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.
Reply Obj. 2: Men's acts and choices are in reference to singulars. Wherefore from the very fact that the sensitive appetite is a particular power, it has great influence in disposing man so that something seems to him such or otherwise, in particular cases.
Reply Obj. 3: As the Philosopher says (Polit. i, 2), the reason, in which resides the will, moves, by its command, the irascible and concupiscible powers, not, indeed, "by a despotic sovereignty," as a slave is moved by his master, but by a "royal and politic sovereignty," as free men are ruled by their governor, and can nevertheless act counter to his commands. Hence both irascible and concupiscible can move counter to the will: and accordingly nothing hinders the will from being moved by them at times. ________________________
THIRD ARTICLE [I-II, Q. 9, Art. 3]
Whether the Will Moves Itself?
Objection 1: It would seem that the will does not move itself. For every mover, as such, is in act: whereas what is moved, is in potentiality; since "movement is the act of that which is in potentiality, as such" [*Aristotle, Phys. iii, 1]. Now the same is not in potentiality and in act, in respect of the same. Therefore nothing moves itself. Neither, therefore, can the will move itself.
Obj. 2: Further, the movable is moved on the mover being present. But the will is always present to itself. If, therefore, it moved itself, it would always be moving itself, which is clearly false.
Obj. 3: Further, the will is moved by the intellect, as stated above (A. 1). If, therefore, the will move itself, it would follow that the same thing is at once moved immediately by two movers; which seems unreasonable. Therefore the will does not move itself.
On the contrary, The will is mistress of its own act, and to it belongs to will and not to will. But this would not be so, had it not the power to move itself to will. Therefore it moves itself.
I answer that, As stated above (A. 1), it belongs to the will to move the other powers, by reason of the end which is the will's object. Now, as stated above (Q. 8, A. 2), the end is in things appetible, what the principle is in things intelligible. But it is evident that the intellect, through its knowledge of the principle, reduces itself from potentiality to act, as to its knowledge of the conclusions; and thus it moves itself. And, in like manner, the will, through its volition of the end, moves itself to will the means.