Dist. 13, Art. 2, Q. 1
by St. Bonaventure
Source text: Public Domain Mark 1.0. English translation/apparatus/encoding: CC BY-NC 4.0, Wroot Press.
https://bonaventure.wrootpress.com/browse/2/d/13/q/bon-sent-II-d13-a2-q1
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## ARTICLE II.

### *On the essence and nature of light itself in itself.*

Next it is asked about the essence and quiddity of corporeal light in itself. And concerning this two [things] are asked. First it is asked, whether light is a body or the form of a body. Secondly it is asked, whether it is a substantial form or an accidental [form].

### Question I. *Whether light is a body, or the form of a body.*

Concerning the first it is so proceeded and shown that light is a body.

*Against the opposite.*

1. Augustine in book three *On Free Choice*: «*Among bodies light holds the first place*».

2. Likewise, Augustine on *Genesis according to the Letter*, book seven: «*The soul excels every corporeal nature by the dignity of nature; nevertheless through light and air, which in the world are the more excellent bodies, it administers the body*».

3. Likewise, Augustine in the third letter to Volusianus: «*The sense of men*, he says, *is this — they are able to think of nothing but bodies, whether the grosser ones, namely water or earth, or the more subtle ones, such as air and light; but bodies, nonetheless*».

4. Likewise, this is seen by reason. Among spirituals one finds *spirit*, which is pure light: therefore in like manner among corporeals it seems that one ought to find a body which is pure light: therefore it seems that what is luminous in bodies is pure light. But that is a body, since it has extension, as is clear in the sun: therefore it seems that light is a body.

5. Likewise, light in the sun is in full actuality and power of multiplying itself; therefore it does not seem that it is mixed with the possibility of matter; but it is established that the sun is a body: therefore it seems that pure light is a body.

6. Likewise, nothing is moved locally with dimensional and successive motion except a body; but that light which was first created made day and night by its motion: therefore it was a body.

*On the contrary:*

*Foundations.*

1. Damascene: «*Light is a natural quality of fire itself*»; but no quality is a body: therefore light is not a body, but a quality of a body.

2. Likewise, the Philosopher says that form is the principle of acting, therefore that which is most of all the principle of acting is most of all form: but light, among other corporeals, is most of all active: therefore it seems that it is purely form. But no body is purely form, since every body is composite: therefore light is not a body.

3. Likewise, Augustine in book twelve on *Genesis according to the Letter*: «*Light is the most subtle [thing] in body, and on account of this is the nearest to the soul*»; but that which is nearest to the most noble form, that most of all shares the character of form: therefore it seems that light itself is purely form.

4. Likewise, nothing is opposed to any body privatively in respect of its being a body; but darkness is opposed privatively to light in respect of its being light: therefore light is not a body.

### CONCLUSION.

> *Light, properly speaking and said in abstraction, is not a body, but the form of a luminous body.*

**I respond:** It must be said that some, not attending to nor inwardly considering the words of Augustine, said that light is a body — on this account, that they posited that some body is purely light, such that in it nothing was mixed in of the darkness of matter, just as is the solar body, from which the other bodies of the world receive illumination. — *Opinion 1.* But since it was proved above that no substance existing through itself, whether corporeal or spiritual, is purely form except God alone, it is plain enough that no body can be purely form. Since also no body

lacks extension, and all extension is founded upon corporeal matter, no body can be without matter: and so, no body can be purely form. If, therefore, light means a *form*, light cannot be the body itself, but something *of* the body. For if light were the body itself — since it belongs to light from itself to multiply itself — some body could multiply itself from itself without the addition of matter from elsewhere; which is impossible to any creature, since matter cannot be brought forth except by creation.

*Opinion 2, with a distinction.* And therefore it must be said otherwise: that just as *moisture* and *heat* are taken in two ways — for sometimes they mean *properties* or *qualities* of a corporeal substance, as one speaks of the moisture of water and the heat of fire itself; but sometimes they name the *substance itself* under such a form, as Augustine says, that *humor* (moisture) and *humus* (earth) are elements, and the philosophers say that *heat* is a certain subtle substance. So is it to be understood on the side of light: that light can be said in *abstraction*, and in this way it names the form of a luminous body, by which that body is able to shine and act; and in this sense Damascene says that light is a quality of fire. — *Conclusion 1.* Sometimes it names in *concretion* the [substance] itself, namely the luminous substance; and so it is taken in that division, namely that there are three species of fire: charcoal, flame, and light. — *Conclusion 2.* And in this manner Augustine speaks when he says that «*light holds the first place among bodies*», and that «*light and air are the more subtle bodies*». For he there calls *light* what we call *fire*, as is gathered expressly from Augustine's own words.

And through this the [arguments] objected on both sides are clear. — *Reply to the foundations.* For the authorities and reasons which say and prove that light is not a body, but a quality, take light in abstraction, as is clear.

*Solution of the opposing [arguments].*

1, 2, 3. The authorities, however, which are adduced for the opposite [view], speak of light as it is taken concretively. — But the reasons which prove that some body is purely light are not cogent.

4. *Note.* For to that which is objected concerning the likeness of spirituals and corporeals, it is not similar — because *spiritual* light is common to Creator and creature according to analogy. And because the Creator is purely act, therefore in spirituals light can be found in every kind of actuality, such that it has nothing of the possibility of matter nor of the darkness of ignorance. *Corporeal* light, however, is not found except in a creature, which, in order that it may exist through itself, needs sustaining matter; and on this account pure light cannot be found by an entire exclusion of the possibility of matter, yet pure light can be found by the exclusion of opacity and darkness — and thus it is in the sun.

5. To that which is objected, that if the light of the sun were mixed with matter it could not multiply itself perfectly, it must be said that the *presence* of matter does not take away the actuality of the form, especially when a body has much of the species and little of the matter; and because in the sun there is an abundance of light, although matter is there, it is not impeded from its action. But those [things] which are said to have incorporated light do not have perfect power of multiplying themselves — not because the light is only there in the matter, but because those bodies have much of matter and little of species.

6. To that which is objected, that the first-created light was moved dimensionally and successively, it must be said that light is there called a *luminous little cloud*, which was truly a body; and that [cloud] was not created — on this account, that out of pre-existing matter the form of light was divinely impressed or brought forth in it. Thus, then, from what has been said, it is clear that light, speaking properly and abstractly, is not a body, but the form of a body.