Book 6: The Intellectual Virtues.
Chapter 13: How prudence is related to moral virtue
This suggests a further consideration of moral virtue; for the case is closely analogous to this—I mean that just as prudence is related to cleverness, being not identical with it, but closely akin to it, so is fully developed moral virtue related to natural virtue.
All admit that in a certain sense the several kinds of character are bestowed by nature. Justice, a tendency to temperance, courage, and the other types of character are exhibited from the moment of birth. Nevertheless, we look for developed goodness as something different from this, and expect to find these same qualities in another form. For even in children and brutes these natural virtues are present, but without the guidance of reason they are plainly hurtful. So much at least seems to be plain—that just as a strong-bodied creature devoid of sight stumbles heavily when it tries to move, because it cannot see, so is it with this natural virtue; but when it is enlightened by reason it acts surpassingly well; and the natural virtue (which before was only like virtue) will then be fully developed virtue.
We find, then, that just as there are two forms of the calculative faculty, viz. cleverness and prudence, so there are two forms of the moral qualities, viz. natural virtue and fully developed virtue, and that the latter is impossible without prudence.
On this account some people say that all the virtues are forms of prudence, and in particular Socrates held this view, being partly right in his inquiry and partly wrong—wrong in thinking that all the virtues are actually forms of prudence, but right in saying that they are impossible without prudence.
This is corroborated by the fact that nowadays every one in defining virtue would, after specifying its field, add that it is a formed faculty or habit in accordance with right reason, “right” meaning “in accordance with prudence.”
Thus it seems that every one has a sort of inkling that a formed habit or character of this kind (i.e. in accordance with prudence) is virtue.
Only a slight change is needed in this expression. Virtue is not simply a formed habit in accordance with right reason, but a formed habit implying right reason. But right reason in these matters is prudence.
So whereas Socrates held that the [moral] virtues are forms of reason (for he held that these are all modes of knowledge), we hold that they imply reason.
It is evident, then, from what has been said that it is impossible to be good in the full sense without prudence, or to be prudent without moral virtue. And in this way we can meet an objection which may be urged. “The virtues,” it may be said, “are found apart from each other; a man who is strongly predisposed to one virtue has not an equal tendency towards all the others, so that he will have acquired this virtue while he still lacks that.” We may answer that though this may be the case with the natural virtues, yet it cannot be the case with those virtues for which we call a man good without any qualifying epithet. The presence of the single virtue of prudence implies the presence of all the moral virtues.
And thus it is plain, in the first place, that, even if it did not help practice, we should yet need prudence as the virtue or excellence of a part of our nature; and, in the second place, that purpose cannot be right without both prudence and moral virtue; for the latter makes us desire the end, while the former makes us adopt the right means to the end.
Nevertheless, prudence is not the mistress of wisdom and of the better part of our nature [the reason], any more than medicine is the mistress of health. Prudence does not employ wisdom in her service, but provides means for the attainment of wisdom—does not rule it, but rules in its interests. To assert the contrary would be like asserting that statesmanship rules the gods, because it issues orders about all public concerns [including the worship of the gods.]