Chapter 081 - Sensuality

Sensuality is the name given to the sensitive appetite, for sensual motion signifies the motion of the sensitive appetite. And such motion implies the operation of the appetitive faculty, which is thus perfected; because, by the act of desire, it is inclined towards the thing desirable.

Now two faculties are to be distinguished in this appetite, viz. the irascible, and the concupiscible. For in natural things, which are subject to dissolution, it is necessary that there should be an inclination not only to pursue what is suitable, and fly from what is hurtful, but also to resist contraries, which place impediment in the way of suitable things, and introduce hurtful ones. Hence in the sensitive appetite, which follows upon the sensitive inclination, there are two faculties; by one of which - called concupiscible - the soul is inclined to pursue suitable and fly from hurtful things; while the other implies strenuous effort, by which it fights against obstacles; and is called irascible. These two faculties are not reducible to a single principle, for when the soul fights against obstacles it undertakes what is painful, contrary to the inclination of the concupiscible faculty; consequently they are different faculties.

Both are subject to the superior part; but they obey reason in one manner, and will in another. For while, in the lower animals, appetite is moved according to the estimative faculty, because they have none higher, in man it is by the cognitive faculty, which, as particular reason, is made to be moved and directed according to the conclusions of universal reason.

The sensitive appetite is also subject to the will as regards execution. This depends upon the strength of the motive; and since in every faculty the motive only moves in virtue of the first mover, the inferior appetite waits for the command of the will. But it does not always obey; for the power of the will is consultative rather than despotic, hence the appetite sometimes contradicts it.