Whether the Sensitive and Intellectual Appetites Are Distinct Powers?
Objection 1: It would seem that the sensitive and intellectual
appetites are not distinct powers. For powers are not differentiated
by accidental differences, as we have seen above (Q. 77, A. 3). But
it is accidental to the appetible object whether it be apprehended by
the sense or by the intellect. Therefore the sensitive and
intellectual appetites are not distinct powers.
Obj. 2: Further, intellectual knowledge is of universals; and so it
is distinct from sensitive knowledge, which is of individual things.
But there is no place for this distinction in the appetitive part:
for since the appetite is a movement of the soul to individual
things, seemingly every act of the appetite regards an individual
thing. Therefore the intellectual appetite is not distinguished from
the sensitive.
Obj. 3: Further, as under the apprehensive power, the appetitive is
subordinate as a lower power, so also is the motive power. But the
motive power which in man follows the intellect is not distinct from
the motive power which in animals follows sense. Therefore, for a
like reason, neither is there distinction in the appetitive part.
_On the contrary,_ The Philosopher (De Anima iii, 9) distinguishes a
double appetite, and says (De Anima iii, 11) that the higher appetite
moves the lower.
_I answer that,_ We must needs say that the intellectual appetite is a
distinct power from the sensitive appetite. For the appetitive power
is a passive power, which is naturally moved by the thing apprehended:
wherefore the apprehended appetible is a mover which is not moved,
while the appetite is a mover moved, as the Philosopher says in _De
Anima_ iii, 10 and _Metaph._ xii (Did. xi, 7). Now things passive and
movable are differentiated according to the distinction of the
corresponding active and motive principles; because the motive must be
proportionate to the movable, and the active to the passive: indeed,
the passive power itself has its very nature from its relation to its
active principle. Therefore, since what is apprehended by the
intellect and what is apprehended by sense are generically different;
consequently, the intellectual appetite is distinct from the
sensitive.
Reply Obj. 1: It is not accidental to the thing desired to be
apprehended by the sense or the intellect; on the contrary, this
belongs to it by its nature; for the appetible does not move the
appetite except as it is apprehended. Wherefore differences in the
thing apprehended are of themselves differences of the appetible. And
so the appetitive powers are distinct according to the distinction of
the things apprehended, as their proper objects.
Reply Obj. 2: The intellectual appetite, though it tends to
individual things which exist outside the soul, yet tends to them as
standing under the universal; as when it desires something because it
is good. Wherefore the Philosopher says (Rhetoric. ii, 4) that hatred
can regard a universal, as when "we hate every kind of thief." In the
same way by the intellectual appetite we may desire the immaterial
good, which is not apprehended by sense, such as knowledge, virtue,
and suchlike.
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