Book 11
3
But again, if there is another kind of substance besides sensible substances, to what kind of sensible things are we to suppose that it corresponds? Why should we suppose that it corresponds to men or horses rather than to other animals, or even to inanimate objects in general? And yet to manufacture a set of eternal substances equal in number to those which are sensible and perishable would seem to fall outside the bounds of plausibility.
4
Yet if the principle which we are now seeking does not exist in separation from bodies, what can we suppose it to be if not matter? Yes, but matter does not exist actually, but only potentially. It might seem rather that a more appropriate principle would be form or shape; but this is perishableForms which are induced in matter are perishable, although not subject to the process of destruction; they are at one time and are not at another (cf. Aristot. Met. 7.15.1). The only pure form (i.e., the only form which is independent of matter in any and every sense) is the prime mover (Aristot. Met. 12.7).; and so in general there is no eternal substance which exists separately and independently.
5
But this is absurd, because it seems natural that there should be a substance and principle of this kind, and it is sought for as existing by nearly all the most enlightened thinkers. For how can there be any order in the universe if there is not something eternal and separate and permanent?
