First then let us assert that Wisdom and Prudence, being
as they are the virtues of the two parts of the intellect respectively, are necessarily
desirable in themselves, even if neither produces any effect.
Secondly, they do in fact produce an effect: Wisdom produces Happiness, not in the sense
in which medicine produces health, but in the sense in which healthiness is the cause of
health. For Wisdom is a part of Virtue as a whole, and therefore by its possession, or
rather by its exercise, renders a man happy.
Also Prudence as well as Moral Virtue determines the complete performance of man's proper
function: Virtue ensures the rightness of the end we aim at, Prudence ensures the
rightness of the means we adopt to gain that end.
（The fourth part1
of the soul on the other hand, the nutritive faculty, has no virtue
contributing to the proper function of man, since it has no power to act or not to
But we must go a little deeper into the objection that Prudence does not render men more
capable of performing noble and just actions. Let us start with the following
consideration. As some people, we maintain, perform just acts and yet are not just men
（for instance, those who do what the law enjoins but do it unwillingly, or in
ignorance, or for some ulterior object, and not for the sake of the actions themselves,
although they are as a matter of fact doing what they ought to do and all that a good man
should）, on the other hand it appears, there is a state of mind in which a man
may do these various acts with the result that he really is a good man: I mean when he
does them from choice, and for the sake of the acts
Now rightness in our choice of an end is
secured by Virtue3
; but to do
the actions that must in the nature of things be done in order to attain the end we have
chosen, is not a matter for Virtue but for a different faculty.
We must dwell on this point to make it more clear.
is a certain faculty called Cleverness, which is the capacity for doing the things
aforesaid that conduce to the aim we propose, and so attaining that aim. If the aim is
noble, this is a praiseworthy faculty: if base, it is mere knavery; this is how we come to
speak of both prudent men and knaves as clever.
faculty is not identical with Prudence, but Prudence implies it. But that eye of the soul
of which we spoke4
cannot acquire the quality of Prudence without possessing Virtue. This we have said
before, and it is manifestly true. For deductive inferences about matters of conduct
always have a major premise of the form ‘Since the End or Supreme Good is so and
so’ （whatever it may be, since we may take it as anything we like for
the sake of the argument）; but the Supreme Good only appears good to the good
man: vice perverts the mind and causes it to hold false views about the first principles
of conduct. Hence it is clear that we cannot be prudent without being good.