Summa summae S. Thomae, Tomus II

[I. — The name virtue is derived from the substantive vis, which expresses fortitude, because the habits of the virtues make the soul strong, and each of their acts supposes some fortitude, without which it cannot be exercised. Sometimes virtus is taken for the very effect of an operative power, as Matth., VII, 22 : In thy name we have done many virtues. But here it is taken for a certain quality superadded to rational creature, whereby it comes to act promptly, easily and rightly.

Virtue is defined by Cicero, book II de Inventione : « A habit of mind consonant with nature in its manner and with reason. » True indeed it is that it is such a habit; but, as St. Aug. observes, book IV contra Julian. Pelagian., c. 3, n. 19, those who thus described virtue « knew not what is consonant with the nature of mortals to be freed and beatified. » He himself says, de Morib. Eccles. cathol., c. 6, that virtue is « a habit and as it were a quality of a wise soul, making the soul most good. » Whence came forth the following definition admitted by the Angelic Doctor¹ : « Virtue is a good quality of the mind, by which one lives rightly, which no one uses ill, which God works in us without us. » Thus the Holy Doctor defends it there: « That definition perfectly embraces the whole reason of virtue. For the perfect reason of anything is gathered from all its causes. Now the aforesaid definition embraces all the causes of virtue. For the formal cause of virtue, as of any thing whatever, is taken from its genus and difference, when it is called a good quality; for the genus of virtue is quality, but the difference good. Yet a more fitting definition would be if habit were put in place of quality, which is the proximate genus. Virtue however has no matter out of which, like the other accidents, but has matter about which, and matter in which, namely subject. And the matter about which is the object of virtue, which could not be put in the aforesaid definition, because through the object virtue is determined to species, whereas here is assigned the definition of virtue in common: whence the subject is put in place of material cause, when it is said that it is a good quality of the mind. — But the end of virtue, since it is an operative habit, is operation itself. But it must be noted that of operative habits some are always toward evil, as vicious habits, others indeed at one time toward good and at another time toward evil, as opinion stands to truth and falsity. Virtue however is a habit always standing toward good. And therefore, that virtue be distinguished from those things which always stand toward evil, it is said, by which one lives rightly; that however it be distinguished from those which stand at one time toward good, at another time toward evil, it is said, which no one uses ill. — But the efficient cause of infused virtue, of which the definition is given, is God. On which account it is said: Which God works in us without us. Which particle indeed, if it be taken away, the remainder of the definition will be common to all virtues both acquired and infused. »

From what has been said you will gather, 1° that virtue is essentially an operative habit of a good act².

That it is a habit, is clear; because habit in common is divided per se into virtue and vice; for by habits the powers of the rational soul are disposed, which stand indeterminately toward many things: if they be disposed fitly, it is virtue; if unfitly, vice³.

That it is an operative habit, also is clear; because virtue, from the very reason of the name, and as was said, imports a certain perfection of a power. Perfection added to any power conforms itself to it. Therefore, as rational powers are operative, so too are the virtues superadded to them⁴.

Finally, that it is an operative habit of a good act, equally is clear; because, since the rational powers are operative of acts, both in the genus of being and in the genus of morals, it must be that virtue, by which they are perfected, should attain both reasons, so as to be conformable to them. For, although a rational power can absolutely and of itself alone attain acts⁵ as to substance and morality, yet this it cannot do promptly, easily and readily; but through virtue it becomes prompt and ready toward both⁶. Of itself nevertheless and first it regards the acts' morality or goodness, secondarily their entity; because virtue is essentially in the genus of morals, since it is essentially ordered unto acting morally well.

You will gather 2° that power and virtue, in the reason of cause, are not placed in number, nor are several causes, but power is the cause and virtue the complement of the cause, whence together power rises into one complete cause. For, as I said, power can do without virtue what it can do with it (speaking of moral virtues in the natural order); but without virtue it can do this imperfectly only, incompletely and with difficulty, with virtue truly completely, easily and readily.

II. — Human virtue generically is divided into moral and intellectual. For human virtue, as was said, is an operative habit of a good act, or a habit perfecting man unto acting well. In man however the principle of acting is twofold, namely intellect or reason, and appetite. Therefore every human virtue is perfective either of reason or of appetite. If it be perfective of the intellect, whether speculative or practical, toward the good act of man, namely unto judging rightly, it will be intellectual virtue; if however it be perfective of the appetitive part, namely unto choosing rightly, it will be moral virtue⁷. Hence the Angelic Doctor rightly infers that moral virtue can indeed be without certain intellectual virtues, as without wisdom, knowledge and art, but not without intellect and prudence. For moral virtue is about election. Election however, that it be morally good, must be right, both as to the end convenient to reason, which cannot be without intellect judging rightly; and as to the means ordered to the end, which cannot be without prudence.

By moral virtue man is ordered unto morally good operation, which is its effect. But the operation itself can be considered as the matter about which moral virtue itself is concerned, and from this head the moral virtues are divided generically into virtues which are about actions and virtues which are about passions. « The reason of which, says St. Thomas, here q. 60, a. 2, o, is that good and evil in certain operations is regarded in themselves, however man be affected toward them, namely inasmuch as good and evil in them is taken according to the reason of commensuration to another. And in such there must be some virtue directive of operations in themselves, as buying and selling, and such-like operations, in which is regarded the reason of due or undue to another. And on this account justice and its parts are properly about operations as about proper matter. But in certain operations good and evil is regarded only according to commensuration to the agent; and therefore in these good and evil must be considered according as man is well or ill affected about suchlike. And on this account it must be that virtues in such are principally about interior affections, which are called passions of the soul: as is clear of temperance, fortitude and other suchlike. It happens however that in operations which are toward another the good of virtue is omitted on account of disordered passion of the soul, and then inasmuch as the commensuration of the exterior operation is corrupted, it is corruption of justice; inasmuch however as the commensuration of interior passions is corrupted, it is corruption of some other virtue: as, when through anger someone strikes another, in the very undue striking justice is corrupted, but in immoderateness of anger meekness is corrupted. And the same is clear in others. »

Thence is clear the nature of those virtues commonly called cardinal, and their number. Indeed, when we speak simply of virtue, human virtue is dealt with. Human virtue however, according to the perfect reason of virtue, is said to be that which requires rectitude of appetite. For such virtue not only makes faculty of acting well, but also causes the very use of the good work. But according to the imperfect reason of virtue, that is called virtue which does not require rectitude of appetite, because it only makes faculty of acting well, but does not cause use of a good work. It is established moreover that the perfect is more principal than the imperfect; and therefore those virtues which contain rectitude of appetite are called principal or cardinal. Suchlike however are the moral virtues, and among the intellectual prudence alone, which also in a certain way is moral, inasmuch as it is right reason of things doable⁸.

Four, as all know, are the cardinal virtues : prudence, justice, temperance and fortitude. The reason of this division is assigned by St. Thomas here a. 2, o : « The number, he says, of certain things can be taken either according to formal principles, or according to subjects, and in both ways four cardinal virtues are found. For the formal principle of the virtue of which we now speak is the good of reason. Which indeed can be considered in two ways: In one way according as it consists in the very consideration of reason; and thus there will be one principal virtue, which is called prudence. In another way, according as the order of reason is posited about something: and this either about operations, and thus it is justice; or about passions, and thus there must needs be two virtues. For the order of reason must needs be posited about passions, their repugnance to reason having been considered. Which indeed can be twofold: In one way, according as passion impels toward something contrary to reason; and thus passion must needs be repressed, and from this temperance is named. In another way, according as passion withdraws from that which reason dictates, as fear of dangers or labors ; and thus man must needs be firm in that which is of reason, lest he withdraw, and from this fortitude is named. — And likewise according to subjects the same number is found. Fourfold indeed is found the subject of this virtue of which we now speak, namely the rationale by essence, which prudence perfects, and the rationale by participation. Which is divided into three, that is, into the will, which is the subject of justice, and into the concupiscible, which is the subject of temperance, and into the irascible, which is the subject of fortitude. »

There are besides theological virtues, so called from their immediate object, which is God, as variously attained. But considered in themselves, according as they perfect the powers of human soul, they are reduced to moral and intellectual virtues. Of which there will be treated singly and fully in IIa IIae.]