py 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 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 lig