summa-contra-gentiles

i82
THE SUMMA CONTRA GENTILES
is manifold in power and has many operations.
Wherefore
it needs various organs in order to accomplish its operations,
of which organs the various powers of the soul are
said to be the acts ;
for instance sight of the eye, hearing of
the ears, and so forth. For this reason perfect animals have
the greatest variety of organs, while plants have the least.
This explains why certain philosophers have stated that
the soul is in some particular part of the :
body thus Aristotle
(De Causa Motus Anim.y says that it is in the heart,
because one of its powers is ascribed to that part of the
body. For the motive power, of which Aristotle was treating
in that book, is chiefly in the heart, by which the soul
communicates movement and other like operations to the
whole body.
THAT THERE IS
CHAPTER LXXni
NOT ONE POSSIBLE INTELLECT IN ALL MEN
From what has been said it is evidently shown that there is
not one possible intellect of all present, future, and past
men, as Averroes fancies (3 De Anima).^
For it has been proved that the substance of the intellect
is united to the human body as its form.^ Now one form
cannot possibly be in more than one matter, because the
proper act is produced in its
proper potentiality, since they
are mutually proportionate. Therefore there is not one
intellect of all men.
Again. To every mover proper instruments are due, for
the piper uses one kind of instrument, and the builder
another. Now the intellect is
compared to the body as the
latter's mover, as Aristotle declares (3 De Anima).* Just as,
therefore, it is impossible for the builder to use the instruments
of a piper, so is it
impossible for the intellect of one
man to be the intellect of another.
Further. Aristotle (i De AnimaY reproves
1 I. •
Text 5. ' Ch. Ixviii.
the ancients
* X. I, 2.
' iii. 23.