Reply Obj. 1: Just as bad things are said metaphorically to be perfect, so are they said to be good: for we speak of a perfect thief or robber; and of a good thief or robber, as the Philosopher explains (Metaph. v, text. 21). In this way therefore virtue is applied to evil things: so that the "virtue" of sin is said to be law, in so far as occasionally sin is aggravated through the law, so as to attain to the limit of its possibility.
Reply Obj. 2: The evil of drunkenness and excessive drink, consists in a falling away from the order of reason. Now it happens that, together with this falling away from reason, some lower power is perfect in reference to that which belongs to its own kind, even in direct opposition to reason, or with some falling away therefrom. But the perfection of that power, since it is compatible with a falling away from reason, cannot be called a human virtue.
Reply Obj. 3: Reason is shown to be so much the more perfect, according as it is able to overcome or endure more easily the weakness of the body and of the lower powers. And therefore human virtue, which is attributed to reason, is said to be "made perfect in infirmity," not of the reason indeed, but of the body and of the lower powers. ________________________
FOURTH ARTICLE [I-II, Q. 55, Art. 4]
Whether Virtue Is Suitably Defined?
Objection 1: It would seem that the definition, usually given, of virtue, is not suitable, to wit: "Virtue is a good quality of the mind, by which we live righteously, of which no one can make bad use, which God works in us, without us." For virtue is man's goodness, since virtue it is that makes its subject good. But goodness does not seem to be good, as neither is whiteness white. It is therefore unsuitable to describe virtue as a "good quality."
Obj. 2: Further, no difference is more common than its genus; since it is that which divides the genus. But good is more common than quality, since it is convertible with being. Therefore "good" should not be put in the definition of virtue, as a difference of quality.
Obj. 3: Further, as Augustine says (De Trin. xii, 3): "When we come across anything that is not common to us and the beasts of the field, it is something appertaining to the mind." But there are virtues even of the irrational parts; as the Philosopher says (Ethic. iii, 10). Every virtue, therefore, is not a good quality "of the mind."
Obj. 4: Further, righteousness seems to belong to justice; whence the righteous are called just. But justice is a species of virtue. It is therefore unsuitable to put "righteous" in the definition of virtue, when we say that virtue is that "by which we live righteously."
Obj. 5: Further, whoever is proud of a thing, makes bad use of it. But many are proud of virtue, for Augustine says in his Rule, that "pride lies in wait for good works in order to slay them." It is untrue, therefore, "that no one can make bad use of virtue."