contemporaneous with that of its object.
Again, while the object of knowledge, if it ceases to exist, cancels
at the same time the knowledge which was its correlative, the converse
of this is not true. It is true that if the object of knowledge does
not exist there can be no knowledge: for there will no longer be
anything to know. Yet it is equally true that, if knowledge of a
certain object does not exist, the object may nevertheless quite
well exist. Thus, in the case of the squaring of the circle, if indeed
that process is an object of knowledge, though it itself exists as
an object of knowledge, yet the knowledge of it has not yet come
into existence. Again, if all animals ceased to exist, there would
be no knowledge, but there might yet be many objects of knowledge.
This is likewise the case with regard to perception: for the
object of perception is, it appears, prior to the act of perception.
If the perceptible is annihilated, perception also will cease to
exist; but the annihilation of perception does not cancel the
existence of the perceptible. For perception implies a body
perceived and a body in which perception takes place. Now if that
which is perceptible is annihilated, it follows that the body is
annihilated, for the body is a perceptible thing; and if the body does
not exist, it follows that perception also ceases to exist. Thus the
annihilation of the perceptible involves that of perception.
But the annihilation of perception does not involve that of the
perceptible. For if the animal is annihilated, it follows that
perception also is annihilated, but perceptibles such as body, heat,
sweetness, bitterness, and so on, will remain.
Again, perception is generated at the same time as the perceiving
subject, for it comes into existence at the same time as the animal.
But the perceptible surely exists before perception; for fire and
water and such elements, out of which the animal is itself composed,
exist before the animal is an animal at all, and before perception.
Thus it would seem that the perceptible exists before perception.