Thomas Aquinas - Summa Theologica, Part I-II (Pars Prima Secundae)

We must now consider what moves the will: and under this head there are six points of inquiry:

(1) Whether the will is moved by the intellect?

(2) Whether it is moved by the sensitive appetite?

(3) Whether the will moves itself?

(4) Whether it is moved by an extrinsic principle?

(5) Whether it is moved by a heavenly body?

(6) Whether the will is moved by God alone as by an extrinsic principle? ________________________

FIRST ARTICLE [I-II, Q. 9, Art. 1]

Whether the Will Is Moved by the Intellect?

Objection 1: It would seem that the will is not moved by the intellect. For Augustine says on Ps. 118:20: "My soul hath coveted to long for Thy justifications: The intellect flies ahead, the desire follows sluggishly or not at all: we know what is good, but deeds delight us not." But it would not be so, if the will were moved by the intellect: because movement of the movable results from motion of the mover. Therefore the intellect does not move the will.

Obj. 2: Further, the intellect in presenting the appetible object to the will, stands in relation to the will, as the imagination in representing the appetible object to the sensitive appetite. But the imagination, in presenting the appetible object, does not remove the sensitive appetite: indeed sometimes our imagination affects us no more than what is set before us in a picture, and moves us not at all (De Anima ii, 3). Therefore neither does the intellect move the will.

Obj. 3: Further, the same is not mover and moved in respect of the same thing. But the will moves the intellect; for we exercise the intellect when we will. Therefore the intellect does not move the will.

On the contrary, The Philosopher says (De Anima iii, 10) that "the appetible object is a mover not moved, whereas the will is a mover moved."

I answer that, A thing requires to be moved by something in so far as it is in potentiality to several things; for that which is in potentiality needs to be reduced to act by something actual; and to do this is to move. Now a power of the soul is seen to be in potentiality to different things in two ways: first, with regard to acting and not acting; secondly, with regard to this or that action. Thus the sight sometimes sees actually, and sometimes sees not: and sometimes it sees white, and sometimes black. It needs therefore a mover in two respects, viz. as to the exercise or use of the act, and as to the determination of the act. The first of these is on the part of the subject, which is sometimes acting, sometimes not acting: while the other is on the part of the object, by reason of which the act is specified.

The motion of the subject itself is due to some agent. And since every agent acts for an end, as was shown above (Q. 1, A. 2), the principle of this motion lies in the end. And hence it is that the art which is concerned with the end, by its command moves the art which is concerned with the means; just as the "art of sailing commands the art of shipbuilding" (Phys. ii, 2). Now good in general, which has the nature of an end, is the object of the will. Consequently, in this respect, the will moves the other powers of the soul to their acts, for we make use of the other powers when we will. For the end and perfection of every other power, is included under the object of the will as some particular good: and always the art or power to which the universal end belongs, moves to their acts the arts or powers to which belong the particular ends included in the universal end. Thus the leader of an army, who intends the common good—i.e. the order of the whole army—by his command moves one of the captains, who intends the order of one company.

On the other hand, the object moves, by determining the act, after the manner of a formal principle, whereby in natural things actions are specified, as heating by heat. Now the first formal principle is universal "being" and "truth," which is the object of the intellect. And therefore by this kind of motion the intellect moves the will, as presenting its object to it.

Reply Obj. 1: The passage quoted proves, not that the intellect does not move, but that it does not move of necessity.

Reply Obj. 2: Just as the imagination of a form without estimation of fitness or harmfulness, does not move the sensitive appetite; so neither does the apprehension of the true without the aspect of goodness and desirability. Hence it is not the speculative intellect that moves, but the practical intellect (De Anima iii, 9).

Reply Obj. 3: The will moves the intellect as to the exercise of its act; since even the true itself which is the perfection of the intellect, is included in the universal good, as a particular good. But as to the determination of the act, which the act derives from the object, the intellect moves the will; since the good itself is apprehended under a special aspect as contained in the universal true. It is therefore evident that the same is not mover and moved in the same respect. ________________________

SECOND ARTICLE [I-II, Q. 9, Art. 2]

Whether the Will Is Moved by the Sensitive Appetite?

Objection 1: It would seem that the will cannot be moved by the sensitive appetite. For "to move and to act is more excellent than to be passive," as Augustine says (Gen. ad lit. xii, 16). But the sensitive appetite is less excellent than the will which is the intellectual appetite; just as sense is less excellent than intellect. Therefore the sensitive appetite does not move the will.

Obj. 2: Further, no particular power can produce a universal effect. But the sensitive appetite is a particular power, because it follows the particular apprehension of sense. Therefore it cannot cause the movement of the will, which movement is universal, as following the universal apprehension of the intellect.

Obj. 3: Further, as is proved in Phys. viii, 5, the mover is not moved by that which it moves, in such a way that there be reciprocal motion. But the will moves the sensitive appetite, inasmuch as the sensitive appetite obeys the reason. Therefore the sensitive appetite does not move the will.

On the contrary, It is written (James 1:14): "Every man is tempted by his own concupiscence, being drawn away and allured." But man would not be drawn away by his concupiscence, unless his will were moved by the sensitive appetite, wherein concupiscence resides. Therefore the sensitive appetite moves the will.

I answer that, As stated above (A. 1), that which is apprehended as good and fitting, moves the will by way of object. Now, that a thing appear to be good and fitting, happens from two causes: namely, from the condition, either of the thing proposed, or of the one to whom it is proposed. For fitness is spoken of by way of relation; hence it depends on both extremes. And hence it is that taste, according as it is variously disposed, takes to a thing in various ways, as being fitting or unfitting. Wherefore as the Philosopher says (Ethic. iii, 5): "According as a man is, such does the end seem to him."

Now it is evident that according to a passion of the sensitive appetite man is changed to a certain disposition. Wherefore according as man is affected by a passion, something seems to him fitting, which does not seem so when he is not so affected: thus that seems good to a man when angered, which does not seem good when he is calm. And in this way, the sensitive appetite moves the will, on the part of the object.

Reply Obj. 1: Nothing hinders that which is better simply and in itself, from being less excellent in a certain respect. Accordingly the will is simply more excellent than the sensitive appetite: but in respect of the man in whom a passion is predominant, in so far as he is subject to that passion, the sensitive appetite is more excellent.