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.