite side of the visible object from the first part. In this case, then, the form of the entire visible object will be inclined [to the visual axis] on the opposite side of where it was originally inclined, except for the final part at the extremity which [originally] lay on the [visual] axis at the center of the eye[‘s surface]. But, throughout this motion the [visual] axis will remain fixed in its situation [relative to the eye as a whole], and this motion will be extraordinarily swift, so it is generally imperceptible on account of its swiftness. Furthermore, during its motion, the [visual] axis does not coincide with the endpoints of the angle subtended by the visible object at the center of sight, nor does it mark out a slice corresponding to the angle subtended by any of the cross-sections of the visible object, for this would only occur if the [visual] axis moved on its own account while the rest of the eye remained immobile, which is impossible.⁑ Instead, the entire eye moves during inspection, and the axis moves along with its motion. However, the sensitive faculty only perceives the size of the angle subtended by the visible object at the center of sight by perceiving the size of the part of the surface of the eye in which the form of the visible object is delineated and by imagining the angle subtended by that part at the center of sight.

3.167 ◉ Et sensus visus comprehendit naturaliter quantitates partium visus in quibus figurantur forme, et naturaliter ymaginatur angulos quos respiciunt iste partes. Sentiens autem non certificat formam rei vise et quantitatem magnitudinis rei vise per motum visus nisi quia per istum motum comprehendit quamlibet partem partium rei vise per eius medium et per locum axis in visu. Et per istum motum movetur forma rei vise super superficiem visus, et sic mutabitur pars superficiei visus in qua fuit forma, quoniam forma rei vise apud motum erit in parte post aliam et partem post aliam in superficie visus. Et quotiens comprehenderit sentiens partem rei vise que est apud extremum axis, comprehendet cum hoc totam rem visam, et comprehendet totam partem superficiei visus in qua pervenit forma totius rei vise, et comprehendet quantitatem illius partis, et comprehendet quantitatem anguli quem respicit illa pars apud centrum visus. Et sic multotiens comprehendet sentiens quantitatem anguli quem respicit illa res visa; quare erit ab eo certificata, et quare etiam virtus distinctiva intelliget quantitatem anguli et quantitatem remotionis, et ex eis comprehendet quantitatem magnitudinis rei vise secundum veritatem. Secundum ergo hunc modum erit intuitio visibilium a visu et certificatio quantitatis magnitudinum rerum visarum per intuitionem.

3.167 ◉ Now the sense of sight perceives the sizes of the areas of the eye on which the forms are delineated naturally, and it imagines the angles subtended by those areas naturally.⁑ But the sensitive faculty does not accurately determine the form of the visible object or the object’s size by the motion of the eye unless, according to that motion, it perceives every portion of the parts⁑ of the visible object through its midpoint or the point on the eye where the axis lies. Through this motion the form of the visible object moves over the surface of the eye, and so the area on the eye’s surface where the form lies will change, because, as the motion continues, the form of the visible object will shift area-by-area on the eye’s surface. Yet every time the sensitive faculty perceives the part of the visible object at the end of the visual axis, it will also perceive the entire visible object, and it will perceive the entire area on the eye’s surface upon which the form of the entire visible object is projected, and it will perceive the size of that area, and it will perceive the size of the angle subtended by that area at the center of sight. And so the sensitive faculty will repeatedly perceive the size of the angle subtended by that visible object. As a result, this angle will be accurately determined by the sensitive faculty, while the faculty of discrimination will apprehend the size of the angle as well as the magnitude of the distance, and from these it will perceive the visible object’s actual size. This, then, is how the visual inspection of visible objects is carried out by sight and how the size of visible objects is accurately determined through visual inspection.

3.168 ◉ Et etiam quando visus comprehendit quantitates longitudinum linearum radialium que sunt inter visum et terminos rei vise aut partes superficiei rei vise, sentiet equalitatem et inequalitatem earum quantitatum. Si autem superficies rei vise quam visus comprehendit fuerit obliqua, sentiet obliquationem eius ex sensu inequalitatis quantitatum remotionum extremorum eius. Et si superficies fuerit directe opposita, sentiet directionem ex sensu equalitatis remotionum. Et sic non latet quantitas magnitudinis eius virtutem distinctivam, quoniam virtus distinctiva comprehendit ex inequalitate remotionum extremorum dyametrorum spatii obliqui obliquationem piramidis continentis ipsum quarum sentiet excessum magnitudinis basis eius propter obliquationem. Et non admiscetur secundum assimilationem quantitas magnitudinis oblique magnitudini directe opposite nisi quando comparatio fuerit ad angulum tantum. Si autem comparatio fuerit ad angulum et ad longitudines linearum radialium interiacentium visum et extrema rei vise, non dubitabit in quantitate magnitudinis.

3.168 ◉ In addition, when sight perceives the lengths of the radial lines extending between the center of sight and the extremities of the visible object or the areas on the surface of the visible object, it will sense the equality or inequality of their lengths. If, on the one hand, the surface of the visible object that sight perceives is oblique, it will sense its obliquity by sensing the inequality of the magnitudes of the distances of its extremities [from the center of sight]. But if the surface faces the eye directly, sight will sense its facing disposition by sensing the equality of the distances [of its extremities from the center of sight]. Accordingly, the size [of the object] does not escape the faculty of discrimination, because it is from the inequality of the distances of the endpoints of the cross-sections of an oblique magnitude [from the center of sight] that the faculty of discrimination perceives the obliquity of the cone that encompasses the object, and from that it will sense the change in the size of its base that is due to obliquity.⁑ Moreover, it will not confuse the size of an oblique magnitude with the size of a directly facing magnitude through assimilation unless the correlation is based on angle alone. But if the correlation is based on angle as well as on the lengths of the radial lines extending between the center of sight and the extremity of the visible object, it will be certain about the size of the magnitude.

3.169 ◉ Quantitates autem magnitudinis linearum et spatiorum comprehenduntur a visu ex comprehensione quantitatum remotionum extremorum earum et ex comprehensione inequalitatis et equalitatis earum. Sed remotior et remotissima remotionum mediocrium respectu rei vise quando res visa fuerit obliqua est minor remotissima remotionum mediocrium respectu illius eiusdem rei vise quando fuerit directe opposita. Quoniam remotio mediocris rei vise est in qua non latet visum pars rei vise habens proportionem sensibilem ad totam rem visam. Et cum res visa fuerit obliqua, angulus quem continent duo radii exeuntes a visu ad aliquam partem rei vise oblique erit minor angulo quem continent radii duo exeuntes a visu ad illam eandem partem et ad illam eandem remotionem quando res visa fuerit directe opposita visui. Et pars habens sensibilem proportionem ad totam rem visam quando res visa fuerit obliqua latet in remotione minori remotione in qua latet eadem illa pars quando illa res visa fuerit directe opposita. Remotissima ergo remotionum mediocrium respectu rei vise obliqua est minor remotissima remotionum mediocrium respectu illius eiusdem rei vise quando illa res visa fuerit directe opposita. Et tota res visa obliqua latet in remotione minori remotione in qua latet illa res visa quando fuerit directe opposita, et diminuitur quantitas eius in remotione minori remotione qua diminuitur quantitas eius quando fuerit directe opposita.

3.169 ◉ The magnitudes of lines and intervals are perceived by sight through the perception of the magnitudes of the distances of their extremities and through the perception of the inequality or equality of those distances. But the farther, or the farthest, moderate distance with respect to a visible object when that object is oblique is less than the farthest moderate distance with respect to that same visible object when it faces the eye directly. For a moderate distance for a visible object is one at which a part of the visible object that has a perceptible size with respect to the whole does not disappear from sight. But when a visible object is oblique, the angles formed by the two rays extending⁑ from the center of sight to any part on the oblique visible object will be smaller than the angle formed by the two rays extending from the center of sight to that same part, at the same distance, when the visible object faces the eye directly. So, when the visible object is oblique, a part that has a perceptible size with respect to the whole disappears from sight at a shorter distance than that same part does when the visible object faces the eye directly. Thus, the farthest moderate distance with respect to an oblique visible object is smaller than the farthest moderate distance with respect to that same visible object when that visible object faces the eye directly. Furthermore, when it is oblique, the entire visible object disappears from sight at a shorter distance than it does when it faces the eye directly, and its size decreases [more quickly] at a shorter distance than it does when it faces the eye directly.

3.170 ◉ Magnitudines ergo rerum visarum quarum quantitates certificantur a visu sunt ille quarum remotio est mediocris et quarum remotio respicit corpora ordinata continuata, et comprehenduntur a visu ex comparatione illarum ad angulos piramidum radialium continentium ipsa et ad longitudines linearum radialium. Remotiones autem mediocres respectu alicuius rei sunt secundum situm illius rei vise in obliquatione aut in directa oppositione. Et anguli non certificantur nisi per motum visus respicientis super dyametros superficiei rei vise aut super spatium cuius magnitudinem voluerit scire, et certificatur remotio per motum visus super corpus respiciens remotiones extremorum illius superficiei aut illius spatii. Et generaliter forma remotionis et forma rei vise cuius remotio est mediocris (et cum hoc est respiciens corpora ordinata continuata) perveniunt communiter in ymaginatione simul apud intuitionem rei vise quando visus comprehendit corpus respiciens remotionem rei vise apud comprehensionem rei vise. Et sic virtus distinctiva comprehendet magnitudinem rei vise secundum quantitatem forme remotionis eius certificate coniuncte cum forma eius. Quantitates ergo huiusmodi visibilium tantum comprehenduntur a visu vera comprehensione. Secundum ergo hunc modum quem declaravimus comprehenduntur magnitudines rerum visarum per sensum visus.

3.170 ◉ Therefore, visible objects have their sizes accurately determined by sight when they lie at a moderate distance and when that distance is spanned by a continuous, ordered range of bodies, and sight perceives their sizes by correlating them to the angles of the cones of rays that encompass them and to the lengths of the radial lines. But [what are considered] moderate distances for any given object depend on the spatial disposition of that object in terms of an oblique or a directly facing orientation. The angles are accurately determined only if sight scans the cross-sections of the surface of the visible object or those of whatever magnitude it wishes to determine, and distance is accurately determined through the motion of the visual axis over the body spanning the distances of the extremities of that surface or that interval. On the whole, the form of the distance, as well as the form of the visible object lying at a moderate distance (provided that this distance is spanned by a continuous, ordered range of bodies), occur simultaneously in the imagination at the moment the visible object is visually inspected, which is when sight perceives the body spanning the distance of the visible object as the visible object is perceived. Accordingly, the faculty of discrimination will perceive the size of the visible object according to the magnitude of the form of its determinate distance along with the visible object’s own form. Hence, the sizes of such visible objects alone are correctly perceived by sight. According to the way we have described, then, the sizes of visible objects are perceived by the sense of sight.

3.171 ◉ Quare vero res visa comprehenditur in maxima remotione minoris quantitatis sue vere, et quare comprehenditur quantitas rei vise in propinquissima remotione maior quantitate sua vera nos declarabimus illud, et dicemus causas eius apud nostrum sermonem in erroribus visus.

3.171 ◉ We shall explain later, in our discussion of visual deceptions, why a visible object is perceived to be smaller than it actually is at an extreme distance, and why a visible object is perceived to be bigger than it actually is from very near, and we shall discuss the causes of these deceptions [at that time].⁑

3.172 ◉ Distinctio vero que est inter visibilia comprehenditur a visu ex distinctione formarum duorum corporum sive duorum visibilium distinctorum pervenientium in visu. Sed in distinctione que est inter quelibet duo corpora distincta, aut erit lux aut corpus coloratum illuminatum, aut erit obscuritas. Cum ergo visus comprehendit duo corpora distincta, forma lucis, aut forma coloris corporis, aut forma obscuritatis que est in loco distinctionis pervenit in partem visus interiacentem duas formas duorum corporum distinctorum pervenientium in visum. Lux autem, aut color, aut obscuritas fortassis erit in corpore medio interiacente duo corpora continuata cum utroque corporum. Si ergo visus non senserit quod lux aut obscuritas que est in loco distinctionis non est in corpore continuato cum utroque corporum que sunt in eius lateribus, non sentiet distinctionem duorum corporum. Et etiam superficies cuiuslibet illorum duorum corporum est obliqua ad locum remotionis in loco distinctionis. Igitur forte erit obliquatio duarum superficierum duorum corporum aut superficiei alterius duorum corporum manifesta visui, et forte non. Cum ergo obliquatio duarum superficierum duorum corporum aut superficiei alterius duorum corporum fuerit manifesta visui, tunc sentiet visus distinctionem duorum corporum. Visus ergo comprehendit distinctionem corporum ex comprehensione utriusque intentionum quas diximus: aut ex comprehensione lucis in loco distinctionis, sentiendo quod illa lux est ex posteriori duarum superficierum duorum corporum distinctorum; aut ex comprehensione corporis colorati in loco distinctionis, sentiendo quod illud est diversum ab utroque corporum distinctorum; aut ex comprehensione obscurationis loci distinctionis, comprehendendo quod illud est obscuritas et non corpus continuatum cum duobus corporibus; et ex comprehensione obliquationis utriusque superficierum duorum corporum in loco distinctionis aut obliquationis superficiei alterius duorum corporum. Omne ergo quod visus comprehendit ex distinctione corporum non comprehenditur nisi secundum aliquam istarum intentionum.

3.172 ◉ Separation between visible objects is perceived by sight from the separation of the forms of two bodies or of two distinct visible objects that reach the eye. But in the gap that separates any two distinct bodies there will be light or a colored and illuminated body, or there will be darkness. Therefore, when sight perceives two separated bodies, the form of the light, or the form of a body’s color, or the form of the darkness that exists in the gap [between the bodies] reaches an area on the eye that lies between the forms of the two separated bodies that reach the eye. Moreover, there may be light, or color, or darkness in a body that lies between the two bodies and is contiguous with both of them. Therefore, if sight does not sense that whatever light or darkness exists in the gap [between the two bodies] does not exist in a body that is contiguous with the two bodies that flank it, it will not sense the separation of the two bodies. Furthermore, the surface of either of those two bodies slopes toward the area where the separation occurs. Therefore, the sloping of the two surfaces of the two bodies or of the surface of either of the two bodies may be obvious to sight, or it may not be.⁑ Accordingly, if the sloping of the two surfaces of the two bodies or of the surface of either of the two bodies is evident to sight, then sight will sense the separation of the two bodies. Hence, sight perceives the separation of the bodies by perceiving any of the things we discussed: either by perceiving light where the separation occurs and sensing that this light lies behind the surfaces of the two separated bodies; or by perceiving a colored body where the separation occurs and sensing that it is different from both of the separated bodies; or by perceiving darkness where the separation occurs and realizing that it is darkness rather than a body contiguous with the two bodies; or by perceiving the slope of both of the surfaces of the two bodies where the separation occurs or the slope of the surface of either of the two bodies. Therefore, no separation between bodies is perceived by sight unless it is done so according to one of these conditions.

3.173 ◉ Distinctio autem forte erit inter duo corpora distincta, et forte erit inter duo corpora non diversa—scilicet quod duo corpora sunt continuata secundum quasdam partes et diversa secundum quasdam inter se, ut digiti et membra animalis, et rami arborum. Et secundum utramlibet dispositionum visus non comprehendit distinctionem nisi secundum modos quos declaravimus. Et forte contingit distinctio corporum per cognitionem et per scientiam antecedentem, sed illa comprehensio non est per sensum visus.

3.173 ◉ A separation may exist between two distinct bodies, or it may exist between two bodies that are not [entirely] distinct—e.g., when two bodies, such as the fingers and members of an animal, or the branches of trees, are continuous according to certain parts and separated from one another according to other parts. In either case, though, sight only perceives the separation in the ways that we have described. Now it may happen that the separation of the bodies is [perceived] by recognition or by previous acquaintance, but that perception does not arise from visual sensation.

3.174 ◉ Et quedam distinctio corporum est ampla, et quedam stricta. Distinctio vero ampla non latet visum in maiori parte propter apparentiam corporis respicientis distantiam distinctam, et propter hoc quod illud corpus apparet diversum ab utroque corporum distinctorum, et propter comprehensionem lucis et vacuitatis illuminati respicientis distantiam. Distantia autem modica et stricta non comprehenditur a visu nisi in remotione in qua non latet visum corpus cuius quantitas est equalis quantitati amplitudinis distantie. Si autem distantia inter duo corpora fuerit stricta occulta, et fuerit remotio illius a visu similis illi in qua lateant corpora quorum quantitas est sicut quantitas amplitudinis distantie, non comprehendet visus illam distantiam, etsi remotio duorum corporum a visu sit ex remotionibus mediocribus, et visus comprehenderit duo corpora vera comprehensione. Quoniam mediocris remotio est illa in qua non latet omnino quantitas sensibilis respectu quantitatis totius remotionis, et vera comprehensio est illa inter quam et veritatem rei vise non est diversitas sensibilis omnino respectu totius rei vise. Amplitudo autem distantie forte erit talis quantitatis carentis proportione sensibili ad remotionem rei vise et carentis quantitate sensibili respectu utriusque duorum corporum distinctorum, quoniam distinctio forte erit quantitatis unius capilli; et tamen istud diminutum non aufert distantiam. Distantia igitur inter visibilia similiter comprehenditur a visu secundum modos quos declaravimus.

3.174 ◉ Some separations between bodies are wide, and some are narrow. A wide separation does not generally escape sight because of the appearance of a body spanning the distance of separation, according to which that body appears distinct from both of the separated bodies, or because of [sight’s] perception of light or of an illuminated gap in the distance [of separation]. A moderate or narrow separation is only perceived by sight at a distance in which a body the same size as the breadth of the distance [of separation] does not disappear from sight. If, however, the distance between the two bodies is [so] narrow [as to be] invisible, and if its distance from the eye is the same as that at which bodies of the same size as the breadth of the distance [of separation] disappear from sight, sight will not perceive that distance, even if the two bodies lie at a moderate distance from the eye, and sight perceives the two bodies correctly. For a moderate distance is one in which a magnitude that has a perceptible size with respect to the magnitude of the whole distance does not in any way disappear from sight, whereas a correct perception is one in which there is no sensible discrepancy at all between the perception and the reality of the visible object in respect to the visible object as a whole. The extent of the distance, however, may be of such a magnitude that it lacks perceptible size in comparison to the distance of the visible object, or it may lack perceptible size with respect to either of the two separated bodies, for a separation may be the size of a hair; nonetheless, this is not [necessarily] so tiny as to make the distance [represented by it] vanish. Thus, the separation between visible objects is perceived by sight in ways like those we have discussed.

3.175 ◉ Continuatio autem comprehenditur a visu ex privatione distantie. Cum ergo visus non senserit in corpore aliquam distantiam, comprehendet ipsum esse continuum, et si in corpore fuerit distantia occulta non comprehensa a visu, comprehendet visus illud corpus esse continuum, quamvis in eo sit discretio.

3.175 ◉ Continuity, for its part, is perceived by sight from the absence of a distance [of separation]. Thus, if sight does not sense some distance [of separation] in a body, it will perceive the body as continuous, or if there is a hidden distance [of separation] in the body that is not perceived by sight, sight will perceive that body as continuous, even though there is separation in it.

3.176 ◉ Et visus comprehendit continuationem et etiam discernit inter continuationem et contiguationem ex comprehensione aggregationis duorum terminorum duorum corporum. Et visus non iudicat contiguationem nisi postquam sciverit quod utrumque duorum corporum contiguorum est diversum ab altero, quoniam differentia que est inter duo contigua forte invenitur in duobus corporibus continuis. Si ergo sentiens non senserit quod utrumque duorum corporum contiguorum est diversum ab altero et distinctum ab eo, non sentiet contiguationem et iudicat continuationem.

3.176 ◉ Moreover, sight perceives continuity and also differentiates between continuity and contiguity by perceiving the joining of two edges of two bodies. But sight does not judge that there is contiguity unless it has realized that each of the two contiguous bodies is different from the other, for the difference between two contiguous bodies can at times be found in two continuous bodies. Thus, if the sensitive faculty does not sense that each of the two contiguous bodies is different from the other and separate from it, it will not sense contiguity but will judge that there is continuity [between them].

3.177 ◉ Numerus comprehenditur a visu et numeri medietas, quoniam visus comprehendit in una hora multa visibilia distincta in simul, et cum visus comprehenderit distinctionem illorum, comprehendet quod quodlibet illorum est diversum ab alio, et sic comprehendet multitudinem. Et virtus distinctiva comprehendet numerum ex multitudine. Numerus ergo comprehendetur per sensum visus ex comprehensione multorum visibilium distinctorum quando visus comprehenderit ipsa in simul, et comprehenderit distinctionem illorum, et comprehenderit quod quodlibet illorum est diversum ab alio. Secundum ergo istum modum comprehenditur numerus per sensum visus.

3.177 ◉ Number, as well as what is numbered, is perceived by sight, for at any given time sight perceives many individual visible objects at once, and when sight perceives that they are separate, it will perceive that each of them is different from the other, and so it will perceive a multitude. But the faculty of discrimination will perceive number on the basis of multitude. Thus, number will be perceived by the sense of sight through the perception of many individual visible objects when sight perceives them at the same time, and it perceives their individuality as well as perceiving that each of them is different from the other. This, then, is how number is perceived by the sense of sight.

3.178 ◉ Motus autem comprehenditur a visu ex comparatione rei mote ad aliud visibile, quoniam visus, quando comprehenderit visibile motum et cum ipso comprehenderit aliud visibile, comprehendet situm eius respectu illius visibilis moti. Et cum visibile fuerit motum et illud aliud visibile fuerit non motum, per motum visibilis illius moti situs visibilis illius moti diversabitur respectu illius visibilis non moti apud motum. Et cum visus comprehenderit ipsum, et comprehenderit cum eo aliud visibile, et comprehendit situm eius respectu illius visibilis, comprehendet motum eius. Motus ergo comprehenditur a visu ex comprehensione diversitatis situs rei vise mote respectu alterius.

3.178 ◉ Motion is perceived by sight through a correlation of the moving object to another visible object, for when sight perceives a moving visible object while it perceives another visible object, it will perceive its spatial disposition with respect to that moving visible object.⁑ So when the visible object is moving and the other visible object is stationary, at the time of motion the spatial disposition of the moving visible object will change with respect to [the spatial disposition] of the stationary visible object because of the moving visible object’s motion. When sight perceives the moving object and at the same time perceives the other object [that is stationary], and when it also perceives the former’s spatial disposition with respect to [that of] the latter, it will perceive its motion. Thus, motion is perceived by sight through the perception of a change in the moving object’s spatial disposition with respect to that of the other [stationary] object.⁑

3.179 ◉ Et motus comprehenditur a visu secundum aliquem trium modorum: aut ex respectu rei vise mote ad multa visibilia, aut ex respectu rei vise mote ad unum visibile, aut ex respectu rei vise ad ipsum visum. Primum autem quando visus comprehenderit rem visam et motum, et comprehenderit ipsam respicientem aliquod visibile, deinde comprehenderit ipsam respicientem aliquod visibile diversum a primo, existente visu in suo loco, sentiet motum illius rei vise. Respectus autem rei vise mote ad unum solum visibile est quando visus comprehenderit rem visam motam, et comprehenderit situm eius respectu alterius visibilis, deinde comprehenderit situm eius qui mutatus est respectu illius alterius eiusdem visibilis, aut quod est remotius, aut quod est propinquius, aut quod est in parte altera, existente visu in loco suo, aut per mutationem situs alicuius partis rei vise mote respectu illius visibilis immoti, aut per mutationem situs partium eius respectu illius visibilis. Et secundum istum ultimum modum comprehendit visus motum visibilis moti circulariter quando homo comparaverit ipsum ad aliud visibile. Cum ergo visus comprehenderit situm rei mote vise, aut situm partium eius, aut situm alicuius partis eius, comprehendet motum rei vise mote.

3.179 ◉ Furthermore, motion is perceived by sight in one of three ways: from the relationship of the moving visible object to several [other] visible objects, from the relationship of the moving visible object to one visible object, or from the relationship of the moving visible object to the center of sight itself. In the first case, when sight perceives a visible object and its motion, and when it perceives that object in line with any [other] visible object, then perceives it in line with another visible object different from the first, while the center of sight remains fixed, it will sense the motion of that visible object. Moreover, when a visible object moves with respect to a single visible object, sight perceives the moving visible object, as well as its spatial disposition with respect to the other visible object, and then perceives that its spatial disposition has changed with respect to that other visible object, [sensing] either that it has drawn farther away, or that it has drawn nearer, or that it has moved to the side, while the center of sight remains fixed; or else it perceives a change in the spatial disposition of any of the parts of the moving visible object with respect to that stationary visible object or a change in the spatial disposition of all of its parts with respect to the [stationary] visible object. It is in this last way that sight perceives the motion of a rotating visible object when someone compares it to another [stationary] visible object. Therefore, when sight perceives the [changing] spatial disposition of a moving visible object, or the [changing] spatial disposition of [all of] its parts, or the [changing] spatial disposition of any of its parts,⁑ it will perceive the motion of the moving visible object.

3.180 ◉ Respectus autem rei vise mote ad ipsum visum est quando visus comprehenderit rem visam motam, comprehendet ubitatem eius et remotionem eius. Et cum visus fuerit quietus, et res visa fuerit mota, et tunc mutabitur situs rei vise mote respectu visus. Si ergo motus rei vise fuerit secundum spatium latum, mutabitur ubitas eius, et sentiet visus mutationem ubitatis eius, et cum visus senserit mutationem ubitatis eius, visu quiescente, sentiet motum eius. Et si motus rei vise fuerit in longitudine extensa inter ipsam et visum, aut res visa tunc elongabitur a visu per motum aut appropinquabitur. Et cum visus senserit elongationem aut appropinquationem eius, visu existente in suo loco, sentiet motum eius. Et si motus rei vise fuerit circularis, necessario mutabitur pars eius que opponitur visui, et cum illa pars rei vise fuerit mutata, et sentiet visus mutationem eius, visu existente in suo loco, sentiet motum rei vise. Secundum ergo istos modos comprehendet visus motum quando visus fuerit fixus in suo loco.

3.180 ◉ Finally, when a visible object moves with respect to the center of sight, sight perceives the moving visible object while perceiving its place and its distance [from the eye]. So when the center of sight is fixed, but the visible object moves, the spatial disposition of the moving visible object will change with respect to the center of sight. Thus, if the visible object moves in the plane facing the eye, its place will change, and sight will sense its change of place, and when sight senses its change in place, it will perceive its motion, provided that the center of sight stays fixed.⁑ If, on the other hand, the motion of the visible object is along the line-of-sight extending between the object and the center of sight, the visible object will either recede from or approach the center of sight by its motion. Then, when sight senses its receding or its approach, it will sense its motion, provided the center of sight remains stationary.⁑ Finally, if the motion of the visible object is rotary, then it necessarily follows that the part of it directly facing the eye will change [place], and when that part of the visible object changes [place], and sight senses its change [of place], it will sense the motion of the visible object, provided the center of sight remains stationary. These, then, are the ways in which sight will perceive motion when the center of sight remains fixed in place.

3.181 ◉ Et visus etiam comprehendet motum secundum quemlibet istorum modorum, quamvis visus etiam moveatur. Et hoc erit quando visus senserit diversitatem situs rei vise mote, sentiendo quod illa diversitas non est propter motum visus et distinguendo inter diversitatem situs que accidit illi rei vise propter motum ipsius rei vise et inter diversitatem situs que accidit ei propter motum visus. Cum ergo visus senserit diversitatem situs rei vise et senserit quod diversitas situs eius non est propter motum visus, sentiet motum rei vise. Et forma rei vise mote movetur etiam in visu propter motum eius. Sed visus non comprehendit motum rei vise ex motu sue forme in visu tantum; immo visus non comprehendit motum rei vise nisi ex comparatione rei vise ad aliam secundum modos quos declaravimus. Quoniam forma rei vise quiescentis aliquando movetur in visu in quiete illius rei vise, et inde visus non comprehendit ipsam motam, quoniam visus, quando movebitur secundum oppositionem rerum visarum, movebitur forma cuiuslibet rei vise opposite visui in superficie visus apud motum eius, sive sit quiescens sive sit motum. Et quia visus iam assuetus est ad motum formarum rerum visarum in superficie eius cum quiete illarum rerum visarum, non iudicabit motum rei vise propter motum forme eius nisi quando in visu pervenerit forma alterius rei vise, et comprehenderit visus diversitatem situs forme rei vise mote respectu alterius forme rei vise aut ex mutatione formarum in eodem loco visus, que erit in loco circulari. Motus ergo non comprehenditur a visu nisi secundum modos quos distinximus.

3.181 ◉ Sight will also perceive motion in one of these ways, even when the center of sight is moving. This will happen when sight senses a change in the spatial disposition of the moving visible object while sensing that this change is not due to the motion of the center of sight and while differentiating between the change in spatial disposition occurring in the visible object that is due to its own motion and the change in spatial disposition occurring in the eye that is due to the motion of the eye. Hence, when sight senses the change in the spatial disposition of the visible object and also senses that its change in spatial disposition is not due to the motion of the center of sight, it will sense the motion of the visible object. Now the form of the moving visible object moves on the eye[‘s surface] according to the object’s motion. But sight does not perceive the motion of the visible object from the motion of its form on the eye alone; on the contrary, sight perceives the motion of a visible object only by comparing the visible object to another according to the ways we described.⁑ For the form of a stationary visible object sometimes moves on the eye[‘s surface] while that visible object remains immobile, and therefore sight does not perceive that it moves, because when sight moves with respect to facing visible objects, the form of each visible object facing the eye will move on the eye’s surface according to its motion, whether the object is moving or is stationary.⁑ But since sight is accustomed to the motion of the forms of visible objects on its surface [even] when those visible objects are stationary, it will not judge the object to be in motion from the motion of its form unless the form of another visible object reaches the eye, and unless sight perceives the change in spatial disposition of the [form of the] moving visible object with respect to the form of the other visible object, or unless [it perceives] a change of forms at the same place on the [surface of the] eye, which will happen in the case of rotation. Thus, motion is perceived by sight only in the ways we have listed.

3.182 ◉ Comprehensio autem qualitatis motus est ex comprehensione spatii super quod movetur res visa quando res visa movebitur secundum se totum, et visus certificat qualitatem motus quando certificaverit figuram spatii super quod movetur res visa mota. Et cum res visa movebitur circulariter, visus comprehendet motum eius esse circularem ex comprehensione mutationis partium eius sequentium visum apud aliquam rem visam, aut ex respicientia alicuius partis illius ad diversa visibilia, unum post alterum, aut ad partes unius rei vise, unam partem post aliam, cum quiete totalitatis rei vise in suo loco.

3.182 ◉ What kind of motion it is is perceived through the perception of the space over which the visible object moves when it moves as a whole, and sight determines the kind of motion it is when it determines the shape of the space over which the moving visible object moves. So when the visible object rotates, sight will perceive its motion as rotary by perceiving the sequential change of its parts on the eye with respect to some other visible object, or the change of any of its parts in consecutive order with respect to various visible objects, or the change of the parts of one visible object in consecutive order while the visible object, as a whole, remains fixed in place.

3.183 ◉ Et si motus rei vise fuerit compositus ex motu circulari et locali, visus comprehendet illum motum esse compositum ex comprehensione mutationis partium rei vise mote respectu visus, aut respectu alterius rei vise, cum comprehensione motus totalitatis rei vise a suo loco. Secundum ergo istos modos visus comprehendit qualitates motus visibilium.

3.183 ◉ Moreover, if the motion of the visible object is composed of rotary motion and locomotion,⁑ sight will perceive that motion as composite by perceiving the change of the parts of the moving visible object with respect to the eye, or with respect to another visible object, while perceiving the motion of the visible object as a whole from its [original] location. It is therefore in these ways that sight perceives how visible objects move.

3.184 ◉ Et visus non comprehendit motum nisi in tempore, quoniam motus non est nisi in tempore, et omnis pars motus non est nisi in tempore. Et visus non comprehendit motum rei vise nisi ex comprehensione rei vise in duobus locis diversis aut secundum duos situs. Locus autem et situs rei vise non diversatur nisi in tempore. Cum ergo visus comprehenderit rem visam in duobus locis diversis aut in duobus sitibus diversis, non erit nisi in duabus horis diversis. Sed inter quaslibet duas horas diversas est tempus. Visus ergo non comprehendit motum nisi in tempore.

3.184 ◉ Furthermore, sight does not perceive motion except over time, for motion occurs only over time, and every part of a motion occurs only over time. Now sight perceives the motion of a visible object only by perceiving the visible object in two different locations or according to two different spatial dispositions. But the location or spatial disposition of a visible object changes only over time. Thus, when sight perceives a visible object in two different places or according to two different spatial dispositions, this will occur only at two different instants. But between any two different instants there is some time-interval. Thus, sight only perceives motion over time.

3.185 ◉ Et etiam dicemus quod tempus in quo visus comprehendit motum non erit nisi sensibile, quoniam visus non comprehendit motum nisi ex comprehensione rei vise in duobus locis diversis, in uno loco post alium, aut secundum duos situs diversos, unum situm post alium. Cum ergo visus comprehendit rem visam motam in secundo loco et non comprehenderit ipsam tunc in primo loco in quo comprehendit ipsam ante, statim sentiet sentiens quod hora in qua comprehendit ipsam in secundo loco est diversa ab hora in qua comprehendit ipsam in primo loco, quare sentiet diversitatem duarum horarum. Et similiter quando comprehenderit motum ex diversitate situs rei mote, quoniam, quando comprehendit rem motam secundum situm secundum et non comprehenderit ipsam tunc secundum primum situm secundum quem comprehendit ipsam ante, statim sentiet diversitatem duarum horarum, quare sentiet tempus quod est inter ipsas. Tempus ergo in quo visus comprehendit motum est sensibile necessario.

3.185 ◉ We shall also point out that the time in which sight perceives motion must be perceptible, for sight perceives motion only by perceiving the visible object in two different locations, one after another, or according to two different spatial dispositions, one after another. Therefore, if sight perceives a moving visible object in a second location and does not at the same time perceive it in a first location where it perceived it before, the sensitive faculty will immediately sense that the instant at which it perceives the object in the second place is different from the instant at which it perceived it in the first place, whence it will sense the difference in the two instants. The same applies when sight perceives motion on the basis of the moving object’s change in spatial disposition, for when it perceives the moving object according to a second spatial disposition and does not at the same time perceive it according to the first spatial disposition that it perceived before, it will immediately sense the difference in the two instants, whence it will perceive the time-interval between them. Therefore, the time in which sight perceives motion is necessarily perceptible.

3.186 ◉ Et cum iste intentiones sunt declarate, narremus modo quod coacervatur ex eis. Dicemus ergo quod visus comprehendit motum ex comprehensione rei vise mote secundum duos situs diversos in duabus horis diversis inter quas est tempus sensibile, et hec est qualitas comprehensionis motus a visu.

3.186 ◉ And since these points have been explained, we shall now recount what can be summarized from them. Accordingly, we shall observe that sight perceives motion by perceiving the moving visible object according to two different spatial dispositions at two different instants between which there is a perceptible amount of time, and this how motion is perceived by sight.

3.187 ◉ Et visus comprehendit diversitatem motuum secundum velocitatem et tarditatem, et equalitatem motuum, ex comprehensione spatiorum super que moventur visibilia mota. Cum ergo visus comprehenderit visibilia duo mota, et comprehenderit duo spatia super que moventur illa duo visibilia, et senserit quod alterum duorum spatiorum que a duobus visibilibus motis pertranseuntur in eodem tempore est maius altero, sentiet velocitatem rei vise transeuntis super maius spatium. Et cum duo spatia equalia super que moventur duo visibilia fuerint pertransita simul aut in duobus temporibus equalibus, et senserit visus equalitatem eorum spatiorum, sentiet equalitatem motus duarum rerum motarum. Et similiter, si visus senserit equalitatem duorum spatiorum cum inequalitate duorum temporum duorum motuum, sentiet velocitatem motus rei mote transeuntis per spatium in minori tempore; et similiter, quando duo mota transierint in duobus temporibus equalibus per duo spatia equalia, et senserit visus equalitatem temporum et equalitatem spatiorum, sentiet equalitatem duorum motuum. Iam diximus qualiter visus comprehendit motum et distinguit motum et qualitates eius et equalitatem et inequalitatem eius.

3.187 ◉ Sight perceives variations in swiftness or slowness among motions, as well as equality among motions, by perceiving the spaces over which moving visible objects pass. Thus, when sight perceives two moving visible objects, and when it perceives the two spaces over which those two visible objects move, and when it senses that one of the two spaces passed over by the two moving visible objects in the same time is longer than the other, it will sense the [greater] swiftness of the visible object passing over the longer space. Furthermore, when the two spaces over which the two visible objects pass in the same time, or in two equal amounts of time, are equal, and when sight senses the equality of those spaces, it will sense the equality of the motion of the two moving objects. So too, when sight senses the equality of the two spaces along with the inequality of the two times over which the two motions take place, it will sense the [greater] swiftness of the moving object passing over the space in less time; and, by the same token, when two moving objects pass over equal spaces in equal times, and when sight senses the equality of times and the equality of spaces, it will sense the equality of the two motions. We have now explained how sight perceives motion and how it differentiates motions, as well as kinds of motions and their equality or inequality.

3.188 ◉ Quies autem comprehenditur a visu ex comprehensione rei vise in tempore sensibili in eodem loco et in eodem situ. Cum ergo visus comprehenderit visum in eodem loco et secundum eundem situm in duabus horis diversis inter quas est tempus sensibile, comprehendet rem visam in illo tempore quiescentem. Et visus comprehendit situm rei vise quiescentis respectu alterius rei vise et respectu ipsius visus. Secundum ergo hunc modum erit comprehensio quietis visibilium a visu.

3.188 ◉ Rest is perceived by sight through perception that the visible object remains at the same location or in the same spatial disposition over a perceptible amount of time. Therefore, when sight perceives a visible object at the same location or according to the same spatial disposition at two different instants between which there is a perceptible time-interval, it will perceive that the visible object is immobile during that time. Moreover, sight perceives the spatial disposition of an immobile visible object with respect to another visible object or with respect to the center of sight itself. This, then is how the perception of the immobility of visible objects will be carried out by sight.

3.189 ◉ Asperitas vero comprehenditur a visu in maiori parte ex forma lucis apparentis in superficie corporis asperi, quoniam asperitas est diversitas situs partium superficiei corporis, quare lux, quando orietur super superficiem illius corporis, partes prominentes facient umbram in maiori parte. Et cum lux pervenerit ad partes profundas, erunt cum ea etiam umbre, et partes prominentes erunt manifeste luci et discooperte luci. Et cum in partes profundas venerint umbre, et super prominentes etiam non fuerit aliqua umbra, diversabitur forma lucis in superficie illius corporis. In superficie autem plana non est ita, quoniam superficiei plane partes sunt consimilis situs, et cum lux orietur super ipsas, erit forma lucis in tota superficie consimilis. Forma ergo lucis in superficie corporis asperi est diversa a forma lucis in superficie plana. Et visus cognoscit formam lucis que est in superficiebus asperis et formam lucis que est in superficiebus planis propter frequentationem visionis superficierum asperarum et planarum. Cum ergo visus senserit lucem que est in superficiebus corporis secundum modum quem assuevit in superficiebus asperis, iudicabit asperitatem illius corporis. Et cum senserit lucem in superficie corporis secundum modum quem assuevit in superficiebus planis, iudicabit planitiem in superficiebus illius corporis.

3.189 ◉ Roughness is generally perceived by sight from the form of light appearing on the surface of a rough body, for roughness consists of a variation in spatial disposition of the parts of the surface of a body, so, when light shines on the surface of that body, the raised portions will generally cast shadows. Meanwhile, when light reaches the depressed portions, it will also create shadows, so the raised portions will be exposed to light and revealed. If shadows are formed in the depressed portions, but no shadows exist on the raised portions, the form of light will vary on the surface of that body. On a smooth surface,⁑ however, such is not the case, for the portions of a smooth surface are uniform in spatial disposition, so when light shines on them, the form of light will be uniform throughout the surface. Thus, the form of light on a rough surface is different from the form of light on a smooth surface. Sight, moreover, recognizes the form of light on rough surfaces and the form of light on smooth surfaces from the frequency with which it sees rough and smooth surfaces. Thus, when sight senses the light on the surfaces of bodies in the way it usually does for rough surfaces, it will impute roughness to that body. But when it senses light on the surface of a body in the way it usually does for smooth surfaces, it will impute smoothness to the surfaces of that body.

3.190 ◉ Et cum asperitas fuerit extranea, erunt partes prominentes alicuius quantitatis, et sic visus comprehendet preminentiam illarum partium, et comprehendet situm superficiei corporis ex comprehensione distantie que est inter partes. Et cum visus comprehenderit diversitatem situum partium superficiei corporis, comprehendet asperitatem eius sine indigentia ad considerandum lucem.

3.190 ◉ Yet when the roughness is inordinate, the raised portions [of the surface] will be of a substantial size, and thus sight will perceive the elevation of those parts, and it will perceive the spatial disposition of the surface of the body by perceiving the distance between parts. So when sight perceives the variations in spatial disposition of the parts of the body’s surface, it will perceive its roughness without having to evaluate the light.

3.191 ◉ Et etiam quando asperitas corporis fuerit extranea, et oriatur super ipsam lux, erit forma lucis in superficie eius etiam diversa maxima diversitate. Videbitur ergo ex diversitate forme lucis distantia partium et diversitas situs earum, et ex hoc apparebit asperitas corporis. Si ergo lux oriens super corpus asperum fuerit ex parte opposita superficiei aspere, et fuerit lux fortis, non comprehendet visus asperitatem huius corporis nisi quando comprehenderit prominentiam quarumdam partium et profunditatem quarumdam. Si ergo asperitas huius corporis fuerit extranea, id est maxima, comprehendet visus distantiam partium et diversitatem situs eorum, et comprehendet asperitatem corporis in maiori parte. Si autem asperitas fuerit modica, et fuerint partes profunde et pori illius corporis in ultimitate parvitatis, latebit visum in maiori parte, et nunquam visus comprehendet asperitatem huius corporis nisi in magna appropinquatione cum intuitu partium superficiei corporis. Cum ergo visus distinxerit distantiam partium huiusmodi corporis, et prominentiam et profunditatem illorum, comprehendet asperitatem eius. Si autem visus non distinxerit distantiam partium eius, nec prominentiam et profunditatem partium eius, non comprehendet asperitatem eius. Asperitas ergo comprehenditur a visu ex comprehensione diversitatis situum partium superficiei corporis aut ex forma lucis quam visus assuevit in superficiebus corporum asperorum. Et visus etiam cognoscit asperitatem ex privatione consimilitudinis. Cum igitur visus nichil senserit in corpore ex consimilitudine, iudicabit eius asperitatem, sed multotiens errat visus in asperitate quando voluerit cognoscere ipsam per istam intentionem. Quoniam erit superficies tersa, et non apparet eius tersitudo, quoniam tersi non apparent nisi in situ proprio.

3.191 ◉ In addition, when the roughness of the body is inordinate, and light shines upon it, the form of light on its surface will vary to an inordinate extent as well. From the variation in the form of light, then, the distance between the parts, as well as the variation in their spatial dispositions, will be seen, and on this basis the roughness of the body will be apparent. Thus, if the light shining on a rough body comes from a location directly opposite the rough surface, and if the light is intense, sight will not perceive the roughness of this body unless it perceives the prominence of some portions [of its surface] and the depression of others.⁑ So if the roughness of this body is inordinate, i.e., as great as possible, sight will perceive the separation between parts and the variation in their spatial dispositions, and it will generally perceive the roughness of the body. On the other hand, if the roughness is slight, and the depressed or hollow portions of that body are exceptionally small, the roughness will generally go unseen, and sight will never perceive the roughness of this body unless it carefully scans [all] portions of the body’s surface from up close. Thus, when sight discerns the separation between parts of such a body,⁑ as well as their elevation or depression, it will perceive its roughness. If, however, sight does not discern the separation between its parts, or the elevation and depression of its parts, it will not perceive its roughness. Roughness is therefore perceived by sight through the perception of variation in the spatial dispositions of the parts of a body’s surface or from the form of light that sight is accustomed to seeing on the surfaces of rough bodies. In addition, sight recognizes roughness from an absence of uniformity. Therefore, if sight senses no uniformity in the body[‘s surface], it will judge it to be rough, but sight frequently errs in [judging] roughness when it tries to recognize it in this way. For a surface may be polished, but its polish may not be apparent because polished objects do not appear polished unless they are placed in a particular way [with respect to the eye].⁑

3.192 ◉ Planities autem, id est equalitas superficiei corporis, comprehenditur a visu in maiori parte ex forma lucis apparenti in superficie corporis plani quam assuevit videre in superficiebus planis. Et cum lux que est in superficiebus corporis fuerit consimilis forme, cognoscet per ipsam planitiem superficiei. Et visus aliquando comprehendit planitiem per intuitum etiam. Cum ergo visus intuebitur superficiem corporis plani, comprehendet equalitatem partium eius, et sic comprehendet planitiem.

3.192 ◉ Smoothness,⁑ which consists of uniformity in the surface of a body, is generally perceived by sight through the form of light that appears on the surface of a smooth body, sight being used to seeing that [kind of] light on smooth surfaces. So when the light on the surfaces of the body is uniform, sight will recognize the smoothness of the surface through it. Sometimes, too, sight perceives smoothness through close scrutiny. Accordingly, when sight scrutinizes the surface of a smooth body, it will perceive the uniformity of its parts, and so it will perceive its smoothness.

3.193 ◉ Tersitudo autem, et est planities fortis, comprehenditur a visu ex scintillatione lucis in superficie sui corporis. Planities ergo comprehenditur a visu ex comprehensione equalitatis superficiei. Equalitas autem superficiei comprehenditur a visu in maiori parte ex consimilitudine forme lucis in superficie corporis, et tersitudo comprehenditur a visu ex scintillatione lucis in superficie corporis et ex situ secundum quem reflectitur lux.

3.193 ◉ Polish, which constitutes extreme smoothness, is perceived by sight through the dazzling light on the surface of a polished body. Thus, smoothness is perceived by sight through the perception of the uniformity of the surface. The uniformity of the surface, for its part, is generally perceived by sight through the uniformity of the light on the surface of the body, whereas polish is perceived by sight from the dazzling light on the surface of the body and from the spatial disposition [of the body] according to which the light is reflected.

3.194 ◉ Et forte in simul aggregantur asperitas et planities in eadem superficie, scilicet quod sint in superficie alicuius corporis partes diversi situs profunde et prominentes, et sint partes cuiuslibet partium diversi situs prominentium et profundarum ad partes quarumdam consimilis situs, ita quod tota superficies sit aspera, et partes eius, aut quedam, sunt plane. Et asperitas huiusmodi superficiei comprehenditur a visu ex comprehensione diversitatis situs partium prominentium et profundarum, et planities partium comprehenditur ex forma lucis que comprehenditur a visu in superficiebus partium. Et aliquando visus comprehendit planitiem huiusmodi partium per intuitionem et ex comprehensione consimilitudinis superficiei cuiuslibet illarum. Secundum ergo istos modos comprehendit visus planitiem, et tersitudinem, et asperitatem.

3.194 ◉ But sometimes roughness and smoothness coexist in the same surface, insofar as some bodies have surfaces with portions that are raised or depressed according to various spatial dispositions, or some portions of the portions are raised or depressed according to various spatial dispositions whereas others are uniform in spatial disposition, the result being that the surface as a whole is rough, whereas some of its portions are smooth. So the roughness of such a surface is perceived by sight from the perception of variations in spatial disposition among the prominent and depressed portions, whereas the smoothness of the [smooth] portions is perceived through the form of light that is perceived by sight on the surfaces of [those] portions. Sometimes, though, sight perceives the smoothness of such portions through close scrutiny and the [resulting] perception of the uniformity of each of them on the surface. It is in these ways, then, that sight perceives smoothness, polish, and roughness.

3.195 ◉ Diafonitas autem comprehenditur a visu per argumentationem ex comprehensione illius quod est in posteriori corporis diafoni. Et diafonitas corporis diafoni non comprehenditur a visu nisi quando fuerit in eo quedam spissitudo, et fuerit diafonitas eius spissior diafonitate aeris interiacentis visum et ipsum. Si autem fuerit in fine diafonitatis, non comprehendet visus diafonitatem eius, et non comprehendet nisi illud quod est in posteriori eius tantum. Et cum in eo fuerit quedam diafonitas, comprehendetur a visu propter illud quod est de spissitudine in eo. Et diafonitas eius comprehenditur ex comprehensione illius quod est in posteriori eius, quoniam, quando in posteriori corporis diafoni fuerit lux aut corpus coloratum illuminatum, videbitur apparens in posteriori corporis diafoni. Et visus non sentit diafonitatem corporis quando senserit illud quod est in posteriori eius nisi cum senserit quod color et lux que comprehenditur in posteriori corporis diafoni est lux et color in posteriori corporis diafoni, et non est color et lux ipsius corporis diafoni. Si autem non, non sentiet diafonitatem corporis diafoni. Si ergo in posteriori parte corporis diafoni non fuerit lux nec corpus illuminatum, nec in circuitu eius, et non apparuerit in posteriori eius nec in alia parte aliqua lux aut color, diafonitas illius corporis non comprehenditur. Et hoc erit quando corpus diafonum fuerit applicatum in aliquo corpore spisso, et illud corpus spissum fuerit continens ipsum, aut respiciens ipsum contra quoque, et corpus diafonum fuerit obscuri coloris. Quoniam tunc visus non sentiet diafonitatem huius corporis.

3.195 ◉ Transparency is perceived by sight through a deduction based on the perception of what lies behind a transparent body. But the transparency of a transparent body is not perceived by sight unless there is some opacity in it, and unless its transparency is less absolute than that of the air intervening between the eye and the transparent body. Indeed, if its transparency is absolute, sight will not perceive its transparency, so it will not perceive anything except what lies behind it.⁑ If, however, there is some transparency in it, it will be perceived by sight according to the opacity it possesses. And its transparency is perceived through the perception of what lies behind it, for when there is light or an illuminated, colored body behind a transparent body, it will be seen behind the transparent body. But sight does not sense the transparency of the body when it senses what lies behind it unless it senses that the color and light that are perceived behind the transparent body are light and color [that actually lie] behind the transparent body, not light and color belonging to the transparent body itself. If not, it will not sense the transparency of the transparent body. So if there is neither light nor an illuminated body behind the transparent body, or in its vicinity, and if no light or color appears behind it or anywhere in its vicinity, then the transparency of that body is not perceived. This will be the case when a transparent body is placed against some opaque body that encompasses it or that coincides with it, and the transparent body is of a dark color.⁑ For in that case sight will not sense the transparency of this body.

3.196 ◉ Et similiter quando in posteriori corporis diafoni fuerit locus obscurus, et non apparuerit in posteriori eius aliqua lux. Cum ergo visus senserit quod color quem comprehendit in posteriori corporis diafoni est color corporis in posteriori corporis diafoni, sentiet diafonitatem corporis diafoni. Et similiter, quando corpus diafonum fuerit debilis diafonitatis, et fuerit corpus quod est in posteriori eius et corpora que sunt in circuitu eius debilis lucis, tunc diafonitas eius non comprehenditur a visu nisi apponeretur forma lucis. Cum enim cognoscet lucem in posteriori eius, comprehendet diafonitatem. Secundum ergo istos modos comprehendit visus diafonitatem corporum diafonorum.

3.196 ◉ The same applies if the region behind the transparent body is dark, and no light appears behind it.⁑ Thus, when sight senses that the color it perceives behind the transparent body belongs to a body behind the transparent body, it will sense the transparency of the transparent body. Likewise, when the transparent body is only slightly transparent, and the body that lies behind it is feebly lit, as are the bodies in its vicinity, then its transparency is not perceived by sight unless the form of light is directly behind the transparent body. For if sight apprehends light behind it, it will perceive its transparency. These, then, are the ways in which sight perceives the transparency of transparent bodies.

3.197 ◉ Spissitudo comprehenditur a visu ex privatione diafonitatis. Cum ergo visus comprehenderit corpus et non senserit in ipso aliquam diafonitatem, arguet eius spissitudinem.

3.197 ◉ Opacity is perceived by sight through the absence of transparency. So when sight perceives a body but senses no transparency in it, it will deduce its opacity.

3.198 ◉ Umbra vero comprehenditur a visu respectu lucis illuminantis aut partis lucis, quoniam umbra est privatio quarumdam lucium cum illuminatione loci umbre ab extranea luce privata a loco umbre. Et cum senserit visus illud quod vicinatur ipsum, et fuerit super illud corpus vicinatum lux fortior luce que est in loco umbre, sentiet obumbrationem illius loci et privationem a luce orienti super corpus vicinans illi. Quoniam, quando visus senserit aliquam lucem in aliquo loco, et caruerit ille locus luce solis aut aliqua luce forti, sentiet obumbrationem loci et privationem loci a luce solis aut ab illa luce forti. Et forte visus sentiet corpus faciens umbram, et forte non distinguetur ab eo statim corpus obumbrans. Sed tandem visus, quando comprehenderit locum in quo est lux debilis et comprehenderit ultima corpora loco lucis debilis esse fortioris lucis illa luce debili, sentiet statim umbram illius loci. Secundum ergo hunc modum visus comprehendit umbram.

3.198 ◉ Shadow is perceived by sight in relation to the light of an object that casts light or a portion of light, for shadow is the absence of some light in the shaded area, which is illuminated by light other than the light blocked from that shaded area.⁑ And when sight senses some object next to that shaded area, and the light on that neighboring object is more intense than the light in the shaded area, it will sense the darkening of that area and the absence in it of the light shining upon the body in its vicinity. For when sight senses any light in any given place, but that place is not exposed to sunlight or some other intense light, it will sense the darkness of the place and the absence of sunlight or any intense light in that place. Moreover, sight may sense the body that casts the shadow, or it may not immediately discern the body casting the shadow. Eventually, though, when sight perceives the area that is feebly lit while it perceives that the bodies abutting on the area of faint light are more intensely lit than that feebly lit area, it will immediately sense the shadow in that area. This, then, is how sight perceives shadow.

3.199 ◉ Obscuritas vero comprehenditur a visu per argumentationem ex privatione lucis. Cum ergo visus comprehenderit aliquem locum et non comprehenderit in ipso aliquam lucem, sentiet obscuritatem eius.

3.199 ◉ Darkness, however, is perceived by sight through deduction on the basis of the absence of light. Thus, when sight perceives some location and does not perceive any light [whatever] in it, it will sense its darkness.⁑

3.200 ◉ Pulcritudo comprehenditur a visu ex comprehensione intentionum particularium quarum comprehensionis qualitas a visu est declarata. Quoniam unaqueque intentionum particularium predictarum faciet per se aliquem modum modorum pulcritudinis, et per coniugationes illarum faciunt etiam alios modos pulcritudinis. Et visus non comprehendit pulcritudinem nisi in formis visibilium que comprehenduntur per sensum visus, et forme visibilium sunt composite ex intentionibus particularibus quarum distinctio iam est declarata. Et visus comprehendit formas ex comprehensione istarum intentionum; ipse ergo comprehendit pulcritudinem ex comprehensione istarum intentionum.

3.200 ◉ Beauty is perceived by sight from the perception of particular characteristics, the means of their perception having already been explained. For each of the aforesaid particular characteristics will create some form of beauty on its own, whereas in conjunction they create other forms of beauty. But sight only perceives beauty in the forms of visible objects that are perceived by the sense of sight, and the forms of visible objects consist of particular characteristics that have already been discussed. So sight perceives forms by perceiving these characteristics; hence, it perceives beauty by perceiving these characteristics.⁑

3.201 ◉ Modi autem pulcritudinis qui comprehenduntur a visu in formis visibilium sunt multi. Quedam ergo habent unam causam ex intentionibus particularibus que sunt in forma, et causa quorumdam non est nisi coniunctio intentionum adinvicem, non ipse intentiones, et causa quorumdam est composita ex intentionibus et ex compositione illarum. Et visus comprehendit quamlibet ex intentionibus que sunt in qualibet forma per se, et comprehendit ipsas compositas, et comprehendit compositionem et coniugationem illarum. Visus ergo comprehendit pulcritudinem secundum diversos modos, et omnes modi ex quibus visus comprehendit pulcritudinem revertuntur ad comprehensionem intentionum particularium.

3.201 ◉ There are many kinds of beauty that are perceived by sight in the forms of visible objects. Accordingly, some are due to one of the particular characteristics in the form, whereas others are due only to a conjunction of characteristics, but not to the characteristics themselves, and others yet are due to the combining of characteristics and their [resulting] combination.⁑ So sight perceives each of the characteristics that are in a given form by itself, but it also perceives them together, and it perceives their combination or conjunction. Sight perceives beauty in different ways, then, but all the ways in which sight perceives beauty hark back to the perception of particular characteristics.

3.202 ◉ Si vero iste intentiones particulares faciunt pulcritudinem et composite (et est dicere facere pulcritudinem inducere dispositionem in anima qua videtur ei quod sit res pulcra quod videtur), et hoc apparebit per modicam inspectionem. Quoniam lux facit pulcritudinem, et propter hoc apparebunt pulcra sol, et luna, et stelle, et non est in sole, luna, et stellis causa propter quam apparebunt decora nisi lux earum. Lux ergo per se facit pulcritudinem.

3.202 ◉ Whether these particular or conjoined characteristics create beauty (to create beauty means to dispose the soul in such a way as to perceive that what is seen is a beautiful object) will be evident from a brief examination. For light creates beauty, which is why the sun, moon, and stars will appear beautiful, but there is nothing beyond the light in the sun, moon, or stars that will make them appear beautiful. Thus, light creates beauty on its own.

3.203 ◉ Et color etiam facit pulcritudinem, quoniam quilibet color scintillans, sicut viridis, et roseus, et sibi similia, apparebunt pulcri visui, et delectatur visus in eis. Et propter hoc apparebunt pulcri panni tincti, et flores, et viridaria. Color ergo per se facit pulcritudinem.

3.203 ◉ Color also creates beauty, for any bright color, such as green, rose-red, or the like, will appear beautiful to sight, and sight delights in them. Accordingly, dyed cloth, flowers, and gardens appear beautiful. On its own, then, color creates beauty.

3.204 ◉ Et remotio etiam aliquando facit pulcritudinem accidentaliter. Quoniam in quibusdam formis pulcris sunt macule et ruge que faciunt turpitudinem in formis, et cum elongabuntur in visu, latent ille intentiones subtiles que faciunt turpitudinem in illis formis, et apud latentiam illarum intentionum apparebit pulcritudo illius forme. Et similiter etiam in multis formis pulcris sunt intentiones subtiles per quas forma est pulcra, sicut lineatio et ordinatio, et multe istarum intentionum latent visum in multis remotionibus mediocribus. Et quando sunt prope visum, apparebunt ille intentiones subtiles visui, et apparebit pulcritudo forme. Remotio ergo et appropinquatio faciunt pulcritudinem.

3.204 ◉ Distance, as well, sometimes creates beauty in an incidental way. For in certain beautiful forms there are spots or wrinkles that disfigure the forms, but when [the objects producing those forms] are removed some distance from the eye, those subtle characteristics that disfigure those forms disappear, and as soon as those characteristics disappear, the beauty of the form will be revealed. So too, in many beautiful forms there are subtle characteristics, such as design or pattern, that make the form beautiful, but many of these characteristics disappear from sight at a variety of moderate distances. When [the objects producing those forms] are near the eye, though, these subtle characteristics will be revealed to sight, and the form’s beauty will appear. Thus, remoteness and nearness create beauty.

3.205 ◉ Et situs aliquando facit pulcritudinem, et plures intentiones pulcre non apparent pulcre nisi propter ordinationem et situm tantum, quoniam omnes distinctiones ordinate quasi punctate non apparent pulcre nisi propter ordinationem. Et scriptura non apparet pulcra nisi propter ordinationem, quoniam pulcritudo non est nisi ex substantione et directione figurarum litterarum et ex compositione earum adinvicem. Si autem compositio litterarum et ordinatio earum non fuerit secundum unam proportionem, scilicet suplet farraginis, ut una magna et alia parva littera, tunc non erit scriptura pulcra, quamvis figure litterarum per se sint bene posite. Et aliquando apparet scriptura pulcra quando compositio eius fuerit proportionalis, quamvis littere non sint in fine bone dispositionis. Et similiter plures forme visibilium non apparent pulcre nisi propter dispositionem et ordinationem partium adinvicem.

3.205 ◉ Spatial disposition sometimes creates beauty, and several beautiful characteristics appear beautiful only according to arrangement or spatial disposition, for all distinctive designs that are arranged in tight order appear beautiful only because of their arrangement. Writing appears beautiful only according to its arrangement, for its beauty lies only in the configuration and evenness of the letters as well as the way in which they are conjoined to one another. If, however, the combination of letters and their arrangement are not proportional, so that it forms a hodge-podge, one letter being large, another small, then the writing will not be beautiful, even though the shapes of the letters, taken individually, are well proportioned.⁑ Sometimes, too, writing appears beautiful when its overall composition is proportional, even though the [individual] letters are not as well proportioned as they might be.⁑ Likewise, several forms of visible objects appear beautiful only because of the relative disposition and arrangement of their parts.

3.206 ◉ Et corporeitas etiam facit pulcritudinem, et propterea apparent pulcra corpora hominis et multorum animalium.

3.206 ◉ Corporeity also creates beauty, which is why the human body and those of many animals appear beautiful.⁑

3.207 ◉ Et figura facit pulcritudinem, et propter hoc luna, et forme pulcre hominis, et multorum animalium, et arborum, et plantarum non apparent pulcre nisi propter formas eorum, aut propter figuras partium eorum, aut propter figuras eorum, aut propter figuras partium forme.

3.207 ◉ Shape, as well, creates beauty, and it is for this reason that the moon and the beautiful forms of people, as well as of several animals, trees, and plants appear beautiful only according to their forms, or according to the shapes of their parts or to their [overall] shapes, or according to the shapes of the parts of the form.

3.208 ◉ Et magnitudo facit pulcritudinem, et propter hoc apparet luna pulcrior stellis et stelle magne pulcriores parvis stellis.

3.208 ◉ Magnitude creates beauty, which is why the moon appears more beautiful than the stars, whereas large stars appear more beautiful than small stars.

3.209 ◉ Et divisio facit pulcritudinem, et propter hoc stelle separate sunt pulcriores stellis extensis et pulcriores stellis galaxie, et propter hoc candele distincte sunt pulcriores igne.

3.209 ◉ Separation, too, creates beauty, and this is why individual stars are more beautiful than clustered stars and more beautiful than the stars in the Milky Way, and it is also why individual candles are more beautiful than a fire.

3.210 ◉ Et continuatio etiam facit pulcritudinem, et propter hoc viridale continuum et plante spisse sunt pulcriores distinctis.

3.210 ◉ Continuity also creates beauty, which is why continuous vegetation or densely [clustered] plants are more beautiful than individual [plants].⁑

3.211 ◉ Et numerus facit pulcritudinem, et propter hoc loca celi multarum stellarum sunt pulcriora locis paucarum stellarum, et propter hoc candele multe numero in eodem loco numerus earum facit pulcritudinem. Et propter hoc loca celi multarum stellarum sunt pulcriora locis laterum.

3.211 ◉ Number, as well, creates beauty, which is why places in the sky where there are many stars are more beautiful than places with few stars, and it is why a large number of candles in the same location creates beauty. It is also why places in the sky where there are many stars are more beautiful than surrounding places [with fewer].⁑

3.212 ◉ Et motus hominis in sermone et operatione eius.

3.212 ◉ The motion of a person making a speech or carrying out some task [creates beauty].

3.213 ◉ Et quies eius facit pulcritudinem, et propter hoc apparet pulcra gravitas, et taciturnitas.

3.213 ◉ A person’s immobility also creates beauty, and this is why gravity and reserve appear beautiful.

3.214 ◉ Et asperitas etiam facit pulcritudinem, et propter hoc apparet villositas pulcra in multis pannis.

3.214 ◉ Roughness, as well, creates beauty, which is why many shaggy fabrics appear beautiful.

3.215 ◉ Et planities etiam facit pulcritudinem, et propter hoc apparet pulcra in pannis.

3.215 ◉ Smoothness, too, creates beauty, and it is for this reason that it appears beautiful in fabrics.

3.216 ◉ Et diafonitas facit pulcritudinem, et propter hoc apparent de nocte micantes diafoni.

3.216 ◉ Transparency creates beauty, which is why transparent objects appear to glitter at night.

3.217 ◉ Et spissitudo facit pulcritudinem, quoniam color, et lux, et figure, et lineatio, et omnes intentiones pulcre apparentes in formis visibilium non comprehenduntur similiter a visu nisi propter spissitudinem et umbram.

3.217 ◉ Furthermore, opacity creates beauty, for color, light, shape, design, and all [other] characteristics that appear beautiful in visible forms are perceived alike by sight on the basis only of opacity or shadow.⁑

3.218 ◉ Et umbra facit apparere pulcritudinem, quoniam in multis formis visibilium sunt macule et pori subtiles redentes eas turpes, et cum fuerint in luce solis, apparebunt macule in eis, quare latebit pulcritudo eorum. Et cum fuerint in umbra aut in luce debili, latebunt ille macule et ruge, quare apprehenditur pulcritudo eorum. Et etiam tortuositates que apparent in plumis avium et in panno qui dicitur alburalmon in umbra non apparent et in luce debili.

3.218 ◉ Shadow also creates beauty, for in many visible forms there are blemishes and tiny pores that render them ugly, and when they are in sunlight their blemishes will be revealed, so their beauty will be obscured. But when they are in shadow or in weak light, those blemishes and wrinkles will disappear, so their beauty is apprehended. Furthermore, the complicated windings that appear in the feathers of birds and in the fabric called »alburalmon«⁑ do not appear in shadow or in weak light.

3.219 ◉ Et obscuritas facit pulcritudinem apparere, quoniam stelle non apparent nisi in obscuro. Et similiter non apparet pulcritudo earum nisi in nigredine noctis et in locis obscuris, et latet in luce diei. Et stelle in noctibus obscuris sunt pulcriores quam in noctibus lune.

3.219 ◉ Darkness makes beauty appear, for the stars only appear in darkness. Likewise, their beauty only appears in the dark of night or in dark locations, and it disappears in daylight. Moreover, stars are more beautiful on dark nights than on moonlit nights.

3.220 ◉ Et similitudo facit pulcritudinem, quoniam membra animalis eiusdem speciei, ut oculus oculo, non apparent pulcra nisi quando fuerint consimilia, quoniam oculi, quando fuerint diverse figure, scilicet quod unus sit rotundus et alter longus, erunt in fine turpitudinis. Et similiter, si unus fuerit niger et alter viridis, erunt etiam turpes, et similiter si unus fuerit maior altero. Et similiter si una gena fuerit profunda et altera prominens, erit in fine turpitudinis, et similiter quando unum superciliorum fuerit grossum et alterum subtile, aut unum illorum grossum et alterum breve, erunt turpia. Omnia ergo animalium membra huiusmodi et dupla non erunt pulcra nisi cum fuerint consimilia. Et similiter picture et littere non apparent pulcre nisi quando fuerint littere que sunt uniusmodi et partes illarum que sunt huiusmodi consimiles.

3.220 ◉ Similarity also creates beauty, for the members of an animal that are of the same kind, such as one eye in relation to [the other] eye, do not appear beautiful unless they are similar, for when the eyes are of different shapes, e.g., when one is round while the other is oblong, they will be extremely ugly. So, too, if one is black and the other green, they will be ugly, and the same holds if one is larger than the other. Similarly, if one cheek is hollow, and the other is bulbous, they will be extremely ugly; and, in the same vein, if one of the eyebrows is thick and the other thin, or if one of them is long and the other short, they will be ugly. Thus, no members of this kind that belong to animals and are paired will be beautiful unless they are similar. So, too, depictions and letters do not appear beautiful unless letters of the same kind, as well as the equivalent parts of those letters, are similar.

3.221 ◉ Et diversitas facit pulcritudinem, quoniam figure membrorum animalis sunt diversarum partium, et non sunt pulcre nisi propter illam diversitatem. Quoniam si nasus totus esset equalis grossitudinis, esset in fine turpitudinis, et pulcritudo eius non est nisi propter diversitatem duorum extremorum eius et eius piramidalitatem. Et similiter pulcritudo superciliorum non est nisi quando extrema eorum fuerint subtiliora residuis anterioribus. Et similiter omnia membra animalis, quando quidem intuentur, invenitur quod pulcritudo eorum non est nisi ex diversitate figurarum partium eorum. Et similiter scripture, quoniam, si partes eius scripture essent equalis grossitudinis, non apparerent pulcre, quoniam extrema litterarum non apparent pulcra nisi quando fuerint subtiliora residuo, quoniam et, si extrema litterarum, et media earum, et continuatio earum essent uniusmodi spissitudinis, esset scriptura in fine turpitudinis. Diversitas ergo facit pulcritudinem in multis formis visibilium.

3.221 ◉ Difference creates beauty, as well, for the shapes of the members of an animal consist of different parts, and they are beautiful only because of such difference. For if the entire nose were of the same thickness throughout, it would be extremely ugly, so its beauty is due only to the difference [in thickness] of its two extremities and to the way it flares out [toward the nostrils]. Likewise, the beauty of the eyebrows is due only to the fact that their outer extremities are narrower than the portions toward the front. And the same holds for all the members of an animal; when they are in fact examined, it is found that their beauty is due only to the different shapes of their parts. So, too, with writing, for if the parts of the writing were of equal thickness [throughout], it would not appear beautiful, because the ends of the letters appear beautiful only if they are thinner than the remainder [of the letter], so that, if the ends, middle, and ligatures of the letters were of the same thickness, the writing would be extremely ugly. Thus, difference creates beauty in many forms of visible objects.

3.222 ◉ Iam ergo declaratum est ex eo quod diximus quod unaqueque intentionum particularium, quando comprehenduntur per sensum visus, aliquando facit pulcritudinem per se. Et cum sermo fuerit factus de multis corporibus inductive per se, cum inducentur omnia corpora, invenietur quod quelibet istarum intentionum facit pulcritudinem in multis locis. Et non diximus ea que diximus ex eis nisi gratia exempli et ut possent adquiri alia exempla per illa. Sed tamen iste intentiones non faciunt pulcritudinem in omnibus locis, nec una istarum intentionum facit pulcritudinem in qualibet forma in qua pervenit illa intentio; sed in quibusdam formis, et in quibusdam non. Verbi gratia, quod non quelibet magnitudo facit pulcritudinem in quolibet corpore alicuius magnitudinis, et similiter non quilibet color facit pulcritudinem, nec inde color facit pulcritudinem in quolibet corpore in quod pervenit ille color. Et similiter non quelibet figura facit pulcritudinem. Sed quelibet illarum intentionum quas diximus facit pulcritudinem per se; sed in quibusdam locis, in quibusdam non, et secundum quosdam modos, et secundum alios non.

3.222 ◉ From our discussion, therefore, it has been shown that, when they are perceived by sight, each of the particular characteristics [of the visible form] can sometimes create beauty on its own. And while the discussion was based on individual instances involving several objects, when all bodies are taken into account, it will be found that each of these characteristics creates beauty in many situations. So we have discussed what we have discussed in these cases only to provide examples so that other examples can be derived from them. Nonetheless, these characteristics do not create beauty in all situations, nor does any one of these characteristics create beauty in every form that possesses it; on the contrary, in some forms it does, and in some it does not. For instance, not every magnitude creates beauty in every body of a given size, and, by the same token, not every color creates beauty, nor, on that account, does a color create beauty in every body that happens to possess that color. Likewise, not every shape creates beauty. Some of the characteristics we have discussed create beauty on their own, but they do so in some situations and not in others, and they do so in certain ways and not in others.

3.223 ◉ Et etiam iste intentiones faciunt pulcritudinem per coniugationem illarum adinvicem, quoniam scriptura pulcra est illa cum figure litterarum sunt pulcre et compositio illarum adinvicem est compositio pulcra, quoniam scriptura in qua adunantur iste due intentiones est pulcrior scriptura in qua est una istarum duarum intentionum tantum. Finis ergo pulcritudinis scripture non est nisi ex coniugatione figure et situs.

3.223 ◉ Moreover, these characteristics create beauty by being conjoined, for writing is beautiful if the shapes of the letters are beautiful and the way they are combined together is beautiful, for writing in which these two characteristics coexist is more beautiful than writing in which only one of the two characteristics is present. The ultimate in beauty for writing is therefore based solely upon the combination of [appropriate] shape and spatial disposition.⁑

3.224 ◉ Et similiter, quando colores scintillantes et picture fuerint ordinata ordinatione consimili ordinata, sunt pulcriores coloribus et picturis carentibus ordinatione consimili. Et similiter pulcritudo apparet in forma hominum et animalium ex coniunctione vel ex coniugatione (quod idem est) intentionum particularium que sunt in eis. Quoniam magnitudo oculorum mediocris cum figura eius amigdalata est pulcrior oculo qui non habet nisi magnitudinem tantum aut figuram amigdalatam tantum. Et similiter rotunditas faciei cum tenuitate et subtilitate coloris est pulcrior quam unum sine altero. Et similiter parvitas oris cum gracilitate labiorum et mediocritate eorum est etiam pulcrior parvitate oris cum grossitudine labiorum et pulcrior gracilitate labiorum cum amplitudine oris. Et ista intentio est multe diversitatis et multorum modorum.

3.224 ◉ Likewise, when bright colors and depictions are arranged in a uniform way, they are more beautiful than colors and depictions that lack uniform arrangement. So too, beauty is revealed in the form of humans or animals through the conjunction or juxtaposition (which is the same thing) of particular characteristics in such forms. For an eye of moderate size that is almond-shaped is more beautiful than an eye that is of moderate size alone or that is only almond-shaped. Likewise, a round face with fine and subtle coloring is more beautiful than a face that has one of these attributes without the other. In the same vein, a small mouth with moderate-sized but slender lips is more beautiful than a small mouth with fat lips or a wide mouth with slender lips. But this case has many variants and subtypes.

3.225 ◉ Et cum feceris inductionem in formas pulcras omni modorum visibilium, invenies quod coniunctio intentionum particularium que sunt in formis faciunt in eis modos pulcritudinis quos non facit una intentionum per se. Et pulcritudo in maiori parte non fit nisi ex coniunctione istarum intentionum adinvicem, quoniam intentiones particulares quas diximus faciunt pulcritudinem per se, et faciunt pulcritudinem per coniunctionem earum adinvicem.

3.225 ◉ If you investigate beautiful forms in every type of visible object, you will find that a conjunction of particular characteristics in the forms create kinds of beauty in them that one characteristic does not create by itself. And, for the most part, beauty is created only through a conjunction of such characteristics, for the particular characteristics we have discussed create beauty on their own, but they also create beauty by being combined together.

3.226 ◉ Et etiam pulcritudo fit ex alia intentione preter istas duas intentiones quas prediximus, et est proportionalitas et consonoritas. Quoniam forme composite ex membris diversis et partibus diversis habent figuras diversas, et magnitudines diversas, et situs diversos, et continuationem et coniunctionem, et perveniunt in quamlibet illarum multe intentiones particulares. Tamen omnes non sunt proportionales, quoniam non quelibet figura est pulcra cum qualibet figura, nec quelibet magnitudo est pulcra cum qualibet magnitudine, nec quilibet situs est pulcer cum quolibet situ, nec quelibet figura cum qualibet magnitudine, nec quelibet magnitudo cum quolibet situ. Sed quelibet intentionum particularium habet proportionem cum quibusdam intentionum, et est assimetra quibusdam. Verbi gratia, simitas nasi cum profunditate oculorum non est pulcra. Et similiter magnitudo nasi cum maxima magnitudine oculorum non est pulcra, et similiter prominentia frontis cum profunditate oculorum non est pulcra, et similiter frontis planities cum prominentia oculorum non est pulcrum. Quodlibet ergo membrorum habet figuram que facit formam eius pulcram, et cum hoc quelibet figura cuiuslibet membri non habet proportionem nisi cum quibusdam figuris residuorum membrorum, et cum aliis non. Et forma fit pulcra per congregationem figurarum proportionalium.

3.226 ◉ In addition, beauty is created from one [more] characteristic beyond the two we have discussed, i.e., proportionality or harmony.⁑ For forms that consist of different members and different parts have different shapes, different sizes, and different spatial dispositions, as well as continuity and contiguity, and in each of them several particular characteristics converge. Still, not all of them are proportionate, for not every shape is beautiful in conjunction with every [other] shape, nor is every magnitude beautiful in conjunction with every [other] magnitude, nor is every spatial disposition beautiful in conjunction with every [other] spatial disposition, nor is every shape beautiful in conjunction with every magnitude, nor is every magnitude beautiful in conjunction with every spatial disposition. On the contrary, every particular characteristic is proportionate to certain characteristics but disproportionate to others. For instance, a flat nose along with deep-set eyes is not beautiful, and, by the same token, a large nose along with very large eyes is not beautiful. Likewise, a bulbous forehead along with deep-set eyes is not beautiful, but neither is a flat forehead along with protruding eyes. Thus, each of the members has a shape that makes its form beautiful, but in addition each shape of each member is proportionate only to some shapes of the remaining members, but not to others. So the form becomes beautiful by the juxtaposition of proportionate shapes.⁑

3.227 ◉ Et similiter magnitudines, et situs, et ordinatio eorum, quoniam magnitudo oculorum cum pulcritudine figure eorum, et cum mediocritate simitatis nasi, et cum magnitudine proportionali ad magnitudinem oculorum est pulcra. Et similiter amigdaleitas oculorum, et dulcedo et tenuitas figure eius, etsi fuerint parvi, cum subtilitate nasi, et mediocritate figure et quantitatis eius, erunt pulcri. Et similiter gracilitas labiorum cum subtilitate oris est pulcra quando subtilitas oris eius fuerit proportionalis ad gracilitatem labiorum—scilicet quod labia non sint in fine gracilitatis et os non sit in fine parvitatis, sed erit parvitas oris mediocris et labia gracilia et cum hoc proportionalia ad quantitatem oris. Et similiter amplitudo faciei, quando fuerit proportionalis ad quantitates membrorum faciei, erit pulcra—scilicet cum facies non sit in fine amplitudinis, et membra faciei sunt proportionalia ad quantitates totius faciei. Quoniam, quando facies fuerit ampla maxime amplitudinis, et membra que sunt in ea sunt parva non proportionalia ad quantitatem eius, non erit facies pulcra, quamvis quantitates membrorum sint proportionales, et figure eorum sunt pulcre. Et similiter, quando fuerit parva facies et stricta, et membra eius fuerint magna (membra dico faciei), erit facies turpis. Et cum membra fuerint proportionalia inter se et proportionalia ad quantitatem amplitudinis faciei, erit forma pulcra, quamvis membra per se non sint pulcra.

3.227 ◉ The same holds for magnitudes and spatial dispositions, as well as for their arrangement, for large eyes having a beautiful shape, along with a moderately flat nose whose size is proportionate to that of the eyes, are beautiful. So, too, even if they are small, eyes of an almond shape, having a charming and delicate shape, will be beautiful when they occur along with a narrow nose of moderate shape and size. Likewise, slim lips along with a delicate mouth are beautiful when the delicacy of the mouth is proportionate to the slimness of the lips—i.e., when the lips are not inordinately slim, nor the mouth inordinately small, but the mouth must be moderately small while the lips are slim and, moreover, proportionate to the size of the mouth. So, too, when the width of the face is proportionate to the size of the facial members, it will be beautiful—i.e., when the face is not inordinately broad, and when the facial members are proportionate [in size] to the size of the whole face. For when the face is inordinately broad, but its members are too small to be proportionate in size to it, the face will not be beautiful, even though the size of the members may be proportionate [among each other], and even though they are beautifully shaped. Likewise, if the face is small and thin but its members are large (I mean the members of the face), the face will be ugly. But if the members are proportionate among each other as well as to the breadth of the face, the form will be beautiful, even if the members are not [particularly] beautiful by themselves.⁑

3.228 ◉ Sed proportionalitas tantum facit pulcritudinem. Cum ergo in forma congregabitur pulcritudo figure cuiuslibet partis eius, erit pulcritudo quantitatis et compositionis earum, et proportionalitas membrorum secundum figuras, et magnitudines, et situs, et fuerint cum hoc proportionalia ad totam figuram faciei et quantitatem eius, erit in fine pulcritudinis.

3.228 ◉ Proportionality by itself can create beauty. Accordingly, when there is beauty in the shape of each part of a form, and when the size and arrangement of such parts are beautiful, and when the members are proportionate in shape, size, and spatial disposition, as well as being proportionate to the shape and size of the face as a whole, the face will be extremely beautiful.

3.229 ◉ Et similiter scriptura non erit pulcra nisi quando littere eius fuerint proportionales in figura, et quantitate, et situ, et ordine. Et similiter de omnibus modis visibilium cum quibus congregantur partes diverse.

3.229 ◉ Similarly, writing will not be beautiful unless the letters are proportionate in shape, size, spatial disposition, and arrangement. And the same holds for every kind of visible object that consists of disparate parts.

3.230 ◉ Et cum consideraveris formas pulcras de omnibus modis visibilium, invenies quod proportionalitas facit pulcritudinem magis quam aliqua alia intentio, vel etiam alique coniuncte per se. Et cum considerabuntur intentiones pulcre quas faciunt intentiones particulares per coniunctionem earum adinvicem, invenietur quod pulcritudo que apparet ex coniunctione illarum non apparet nisi propter proportionalitatem illarum intentionum coniunctarum inter se. Quoniam non quandocumque adunabuntur ille intentiones fit pulcritudo; sed in quibusdam formis, et in aliis non. Et est propter proportionalitatem que contingit inter illas intentiones. Pulcritudo ergo non est nisi ex intentionibus particularibus, et perfectio eius est ex proportionalitate et consonantia que fit inter intentiones particulares.

3.230 ◉ And when you examine the beautiful forms of every kind of visible object, you will find that proportionality creates beauty more than any other characteristic on its own or, for that matter, any conjunction [of characteristics] on its own.⁑ Moreover, when the expressions of beauty created by particular characteristics in combination are examined, it will be found that the beauty that appears through their combinations appears only because of the proportionality of those characteristics that are combined with each other. For combinations of such characteristics will not always create beauty; in some forms they will, but in others they will not. So the beauty expressed by these characteristics [in combination] is due to the proportionality that obtains among them. Beauty therefore is [ultimately contingent] upon particular characteristics alone, but its perfection comes from the proportionality or harmony that obtains among particular characteristics.⁑

3.231 ◉ Iam ergo declaratum est ex omni quod diximus quod forme pulcre comprehense a visu non sunt pulcre nisi ex intentionibus particularibus que comprehenduntur per sensum visus, et ex coniunctione earum adinvicem, et ex proportionalitate earum adinvicem. Et visus comprehendit intentiones particulares predictas simplices et compositas. Cum ergo visus comprehenderit aliquam rem visam, et fuerit aliqua intentio in illa re visa particularis faciens pulcritudinem per se, et intueatur visus illam intentionem per se, pervenit forma illius intentionis post intuitum apud sentientem. Et comprehendet virtus distinctiva pulcritudinem rei vise in qua est illa intentio, quoniam forma cuiuslibet rei vise est composita ex multis intentionibus intentionum quarum divisionem prediximus. Cum ergo visus comprehenderit rem visam et non distinxerit intentiones que sunt in ea, non comprehendet pulcritudinem eius. Et cum distinxerit intentiones que sunt in ea, et fuerit aliqua intentio earum secundum modum facientem pulcritudinem in anima, statim visus apud intuitionem illius intentionis comprehendet illam intentionem per se. Et cum comprehenderit illam intentionem per se, perveniet illa comprehensio apud sentientem, et sic virtus distinctiva comprehendet pulcritudinem que est in ea. Et per istam comprehensionem comprehendet pulcritudinem illius rei vise. Cum ergo visus comprehenderit aliquam rem visam, et in illa re visa fuerit pulcritudo composita ex intentionibus coniunctis, et intuens fuerit visus illam rem visam, et distinxerit intentiones que sunt in ea, et comprehenderit intentiones que faciunt pulcritudinem per coniunctionem earum adinvicem aut proportionalitatem earum adinvicem, et pervenerit illa comprehensio apud sentientem, et comparaverit virtus distinctiva illas intentiones adinvicem, comprehendet pulcritudinem illius rei vise composite ex coniunctione intentionum que sunt in ea. Visus ergo comprehendet pulcritudinem illius rei vise composite ex coniunctione intentionum que sunt in ea. Visus ergo comprehendet pulcritudinem que est in visibilibus ex comparatione illarum intentionum adinvicem secundum modum quem declaravimus.

3.231 ◉ From everything we have said, then, it is clear that the beautiful forms perceived by sight are only beautiful by dint of the particular characteristics that are perceived by the sense of sight, the conjunction of those characteristics among each other, and their proportionality to one another. But sight perceives the aforesaid particular characteristics either individually or in combination. Thus, when sight perceives some visible object, if there is a particular characteristic in that visible object that, by itself, makes the object beautiful, and if sight examines that lone characteristic, the form of that characteristic reaches the sensitive faculty after the process of visual scrutiny. Then the faculty of discrimination will perceive the beauty of the visible object possessing that characteristic, for the form of every visible object is composed of several of the characteristics we listed earlier.⁑ Accordingly, when sight perceives a visible object but does not discern the characteristics the object possesses, it will not perceive its beauty. When it does discern the characteristics the object possesses, and when any of its characteristics somehow creates the impression of beauty in the soul, as soon as it apprehends this characteristic, sight will perceive that characteristic by itself. And when it perceives that characteristic by itself, that perception will reach the sensitive faculty, and thus the faculty of discrimination will perceive the beauty that it possesses. Moreover, by means of this perception it will perceive the beauty of that visible object. Thus, when sight perceives any visible object, if there is beauty in that object arising from a combination of characteristics, if sight examines that visible object and discerns the characteristics possessed by that object, if it then perceives the characteristics that create beauty by combining together or by being proportionate among one another, and if that perception occurs to the sensitive faculty, then, when the faculty of discrimination correlates those characteristics to one another, it will perceive the beauty of that visible object, which arises from the combination of characteristics the object possesses. Thus, sight will perceive the beauty of that visible object, which arises from the combination of characteristics the object possesses. Sight will therefore perceive beauty in visible objects by correlating those characteristics to one another in the way we explained.

3.232 ◉ Turpitudo vero est forma carens qualibet intentione pulcra. Quoniam iam predictum est quod intentiones particulares faciunt pulcritudinem, sed non in omnibus locis nec in omnibus formis; sed in quibusdam, et in aliis non. Et similiter proportionalitas non est in omnibus formis; sed in quibusdam formis, et in aliis non. Forme ergo in quibus non faciunt intentiones particulares aliquam pulcritudinem per se nec per suam coniunctionem, et in quibus non est aliqua proportionalitas inter partes earum carent omni pulcritudine, et sic sunt turpes, quoniam turpitudo formarum est privatio pulcritudinis in eis. Et forte congregantur in eadem forma intentiones pulcre et turpes, sed visus comprehendet pulcritudinem ex pulcro et turpitudinem ex turpibus quando distinxerit et fuerit intuens intentiones que sunt in ea. Turpitudo ergo comprehenditur a visu in formis carentibus omnibus pulcritudinibus ex privatione pulcritudinis ab eo apud comprehensionem.

3.232 ◉ Ugliness, for its part, comes about when the form lacks any beautiful characteristic. For it has already been said that particular characteristics create beauty, but not in every situation or in every form; in some it does, but in others it does not. So, too, proportionality does not exist in every form; in some forms it does, but in others it does not. Therefore, forms whose particular characteristics do not create any beauty on their own or in combination, or forms whose parts are disproportionate to one another lack beauty entirely, and so they are ugly, because ugliness of forms consists in the absence of beauty in them. There may be a combination of beautiful and ugly characteristics in the same form, but sight will perceive beauty from what is beautiful and ugliness from what is ugly in the form when it differentiates and evaluates the characteristics the form possesses. Thus, ugliness is perceived by sight in forms that lack any beauty through the absence of beauty [that it senses] when it perceives the form.⁑

3.233 ◉ Consimilitudo autem est equalitas duarum formarum aut duarum intentionum in re in qua sunt consimiles. Cum ergo visus comprehenderit duas formas aut duas intentiones consimiles in simul, comprehendet consimilitudinem illarum ex comprehensione cuiuslibet duarum formarum vel intentionum et ex comparatione alterius illarum ad alteram. Visus ergo comprehendet consimilitudinem in formis et intentionibus consimilibus ex comprehensione cuiuslibet formarum et intentionum secundum suum esse et ex comparatione illarum adinvicem.

3.233 ◉ Similarity consists of the equality of two forms or of two characteristics that are identical in an object. Thus, when sight perceives two identical forms or two identical characteristics at the same time, it will perceive their similarity through the perception of each of the two forms or characteristics and the correlation of one to the other. Sight will therefore perceive the similarity of forms or of identical characteristics by perceiving each of the forms or characteristics as they actually exist and by correlating them to one another.

3.234 ◉ Diversitas autem comprehenditur a visu in formis diversis ex comprehensione cuiuslibet formarum diversarum, et ex comparatione alterius illarum ad alteram, et ex comprehensione privationis equalitatis in eis. Diversitas ergo comprehenditur per sensum visus ex comprehensione cuiuslibet formarum et intentionum per se, et ex comparatione eorum adinvicem, et ex sensu privationis equalitatis a sentiente.

3.234 ◉ Difference, on the other hand, is perceived by sight in various forms through perception of each of the various forms, comparison of one to the other, and perception of the lack of equality among them. Thus, difference is perceived by the sense of sight through a perception of each of the forms or characteristics by itself, as well as through a comparison of them among each other and [the resulting] sensation of an absence of equality arising in the sensitive faculty.

3.235 ◉ Iam ergo complevimus et declaravimus declarationem qualitatis comprehensionis cuiuslibet intentionum particularium que comprehenduntur per sensum visus. Et declaratum est ex omnibus hoc quod quedam intentiones particulares comprehenduntur solo sensu, et quedam comprehenduntur per cognitionem, et quedam per argumentationem et significationem secundum vias quarum declarationem prediximus. Et iste sunt intentiones quarum declarationem intendimus in isto opere.

3.235 ◉ We have now finished, having explained how each of the particular characteristics [of visible objects] is perceived by the sense of sight. Moreover, from all we have discussed it has been shown that some particular characteristics are perceived by brute sensation, some are perceived by recognition, and some are perceived by deduction and implication in the ways we have explained earlier. These are the things we meant to explain in this [Chapter of the] work.

◉[Capitulum 4]

◉[Chapter 4]

4.1 ◉ Iam declaratum est quomodo visus comprehendit quamlibet intentionum particularium que comprehenduntur per sensum visus, et visus non comprehendit nisi formas visibilium, que sunt corpora. Sed forme visibilium sunt composite ex intentionibus particularibus predictis, sicut figura, et magnitudine, et colore, et situ, et ordine, et sibi similibus. Visus ergo non comprehendit quamlibet intentionum nisi ex comprehensione formarum visibilium compositarum ex intentionibus particularibus, et visus comprehendet quamlibet formarum visibilium secundum omnes intentiones particulares que sunt in forma in simul. Et nichil comprehendit visus ex intentionibus particularibus per se, quoniam nulla intentionum particularium predictarum est sola per se, nam omnes iste intentiones particulares non inveniuntur nisi in corporibus, et nullum corpus est in quo est aliqua istarum intentionum sola sine alia. Visus ergo non comprehendit nisi formas visibilium, sed quelibet formarum visibilium est composita ex multis intentionibus particularibus. Ergo visus comprehendit in qualibet formarum visibilium multas intentiones particulares, et distinguentur in ymaginatione. Visus ergo comprehendit quamlibet intentionum particularium apud visionem rei vise coniunctam cum aliqua intentionum particularium, et ex distinctione eius inter intentiones que sunt in forma comprehendit quamlibet intentionum per se.

4.1 ◉ It has now been shown how sight perceives any of the particular characteristics that are perceived by the sense of sight, and sight perceives only the forms of visible objects, which are bodies. But the forms of visible objects are composed of the aforesaid particular characteristics, such as shape, size, color, spatial disposition, arrangement, and the like. Thus, sight perceives any such characteristic only by perceiving the forms of visible objects, those forms being composed of particular characteristics, and sight will perceive each of the forms of visible objects according to all of the particular characteristics that are in them [which it perceives] all at the same time. But sight perceives none of the particular characteristics by itself, because none of the aforementioned particular characteristics exists on its own, for these particular characteristics are all found in bodies, and only in bodies, and there is no body in which any of these characteristics exists by itself without some other. Sight therefore perceives only the forms of visible objects, and each of the forms of visible objects consists of several particular characteristics. Thus, sight perceives many particular characteristics in each of the forms of visible objects, and they will be differentiated individually in the imagination.⁑ So, when a visible object is seen, sight perceives each of its particular characteristics in conjunction with some other particular characteristic, and by differentiating among the characteristics that are in the form, it perceives each characteristic by itself.

4.2 ◉ Et iam declaratum est, et etiam determinatum, qualiter visus comprehendit formas visibilium que componuntur ex intentionibus particularibus. Et quedam intentiones particulares ex quibus componuntur forme visibilium apparent apud aspectum rei vise, et quedam non apparent nisi post intuitionem et considerationem subtilem, sicut scriptura subtilis, et lineatio subtilis, et diversitas colorum consimilium fere. Et generaliter omnes intentiones subtiles non apparent visui apud aspectum rei vise, sed post intuitionem et considerationem. Et forma rei vise comprehensa per sensum visus est illa que componitur ex omnibus intentionibus particularibus que sunt ex forma rei vise quas possibile est visum comprehendere. Et visus non comprehendit veram formam rei vise nisi per comprehensionem omnium intentionum particularium que sunt in forma rei vise. Et cum ita est, forma ergo vera rei vise in qua sunt intentiones subtiles non comprehenditur a visu nisi post intuitionem.

4.2 ◉ It has already been shown and also explained how sight perceives the forms of visible objects that are composed of particular characteristics.⁑ Some of the particular characteristics that comprise the forms of visible objects are seen as soon as the visible object is looked at, but others are seen only after visual scrutiny and careful evaluation, for instance, tiny writing, or subtle designs, or various colors that are almost identical in hue. Generally, no subtle characteristics are seen by sight when the visible object is first looked at, only after visual scrutiny and evaluation. The form of the visible object that is perceived by the sense of sight is composed of all the particular characteristics that can be grasped by the eye from the form of the visible object. So sight does not perceive the proper form of the visible object unless it perceives all the particular characteristics that are in the form of the visible object. And that being the case, the proper form of a visible object that possesses subtle characteristics is perceived by sight only after visual scrutiny.

4.3 ◉ Et etiam cum visus non comprehenderit intentiones subtiles nisi per intuitionem, et non apparent intentiones subtiles visui apud aspectum, quando visus comprehenderit aliquam rem visam, et comprehenderit formam eius, et fuerint in illa re visa intentiones subtiles, intentiones subtiles non apparent per aspectum, sed per intuitionem. Cum ergo visus comprehenderit aliquam rem visam, et non fuerit in ea aliqua intentio subtilis, etiam comprehendet veram eius formam, etsi non certificabit quod illa forma est vera nisi postquam habuerit fortem intuitionem ad quamlibet partem illius rei vise. Et certificaverit quod nulla intentio subtilis est in ea, et tunc certificabit quod forma quam comprehendit est vera forma.

4.3 ◉ Also, since sight perceives subtle characteristics only through visual scrutiny, and since subtle characteristics are not seen at first glance, then, when sight perceives some visible object and perceives its form, and when that visible object possesses subtle characteristics, those subtle characteristics are not seen at first glance, but only after visual scrutiny. Thus, when sight perceives some visible object that possesses no subtle characteristic, it will perceive its proper form, even though it will not determine that the form is proper until after it subjects each part of the visible object to intense visual scrutiny. It then determines that the object possesses no subtle characteristic, and thus it will determine that the form it is perceiving is the proper form.

4.4 ◉ Secundum ergo omnes dispositiones non certificat visus formam rei vise nisi per considerationem omnium partium rei vise et per intuitionem omnium intentionum que possunt apparere in re visa.

4.4 ◉ Without exception, then, sight determines [the true status] of a visible object’s form by evaluating all parts of the visible object and by subjecting all of the characteristics that can be seen in the visible object to visual scrutiny.

4.5 ◉ Et cum hoc est declaratum, dicamus quod comprehensio visibilium erit secundum duos modos, et sunt comprehensio superficialis et comprehensio per intuitionem que profundum aspicit. Quoniam, quando visus aspicit rem visam, comprehendet intentiones manifestas que sunt in ea apud aspectum. Deinde, si preter illud intuerit ipsum et consideraverit omnes partes eius, certificabit formam eius. Si autem non intuerit partes eius, comprehendet formam non certificatam, et illa forma aut eius forma vera erit (sed ipse non certificat quod forma eius sit vera), aut non erit forma eius vera. Et cum ita est, comprehensio ergo visibilium a visu erit secundum duos modos: et comprehensio superficialis, que est in primo aspectu, et comprehensio per intuitionem. Comprehensio autem per primum aspectum est comprehensio non certificata, et comprehensio per intuitionem est comprehensio per quam certificantur forme visibilium.

4.5 ◉ And now that this has been made clear, let us add that the perception of visible objects will occur in two ways: i.e., by superficial perception or by perception based on close visual scrutiny. For when the eye looks at a visible object, it will perceive the obvious characteristics the object possesses at first glance. Then, if it goes on to scrutinize the object and evaluate all of its parts, it will determine [the true status of] its form. On the other hand, if it does not scrutinize its parts, it will perceive its form in an indeterminate way,⁑ and that form will either be its proper form (although sight does not determine that the form is proper), or it will not be its proper form. And since this is so, the perception of visible objects by sight will occur in two ways: either [by] superficial perception, which occurs at first glance, or [by] perception based on visual scrutiny. Moreover, perception at first glance is indeterminate, whereas perception based on visual scrutiny is the perception by means of which [the true status of] the forms of visible objects is determined.

4.6 ◉ Et cum hoc declaratum est, dicamus quod intuitio per quam comprehenduntur forme vere visibilium erit per ipsum visum, et erit per distinctionem. Quoniam iam declaratum est in distinctione linearum radialium quod forme que a visu comprehenduntur ex axe radiali et ex illo quod est prope axem sunt manifestiores et maioris certificationis formis que comprehenduntur ex residuis verticationibus. Cum ergo visus fuerit oppositus alicui rei vise, et illa res visa non fuerit in fine parvitatis sed alicuius quantitatis, et visus fuerit fixus in oppositione eius apud aspectum illud quod opponitur medio visus ex illa re visa, et fuerit super axem aut prope axem, erit manifestius partibus residuis rei vise. Et visus percipit istam dispositionem, quoniam, quando comprehenderit rem visam totam, inveniet locum oppositum medio eius cuius forma pervenit in medio visus esse manifestiorem partibus residuis.

4.6 ◉ Having clarified this point, we should say that the visual scrutiny through which the proper forms of visible objects are perceived will be carried out by sight itself, or it will be carried out through differentiation. For it has already been shown in our account of radial lines that the forms perceived by sight along the [visual] axis, or along rays near that axis, are clearer and more determinate than forms that are perceived along the remaining rays.⁑ Thus, when the eye faces any visible object, provided that the object is not inordinately small but is of some [perceptible] size, and when the eye, having looked at the object, focuses on the part of it directly opposite the middle of the eye[’s surface], so that it lies on or near the visual axis, it will be [seen] more clear[ly] than the rest of the visible object. Moreover, sight perceives this fact, because, when it perceives the whole visible object, it will find that the location directly opposite, whose form reaches the middle of the eye[’s surface], is more clear[ly seen] that the rest of the object.

4.7 ◉ Et superius declaratum est quod ista intentio apparet sensui quando res visa fuerit magne quantitatis. Cum ergo visus comprehenderit totam rem visam, inveniet quod forma partis opposite medio eius est manifestior omnibus partibus residuis, et cum voluerit certificare formam rei vise, movebitur ita quod medium eius sit oppositum cuilibet parti partium rei vise. Et sic comprehendet formam cuiuslibet partis partium rei vise comprehensione manifesta certificata sicut comprehendit partem oppositam medio eius apud aspectum rei vise. Cum igitur sentiens voluerit certificare rem visam, movebitur visus ita quod sit medium eius oppositum cuilibet parti partium rei vise, et per istum modum comprehendet formam cuiuslibet partium rei vise valde manifeste.

4.7 ◉ It was shown above that this fact is evident to sense when the visible object is large.⁑ Therefore, when the eye perceives the entire visible object, it will find that the form of the part directly opposite the center [of its surface] is clearer than all the remaining parts, so when it wants to determine the form of the visible object,⁑ it will move in such way that its center lies directly opposite every area on every part of the visible object. Thus, it will perceive the form of every area on every part of the visible object in a clear and determinate way, just as it perceives the part directly opposite its center when it first looks at the visible object. When the sensitive faculty wishes to determine the visible object, then, it will move the eye in such a way that its center lies directly opposite every portion of every part of the visible object, and in this way it will perceive the form of every part of the visible object with utmost clarity.

4.8 ◉ Et virtus distinctiva distinguet omnes formas venientes ad ipsam, et distinguet colores partium, et diversitatem colorum, et ordinationem partium adinvicem—et generaliter omnes intentiones rei vise que apparent per intuitionem et formam totius rei vise compositam ex illis partibus et ex illis intentionibus. Secundum ergo hunc modum erit certificatio cuiuslibet partium rei vise secundum suum esse et certificatio omnium intentionum rei vise. Et non certificatur forma cuiuslibet partium rei vise nisi post motum visus super omnes partes, et cum hoc natus est visus ad motum intuitionis et ad faciendum axem radialem transire super omnes partes rei vise. Cum ergo virtus distinctiva quesierit intueri rem visam, movebitur axis radialis super omnes partes rei vise. Et cum intentiones subtiles que sunt in re visa non apparent nisi per motum visus et pertransitum axis aut radialium linearum que sunt prope ipsum super quamlibet partium rei vise, non perveniet forma rei vise certificata apud sentientem (quando corpus eius fuerit alicuius quantitatis) nisi per motum visus et per oppositionem cuiuslibet partium rei vise medio visus.

4.8 ◉ Meanwhile, the faculty of discrimination will differentiate all the forms reaching it, and it will differentiate the colors of the parts, the differences among the colors, and the arrangement of the parts among each other—and generally speaking [it will differentiate] all the characteristics of the visible object that are apprehended through visual scrutiny as well as the form of the entire visible object, that form being composed of its parts and its characteristics. This, then, is how every part of the visible object will be determined according to its actuality and how all the characteristics of the visible object will be determined. But the form of every part of the visible object is not determined unless the eye has scanned all the parts [of the object]. The eye, moreover, is naturally disposed to scan [objects for the sake of] visual scrutiny and to cause the visual axis to pass over all parts of a visible object. Thus, when the faculty of discrimination seeks to scrutinize the visible object, the visual axis will move over all parts of the visible object. And since the subtle characteristics possessed by the visible object are revealed only when the eye moves and the [visual] axis or the radial lines near it pass over every part of the visible object, the form of the visible object that reaches the sensitive faculty (assuming that the object is of a perceptible size) will not be determinate unless the eye moves so that the center of the eye lies directly opposite every part of the visible object.

4.9 ◉ Et etiam, quando res visa fuerit in fine parvitatis et non fuerit opposita medio visus etiam, non complebitur intuitio eius nisi postquam movebitur visus donec axis pertranseat in illam rem visam; et perveniet forma illius rei vise in medium visus, et appareat forma rei vise. Et cum ita est, intuitio per quam visus comprehendit veras formas visibilium forte erit per ipsum visum et forte per distinctionem in simul. Comprehensio ergo forme vere rei vise non erit nisi per intuitionem, et intuitio per quam certificatur forma rei vise non complebitur nisi per motum visus. Et cum corpus rei vise fuerit alicuius quantitatis, non complebitur intuitio eius nisi per motum axis radialis in omnes dyametros rei vise. Et istam intentionem voluit dicere ille qui opinabatur quod visio non fuerit nisi per motum et quod nulla res visa videbitur tota simul, quoniam ipse intendebat dicere visionem certificatam que non potest esse nisi per intuitionem, et per motum visus, et per motum axis radialis super omnes diametros rei vise.

4.9 ◉ In addition, when the visible object is exceptionally small and does not lie directly opposite the middle [portion] of the eye, the visual scrutiny to which it is subject will not be accomplished until after the eye moves so that the visual axis passes over that visible object; then the form of that visible object will reach the middle [portion] of the eye, and the form of the object may be revealed. And since this is the case, the visual scrutiny through which sight perceives the proper forms of visible objects may occur through sight per se or through [sight and] differentiation together. Thus, perception of the proper form of a visible object will occur only through visual scrutiny, and the scrutiny through which the form of the visible object is determined will only be accomplished through the motion of the eye. So when the body of the visible object is of a perceptible size, the scrutiny to which it is subjected will not be accomplished until the visual axis moves over all the cross-sections of the visible object. This is what was meant by whoever supposed that vision occurs only through the motion [of the eye] and that no visible object will be seen as a whole, all at once, for what he meant is that vision cannot be determinate except through visual scrutiny [which occurs] through the motion of the eye and the motion of the visual axis over all the cross-sections of the visible object.⁑

4.10 ◉ Quomodo vero sentiens certificat per intuitionem et motum formam rei vise est quia, quando visus fuerit oppositus rei vise, sentiens etiam comprehendet totam formam apud oppositionem comprehensione qualicumque, et comprehendet partem que est apud extremum axis vera comprehensione in fine veritatis. Et cum hoc, tunc comprehendet quamlibet partium residuarum forme aliqua comprehensione. Deinde, quando visus movebitur et mutabitur axis a parte in qua erat ad aliam partem, comprehendet sentiens in ista dispositione formam totius rei vise secunda comprehensione, et comprehendet partem eius que est apud extremum axis secunda comprehensione etiam. Et cum hoc erit comprehensio istius partis que est apud extremum axis in secunda dispositione manifestior comprehensione eius in prima dispositione, et in ista dispositione etiam comprehendet sentiens partes residuas aliqua comprehensione. Et similiter, quando axis mutabitur per motum ad tertiam partem, comprehendet sentiens in tertia dispositione totam rem visam tertia comprehensione, et comprehendet partem que est apud extremum axis tertia comprehensione etiam, et erit comprehensio istius partis ab eo in ista dispositione manifestior comprehensione in duabus primis dispositionibus. Et cum hoc sentiens comprehendet in ista dispositione etiam quamlibet partium residuarum aliqua comprehensione. Per motum ergo visus super partes rei vise adquirit sentiens duas dispositiones quarum altera est frequentatio comprehensionis totius rei vise; et secunda est que comprehendit quamlibet partium rei vise per axem radialem aut per illud quod est prope axem radialem manifesta comprehensione. Apparet ergo sensui omne quod est possibile apparere ex illis partibus. Et cum sentiens sepe comprehenderit totam rem visam et quamlibet partium rei vise, comprehendet per istam dispositionem omne quod possibile est comprehendi ex illa re vise.

4.10 ◉ How the sensitive faculty determines the form of a visible object through visual scrutiny and the motion [of the eye] is as follows. When the eye faces the visible object, the sensitive faculty will somehow perceive⁑ the whole form according to the facing disposition, and it will also perceive the part at the endpoint of the [visual] axis as accurately as possible. But in the process it will perceive every other part of the form in some way. Then, if the eye moves and the [visual] axis shifts its focus from where it was to somewhere else, the sensitive faculty will in that case perceive the form of the whole visible object a second time, and it will also perceive the part at the end of the [visual] axis a second time. Moreover, the part at the end of the [visual] axis will be perceived more clearly in the second case than it was in the first, and in this case the sensitive faculty will again perceive the remaining parts [of the form] in some way. By the same token, when the [visual] axis shifts to a third part, the sensitive faculty will perceive the entire visible object yet a third time, and it will also perceive the part [of the object] at the end of the [visual] axis in this third situation, and under these conditions it will perceive this part more clearly than it did in the first two instances. In this case, moreover, the sensitive faculty will also perceive each of the remaining parts [of the form] in some way. Thus, by moving the eye over the parts of the visible object, the sensitive faculty is affected in two [complementary] ways. First, it perceives the visible object as a whole at numerous reprises, and second, it perceives with clarity each part of the visible object along the visual axis or along a radial line that is near the visual axis. Thus, everything about those parts that can be seen is revealed to the sense [of sight]. And if the sensitive faculty perceives both the visible object as a whole and each of its parts frequently, it will then perceive everything that can be perceived about that visible object.

4.11 ◉ Et cum hoc comprehensione multotiens iterata et in duabus duplicationibus et iterationibus comprehensionis totius rei vise distinguit virtus distinctiva illud quod apparet ex coloribus partium, et luce, et magnitudine, et remotione, et figura, et situ earum, et equalitate illarum que sunt consimiles in istis distinctionibus, et diversitate earum que sunt diverse in omnibus istis intentionibus aut in quibusdam, et ex ordine partium adinvicem. Et comprehendit ex distinctione omnium istarum intentionum et comparatione istarum intentionum ad ea que cognoscuntur ex similibus earum formam compositam ex omnibus istis. Et sic signatur in ymaginatione forma composita ex omnibus similibus intentionibus, et sic certificatur forma rei vise per quam appropriatur illa res visa apud sentientem. Secundum ergo hunc modum certificat sentiens per intuitionem formas visibilium.

4.11 ◉ In addition, as the perception occurs repeatedly in terms of the twofold [perception of whole and parts] and the repetition of the perception of the entire visible object, the faculty of discrimination differentiates what is revealed of the color of the parts, their light, their size, their distance, their shape, their spatial disposition, the equality of those things that are identical among what is differentiated, and differences among all these characteristics or among some of them, as well as the arrangement of their parts among one another. Moreover, by differentiating all of these characteristics and comparing these characteristics to ones that are known to be similar to them, it perceives the form comprising all of them. In this way the form comprising all similar characteristics is impressed in the imagination, and thus the visible object’s form, which provides the means by which the visible object itself is apprehended by the sensitive faculty, is determined. This, therefore, is how the sensitive faculty determines the forms of visible objects by means of visual scrutiny.

4.12 ◉ Et etiam dicamus quod visus, quando comprehendit aliquam rem visam, et fuerit certificata forma eius apud sentientem, forma illius rei vise remanet in anima, et figurabitur in ymaginatione. Et iterabitur comprehensio rei vise, et erit forma eius magis fixa in anima quam forma rei vise quam visus non comprehendit nisi semel aut raro. Et dico quod visus, quando comprehenderit aliquod individuum, deinde comprehenderit alia individua illiusmodi individui, et iterabitur comprehensio individuorum frequenter, quiescet forma illiusmodi in anima, et perveniet forma universaliter figurata ymaginatione. Et significatio super hoc quod forme visibilium remanent in anima et in ymaginatione est quia homo, quando meminit de aliquo homine quem cognovit ante, et certificavit formam eius, et fuerit memorans tempus in quo vidit illum hominem et locum vera memoratione, statim ymaginabitur formam illius hominis, et figuram faciei eius, et situm eius in quo erat in illo tempore. Et ymaginabitur locum in quo vidit ipsum, et forte ymaginabitur alia visibilia que fuerunt presentia in illo loco in quo vidit ipsum. Et hec est significatio manifesta quod forma illius hominis et forma illius loci sunt fixa in anima et remanentia in ymaginatione. Et propter hoc, quando homo fuerit memorans de aliqua civitate quam vidit, ymaginabitur formam illius civitatis, et formas locorum in quibus fuit in illa civitate, et formas individuorum que cognovit in illa civitate. Et similiter omnia que homo vidit ex visibilibus, quando ei occurrunt ad memoriam, ymaginabitur formas eorum secundum modum et esse que percepit circa ea ante. Ymaginatio ergo formarum visibilium quas ante homo vidit et modo sciverit cum sunt absentes est significatio quod forme visibilium quas visus comprehendit perveniunt in anima et figurantur in ymaginatione.

4.12 ◉ We should also say that when sight perceives some visible object, and when its form is determined by the sensitive faculty, the form of that visible object remains in the soul to be impressed in the imagination. So the perception of the visible object will be repeated, and its form will be more firmly implanted in the soul than the form of a visible object that sight perceives only once or on rare occasions. I also say that when sight perceives any individual and then perceives another individual of the same kind, if it perceives such individuals continually, a form of that kind [of individual] will become ensconced in the soul, and the form will come to be impressed as a general representation [of its kind] in the imagination. Evidence that the forms of visible objects persist in the soul and in the imagination is to be found in the fact that, when someone remembers a person he knew before, and when he determines his form and correctly recalls the time and place at which he saw that person, he will immediately imagine the form of that person, as well as the shape of his face and the situation he was in at that time. He will also imagine the place where he saw him, and he may imagine other visible objects that were present at the place where he saw him. This is clear evidence that the form of that person, as well as the form of that place, is implanted in the soul and persists in the imagination. Accordingly, when a person remembers some city that he has seen [before], he will imagine the form of that city, as well as the forms of the places he was in that city and the forms of individuals he knew in that city. And the same holds for all the visible objects a person has seen; when they crop up in [his] memory, he will imagine their forms according to the actual disposition of those objects as they were perceived at that earlier time. Thus, imagining the forms of visible objects that a person saw before and still recalls when they are no longer present indicates that the forms of visible objects that sight perceives reach the soul and are impressed in the imagination.⁑

4.13 ◉ Quod vero forma rei vise cuius comprehensio iterabitur a visu est magis fixa in anima et in ymaginatione quam forma rei vise cuius comprehensio non iterabitur est quia, quando ad animam venit aliqua intentio, statim perveniet forma illius intentionis in anima. Et cum tempus pertransierit et prolongaverit, et non redierit iterum ad animam, forte tradetur illa intentio oblivioni ab anima aut aliqua intentionum que sunt in illa intentione. Et si redierit ad animam ante oblivionem, renovatur forma illius in anima, et rememorabit anima per formam secundam formam primam. Et cum multotiens iterabitur eventus illius intentionis super animam, erit anima magis rememorans de illa intentione, et sic erit illa intentio magis fixa in anima.

4.13 ◉ The reason that the form of a visible object that is continually perceived by sight is more firmly planted in the soul and in the imagination than the form of a visible object that is not repeatedly perceived is as follows: When some [sensible] impression comes to the soul, the form of that impression will immediately reach the soul, but as time continues to pass, and that impression fails to recur in the soul, the impression, or something characteristic of it, may be forgotten by the soul. But if it recurs to the soul before it is forgotten, its form is renewed in the soul, and the soul will remember the first form by means of the second form. And as this impression is made time and again on the soul, the soul will remember the impression better, and thus that impression will be more firmly implanted in the soul.

4.14 ◉ Et etiam in prima vice in qua intentio venit ad animam aut in qua forma rei vise venit ad animam forte anima non comprehendet omnes intentiones que sunt in illa forma nec certificabit ipsas. Et comprehendet quasdam intentiones que sunt in ea, et cum forma redierit secundo, comprehendet anima ex ea aliquid quod in prima vice non comprehendidit, et quanto magis forma iterabitur super animam, tanto magis manifestabitur ex ea quod non prius apparebat. Et cum anima comprehenderit ex forma intentiones subtiles eius et certificaverit formam eius, erit magis fixa in anima et magis fixa in ymaginatione quam forma ex qua vere non comprehendit mens omnes intentiones que sunt in ea. Et cum anima comprehenderit ex forma omnes intentiones que sunt in ea ex prima vice, deinde iterabitur eventus forme super ipsam, et comprehenderit in ipsa secundo intentionem, plus certificabit quod illud quod in prima vice comprehendidit est vera forma eius. Forma autem vera verificata et certificata est magis fixa in anima et ymaginatione quam forma non certificata. Forma ergo rei vise, quando multotiens iterabitur comprehensio eius, erit magis certificata apud animam et in ymaginatione. Et per fixionem forme in anima et in ymaginatione erit memoratio illarum ab anima.

4.14 ◉ In addition, the first time an impression or form of a visible object reaches the soul, the soul may not perceive or accurately determine all of the characteristics that belong to that form. But it will perceive some of the characteristics belonging to it, and when the form recurs a second time, the soul will perceive something about it that it did not perceive the first time, and the more often the form recurs to the soul, the more the characteristics of it that were not apparent before will become evident. And as the soul perceives the form’s subtle characteristics and [thereby] determines the form, the more firmly implanted in the soul and imagination it will be than a form in which not all the characteristics belonging to it are [yet] properly perceived by the mind.⁑ But when the soul perceives all of the characteristics in the form the first time, and then the form recurs to it, if it perceives the [same] impression a second time, it will more clearly determine that what it perceived the first time is the proper form. But a properly verified and determinate form is more firmly implanted in the soul and the imagination than a form that is not determinate. Therefore, as the form of a visible object is continually perceived, it will become more determinate in the soul and in the imagination. So it is by having their forms implanted in the soul and in the imagination that things are remembered by the soul.

4.15 ◉ Et significatio super hoc manifesta quod intentiones et forme quando iterabuntur in anima erunt magis fixe quam intentiones et forme non iterate est quia, quando homo voluerit corde tenere aliquem sermonem vel versum aliquem, iterabit sermonem illius intentionis multotiens, et sic figentur in sua anima. Et quanto magis iterabit lectionem eius tanto magis erit fixa in anima et remotioris oblivionis. Et si semel legerit ipsam, non remanebit versus ille fixus in anima. Et similiter si bis legerit versum in anima forte non figetur in anima eius, et si figatur, statim tradetur oblivioni. Et ex experimentatione ergo istius intentionis patet quod forme venientes ad animam, quanto magis iterabuntur tanto magis erunt fixa in anima et in ymaginatione.

4.15 ◉ That impressions and forms that recur in the soul will be more firmly implanted than impressions and forms that do not recur is clearly borne out by the fact that, when someone wants to learn some speech or some verse by heart, he will rehearse the words over and over again, and they will thus become implanted in his soul. And the more he rehearses the words, the more firmly they will be implanted in the soul, and the less likely they will be to be forgotten. But if he reads it once, the verse will not stay implanted in the soul. Likewise, if he goes through the verse a couple of times in his mind,⁑ it [may or] may not be impressed in his soul, but if it is impressed, it will soon be forgotten. From this sort of experience, then, it is clear that the more often forms recur in the soul, the more firmly implanted they will be in the soul and in the imagination.

4.16 ◉ Perventus autem formarum universalium modorum visibilium in anima et figuratio earum in ymaginatione est quia quilibet modorum visibilium, sicut forma et figura, sunt in quibus equabuntur omnia individua illiusmodi, et illa individua diversantur intentionibus particularibus comprehensis per sensum visus. Et forte erit color in omnibus individuis illiusmodi unus; et forma, et figura, et color, et omnes intentiones ex quibus componitur forma cuiuslibet individuorum speciei est forma universalis illiusmodi. Et visus comprehendit illam formam et illam figuram et comprehendit omnem intentionem in qua equabuntur individua speciei in omnibus individuis que comprehenduntur ex individuis illius speciei. Et comprehenduntur ex individuis illius speciei etiam intentiones particulares per quas diversantur illa individua. Per intentionem ergo comprehensionis individuorum uniusmodi a visu iterabitur forma universalis que est in illa specie cum diversitate formarum particularium illorum individuorum. Et cum forma universalis iterabitur in anima, figetur in anima et quiescet, et ex diversitate formarum particularium venientium cum formis universalibus apud intuitionem comprehendit anima quod forma in qua equabuntur omnia individua illiusmodi est forma universalis illiusmodi. Secundum ergo hunc modum erit proventus formarum universalium quas visus comprehendit ex modis visibilium in anima et in ymaginatione.

4.16 ◉ That universal forms of visible aspects occur in the soul and are impressed in the imagination is due to the fact that that there are certain kinds of visible characteristics, such as form or shape, according to which all individuals of a certain kind will be identical, whereas those individuals vary according to [other] particular characteristics that are perceived by the sense of sight. So there may be one color in all individuals of that kind; but form, shape, color, and all the [other] characteristics from which the form of every individual of a given kind derives is a universal form of that kind. So sight perceives that form, that shape, and all the [other] characteristics according to which every individual of a given kind will be identical to all individuals of that kind that are perceived by sight. The particular characteristics by dint of which the individuals of that species differ are perceived as well. It is thus through the effect of perceiving individuals of the same kind by sight that the universal form of their kind will recur [in the soul] along with the various particular forms of those individuals. And when the universal form recurs in the soul, it will be impressed in the soul and will become ensconced there, and from the various particular forms that arrive along with the universal forms after close visual scrutiny the soul perceives that the form according to which all of the individuals of that kind agree is the universal form of that kind. This, then, is how universal forms will arise in the soul and in the imagination from the perception by sight of [various] kinds of visible objects.⁑

4.17 ◉ Forme ergo individuorum visibilium et forme modorum visibilium quas visus comprehendit remanent in anima et figurantur in ymaginatione, et quanto magis iterabitur comprehensio earum a visu tanto magis erunt fixa in anima et in ymaginatione. Et sustentatio sentientis in comprehensione quiditatis visibilium non est nisi super formas pervenientes in animam, quoniam comprehensio quiditatis visibilium non erit nisi per cognitionem. Et cognitio non est nisi ex comparatione forme quam visus comprehendit modo ad formam secundam que est in ymaginatione ex formis visibilium quas visus comprehendit ante, et ex comprehensione considerationis forme comprehense modo ad aliam formarum pervenientium in ymaginatione. Comprehensio ergo quiditatis rei vise non est nisi ex comprehensione assimulationis forme rei vise alicui formarum quiescentium in anima fixarum in ymaginatione. Sustentatio ergo sentientis in comprehensione quiditatum visibilium non est nisi super formam universalem pervenientem in animam modorum visibilium, et sustentatio eius in cognitione individuorum visibilium non est nisi super formas individuorum pervenientes in animam cuiuslibet individuorum que visus comprehendit ante, et fuerint forme eorum ymaginate ante et intellecte. Et virtus distinctiva naturaliter assimulat formas visibilium apud visionem formis fixis in ymaginatione quas anima adquirit ex formis visibilium. Cum ergo visus comprehenderit aliquam rem visam, statim virtus distinctiva querit eius simile in formis existentibus in ymaginatione, et cum invenerit in ymaginatione aliquam similem forme illius rei vise, cognoscet illam rem visam et comprehendet quiditatem eius. Et si non invenerit ex formis existentibus in ymaginatione formam similem forme illius rei vise, non cognoscet illam rem visam nec comprehendet quiditatem eius. Et propter velocitatem assimulationis forme rei vise apud visionem a virtute distinctiva, forte accidet ei error ita quod assimulabit rem visam alii rei vise quando in re visa fuerit aliqua intentio que est in illa alia re. Deinde si consideraverit cum intuitione illam rem visam post illam dispositionem et certificaverit formam eius, assimulabit ipsam forme simili illi in rei veritate, et manifestabitur illi secundo quod erraverat in prima assimulatione. Secundum ergo hunc modum comprehenduntur quiditates visibilium per sensum visus.

4.17 ◉ Accordingly, the forms of individual visible objects, as well as the form of the kinds of visible objects that sight perceives, persist in the soul and are impressed in the imagination, and the more often they are perceived by sight, the more firmly implanted they will be in the soul and in the imagination. Moreover, the sensitive faculty’s comprehension of what kinds of things visible objects are is based entirely upon the forms that reach the soul, for the perception of what kinds of things visible objects are will only occur through recognition. Recognition, for its part, depends upon a correlation of the form that sight perceives at the moment to a second form in the imagination that derives from the forms of visible objects that sight has perceived before, and [it also depends] upon a perception of how the form perceived at the moment compares to another of the forms occurring in the imagination. Thus, the perception of what kind of thing a visible object is depends entirely on the perception of the similarity of the form of the visible object to one of the forms ensconced in the soul and implanted in the imagination. In perceiving what kinds of things visible objects are, then, the sensitive faculty depends entirely upon the universal form of the kinds of visible objects that occurs in the soul, whereas the sensitive faculty’s recognition of individual visible objects depends entirely upon the forms of individuals that arise in the soul from each of the individuals that sight has perceived earlier, provided that their forms have been imagined and understood before. Furthermore, the faculty of discrimination naturally assimilates the forms of visible objects, as soon as they are seen, to forms that are derived by the soul from the forms of visible objects and that are implanted in the imagination. Hence, when sight perceives some visible object, the faculty of discrimination immediately seeks its counterpart among the forms persisting in the imagination, and when it finds some form in the imagination that is like the form of that visible object, it will recognize that visible object and will perceive what kind of thing it is. But if it does not find a form similar to the form of that visible object among the forms persisting in the imagination, it will not recognize that visible object or perceive what kind of thing it is. Also, on account of the speed with which the faculty of discrimination assimilates the form of the visible object at the moment it is seen, it may err by assimilating the visible object to another visible object [simply] because the visible object has some characteristic that the other object possesses. If it then subjects that visible object to close visual scrutiny and determines its form, it will assimilate that form to one that actually does resemble it, and it will become clear to it while carrying out this second assimilation that it erred the first time. It is in this way, therefore, that the sense of sight perceives what kinds of things visible objects are.

4.18 ◉ Et cum omnes iste intentiones sint declarate, dicamus modo quod comprehensio visibilium per intuitionem erit duobus modis: comprehensio sola intuitione et comprehensio per intuitionem cum scientia precedente. Comprehensio vero que est sola intuitione est comprehensio visibilium extraneorum que visus non vidit ante aut visibilium que visus comprehendit ante sed non est rememoratus visionis illorum. Quoniam visus, quando comprehendit aliquam rem visam quam ante non percepit videndo, nec rem visam huius speciei, et voluerit aspiciens certificare formam huius rei vise, intuebitur ipsam et considerabit per intuitionem omnes intentiones que sunt in ea. Et comprehendet per intuitionem formam eius veram, et cum ante non percepit illam rem visam nec aliquam rem huius speciei, non cognoscet illam formam eius apud eius comprehensionem. Et in talibus indigetur intuitione ad ipsam formam propriam. Erit ergo certificatio forme huiusmodi visibilium non nisi per solam intuitionem tantum. Et similiter, quando visus comprehenderit aliquam rem visam quam ante percepit et non est rememorans ipsius, non cognoscet formam eius secundo apud intuitionem, sed erit comprehensio huiusmodi visibilium per solam intuitionem.

4.18 ◉ Now that all these points are clarified, we should observe that the perception of visible objects through visual scrutiny will occur in two ways: perception through visual scrutiny alone and perception through visual scrutiny along with previous knowledge. Now perception through visual scrutiny alone involves a perception of unfamiliar visible objects that sight has not seen before or visible objects that sight has seen before but does not remember having seen. For when the visual faculty perceives some visible object it has not perceived by sight before, nor anything of its kind, and when the observer wishes to determine the form of this visible object, he will focus upon it and evaluate all the characteristics it possesses through visual scrutiny. Through [such] scrutiny he will then perceive its proper form, but since he never saw that object or anything of its kind before, he will not recognize its form when he perceives it. But in such cases visual scrutiny is necessary for [the perception of] the actual proper form. Thus, the determination of the form of such visible objects occurs through visual scrutiny alone. Likewise, when sight perceives some visible object it has perceived before but fails to remember, it will not recognize its form the next time after visual scrutiny, so this kind of perception of visible objects will occur through visual scrutiny alone.

4.19 ◉ Comprehensio vero que est per intuitionem cum scientia precedente est comprehensio omnium modorum visibilium que visus comprehendit ante aut de quorum specie aliquod comprehendidit visus ante et pervenerint forme specierum et individuorum eorum in anima. Cum ergo visus comprehenderit aliquam rem visam quam ante comprehendidit aut cuius speciei aliquam rem prius comprehenderit, statim apud aspectum illius rei vise comprehendet totam formam eius. Deinde modica intuitione comprehendet totam formam eius que est forma universalis sive speciei. Cum ergo ante comprehendidit visibilia illiusmodi rei vise, et pervenerit forma speciei illius rei vise in sua anima, et fuerit rememorans ex forma universali illiusmodi rei vise, cognoscet formam universalem quam comprehendit in illa re visa apud comprehensionem eius et apud cognitionem forme universalis quam comprehendit in illa re visa, et statim cognoscet illam rem visam specialiter. Deinde quando intuerit intentiones residuas que sunt in illa re visa, certificabit formam eius particularem. Si autem non percepit ante illam rem visam aut forte percepit illam sed non meminit de perceptione illius, non cognoscet formam particularem. Et cum non cognoverit particularem, non cognoscet illam rem visam, et sic erit cognitio illius rei vise ab eo secundum speciem tantum. Et adquirit ex intuitione et certificatione forme eius formam eius particularem que appropriatur suo individuo. Et si ante percepit illam rem visam, et non percepit alia individua huiusmodi speciei, et fuerit rememorans illius et forme quam ante comprehendidit ex illa re visa, quando comprehenderit formam eius particularem, cognoscet apud cognitionem formam particularem. Et apud cognitionem forme particularis comprehendet rem visam, et sic per comprehensionem forme eius particularis certificabit formam rei vise, et cum hoc cognoscet ipsam rem visam. Et erit cognitio illius rei vise ab eo sic specialiter et secundum individuum in simul. Et si ante perceperit illam rem visam, sed non perceperit ex modo illius rei vise nisi individuum tantum, et non distinguitur ab eo forma universalis illiusmodi rei vise, quando comprehenderit illam rem visam et comprehendit intentiones universales que sunt in illa re visa et in omnibus rebus illius speciei, non cognoscet illam rem visam nec comprehendet quiditatem eius ex comprehensione forme universalis. Cum ergo comprehenderit intentiones residuas que sunt in illa re visa, et comprehenderit formam particularem eius, et fuerit rememorans forme particularis quam comprehendit in illa re visa, cognoscet formam particularem apud comprehensionem eius. Et cum cognoverit formam particularem, cognoscet eandem rem visam ipsam, et erit cognitio illius rei vise ab eo individualiter. Et nulla res visa comprehenditur per intuitionem nisi secundum aliquem istorum modorum. Comprehensio ergo omnium visibilium secundum intuitionem erit duobus modis: sola intuitione et comprehensio per intuitionem cum scientia antecedente. Cognitio autem talis et scientia quandoque erit secundum speciem tantum, quandoque secundum speciem et individuum in simul.

4.19 ◉ Perception through visual scrutiny along with previous knowledge, on the other hand, is perception of all types of visible objects that sight has perceived before or about whose kind sight has perceived something before, so that the forms of their kinds as well as of their individuals reach the soul. Thus, when sight perceives some visible object it has perceived before, or when it perceives some object of the same kind, as soon as it glimpses that visible object it will perceive its entire form. Then, after a brief scrutiny, it will perceive its overall form,⁑ which constitutes its universal form or the form specifying its kind. Therefore, if it has perceived visible objects of this sort before, and if the form specifying what kind of thing that visible object is occurs in the soul, and if the soul remembers the universal form of that kind of visible object, it will recognize the universal form that it perceives in that visible object as soon as it perceives it and recognizes the universal form it perceives in that object, so it will immediately recognize that visible object as of such-and-such a kind. Then, when it scrutinizes the rest of the characteristics possessed by that visible object, it will determine its particular form. If, however, it has not perceived that visible object before, or perhaps it has perceived it but does not remember having perceived it, it will not recognize the particular form. If it does not recognize the particular [form], though, it will not recognize that visible object, and so its recognition of that visible object will be according to kind alone. So it is through visual scrutiny and the determination of its form that the soul acquires the particular form belonging to that individual. If it has perceived that visible object before but has not perceived another individual of that kind, and if it remembers it as well as the form of that visible object that it perceived before, then, when it perceives its particular form it will recognize its particular form as soon as it apprehends it.⁑ Moreover, as soon as it recognizes its particular form it will apprehend the visible object, and thus it is through the perception of its particular form that sight will determine the form of the visible object and will accordingly recognize the visible object itself. So its recognition of that visible object will be according to kind and individual at the same time. If, however, it has perceived that visible object before, but it has seen only an individual representation of that visible object and [thus] does not discern the universal form of that sort of visible object, then, when it perceives that visible object and perceives the universal characteristics possessed by that object as well as by all other objects of that kind, it will not recognize that visible object or apprehend what kind of thing it is by perceiving its universal form. Therefore, when it perceives the remaining characteristics possessed by that visible object, and when it perceives its particular form and remembers the particular form it perceives in that visible object, it will recognize the particular form at the moment of perception. So when it recognizes the particular form, it will recognize the visible object itself, but its recognition of that visible object will be on the basis of its individuality. No visible object is perceived through visual scrutiny unless [it is perceived] according to these ways. Thus, the perception of all visible objects on the basis of visual scrutiny will occur in two ways: perception through visual scrutiny alone and perception through visual scrutiny along with previous knowledge. Moreover, such recognition or knowledge will sometimes be according to kind and sometimes according to kind and individual together.

4.20 ◉ Et etiam comprehensio per intuitionem non erit nisi in tempore. Quoniam intuitio non erit nisi per intuitionem et motum visus, sed distinctio et motus non erit nisi in tempore. Intuitio ergo non erit nisi in tempore. Et superius declaratum est etiam quod comprehensio per cognitionem et comprehensio per distinctionem non erit nisi in tempore. Et cum declaratum est quod comprehensio visibilium per intuitionem quandoque erit sola intuitione et quandoque per intuitionem cum cognitione precedenti, et quod illud quod comprehenditur per intuitionem et quod comprehenditur per cognitionem non comprehenditur nisi in tempore, dicemus quod comprehensio que erit per intuitionem cum cognitione precedenti erit in maiori parte in minori tempore quam sit tempus in quo erit comprehensio per solam intuitionem. Quoniam intentiones existentes in anima et presentes memorie non indigent ut cognoscantur omnes intentiones que sunt in eis ex quibus componuntur in rei veritate; sed sufficit in comprehensione earum comprehensio alicuius intentionis proprie illis. Cum ergo virtus distinctiva comprehendit in forma veniente ad ipsam aliquam intentionem propriam illi forme et fuerit rememorans prime forme, cognoscet omnes formas venientes ad ipsam, quoniam omnis intentio que appropriatur alicui forme est signum significans super illas formas.

4.20 ◉ Furthermore, perception through visual scrutiny must occur over time. For visual scrutiny will only occur if the eye moves and examines [the object], but differentiation and motion will not take place except over time. Therefore, visual scrutiny will only occur over time. It has also been shown above that perception through recognition and perception through differentiation will occur only over time.⁑ And now that it has been shown that the perception of visible objects through visual scrutiny will sometimes occur through visual scrutiny alone and sometimes through visual scrutiny along with previous knowledge, and [now that it has been shown] that whatever is perceived through visual scrutiny as well as whatever is perceived through recognition is perceived only over time, we shall add that perception occurring through visual scrutiny along with previous knowledge will generally take less time than perception through visual scrutiny alone. For, to recognize the impressions existing in the soul that are presented to the memory does not require that all of the characteristics which go into their actual formation be perceived; rather, a perception of certain of their specific properties is sufficient. Thus, when the faculty of discrimination perceives some specific property that characterizes a form reaching it, and when it remembers the first form, it will recognize all forms [of that kind] that reach it, for every specific property that characterizes a given form is a defining feature of such forms.⁑

4.21 ◉ Verbi gratia, quia, quando visus comprehenderit individuum hominis et comprehenderit lineationem sue manus tantum, statim comprehendet quod sit homo antequam comprehendat lineationem sue faciei, et antequam comprehendat lineationem partium residuarum eius; et similiter si comprehenderit lineationem faciei eius antequam comprehendat partes residuas eius. Ex comprehensione ergo quarumdam intentionum que appropriantur forme hominis comprehendet quod illud visibile sit homo sine indigentia comprehensionis partium residuarum. Quoniam comprehendet partes residuas per cognitionem precedentem ex formis residentibus in anima, formis dico hominum. Et similiter, quando visus comprehenderit aliquas intentiones que appropriantur forme particulari alicuius individui quod ante visus percepit, sicut simitatem in naso, aut viriditatem in oculo, aut arcualitatem in superciliis, comprehendet cum comprehensione totius sue forme illud individuum, et cognoscet ipsum. Et similiter cognoscet equum per aliquam maculam in fronte eius aut per diversitatem coloris. Et similiter scriptor, quando comprehenderit formam alicuius dictionis superficialiter, cognoscet eam antequam consideret litteras particulares, et similiter omnes partes quas scriptor frequenter et continue videt cognoscuntur ab eo apud comprehensionem ex comprehensione quarumdam litterarum.

4.21 ◉ For instance, if sight perceives an individual person but only perceives the outline of his hand, it will immediately perceive that [what it sees] is human before it perceives the outline of his face or before it perceives the outline of his remaining features; and the same thing applies if sight perceives the outline of his face before perceiving his remaining features. From the perception of any of the properties that are specific to the form of a human being, then, sight will perceive that this visible object is a human being without having to perceive the remaining features. For it will perceive the remaining features through previous knowledge on the basis of the forms residing in the soul, i.e., the forms of human beings. Likewise, when sight perceives certain properties that are specific to the particular form of some individual that sight has perceived before, e.g., a flat nose, green eyes, or arched eyebrows, it will perceive that individual when it perceives his entire form, and it will recognize him. So, too, sight will recognize a [given] horse from some spot on his forehead or from some variation in his color. By the same token, when a writer perceives the form of some word in a cursory way, he will recognize it before he examines its individual letters, and all words that the writer sees continually are likewise recognized by him as soon as they are perceived on the basis of his perception of certain of their letters.

4.22 ◉ Visibilia ergo que visus ante comprehendit, et cognoscit modo formas illorum, et est rememorans illorum comprehenduntur a visu per signa. Visibilia autem extranea que visus ante non percepit aut visibilia que ante percepit sed tamen non est rememorans illorum non sunt ita. Quoniam, quando visus comprehenderit aliquam rem visam quam ante non vidit et comprehenderit lineationem quarumdam partium, non comprehendet ex eo quiditatem illius rei vise, quoniam non est apud ipsum forma quiescens partium residuarum. Visus ergo non comprehendit certitudinem rei vise quam ante non vidit nisi per considerationem omnium suarum partium et omnium intentionum que sunt in ea. Et similiter forma rei vise quam visus ante percepit sed non rememoratur non certificatur ab eo nisi post considerationem omnium intentionum que sunt in ea. Sed comprehensio quarumdam intentionum que sunt in forma erit in minori tempore illo in quo comprehendit comprehensionem omnium intentionum que sunt in forma. Visio ergo que est per intuitionem cum cognitione precedenti erit in maiori parte in breviori tempore tempore in quo erit visio sola intuitione, et propter hoc visus comprehendit visibilia assueta comprehensione valde veloci in tempore latente sensum; et non erit inter oppositionem visus ad rem visam et inter comprehensionem quiditatis rei vise assuete tempus sensibile in maiori parte. Quoniam homo ex pueritia et ex principio crementi comprehendit visibilia, et iterantur super eius aspectum individua visibilium et forme universales modorum visibilium. Et etiam declaratum est quod forme visibilium quas visus comprehendit perveniunt in anima et figurantur in ymaginatione, et quod forme que iterantur visui figurantur in anima, et quiescit figuratio earum in ymaginatione. Omnia ergo visibilia assueta et omnes modi assueti sunt existentes in anima, et quiescentes figurati in ymaginatione, et presentes memorie. Cum ergo visus comprehenderit aliquam rem visam assuetam, et comprehenderit totam suam formam, et post illud comprehenderit aliquod signum proprium illi rei vise, comprehendet quiditatem illius rei vise apud comprehensionem illius signi, et erit comprehensio rei vise ab eo per comprehensionem precedentem et per modicam intuitionem. Visibilia ergo assueta comprehenduntur a visu per signa et per cognitionem precedentem, quare ergo erit comprehensio quiditatum eorum in maiori parte in tempore insensibili.

4.22 ◉ Hence, visible objects that sight has perceived earlier and whose forms it recognizes and remembers at the present moment are perceived by sight through defining features. On the other hand, unfamiliar visible objects that sight has not perceived before, or visible objects it has perceived before but does not yet remember are not perceived in this way. For when sight perceives some visible object it has not seen before and perceives the outline of some of its parts, it will not thereby perceive what kind of thing that visible object is, because the form of the remaining parts is not ensconced in the soul. Thus, sight does not gain a determinate perception of a visible object it has not seen before unless it evaluates all of its parts and all the characteristics it possesses. Likewise, the form of a visible object the eye has seen before but does not remember is only determined by it after an evaluation of all the characteristics it possesses. But the perception of certain characteristics possessed by a form will take less time than the perception of all the characteristics possessed by the form. Thus, vision that entails visual scrutiny along with previous knowledge will generally take less time than vision entailing visual scrutiny alone, and this is why sight perceives familiar visible objects with such extraordinary speed that the time it takes is imperceptible, so between the time sight is directed at a familiar visible object and the time it perceives what that familiar visible object is there will generally not be a perceptible time-interval. For from childhood and the beginning of his development, a person perceives visible objects, and individual visible objects as well as the universal forms of types of visible objects are continually presented to his sight. It has also been shown that the forms of visible objects perceived by sight reach the soul and are impressed in the imagination, and forms that are seen repeatedly are impressed in the soul so that such impressions become ensconced in the imagination.⁑ Thus [the forms of] all familiar objects and all familiar kinds of objects are present in the soul, and they remain impressed in the imagination and present to memory. Accordingly, when sight perceives some familiar visible object and perceives its overall form,⁑ and after that it perceives some defining feature that specifies that visible object, it will perceive what kind of thing that visible object is when it perceives that defining feature, and it will perceive the visible object through previous perception as well as through brief visual scrutiny. Therefore, familiar visible objects are perceived by sight through defining features and through previous knowledge, so the perception of what kinds of things they are will generally occur in an imperceptible amount of time.

4.23 ◉ Et etiam quod comprehensio speciei rei vise est in minore tempore quam comprehenditur individuitas rei vise est quoniam, quando visus comprehenderit aliquod individuum hominum, comprehendit ipsum esse hominem antequam comprehendet formam eius particularem. Et forte comprehendet ipsum esse hominem, quamvis non comprehendat lineationem faciei; sed ex erectione sui corporis et ordinatione membrorum corporis eius comprehendet ipsum esse hominem, quamvis non viderit faciem eius. Et similiter visus forte comprehendit quandoque specialitatem alicuius modorum visibilium assuetorum per quedam signa que appropriantur illi speciei. Et non est sic comprehensio individualitatis rei vise, quoniam individualitas rei vise non comprehendetur nisi ex comprehensione intentionum particularium que appropriantur illi individuo aut ex comprehensione quarumdam. Sed comprehensio quarumdam intentionum particularium que appropriantur individuo non comprehenduntur nisi post comprehensionem intentionum universalium que sunt in illo individuo aut post comprehensionem quarumdam. Aut generaliter intentiones que sunt in formis universalibus modi illius individui sunt quedam intentiones que sunt in forma eius individuali, sed comprehensio partis est in minori tempore quam tempus in quo comprehenditur totum. Comprehensio ergo specialitatis rei vise a visu est in minori tempore quam tempus in quo comprehenditur individualitas illius rei vise.

4.23 ◉ Moreover, the reason that the perception of a visible object’s general type takes less time than the perception of the visible object’s individual nature is that, when sight perceives some individual human, it perceives him to be human before it will perceive his particular form. And it may perceive him to be human even though it does not perceive the outline of his face; instead sight will perceive him to be human from the upright stance of his body or the arrangement of the members of his body without having seen his face. Likewise, sight may perceive certain kinds of familiar visible objects as general types by means of certain defining features that specify that kind of thing. But this is not the case with the perception of a visible object’s individual nature, for a visible object’s individual nature will not be perceived until the particular characteristics that define that individual or some of those characteristics are perceived. But the perception of each of the particular characteristics defining that individual does not occur until after [all] or some of the universal characteristics possessed by that individual are perceived. Generally, the characteristics of the universal forms of those sorts of individuals are some of the characteristics possessed by the individual form, but the perception of the part takes less time than the perception of the whole. Thus, the perception by sight of a what kind of thing a visible object is takes less time than the perception of the individual nature of that visible object.

4.24 ◉ Et etiam comprehensionis specialitatis tempus visibilium (scilicet assuetorum) diversitatur, quoniam quedam specierum visibilium assuetorum assimulantur aliis speciebus et quedam non, ut species hominis et species equi, quoniam forme speciei hominis non assimulantur alii speciei animalium. Et non est ita equus, quoniam equus assimulatur multis animalibus in tota forma. Tempus ergo in quo visus comprehendit speciem individui hominis et comprehendit ipsum esse hominem non est sicut tempus in quo comprehendit speciem equi et comprehendit ipsum esse equum, et maxime quando comprehenderit utrumque in remotione alicuius quantitatis. Quoniam, quando visus comprehenderit individuum alicuius hominis motum localiter, statim comprehendet ipsum esse animal ex motu, et ex erectione corporis comprehendet ipsum esse hominem. Et non est ita quando comprehenderit equum, quoniam, quando visus comprehenderit individuum equi movens se et comprehenderit cum hoc motum eius et numerum pedum, non comprehendet ex hoc ipsum esse equum, quoniam iste intentiones sunt in pluribus quadrupedum que assimulantur equo in pluribus intentionibus, et maxime in mulo, quoniam mulus assimulatur equo in multis dispositionibus. Quoniam mulus non distinguitur ab equo nisi per intentiones fere non manifestas, sicut lineationem faciei, et extensionem colli, et velocitatem motus, et amplitudinem passuum. Si autem visus non comprehenderit aliquam istarum intentionum per quas comprehenditur equus cum comprehensione totius sue forme, non comprehendet ipsum esse equum. Et tempus in quo visus comprehendit erectionem corporis hominis non est sicut tempus in quo comprehendit formam equi cum intentionibus particularibus per quas distinguitur equus ab alio. Comprehensio igitur speciei hominis est in minori tempore quam tempus in quo comprehenditur species equi. Quamvis enim duo tempora sint parva, tamen unum eorum secundum omnes dispositiones eius est maius altero.

4.24 ◉ Moreover, the time it takes to perceive visible objects (familiar ones, that is) according to general type varies, because certain kinds of familiar visible objects resemble other kinds, and certain do not, e.g., the general type »human« and the general type »horse,« for the form of the general type »human« does not resemble the [form of the general type of] other kinds of animal. But that is not the case for a horse, since a horse resembles many animals in its overall form. Thus, the time it takes sight to perceive an individual human according to general type and to perceive that [what it sees] is human is not the same as the time it takes to perceive an [individual] horse according to general type and to perceive that [what it sees] is a horse, especially if it perceives them both at some distance. For, when sight perceives some individual human who is walking, it will immediately perceive him to be an animal from his movement and then, by dint of his upright body, it will perceive him to be human. But that is not how it is when sight perceives a horse, for when sight perceives an individual horse that is moving and, along with that, perceives its motion as well as the number of its legs, it will not perceive it to be a horse on that basis, for those characteristics belong to several quadrupeds that share several characteristics with the horse, especially the mule, because the mule resembles the horse in numerous ways. Hence, the mule is only differentiated from the horse according to characteristics that are not particularly evident, such as the outline of the face, the length of the neck, the speed of the gait, and the length of the gait. But if sight fails to perceive any of those characteristics according to which a horse is perceived when its overall form is apprehended, then it will not perceive it to be a horse. Furthermore, the time it takes sight to perceive the upright posture of the human body is not the same as the time it takes to perceive the form of a horse along with the particular characteristics according to which a horse is distinguished from any other [quadruped]. Thus, the time it takes for a human to be perceived according to general type is less than the time it takes for a horse to be perceived according to general type. For, even though the two time-intervals are small, one of them is still smaller than the other, all things taken into account.

4.25 ◉ Et similiter, quando visus comprehenderit colorem roseum in floribus cuiusdam orti, statim comprehendet quod substantie illorum colorum sunt rose propter colorem proprium rosarum, et cum hoc quod ille color est in rebus existentibus in orto, ante comprehensionem rotunditatis, et ante rotunditatem foliorum eius et applicationem foliorum eius unius super alterum, et ante comprehensionem omnium intentionum eius ex quibus componitur forma rose. Et non est ita quando comprehenderit viriditatem mirti in orto. Quoniam, quando visus comprehenderit viriditatem mirti tantum in orto, non comprehendet ipsam esse mirtum ex comprehensione viriditatis tantum, quoniam plures plantarum sunt virides, et cum hoc plures plante assimulantur mirto in viriditate et in figura. Si ergo non comprehenderit figuram foliorum eius, et spissitudinem eorum, et intentionem propriam mirti, non comprehendet ipsam esse mirtum. Et tempus in quo visus comprehendit figuram foliorum mirti et intentiones secundum quas appropriatur mirtus cum comprehensione viriditatis non est sicut tempus in quo comprehendit colorem roseaceum tantum. Et similiter quiditates omnium specierum que possunt assimulari aliis non comprehenduntur a visu nisi per magnam intuitionem. Quiditas autem visibilium pauce assimulationis ad alia comprehenditur a visu pauca intuitione. Et similiter de individuis, quoniam individuum quod non assimulatur alii individuo comprehenditur a visu per modicam intuitionem et per signa, et individuum quod visus cognoscit et assimulatur alii individuo quod visus cognoscit comprehenditur a visu per magnam intuitionem.

4.25 ◉ Likewise, when sight perceives a rose-red color among the flowers in some garden, it will immediately perceive that the things in which that color inheres⁑ are roses because that color is specific to roses and, moreover, because that color is [found] in objects that are in a garden, [and it perceives this] before it perceives the roundness [of the flowers], or the roundness of their petals, or the way their petals fit upon one another, and before the perception of all the characteristics that go into making the form of a rose. But this does not happen when sight perceives a myrtle-green color in the garden. For when sight perceives only the myrtle-green in the garden, it will not perceive the [plant that is] myrtle-green to be myrtle simply from the perception of the green, because several plants are green, and, in addition, several plants resemble myrtle in greenness and shape. Thus, if sight does not perceive the shape of its leaves, its density, or a[ny other] defining characteristic of myrtle, it will not perceive that plant to be myrtle. Moreover, the time it takes sight to perceive the shape of the myrtle’s leaves and the characteristics that are specific to myrtle, as well as to perceive its greenness, is not the same as the time it takes to perceive the color of roses alone. Likewise, the essential natures of all kinds [of things] that can resemble others are perceived by sight only after considerable scrutiny. But the essential natures of visible objects that resemble others only a little are perceived by sight after brief scrutiny. And the same holds for individuals, for an individual that does not resemble another individual is perceived by sight after minimal scrutiny on the basis of defining features, but an individual known to sight and resembling another individual known to sight is perceived by sight [only] after considerable scrutiny.⁑

4.26 ◉ Species ergo et individuum omnium visibilium assuetorum comprehenditur a visu per modicam intuitionem cum cognitione precedenti, et erit comprehensio eorum in maiori parte in tempore insensibili. Tamen diversatur tempus comprehensionis eorum secundum diversitatem specierum individuorum eorum. Et erit comprehensio speciei velocior comprehensione individui, et erit comprehensio speciei pauce assimulationis ad alia velocior comprehensione speciei multe assimulationis, et erit comprehensio individui pauce assimulationis ad alia velocior comprehensione individui multe assimulationis.

4.26 ◉ Therefore, the general type or individual nature of all familiar visible objects is perceived by sight after minimal scrutiny when [the perception is based] upon previous knowledge, and, for the most part, that perception will take an imperceptible amount of time. Nonetheless, the time it takes to perceive such objects varies according to differences among their general types or their individual natures. The perception of general type will be quicker than the perception of individual nature, whereas the perception of a general type that scarcely resembles others will be quicker than the perception of a general type closely resembling others, and the perception of an individual that scarcely resembles others will be quicker than the perception of an individual closely resembling others.

4.27 ◉ Similiter et tempus intuitionis diversatur secundum intentiones quas quisque intuetur in visibilibus. Verbi gratia, quia quando visus comprehenderit multipes animal parvorum pedum, et illud animal fuerit in motu, per modicam intuitionem comprehendet motum eius, et cum comprehenderit motum eius, comprehendet ipsum esse animal. Deinde per modicam intuitionem in pedibus comprehendet ipsum esse multipes ex comprehensione distantie inter pedes. Et cum hoc non cognoscet statim numerum pedum, et si voluerit cognoscere numerum pedum, indigebit pluriori intuitione et maiori tempore. Comprehensio ergo animalitatis eius erit in tempore parvo. Deinde comprehensio multitudinis pedum erit in parvo tempore, et numerus pedum non comprehenditur nisi postquam fuerit visus intuens quemlibet pedum et numeraverit ipsos, quod non potest esse nisi in tempore alicuius quantitatis. Et erit quantitas temporis secundum multitudinem pedum et paucitatem eorum. Et similiter, quando visus comprehendit figuram rotundam intra quam est figura multorum laterum, et fuerint latera illius figure parva, et cum hoc fuerit diversorum laterum non maxima diversitate, apud comprehensionem totalis figure comprehendet ipsam esse rotundam. Et non comprehendet statim quod intra illam sit laterata figura quando latera illius fuerint in fine parvitatis, et cum intuerit figuram rotundam profundiori intuitione, apparebit ei figura laterata que est intra rotundum. Erit ergo comprehensio rotunditatis figure velocior comprehensione figure laterate que est intra. Deinde apud comprehensionem istius non apparebit diversitas laterum istius figure, nec distinguitur ab eo sive sint equalia sive non, et non apparebit inequalitas laterum figure laterate nisi post magnam intuitionem et in tempore alicuius quantitatis.

4.27 ◉ So, too, the time it takes for visual scrutiny varies according to the characteristics one scrutinizes in visible objects. For instance, when sight perceives an animal with several small legs, and if that animal is moving, it will perceive its motion on the basis of minimal scrutiny, and when it perceives its motion, it will perceive that it is an animal. Then, after briefly scrutinizing its legs it will perceive that it has several legs by perceiving the separation between its legs. But nonetheless it will not immediately apprehend the number of its legs, and if it wants to know the number of legs, it will have to spend more time scrutinizing it more intensely. Thus, the perception that it is an animal will take little time. The subsequent perception that the animal has many legs also takes little time, but the number of its legs is not perceived until sight has scrutinized each of its legs and counted them, and that can only happen during some measurable amount of time. Moreover, the amount of time [required] will depend upon how many or how few legs the animal has. Likewise, when sight perceives a circle circumscribing a polygon of many sides, and if the sides of that [inscribed] figure are small but not inordinately different in size, then, as soon as the whole figure is perceived sight will perceive it as circular. Furthermore, it will not immediately perceive that there is a polygon inside it if the sides of that polygon are extremely small, but when it scrutinizes the circular figure more closely, the inscribed polygon will be revealed to it. Thus, the perception of the circularity of the figure will be quicker than the perception of the polygon inside it. After having perceived the polygon, sight will not see the difference in sizes among its sides, nor does it discern whether they are equal or not, nor will the inequality of the sides of the polygon be seen until after a very close scrutiny that takes place in a measurable amount of time.

4.28 ◉ Et etiam sentiens, quando voluerit intueri figuram totius rei vise, sufficit ei ut transeat visus super superficiem rei vise tantum. Et similiter, quando voluerit intueri colorem rei vise, sufficit ei transire visum super ipsum tantum—et similiter intueri asperitatem superficiei rei vise, aut planitiem, aut diafonitatem, aut spissitudinem. Et non sunt ita intentiones occulte et subtiles que sunt in visibilibus, sicut figure que sunt in quibuslibet partibus visibilium, et consimilitudo figurarum, et quantitatis partium, et diversitas quantitatum et colorum, et consimilitudo eorum, et ordinatio partium parvarum adinvicem, quoniam iste intentiones non comprehenduntur per intuitionem nisi postquam fuerit visus fixus super quamlibet partium, et consideraverit figuras illarum partium, et comparaverit unam ad alteram. Et hoc non complebitur in tempore parvo et per motum velocem sed in tempore alicuius quantitatis. Tempus igitur intuitionis intentionum visibilium diversatur secundum diversitatem intentionum intuitarum.

4.28 ◉ Also, when the sensitive faculty wishes to scrutinize the shape of the entire visible object, it only needs to pass the line-of-sight over the surface of the visible object. Likewise, when it wishes to scrutinize the color of a visible object, it only needs to pass the line-of-sight over it—and the same holds [if it wishes] to scrutinize the roughness of the surface of a visible object, or its smoothness, or its transparency, or its opacity. But such is not the case for the inconspicuous or subtle characteristics possessed by visible objects, characteristics such as the shapes of any of the parts of visible objects, the similarity of their shapes, the size of their parts, differences among their sizes or colors, similarities among them, or the relative arrangement of the small parts; these characteristics are perceived through visual scrutiny only after the eye focuses on every part, evaluates the shapes of those parts, and correlates them one to another. But this will be accomplished not in a short time or through a quick [axial] scan but in a measurable amount of time. Hence, the time it takes to scrutinize the characteristics of visible object varies according to differences among the characteristics that are being scrutinized.

4.29 ◉ Et cum declaratum sit hoc, dicamus quod visio que est per cognitionem precedentem, et per signa, et per modicam intuitionem non est comprehensio certificata. Quoniam comprehensio rei vise per cognitionem precedentem et per signa non est nisi circa totalitatem et universalitatem rei vise in grosso, et virtus distinctiva comprehendit intentiones particulares que sunt in illa re visa secundum modum quo cognovit illas res visas ex prima forma illius rei vise existente in anima. Sed iste intentiones particulares que sunt in visibilibus mutantur secundum transitum temporis, et cum hoc visus non comprehendit intentiones que sunt mutate in re visa per cognitionem precedentem. Et cum mutatio fuerit occulta, non bene manifesta, non comprehenditur a visu primo aspectu, et non comprehenditur quando non fuerit valde manifesta nisi per intuitionem. Verbi gratia quod, quando visus cognoscit aliquem hominem, et fuerit facies illius hominis munda, et certificaverit visus formam eius, deinde recesserit ille homo a visu longo tempore, et contingit in facie eius macula, et fuerit occulta illa macula, et comprehenderit ipsum post ipsam distinctionem, cognoscet ipsum apud comprehensionem. Sed tamen non propter comprehensionem et cognitionem illius hominis comprehendet maculam in facie eius nisi sit manifesta, et si non intuerit ipsam, comprehendet ipsum non secundum suum esse. Et si intuerit ipsum puriori intuitione, apparebit ei macula que est in facie eius, et tunc comprehendet formam eius secundum suum esse.

4.29 ◉ And having made this clear, we should add that vision that depends on previous knowledge, or defining features, or minimal visual scrutiny is not truly determinate. For perception of a visible object through previous knowledge or through defining features only involves the object as a whole according to its general nature, and the faculty of discrimination perceives the particular characteristics possessed by that visible object in the way that it apprehended those visible characteristics from the initial form of that visible object that exists in the soul. But these particular characteristics possessed by visible objects change with the passage of time, and, given this fact, sight does not, on the basis of previous knowledge, perceive the characteristics of the visible object that have changed. And when the change is inconspicuous or not very evident, it is not perceived by sight at first glance, nor is it perceived when it is not very evident unless [it is subjected] to visual scrutiny. For instance, when sight apprehends some person whose facial complexion is clear, and if sight determines his form, after which that person disappears from view for a long time, and if a blemish forms on his face, but that blemish is inconspicuous, then, when sight perceives that person after this development, it will recognize him as soon as it perceives him. Nonetheless, on the basis of its perception and recognition of that person, the visual faculty will not perceive the blemish on his face unless it is obvious; if it does not look carefully for that blemish, then, it will not perceive him as he actually exists. But if the visual faculty scrutinizes him with a more intense focus, the blemish on his face will be revealed to it, and then it will perceive his form as it actually exists.

4.30 ◉ Et similiter, quando visus comprehenderit aliquam arborem, et intuerit ipsam, et certificaverit formam eius, deinde recessit ab ea diu dum crevit illa arbor, et augmentabatur, et mutabatur figura eius, et crevit et intendebatur aliquis rubor in ea (si forte aliquis esset in ea), et illa mutatio que contingit in arbore non fuerit modica, deinde si revertatur visus ad illam arborem et cognoscat eam, non comprehendet apud comprehensionem et cognitionem illam modicam mutationem que contingit in ea. Si autem intuerit ipsam secundo et cum hoc fuerit rememorans vere forme quam habebat in prima vice, comprehendet mutationem que contingit in ea et certificabit formam eius secundo. Et si non intuerit ipsam, non erit illa forma quam comprehendit ex illa arbore per cognitionem antecedentem ipsa forma vera quam habet post secundam comprehensionem.

4.30 ◉ By the same token, when sight perceives some tree, scrutinizes it, and accurately determines its form, if it then leaves it for awhile while the tree grows, gets larger, and changes shape, or if, as it grows, some redness in it intensifies (assuming it was there before), and if the change that occurs to the tree is not minimal, then, if sight refocuses on that tree and recognizes it, it will not perceive the slight change occurring in it at the time it perceives and recognizes it. However, if it scrutinizes it a second time and, in addition, remembers the proper form it initially possessed, then it will perceive the change occurring in it and will determine its form [during the] second [scrutiny]. But if sight does not scrutinize it [again in this way], the form that it perceives of the tree on the basis of previous knowledge will not be the proper form, which it acquires after the second scrutiny.

4.31 ◉ Et similiter, quando visus comprehenderit parietem in quibusdam locis, et ille paries fuerit planus, et fuerint in eo picture et sculpture, et intuerit visus illum parietem, et certificaverit formam eius, deinde recesserit ab illo loco diu, et contingit in illo pariete post mutatio ex asperitate superficiei aut ex intentione quarumdam picturarum, et non fuerit illa mutatio valde manifesta, deinde si revertatur visus ad illum locum, et aspexerit illum parietem, et fuerit rememorans forme prime, igitur comprehendet ipsam apud primam visionem. Sed apud comprehensionem et cognitionem non comprehendet mutationem occultam que in eo contingit, et ipse cognoscet formam eius sine aliqua mutatione. Si ergo in eo contingit aliqua asperitas, existimabit ipsam esse lenem sicut assuevit esse, et si picture primo fuerint vere certificate et fuerint mutate, existimabit eas quasi esse certificatas.

4.31 ◉ Likewise, if sight perceives a wall somewhere, and if that wall is smooth but has depictions or etchings in it, and if sight scrutinizes that wall, accurately determines its form, and then shifts its focus away from it for awhile, and afterward, if there is some change in the texture of the surface of that wall or some change in the design of any of its depictions, but that change is not particularly obvious, then, if sight refocuses on that place and looks at the wall as it remembers the initial form, it will perceive the wall according to how it saw it the first time. But when it perceives and recognizes the wall, sight will not perceive the inconspicuous change occurring in it; so it will recognize its form without any change. Thus, if some roughness has developed in the wall, sight will judge it to be smooth, as it used to be, and if the original depictions in it were properly determined but have since changed, it will judge them to be accurately determined [as they were when previously apprehended].

4.32 ◉ Et omnia visibilia que sunt apud nos sunt recipientia mutationem secundum colorem, et figuram, et magnitudinem, et situm, et lenitatem, et asperitatem, et ordinationem partium et secundum multas intentiones particulares. Quoniam nature earum sunt mutabiles et preparate passioni ab eo quod accidit eis ex extrinseco, et mutatio quam est possibile comprehendi a visu est possibile in omnibus illorum. Et quamvis in eis sit aliqua mutatio quam non est possibile apparere visui, nichil est ex eis in quo non accidit ex extrinseco mutatio possibilis apparere visui. Et cum omnia visibilia sint preparata mutationi possibili comprehendi a visu, nullum ergo visibile quod visus comprehendit modo, et erat prius comprehensum et certificatum, est certificatum apud secundam comprehensionem a visu, scilicet quod visus sit securus secundo quod non fuerit mutatum cum mutatio sit possibilis in omnibus visibilibus. Cum ergo visus comprehenderit aliquam rem visam quam ante comprehenderit, et intuerit ipsam, et certificaverit formam eius, et fuerit rememorans sue forme apud comprehensionem, cognoscet ipsam. Et si in illa re visa contingit mutatio manifesta, comprehendet illam mutationem apud visionem. Si autem non fuerit manifesta, cognoscet illam rem et existimabit illam esse apud cognitionem secundum modum primum. Et cum hoc, si non iteraverit intuitionem, non erit securus quod forma quam ante cognoscebat sit remanens secundum suum esse, cum sit possibile quod in ea contingerit mutatio occulta que non potest apparere nisi per intuitionem. Si ergo iteraverit intuitionem, certificabit formam eius, et si non iteraverit intuitionem, non erit comprehensio illius rei vise certificata. Comprehensio ergo visibilium per cognitionem precedentem, et per signa, et per modicam intuitionem non est vera comprehensio; et visus non comprehendit rem visam vera comprehensione nisi per intuitionem rei vise apud comprehensionem eius, et per considerationem omnium intentionum que sunt in illa re visa, et per distinctionem omnium apud comprehensionem illius rei vise.

4.32 ◉ Now all the visible objects around us are susceptible to change in color, shape, size, spatial disposition, smoothness, roughness, arrangement of parts, and many [other] particular characteristics. For they are by nature changeable and disposed to be affected by what happens to them through external influences, and whatever change can be perceived by sight can occur in all of them. So, although there may be some [internal] change occurring in them that cannot be seen by sight, there is no kind of change produced by external agents that cannot be seen by sight.⁑ And since all visible objects are disposed to undergo changes that can be perceived by sight, no visible object that sight perceives at [any given] moment and that has been perceived and determined earlier, is accurately determined by sight when it is perceived a second time; that is, sight cannot be certain at that second time that the object did not suffer change, since change is possible in all visible objects. Thus, when sight perceives some visible object it perceived before, and when it scrutinizes it, determines its form, and remembers its form when it perceives it, it will recognize it. And if some obvious change occurs in that visible object, sight will perceive that change as soon as it sees the object. But if the change is not obvious, sight will recognize that visible object and will judge it to be the way it was when it apprehended it the first time. Moreover, if it does not repeat its scrutiny, it will not be certain that the form it apprehended before remained as it was, since an inconspicuous change might occur in it that can only be revealed through visual scrutiny. If, therefore, sight repeats its scrutiny, it will accurately determine the object’s form, but if it does not repeat its scrutiny, its perception of that visible object will not be truly determinate. Thus, the perception of visible objects on the basis of previous knowledge, or defining features, or minimal scrutiny is not proper perception; so sight does not properly perceive a visible object unless it scrutinizes the visible object when it perceives it and unless it examines all the characteristics possessed by that visible object and discerns them all when it perceives that visible object.

4.33 ◉ Visio ergo erit secundum duos modos: visio in primo aspectu et visio que est per intuitionem. Et per visionem que est in primo aspectu comprehendet intentiones manifestas rei vise tantum, et non certificatur per huiusmodi aspectum forma rei vise. Et visio que est in primo aspectu quandoque est solum fantastica et quandoque cum cognitione precedente. Et visio talis que est secundum fantasiam est visio visibilium que visus non cognoscit apud aspectum, et cum hoc non intuetur ipsa. Et visio que est secundum fantasiam cum cognitione precedente est visio visibilium que visus ante cognoscit, et cum hoc non intuerit intentionem eorum. Et secundum utriusque dispositiones eorum non comprehendit visus per fantasiam veritatem rei vise, sive precognoverit illam rem visam sive non.

4.33 ◉ Vision will therefore occur in two ways: vision at first glance and vision based on scrutiny. Through vision at first glance sight will perceive only the obvious characteristics of the visible object, but the form of the visible object is not accurately determined by such a glancing perusal. Moreover, vision at first glance is sometimes based on initial impression alone,⁑ whereas at other times it also entails previous knowledge. The kind of vision based on initial impression [alone] is vision of visible objects that sight does not recognize at first glance and does not scrutinize. Vision based on initial impression that also entails previous knowledge is vision of visible objects that sight has apprehended before but whose impressions sight does not scrutinize. In both cases, though, sight does not perceive the visible object as it actually is through initial impression, whether or not it has apprehended that visible object before.

4.34 ◉ Et visio per intuitionem erit secundum duos modos: visio sola intuitione et visio per intuitionem cum cognitione precedente. Visio autem que est sola intuitione est visibilium que ante visus non comprehendit aut non est rememorans comprehensionis eorum quando intuetur modo ipsa. Et visio per intuitionem cum precedenti cognitione est visio omnium visibilium que visus comprehendit et est rememorans visionis eorum quando intuerit intuitionem eorum et consideraverit intentiones omnes que sunt in eis. Et ista visio dividitur in duo quorum unum est visio assueta visibilium assuetorum, et ista pars erit per signa que comprehenduntur modica intuitione et per considerationem quarumdam intentionum que sunt in illa re visa cum cognitione precedente. Et ista visio in maiori parte est in tempore insensibili, et comprehensio illius quod comprehenditur secundum hunc modum non est comprehensio in fine certificationis. Pars autem secunda est que erit per finem intuitionis et per considerationem omnium intentionum que sunt in re visa apud comprehensionem illius rei vise et cum cognitione precedente. Et erit in maiori parte in tempore sensibili, et diversatur tempus secundum intentiones que sunt in re visa.

4.34 ◉ Vision based on scrutiny will also occur in two ways: vision based on scrutiny alone and vision based on scrutiny as well as previous knowledge. On the one hand, vision based on scrutiny alone involves visible objects that sight has not perceived before or that it does not remember having perceived before at the moment it scrutinizes them. On the other, vision based on scrutiny as well as previous knowledge is vision of all visible objects that sight has perceived [before] and remembers having perceived when it scrutinizes their impression and examines all the characteristics possessed by them. This kind of vision is also divided into two types, one of which is customary vision of familiar visible objects, this kind of vision occurring by means of defining features that are perceived after minimal scrutiny and after an evaluation of some of the characteristics possessed by that visible object, [and it is accomplished] along with previous knowledge. This type of vision, moreover, generally occurs in an imperceptible amount of time, so the perception of what is perceived in this way is not as determinate as it could be. The second subtype of vision will entail exquisite scrutiny as well as an evaluation of all the characteristics possessed by the visible object when that visible object is perceived, [and it is accomplished] along with previous knowledge. This type of vision will generally occur in a perceptible amount of time, but the amount of time depends on the characteristics the visible object possesses.⁑

4.35 ◉ Et visio que est per quam visibilia assueta comprehenduntur comprehensione in fine certificationis non est nisi per intuitionem omnium intentionum que sunt in re visa, et per considerationem omnium partium rei vise, et per distinctionem omnium intentionum que sunt in re visa apud comprehensionem rei vise, sive precognoverit illam rem visam sive non. Et ista certificatio que est respectu sensus est intentio certificata, et est dicere finem certificationis in istis locis finem illius quod possibile est comprehendi a sensu. Et cum omnibus istis comprehensio visibilium a visu est secundum fortitudinem visus, quoniam sensus visuum oculorum diversatur secundum vigorem et debilitatem.

4.35 ◉ The type of vision according to which familiar visible objects are perceived in as determinate a way as possible occurs only through a scrutiny of all the characteristics possessed by the visible object, an evaluation of all the parts of the visible object, and a differentiation of all the characteristics possessed by the visible object when it is perceived, whether or not sight has recognized that visible object before. But this determination is determinate relative to the sense, which is to say that, in such situations, the determinateness [of the perception] is limited by what the sense is capable of perceiving. Furthermore, the perception of visible objects by sight depends on the acuity of vision, for the sense of sight varies [in capacity] with the strength or weakness of the eyes.

4.36 ◉ Secundum ergo istos modos erit comprehensio visibilium a visu, et isti sunt omnes modi visionum, et hoc est illud quod intedebamus ad declarandum in isto capitulo. Et iam complevimus divisionem omnium visibilium et divisionem omnium intentionum visibilium, et declaravimus omnes intentiones per quas pervenit visus ad comprehensionem visibilium et intentionum visibilium, et distinximus omnes partes in quas dividuntur omnes modi visionum. Iste sunt intentiones quas intendebamus declarare in isto tractatu.

4.36 ◉ These, then, are the ways in which visible objects will be perceived by sight, and they exhaust the ways in which vision occurs, so this is what we meant to show in this chapter. We have now finished discussing all of the visible objects and all of the visible properties, and we have explained all of the ways in which sight arrives at the perception of visible objects and visible characteristics, and we have laid out all of the categories into which the modes of vision can be subdivided. These are the things we meant to explain in this book.