a material subject.

_On the contrary,_ It is said in the book _De Ecclesiasticis
Dogmatibus_ xv: "Nor do we say that there are two souls in one man,
as James and other Syrians write; one, animal, by which the body is
animated, and which is mingled with the blood; the other, spiritual,
which obeys the reason; but we say that it is one and the same soul
in man, that both gives life to the body by being united to it, and
orders itself by its own reasoning."

_I answer that,_ Plato held that there were several souls in one body,
distinct even as to organs, to which souls he referred the different
vital actions, saying that the nutritive power is in the liver, the
concupiscible in the heart, and the power of knowledge in the brain.
Which opinion is rejected by Aristotle (De Anima ii, 2), with regard
to those parts of the soul which use corporeal organs; for this
reason, that in those animals which continue to live when they have
been divided in each part are observed the operations of the soul, as
sense and appetite. Now this would not be the case if the various
principles of the soul's operations were essentially different, and
distributed in the various parts of the body. But with regard to the
intellectual part, he seems to leave it in doubt whether it be "only
logically" distinct from the other parts of the soul, "or also
locally."

The opinion of Plato might be maintained if, as he held, the soul was
supposed to be united to the body, not as its form, but as its motor.
For it involves nothing unreasonable that the same movable thing be
moved by several motors; and still less if it be moved according to
its various parts. If we suppose, however, that the soul is united to
the body as its form, it is quite impossible for several essentially
different souls to be in one body. This can be made clear by three
different reasons.

In the first place, an animal would not be absolutely one, in which
there were several souls. For nothing is absolutely one except by one
form, by which a thing has existence: because a thing has from the
same source both existence and unity; and therefore things which are
denominated by various forms are not absolutely one; as, for instance,
"a white man." If, therefore, man were _living_ by one form, the
vegetative soul, and _animal_ by another form, the sensitive soul, and
_man_ by another form, the intellectual soul, it would follow that man
is not absolutely one. Thus Aristotle argues, _Me