10. In what sense, therefore, could each of the elements of essence
be called "one"? In that it is something unitary, without being unity
itself; for what is a "certain one" is already manifold. No species is
"one" except figuratively[306]; for in itself it is manifold. It is
in the same sense that, in this sense-world, we say that an army, or
a choric ballet, constitute a unity. Not in such things is absolute
unity; and therefore it may not be said that unity is something common.
Neither does unity reside in essence itself, nor in the individual
essences; therefore, it is not a genus. When a genus is predicated of
something, it is impossible to predicate of the same thing contrary
properties; but of each of the elements of universal essence it is
possible to assert both unity and its opposite. Consequently (if we
have called unity a genus), after having predicated of some essence
unity as a genus, we would have affirmed, of the same essence, that
unity was not a genus. Unity, therefore, could not be considered one
of the primary genera; for essence is no more one than it is manifold.
As to the other genera, none of them is one without being manifold;
much less could unity be predicated of the secondary genera of which
each is quite manifold. Besides, no genus, considered in its totality,
is unitary; so that if unity were a genus, it would merely thereby
cease being unity; for unity is not a number, and nevertheless it would
become a number in becoming a genus. Of course, numbers include an
alleged unity, as soon as we try to erect it into a genus, it is no
longer a unity, in a strict sense. Among numbers unity is not applied
to them as would have been a genus; of such unity it is merely said
that it is among numbers, not that it is a genus; likewise, if unity
were among the essences, it would not be there as genus of essence, nor
of anything else, nor of all things. Again, just as the simple is the
principle of the composite without being considered a genus in respect
to it--then it would be simultaneously simple and composite--so, if one
were considered to be a principle, it could not be a genus in respect
to things subsumed under it; and therefore will be a genus neither for
essence, nor for other (categories or things).