Thomas Aquinas, Disputed Questions on Truth (De Veritate)

1. In the Epistle to the Romans (7:15) it is written: "For [the good] which I will, I do not; but the evil which I will not, that I do." As a comment in the Gloss explains, this is said because of the motions of sensuality. Sensuality therefore does not obey the will and reason.

2. In the same Epistle (7:23) it is written: "But I see another law in my members, fighting against the law of my mind. . . ." Now this law is concupiscence. It is therefore fighting against the law of the mind, that is, reason; and so it does not obey it.

3. The relation among the appetitive powers is the same as that among the apprehensive. But the intellect does not have control of the acts of the external senses, for we do not see or hear whatever the intellect decides. Then neither are the motions of sensuality under the control of rational appetite.

4. Natural activities in us are not subject to reason. But sensuality tends to the object of its desire by a natural appetite. Consequently the motions of sensuality are not subject to reason.

5. The motions of sensuality are passions of the soul, for which definite dispositions of the body are required, as Avicenna determines. Thus for anger, hot thin blood is needed; and for joy, temperate blood. But one's bodily disposition is not subject to reason. Then neither are the motions of sensuality.

To the Contrary:

Damascene says that the irascible and the concupiscible powers participate to some extent in reason. But they are the parts of sensuality. Consequently the motions of sensuality also are under the control of reason. And the same can be gathered from what is said by the Philosopher and by Gregory of Nyssa.

REPLY:

In a series of mobile beings and movers we must arrive at some first being which moves itself and by which is moved whatever is not moved by itself, because everything that exists through another is reduced to that which exists through itself, as is gathered from the Physics. Then, since the will moves itself by reason of its being the master of its own act, the other powers which do not move themselves must somehow be moved by the will. Now the nearer any of the other powers comes to the will, the more it participates in the will's motion. Consequently the lower appetitive powers obey the will in their principal acts as being nearest to the will; and the other powers farther removed, as the nutritive and generative, are moved by the will in some of their external acts.

Now the lower appetitive powers, the irascible and the concupiscible, are subject to reason in three respects: (1) On the part of reason itself. For since the same thing considered under different conditions can be made either pleasurable or repulsive, by means of the imagination reason lays a particular thing before sensuality under the aspect of the pleasurable or the disagreeable as it appears to reason; and so sensuality is moved to joy or to sorrow. The Philosopher accordingly says that reason persuades "to the best." (2) On the part of the will. For among powers hierarchically connected the situation is such that an intense movement in one, and especially in the higher, overflows into the other. Accordingly, when by a choice the movement of the will is directed to something intensely, even the irascible and the concupiscible powers follow the movement of the will. It is accordingly said in The Soul that appetite moves appetite (that is, the higher moves the lower) as sphere moves sphere among the heavenly bodies. (3) On the part of the motive power which carries it out. For just as in an army the advance to battle depends upon the command of the general, so in us the motive power moves the members only at the command of that which rules in us, namely reason, whatever sort of movement may occur in the lower powers. Reason therefore holds the irascible and the concupiscible powers in check lest they proceed to an external act. On this account it is said in Genesis (4:7): "The lust thereof shall be under thee."

Thus it is clear that the irascible and the concupiscible powers are subject to reason, and likewise sensuality, though the name sensuality does not refer to these powers according to their participation in reason but according to the nature of the sensitive part of the soul. It is consequently not said in as proper a sense that sensuality is subject to reason as that the irascible and the concupiscible powers are so subject.

Answers to Difficulties:

1. The statement of the Apostle is to be understood as meaning that it is not in our power universally to prevent all inordinate movements of sensuality, though we can prevent individual ones, as is clear from what has been said.

2. As far as sensuality itself goes, it fights against reason; yet reason can keep it in check, as is clear from what has been said.*

3. The lower apprehensive powers also obey the higher, as is clear in the case of the imagination and the other internal senses; but the fact that the external senses do not obey the intellect is due to their need of a sensible thing, and to their inability to sense without it.

4. The lower appetitive power does not naturally tend to anything until after that thing is presented to it under the aspect of its proper object, as is clear from what has been said. Since it is in the power of reason to present one and the same thing under different aspects, a particular sort of food, for instance, as delicious or as deadly, reason is able to move sensuality to different objects.

5. A disposition of the body which is in its very constitution is not subject to reason. But that such a disposition be had is a requisite not [directly] for the actualization of the passions in question, but for man to be capable of them. The actual modification of the body, however, such as the boiling of the blood around the heart, or something of the sort, which actually accompanies passions of this kind, depends upon the imagination, and on that account is subject to reason.