Quaestio 67 Question 67 De opere distinctionis secundum se et primo, de opere primae diei The Work of Distinction and the First Day Consequenter considerandum est de opere distinctionis secundum se et primo, de opere primae diei; secundo, de opere secundae diei; tertio, de opere tertiae. We must consider next the work of distinction in itself. First, the work of the first day; second, the work of the second day; third, the work of the third day. Circa primum quaeruntur quatuor. Under the first head there are four points of inquiry: Primo, utrum lux proprie in spiritualibus dici possit. (1) Whether the word light is used in its proper sense in speaking of spiritual things? Secundo, utrum lux corporalis sit corpus. (2) Whether light, in corporeal things, is itself corporeal? Tertio, utrum sit qualitas. (3) Whether light is a quality? Quarto, utrum conveniens fuit prima die fieri lucem. (4) Whether light was fittingly made on the first day? Articulus 1 Article 1 Utrum lux proprie in spiritualibus dicatur Whether the word ‘light’ is used in its proper sense in speaking of spiritual things? Ad primum sic proceditur. Videtur quod lux proprie in spiritualibus dicatur. Dicit enim Augustinus, IV super Gen. ad Litt., quod in spiritualibus melior et certior lux est, et quod Christus non sic dicitur lux quo modo lapis, sed illud proprie, hoc figurative. Objection 1: It would seem that light is used in its proper sense in spiritual things. For Augustine says (Gen ad lit. iv, 28) that in spiritual things light is better and surer: and that Christ is not called Light in the same sense as He is called the Stone; the former is to be taken literally, and the latter metaphorically. Praeterea, Dionysius, IV cap. de Div. Nom., ponit lumen inter nomina intelligibilia Dei. Nomina autem intelligibilia proprie dicuntur in spiritualibus. Ergo lux proprie dicitur in spiritualibus. Obj. 2: Further, Dionysius (Div. Nom. iv) includes Light among the intellectual names of God. But such names are used in their proper sense in spiritual things. Therefore light is used in its proper sense in spiritual matters. Praeterea, Apostolus dicit, ad Ephes. V, omne quod manifestatur, lumen est. Sed manifestatio magis proprie est in spiritualibus quam in corporalibus. Ergo et lux. Obj. 3: Further, the Apostle says (Eph 5:13): All that is made manifest is light. But to be made manifest belongs more properly to spiritual things than to corporeal. Therefore also does light. Sed contra est quod Ambrosius, in libro de Fide, ponit splendorem inter ea quae de Deo metaphorice dicuntur. On the contrary, Ambrose says (De Fide ii) that Splendor is among those things which are said of God metaphorically. Respondeo dicendum quod de aliquo nomine dupliciter convenit loqui, uno modo, secundum primam eius impositionem; alio modo, secundum usum nominis. Sicut patet in nomine visionis, quod primo impositum est ad significandum actum sensus visus; sed propter dignitatem et certitudinem huius sensus, extensum est hoc nomen, secundum usum loquentium, ad omnem cognitionem aliorum sensuum (dicimus enim, vide quomodo sapit, vel quomodo redolet, vel quomodo est calidum); et ulterius etiam ad cognitionem intellectus, secundum illud Matth. V, beati mundo corde, quoniam ipsi Deum videbunt. Et similiter dicendum est de nomine lucis. Nam primo quidem est institutum ad significandum id quod facit manifestationem in sensu visus, postmodum autem extensum est ad significandum omne illud quod facit manifestationem secundum quamcumque cognitionem. Si ergo accipiatur nomen luminis secundum suam primam impositionem, metaphorice in spiritualibus dicitur, ut Ambrosius dicit. Si autem accipiatur secundum quod est in usu loquentium ad omnem manifestationem extensum, sic proprie in spiritualibus dicitur. I answer that, Any word may be used in two ways—that is to say, either in its original application or in its more extended meaning. This is clearly shown in the word sight, originally applied to the act of the sense, and then, as sight is the noblest and most trustworthy of the senses, extended in common speech to all knowledge obtained through the other senses. Thus we say, Seeing how it tastes, or smells, or burns. Further, sight is applied to knowledge obtained through the intellect, as in those words: Blessed are the clean of heart, for they shall see God (Matt 5:8). And thus it is with the word light. In its primary meaning it signifies that which makes manifest to the sense of sight; afterwards it was extended to that which makes manifest to cognition of any kind. If, then, the word is taken in its strict and primary meaning, it is to be understood metaphorically when applied to spiritual things, as Ambrose says (De Fide ii). But if taken in its common and extended use, as applied to manifestation of every kind, it may properly be applied to spiritual things. Et per hoc patet responsio ad obiecta. The answer to the objections will sufficiently appear from what has been said. Articulus 2 Article 2 Utrum lux sit corpus Whether light is a body? Ad secundum sic proceditur. Videtur quod lux sit corpus. Dicit enim Augustinus, in libro de Lib. Arbit., quod lux in corporibus primum tenet locum. Ergo lux est corpus. Objection 1: It would seem that light is a body. For Augustine says (De Lib. Arb. iii, 5) that light takes the first place among bodies. Therefore light is a body. Praeterea, Philosophus dicit quod lumen est species ignis. Sed ignis est corpus. Ergo lumen est corpus. Obj. 2: Further, the Philosopher says (Topic. v, 2) that light is a species of fire. But fire is a body, and therefore so is light. Praeterea, ferri, intersecari, et reflecti est proprie corporum, haec autem omnia attribuuntur lumini vel radio. Coniunguntur etiam diversi radii et separantur, ut Dionysius dicit, II cap. de Div. Nom., quod etiam videtur non nisi corporibus convenire posse. Ergo lumen est corpus. Obj. 3: Further, the powers of movement, intersection, and reflection belong properly to bodies; and all these are attributes of light and its rays. Moreover, different rays of light, as Dionysius says (Div. Nom. ii), are united and separated, which seems impossible unless they are bodies. Therefore light is a body. Sed contra, duo corpora non possunt simul esse in eodem loco. Sed lumen est simul cum aere. Ergo lumen non est corpus. On the contrary, Two bodies cannot occupy the same place simultaneously. But this is the case with light and air. Therefore light is not a body. Respondeo dicendum quod impossibile est lumen esse corpus. Quod quidem apparet tripliciter. Primo quidem, ex parte loci. Nam locus cuiuslibet corporis est alius a loco alterius corporis, nec est possibile, secundum naturam, duo corpora esse simul in eodem loco, qualiacumque corpora sint; quia contiguum requirit distinctionem in situ. I answer that, Light cannot be a body, for three evident reasons. First, on the part of place. For the place of any one body is different from that of any other, nor is it possible, naturally speaking, for any two bodies of whatever nature, to exist simultaneously in the same place; since contiguity requires distinction of place. Secundo, apparet idem ex ratione motus. Si enim lumen esset corpus, illuminatio esset motus localis corporis. Nullus autem motus localis corporis potest esse in instanti, quia omne quod movetur localiter, necesse est quod prius perveniat ad medium magnitudinis quam ad extremum. Illuminatio autem fit in instanti. Nec potest dici quod fiat in tempore imperceptibili. Quia in parvo spatio posset tempus latere, in magno autem spatio, puta ab oriente in occidentem, tempus latere non posset; statim enim cum sol est in puncto orientis, illuminatur totum hemisphaerium usque ad punctum oppositum. Est etiam aliud considerandum ex parte motus. Quia omne corpus habet motum naturalem determinatum, motus autem illuminationis est ad omnem partem, nec magis secundum circulum quam secundum rectitudinem. Unde manifestum est quod illuminatio non est motus localis alicuius corporis. The second reason is from movement. For if light were a body, its diffusion would be the local movement of a body. Now no local movement of a body can be instantaneous, as everything that moves from one place to another must pass through the intervening space before reaching the end: whereas the diffusion of light is instantaneous. Nor can it be argued that the time required is too short to be perceived; for though this may be the case in short distances, it cannot be so in distances so great as that which separates the East from the West. Yet as soon as the sun is at the horizon, the whole hemisphere is illuminated from end to end. It must also be borne in mind on the part of movement that whereas all bodies have their natural determinate movement, that of light is indifferent as regards direction, working equally in a circle as in a straight line. Hence it appears that the diffusion of light is not the local movement of a body. Tertio, apparet idem ex parte generationis et corruptionis. Si enim lumen esset corpus, quando aer obtenebrescit per absentiam luminaris, sequeretur quod corpus luminis corrumperetur, et quod materia eius acciperet aliam formam. Quod non apparet, nisi aliquis dicat etiam tenebras esse corpus. Nec etiam apparet ex qua materia tantum corpus, quod replet medium hemisphaerium, quotidie generetur. Ridiculum est etiam dicere quod ad solam absentiam luminaris, tantum corpus corrumpatur. Si quis etiam dicat quod non corrumpitur, sed simul cum sole accedit et circumfertur, quid dici poterit de hoc, quod ad interpositionem alicuius corporis circa candelam, tota domus obscuratur? Nec videtur quod lumen congregetur circa candelam, quia non apparet ibi maior claritas post quam ante. The third reason is from generation and corruption. For if light were a body, it would follow that whenever the air is darkened by the absence of the luminary, the body of light would be corrupted, and its matter would receive a new form. But unless we are to say that darkness is a body, this does not appear to be the case. Neither does it appear from what matter a body can be daily generated large enough to fill the intervening hemisphere. Also it would be absurd to say that a body of so great a bulk is corrupted by the mere absence of the luminary. And should anyone reply that it is not corrupted, but approaches and moves around with the sun, we may ask why it is that when a lighted candle is obscured by the intervening object the whole room is darkened? It is not that the light is condensed round the candle when this is done, since it burns no more brightly then than it burned before. Quia ergo omnia haec non solum rationi, sed sensui etiam repugnant, dicendum est quod impossibile est lumen esse corpus. Since, therefore, these things are repugnant, not only to reason, but to common sense, we must conclude that light cannot be a body. Ad primum ergo dicendum quod Augustinus accipit lucem pro corpore lucido in actu, scilicet pro igne, quod inter quatuor elementa nobilissimum est. Reply Obj. 1: Augustine takes light to be a luminous body in act—in other words, to be fire, the noblest of the four elements. Ad secundum dicendum quod Aristoteles lumen nominat ignem in propria materia, sicut ignis in materia aerea dicitur flamma, et in materia terrea dicitur carbo. Non tamen est multum curandum de eis exemplis quae Aristoteles inducit in libris logicalibus, quia inducit ea ut probabilia secundum opinionem aliorum. Reply Obj. 2: Aristotle pronounces light to be fire existing in its own proper matter: just as fire in aerial matter is flame, or in earthly matter is burning coal. Nor must too much attention be paid to the instances adduced by Aristotle in his works on logic, as he merely mentions them as the more or less probable opinions of various writers. Ad tertium dicendum quod omnia illa attribuuntur lumini metaphorice, sicut etiam possent attribui calori. Quia enim motus localis est naturaliter primus motuum, ut probatur in VIII Physic., utimur nominibus pertinentibus ad motum localem, in alteratione et in omnibus motibus, sicut etiam nomen distantiae derivatum est a loco ad omnia contraria, ut dicitur in X Metaphys. Reply Obj. 3: All these properties are assigned to light metaphorically, and might in the same way be attributed to heat. For because movement from place to place is naturally first in the order of movement, as is proved in Phys. viii, text. 55, we use terms belonging to local movement in speaking of alteration and movement of all kinds. For even the word distance is derived from the idea of remoteness of place, to that of all contraries, as is said Metaph. x, text. 13. Articulus 3 Article 3 Utrum lux sit qualitas Whether light is a quality? Ad tertium sic proceditur. Videtur quod lux non sit qualitas. Omnis enim qualitas permanet in subiecto etiam postquam agens discesserit; sicut calor in aqua postquam removetur ab igne. Sed lumen non remanet in aere recedente luminari. Ergo lumen non est qualitas. Objection 1: It would seem that light is not a quality. For every quality remains in its subject, though the agent cause of the quality be removed, as heat remains in water removed from the fire. But light does not remain in the air when the source of light is withdrawn. Therefore light is not a quality. Praeterea, omnis qualitas sensibilis habet contrarium; sicut calido contrariatur frigidum, et albo nigrum. Sed lumini nihil est contrarium, tenebra enim est privatio luminis. Ergo lumen non est qualitas sensibilis. Obj. 2: Further, every sensible quality has its opposite, as cold is opposed to heat, blackness to whiteness. But this is not the case with light since darkness is merely a privation of light. Light therefore is not a sensible quality. Praeterea, causa est potior effectu. Sed lux caelestium corporum causat formas substantiales in istis inferioribus. Dat etiam esse spirituale coloribus, quia facit eos visibiles actu. Ergo lux non est aliqua qualitas sensibilis, sed magis substantialis forma, aut spiritualis. Obj. 3: Further, a cause is more potent than its effect. But the light of the heavenly bodies is a cause of substantial forms of earthly bodies, and also gives to colors their immaterial being, by making them actually visible. Light, then, is not a sensible quality, but rather a substantial or spiritual form. Sed contra est quod Damascenus dicit, in libro I, quod lux est quaedam qualitas. On the contrary, Damascene (De Fide Orth. i) says that light is a species of quality. Respondeo dicendum quod quidam dixerunt quod lumen in aere non habet esse naturale, sicut color in pariete; sed esse intentionale, sicut similitudo coloris in aere. Sed hoc non potest esse, propter duo. Primo quidem, quia lumen denominat aerem, fit enim aer luminosus in actu. Color vero non denominat ipsum, non enim dicitur aer coloratus. Secundo, quia lumen habet effectum in natura, quia per radios solis calefiunt corpora. Intentiones autem non causant transmutationes naturales. I answer that, Some writers have said that the light in the air has not a natural being such as the color on a wall has, but only an intentional being, as a similitude of color in the air. But this cannot be the case for two reasons. First, because light gives a name to the air, since by it the air becomes actually luminous. But color does not do this, for we do not speak of the air as colored. Second, because light produces natural effects, for by the rays of the sun bodies are warmed, and natural changes cannot be brought about by mere intentions.