[
1041a]
[1]
none
the less there would be eternal substances besides those which we
knew; and so in the present case even if we cannot apprehend what they
are, still there must be eternal substances of some kind.
It is clear, then, both that no universal
term is substance and that no substance is composed of
substances.
As for what and what sort of thing we
mean by substance, let us explain this by making, as it were, another
fresh start. Perhaps in this way we shall also obtain some light upon
that kind of substance which exists in separation from sensible
substances. Since, then, substance is a kind of principle and cause,
we had better pursue our inquiry from this point.
Now when we ask why a thing is, it is always in the
sense "why does A belong to B?"To ask why the cultured man is a cultured man
is to ask either, as we have said, why the man is cultured, or
something else. Now to ask why a thing is itself is no question;
because when we ask the reason of a thing the fact must first be
evident; e.g., that the moon suffers eclipse;and "because it is itself" is the one
explanation and reason which applies to all questions such as "why is
man man?" or "why is the cultured person cultured?" (unless one were
to say that each thing is indivisible from itself, and that this is
what "being one" really means);
[20]
but this, besides being a general answer, is a
summary one.
1 We may, however, ask why a man is
an animal of such-and-such a kind.It is clear, then, that we are not asking why
he who is a man is a man; therefore we are asking why A, which is
predicated of B, belongs to B. (The fact that A does belong to B must
be evident, for if this is not so, the question is pointless.) E.g.,
"Why does it thunder?" means "why is a noise produced in the clouds?"
for the true form of the question is one thing predicated in this way
of another.Or again, "why
are these things, e.g. bricks and stones, a house?" Clearly then we
are inquiring for the cause (i.e., to speak abstractly, the essence);
which is in the case of some things, e.g. house or bed, the
end , and in others the prime mover—for this
also is a cause. We look for the latter kind of cause in the case of
generation and destruction, but for the former also in the case of
existence.
What we are now looking for is most
obscure when one term is not predicated of another;