Virtue and Vice
These two words as used in everyday speech have acquired strange and even wrong meanings. The word "virtue," for example, is still often identified with a woman's chastity though with the advent of the women liberation movement, that strange meaning either has disappeared or will soon do so.
From a philosophical point of view, the words "virtue" and "vice" are definitely misused when they are used in the plural. Most people think that there are many virtues and vices, and that is possible for a person to be virtuous in certain respects, though not in others.
In the first place, we must distinguish between intellectual virtues (in the plural) and moral virtue (in the singular).
There are five intellectual virtues, three of them in the sphere of knowing (science, understanding,and wisdom) and two of them in the sphere of making and acting (skill and prudence). It is possible to have one or another of these intellectual virtues without having all of them. Prudence, which is sometimes called practical wisdom, is also one of the four cardinal aspects of moral virtue (temperance, courage or fortitude, justice, and prudence.)
Readers should note that I referred to the aforementioned aspects of moral virtue, not to them as if they were existentially separate virtues; as if we could be temperate without also being courageous, or as if we could be just without also being prudent.
The basic point here is that moral virtue is one habit -- a habit of right desire that has four distinct but existentially inseparable aspects. Moral virtue is acquired and formed by repeated morally good acts. But an individual who possesses the basis of moral virtue to any degree may commit morally wrong acts without losing his or her moral virtue. The habit may be weakened by such wrongful actions, if they are committed too frequently, just as it may be strengthened and fortified by repeated morally good acts.
Aristotle's Nicomachean Ethics is the only sound, practical, and undogmatic moral philosophy in which the pivotal notion is habit. It is a moral philosophy without rules.
Aristotle is the only philosopher who affirms the unity of moral virtue, and thus explains how moral virtue is at once self-regarding and other-regarding, at once selfish in its motivation and altruistic.
For our own good, our own happiness, we have to be temperate and courageous, and for the happiness of others, we have to be just in our habitual actions toward them. The other basic notions in Aristotle's ethics are real and apparent goods, needs, and wants (natural and acquired desires).
Adler's Philosophical Dictionary (1995)
Great Ideas from the Great Books (1963)
by Mortimer J. Adler