Summa Theologica Part I (Prima Pars) Part 103

_On the contrary,_ Augustine says (Gen. ad lit. i, 3): "Both spiritual and corporeal creatures were created at the beginning of time."

_I answer that,_ It is commonly said that the first things created were these four--the angelic nature, the empyrean heaven, formless corporeal matter, and time. It must be observed, however, that this is not the opinion of Augustine. For he (Confess. xii, 12) specifies only two things as first created--the angelic nature and corporeal matter--making no mention of the empyrean heaven. But these two, namely, the angelic nature and formless matter, precede the formation, by nature only, and not by duration; and therefore, as they precede formation, so do they precede movement and time. Time, therefore, cannot be included among them. But the enumeration above given is that of other holy writers, who hold that the formlessness of matter preceded by duration its form, and this view postulates the existence of time as the measure of duration: for otherwise there would be no such measure.

Reply Obj. 1: The teaching of Augustine rests on the opinion that the angelic nature and formless matter precede time by origin or nature.

Reply Obj. 2: As in the opinion of some holy writers matter was in some measure formless before it received its full form, so time was in a manner formless before it was fully formed and distinguished into day and night.

Reply Obj. 3: If the movement of the firmament did not begin immediately from the beginning, then the time that preceded was the measure, not of the firmament's movement, but of the first movement of whatsoever kind. For it is accidental to time to be the measure of the firmament's movement, in so far as this is the first movement.

But if the first movement was another than this, time would have been its measure, for everything is measured by the first of its kind. And it must be granted that forthwith from the beginning, there was movement of some kind, at least in the succession of concepts and affections in the angelic mind: while movement without time cannot be conceived, since time is nothing else than "the measure of priority and succession in movement."

Reply Obj. 4: Among the first created things are to be reckoned those which have a general relationship to things. And, therefore, among these time must be included, as having the nature of a common measure; but not movement, which is related only to the movable subject.

Reply Obj. 5: Place is implied as existing in the empyrean heaven, this being the boundary of the universe. And since place has reference to things permanent, it was created at once in its totality. But time, as not being permanent, was created in its beginning: even as actually we cannot lay hold of any part of time save the "now."

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QUESTION 67

ON THE WORK OF DISTINCTION IN ITSELF (In Four Articles)

We must consider next the work of distinction in itself. First, the work of the first day; secondly, the work of the second day; thirdly the work of the third day.

Under the first head there are four points of inquiry:

(1) Whether the word light is used in its proper sense in speaking of spiritual things?

(2) Whether light, in corporeal things, is itself corporeal?

(3) Whether light is a quality?

(4) Whether light was fittingly made on the first day?

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FIRST ARTICLE [I, Q. 67, Art. 1]

Whether the Word "Light" Is Used in Its Proper Sense in Speaking of Spiritual Things?

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."

Obj. 2: Further, Dionysius (Div. Nom. iv) includes Light among the intellectual names of G.o.d. But such names are used in their proper sense in spiritual things. Therefore light is used in its proper sense in spiritual matters.

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.

_On the contrary,_ Ambrose says (De Fide ii) that "Splendor" is among those things which are said of G.o.d metaphorically.

_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 n.o.blest 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 G.o.d" (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.

The answer to the objections will sufficiently appear from what has been said.

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SECOND ARTICLE [I, Q. 67, Art. 2]

Whether Light Is a Body?

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.

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.

Obj. 3: Further, the powers of movement, intersection, 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.

_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.

_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.

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 pa.s.s through the intervening s.p.a.ce 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.

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.

Since, therefore, these things are repugnant, not only to reason, but to common sense, we must conclude that light cannot be a body.

Reply Obj. 1: Augustine takes light to be a luminous body in act--in other words, to be fire, the n.o.blest of the four elements.

Reply Obj. 2: Aristotle p.r.o.nounces 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.

Reply Obj. 3: All these properties are a.s.signed 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 _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.

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THIRD ARTICLE [I, Q. 67, Art. 3]

Whether Light Is a Quality?

Objection 1: It would seem that light is not a quality. For every quality remains in its subject, though the active 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.

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.

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.

_On the contrary,_ Damascene (De Fide Orth. i) says that light is a species of quality.

_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. Secondly, 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. Others have said that light is the sun's substantial form, but this also seems impossible for two reasons. First, because substantial forms are not of themselves objects of the senses; for the object of the intellect is what a thing is, as is said _De Anima_ iii, text. 26: whereas light is visible of itself. In the second place, because it is impossible that what is the substantial form of one thing should be the accidental form of another; since substantial forms of their very nature const.i.tute species: wherefore the substantial form always and everywhere accompanies the species. But light is not the substantial form of air, for if it were, the air would be destroyed when light is withdrawn. Hence it cannot be the substantial form of the sun.

We must say, then, that as heat is an active quality consequent on the substantial form of fire, so light is an active quality consequent on the substantial form of the sun, or of another body that is of itself luminous, if there is any such body. A proof of this is that the rays of different stars produce different effects according to the diverse natures of bodies.

Reply Obj. 1: Since quality is consequent upon substantial form, the mode in which the subject receives a quality differs as the mode differs in which a subject receives a substantial form. For when matter receives its form perfectly, the qualities consequent upon the form are firm and enduring; as when, for instance, water is converted into fire. When, however, substantial form is received imperfectly, so as to be, as it were, in process of being received, rather than fully impressed, the consequent quality lasts for a time but is not permanent; as may be seen when water which has been heated returns in time to its natural state. But light is not produced by the trans.m.u.tation of matter, as though matter were in receipt of a substantial form, and light were a certain inception of substantial form. For this reason light disappears on the disappearance of its active cause.