m, by which the body is established in its
being as movable by the soul. If, however, the intellectual soul be
united to the body as its substantial form, as we have said above
(A. 1), it is impossible for another substantial form besides the
intellectual soul to be found in man.

In order to make this evident, we must consider that the substantial
form differs from the accidental form in this, that the accidental
form does not make a thing to be "simply," but to be "such," as heat
does not make a thing to be simply, but only to be hot. Therefore by
the coming of the accidental form a thing is not said to be made or
generated simply, but to be made such, or to be in some particular
condition; and in like manner, when an accidental form is removed, a
thing is said to be corrupted, not simply, but relatively. Now the
substantial form gives being simply; therefore by its coming a thing
is said to be generated simply; and by its removal to be corrupted
simply. For this reason, the old natural philosophers, who held that
primary matter was some actual being--for instance, fire or air, or
something of that sort--maintained that nothing is generated simply,
or corrupted simply; and stated that "every becoming is nothing but an
alteration," as we read, _Phys._ i, 4. Therefore, if besides the
intellectual soul there pre-existed in matter another substantial form
by which the subject of the soul were made an actual being, it would
follow that the soul does not give being simply; and consequently that
it is not the substantial form: and so at the advent of the soul there
would not be simple generation; nor at its removal simple corruption,
all of which is clearly false.

Whence we must conclude, that there is no other substantial form in
man besides the intellectual soul; and that the soul, as it virtually
contains the sensitive and nutritive souls, so does it virtually
contain all inferior forms, and itself alone does whatever the
imperfect forms do in other things. The same is to be said of the
sensitive soul in brute animals, and of the nutritive soul in plants,
and universally of all more perfect forms with regard to the
imperfect.

Reply Obj. 1: Aristotle does not say that the soul is the act of a
body only, but "the act of a physical organic body which has life
potentially"; and that this potentiality "does not reject the soul."
Whence it is clear that when the soul is called the act, the soul
itself is included; as when