Again, there are certain general mathematical theorems which are not restricted to these substances.Here, then, we shall have yet another kind of substance intermediate between and distinct from the Ideas and the intermediates, which is neither number nor points nor spatial magnitude nor time. And if this is impossible, clearly it is also impossible that the aforesaid substances should exist separately from sensible objects.

In general, consequences result which are contrary both to the truth and to received opinion if we thus posit the objects of mathematics as definite separately-existent entities. For if they exist in this way, they must be prior to sensible spatial magnitudes, whereas in truth they must be posterior to them; for the incomplete spatial magnitude is in point of generation prior, but in point of substantiality posterior, [20] as the inanimate is to the animate.

Again, in virtue of what can we possibly regard mathematical magnitudes as one? Things in this world of ours may be reasonably supposed to be one in virtue of soul or part of the soul, or some other influence; apart from this they are a plurality and are disintegrated. But inasmuch as the former are divisible and quantitative, what is the cause of their unity and cohesion?

Again, the ways in which
the objects of mathematics are generated prove our point;for they are generated first
in the dimension of length, then in that of breadth, and finally in
that of depth, whereupon the process is complete. Thus if that which
is posterior in generation^{1} is prior in substantiality, body will be prior
to plane and line, and in this sense it will also be more truly
complete and whole, because it can become animate; whereas how could a
line or plane be animate? The supposition is beyond our powers of
apprehension.

Further, body is a kind of substance, since it already in some sense possesses completeness; but in what sense are lines substances? Neither as being a kind of form or shape, as perhaps the soul is, nor as being matter, like the body; for it does not appear that anything can be composed either of lines or of planes or of points,whereas if they were a kind of material substance it would be apparent that things can be so composed.