bj. 2: Further, what obeys a certain thing does not resist it. But
the irascible and concupiscible appetites resist reason: according to
the Apostle (Rom. 7:23): "I see another law in my members fighting
against the law of my mind." Therefore the irascible and
concupiscible appetites do not obey reason.

Obj. 3: Further, as the appetitive power is inferior to the rational
part of the soul, so also is the sensitive power. But the sensitive
part of the soul does not obey reason: for we neither hear nor see
just when we wish. Therefore, in like manner, neither do the powers
of the sensitive appetite, the irascible and concupiscible, obey
reason.

_On the contrary,_ Damascene says (De Fide Orth. ii, 12) that "the
part of the soul which is obedient and amenable to reason is divided
into concupiscence and anger."

_I answer that,_ In two ways the irascible and concupiscible powers
obey the higher part, in which are the intellect or reason, and the
will; first, as to reason, secondly as to the will. They obey the
reason in their own acts, because in other animals the sensitive
appetite is naturally moved by the estimative power; for instance,
a sheep, esteeming the wolf as an enemy, is afraid. In man the
estimative power, as we have said above (Q. 78, A. 4), is replaced
by the cogitative power, which is called by some "the particular
reason," because it compares individual intentions. Wherefore in man
the sensitive appetite is naturally moved by this particular reason.
But this same particular reason is naturally guided and moved
according to the universal reason: wherefore in syllogistic matters
particular conclusions are drawn from universal propositions.
Therefore it is clear that the universal reason directs the sensitive
appetite, which is divided into concupiscible and irascible; and this
appetite obeys it. But because to draw particular conclusions from
universal principles is not the work of the intellect, as such, but
of the reason: hence it is that the irascible and concupiscible are
said to obey the reason rather than to obey the intellect. Anyone
can experience this in himself: for by applying certain universal
considerations, anger or fear or the like may be modified or excited.

To the will also is the sensitive appetite subject in execution,
which is accomplished by the motive power. For in other animals
movement follows at once the concupiscible and irascible appetites:
for instance, the sheep, fearing the