as in the case of the primary
substances; e.g. crookedness and "essence of crookedness," if this is
I mean that which does not imply the presence of something in
something else as a material substrate. But such things as are
material or are compounded with matter are not the same as their
essence; not even if they are accidentally one, e.g.
Socrates and "cultured"; for these
are only accidentally the same.
Now let us first
deal with definition, in so far as it has not been dealt with in the
; for the problem stated there1
has a bearing upon our
discussion of substance. The problem I mean is this: what constitutes
the unity of the thing of which we say that the formula is a
definition? E.g., in the case of man, "two-footed animal"; for let us
take this as the formula of "man."Why, then, is this a unity and not a
plurality, "animal" and "two-footed"? For in the case of "man" and
"white" we have a plurality when the latter does not refer to the
former, but a unity when it does refer to it, and the subject, "man,"
has an attribute; for then they become a unity and we have "the white
man."But in the
case before us one term does not partake of the other; the genus is
not considered to partake of its differentiae, for then the same thing
would be partaking simultaneously of contraries,
since the differentiae by which the
genus is distinguished are contrary. And even if it does partake of
them, the same argument applies, since the differentiae are many; e.g.
terrestrial, two-footed, wingless.Why is it that these are a unity and not a
plurality? Not because they are present in one genus, for in that case
all the differentiae of the genus will form a unity. But all the
elements in the definition must form a unity, because the definition
is a kind of formula which is one and defines substance, so that it
must be a formula of one particular thing; because the substance
denotes one thing and an individual, as we say.
We must first2
definitions which are reached by the process of division.For there is nothing else in
the definition but the primary genus and the differentiae; the other
genera consist of the primary genus together with the differentiae
which are taken with it. E.g., the primary genus is "animal"; the next
below it, "two-footed animal"; and again, "two-footed wingless
animal"; and similarly also if the expression contains more terms