Thomas Aquinas, Disputed Questions on Truth (De Veritate)

1. An accidental difference in objects does not distinguish powers. But the objects of the will and of the sense appetite are differentiated only by accidental differences in good, which is essentially the object of appetite. They do not, indeed, seem to differ except inasmuch as the will has as its object the good apprehended by the intellect, and sense appetite, that apprehended by sense. But these differences are accidental to good as such. Therefore the will is not a power distinct from sense appetite.

2. Sensitive and intellectual apprehensive powers differ as particular and universal, for sense apprehends particulars and intellect universals. But the appetite of the sensitive and intellective parts cannot be distinguished in this way, because any appetite is for the good as it exists in reality. This, however, is not universal but singular. The rational appetite--the will--must therefore not be said to be a power other than sense appetite as intellect is other than sense.

3. The motive power follows the appetitive just as the appetitive follows apprehension. But the motive power is not one thing in rational beings and another in irrational. Then neither is the appetitive. And so the conclusion is the same as before.

4. The Philosopher distinguishes five kinds of powers and operations of the soul. One includes generation, nutrition, and growth; the second is sense; the third, appetite; the fourth, locomotion; and the fifth, intellect. Intellect is here distinguished from sense, but not intellective appetite from sense appetite. It therefore seems that a higher appetitive power is not distinguished from a lower as a higher apprehensive power is distinguished from a lower.

To the Contrary:

1'. The Philosopher distinguishes the will from sense appetite.

2'. All things that stand in a series must be distinct. But intellective appetite is higher than that of sense according to the Philosopher, and even moves it "as sphere moves sphere," as he says in the same place. The will is therefore a power other than sense appetite.

REPLY:

The will is a power distinct from sense appetite. It should be noted in this connection that rational appetite is distinguished from that of sense in just the same way as sensitive appetite is distinguished from that of nature--because of a more perfect way of tending. The closer a nature is to God, the more pronounced is the likeness of the divine excellence which is found in it. Now it belongs to the divine excellence to move and incline and direct all things while not being moved, inclined, or directed by any other. Hence the nearer a nature is to God, the less it is inclined by another and the more it is capable of inclining itself.

An insensible nature, therefore, being by reason of its materiality the farthest removed from God, is inclined to an end, to be sure, but has within it nothing which inclines, but only a principle of inclination, as was explained above.

A sensitive nature, however, being closer to God, has within itself something which inclines, i.e., the apprehended object of appetite. Yet this inclination is not within the control of the animal which is inclined but is determined by something else. An animal is not able at the sight of something attractive not to crave it, because animals do not themselves have the mastery over their own inclination. Hence "they do not act but are rather acted upon," as Damascene says. This is because the sensuous appetitive power has a bodily organ and so is nearly in the condition of matter and of corporeal things so as rather to be moved than to move.

But a rational nature, being closest to God, not merely, like inanimate things, has an inclination to something, and, like a sentient nature, a mover of this inclination determined as it were extrinsically, but further so has its inclination within its own power that it does not necessarily incline to anything appetible which is apprehended, but can incline or not incline. And so its inclination is not determined for it by anything else but by itself. This belongs to it inasmuch as it does not use a bodily organ; and so, getting farther away from the nature of what is moved, it approaches that of what moves and acts. It can come about that something determines for itself its inclination to an end only if it knows the end and the bearing of the end upon the means to it. But this belongs to reason alone. Thus such an appetite, which is not determined of necessity by something else, follows the apprehension of reason. Hence, rational appetite, called will, is a power distinct from sense appetite.

Answers to Difficulties:

1. The will is not distinguished from sense appetite directly on the basis of the apprehension which it follows but on that of determining one's inclination for oneself or having it determined by another. These two sorts of inclination require different kinds of powers. And such a diversity further demands a difference in the apprehensions, as appears from what has been said.* Hence the distinction of the appetitive powers is more or less resultantly based upon the distinction of the apprehensive, not principally.

2. Although appetite always looks to something existing in reality as a particular and not as a universal, nevertheless it is sometimes moved to tend by the apprehension of some universal condition. We tend to this particular good, for instance, from the consideration of the fact that we look upon good as simply to be sought. At other times we tend as a result of the apprehension of a particular thing in its particularity. Thus appetite is distinguished into universal and particular in a secondary sense, just as it is distinguished in a secondary sense according to the difference in the apprehension which it follows.

3. Motion and operations are found in singulars. But there can be a descent from a universal proposition to a particular conclusion only through the mediation of a particular assumption. Now in matters of operating the choice of a deed is a sort of conclusion, as is said in the Ethics. A universal conception of the intellect, accordingly, can be applied to the choice of a deed only by means of a particular apprehension. Consequently the motion which follows upon a universal apprehension of the intellect by means of a particular sense apprehension does not require one motive power corresponding to intellect and another corresponding to sense, as is true of the appetite which follows apprehension immediately. Moreover, the motive power in question in the difficulty, that which is commanded, is a power attached to the muscles and nerves. Hence it cannot pertain to the intellective part, which uses no organ.

4. Because sense and the intellect differ according to the formal aspects of the apprehensible in so far as it is apprehensible, they therefore belong to different genera of powers. Sense is concerned with apprehending the particular; the intellect, with apprehending the universal. But higher and lower appetite are not differentiated by differences in the appetible as such, since either appetite sometimes tends to the same good. They differ rather in their different ways of tending, as is evident from what has been said.* Hence they are indeed distinct powers but not distinct kinds of powers.