Now it happens that the intellect is moved by the will, just as are the other powers: for a man considers something actually, because he wills to do so. And therefore the intellect, in so far as it is subordinate to the will, can be the subject of virtue absolutely so called. And in this way the speculative intellect, or the reason, is the subject of Faith: for the intellect is moved by the command of the will to assent to what is of faith: for "no man believeth, unless he will" [*Augustine: Tract. xxvi in Joan.]. But the practical intellect is the subject of prudence. For since prudence is the right reason of things to be done, it is a condition thereof that man be rightly disposed in regard to the principles of this reason of things to be done, that is in regard to their ends, to which man is rightly disposed by the rectitude of the will, just as to the principles of speculative truth he is rightly disposed by the natural light of the active intellect. And therefore as the subject of science, which is the right reason of speculative truths, is the speculative intellect in its relation to the active intellect, so the subject of prudence is the practical intellect in its relation to the right will.
Reply Obj. 1: The saying of Augustine is to be understood of virtue simply so called: not that every virtue is love simply: but that it depends in some way on love, in so far as it depends on the will, whose first movement consists in love, as we have said above (Q. 25, AA. 1, 2, 3; Q. 27, A. 4; I, Q. 20, A. 1).
Reply Obj. 2: The good of each thing is its end: and therefore, as truth is the end of the intellect, so to know truth is the good act of the intellect. Whence the habit, which perfects the intellect in regard to the knowledge of truth, whether speculative or practical, is a virtue.
Reply Obj. 3: This objection considers virtue simply so called. ________________________
FOURTH ARTICLE [I-II, Q. 56, Art. 4]
Whether the Irascible and Concupiscible Powers Are the Subject of
Virtue?
Objection 1: It would seem that the irascible and concupiscible powers cannot be the subject of virtue. For these powers are common to us and dumb animals. But we are now speaking of virtue as proper to man, since for this reason it is called human virtue. It is therefore impossible for human virtue to be in the irascible and concupiscible powers which are parts of the sensitive appetite, as we have said in the First Part (Q. 81, A. 2).
Obj. 2: Further, the sensitive appetite is a power which makes use of a corporeal organ. But the good of virtue cannot be in man's body: for the Apostle says (Rom. 7): "I know that good does not dwell in my flesh." Therefore the sensitive appetite cannot be the subject of virtue.
Obj. 3: Further, Augustine proves (De Moribus Eccl. v) that virtue is not in the body but in the soul, for the reason that the body is ruled by the soul: wherefore it is entirely due to his soul that a man make good use of his body: "For instance, if my coachman, through obedience to my orders, guides well the horses which he is driving; this is all due to me." But just as the soul rules the body, so also does the reason rule the sensitive appetite. Therefore that the irascible and concupiscible powers are rightly ruled, is entirely due to the rational powers. Now "virtue is that by which we live rightly," as we have said above (Q. 55, A. 4). Therefore virtue is not in the irascible and concupiscible powers, but only in the rational powers.
Obj. 4: Further, "the principal act of moral virtue is choice" (Ethic. viii, 13). Now choice is not an act of the irascible and concupiscible powers, but of the rational power, as we have said above (Q. 13, A. 2). Therefore moral virtue is not in the irascible and concupiscible powers, but in the reason.