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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 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