But the further question may be raised, What is the use of these intellectual virtues?
Wisdom does not consider the means to human happiness at all, for it does not ask how anything comes into existence. Prudence, it
must be granted, does do this; but what do we need it for? seeing that it studies that
which is just and noble and good for man, but these are the things that a good man does by
nature. Knowing about them does not make us any more capable of doing them, since the
virtues are qualities of character; just as is the case with the knowledge of what is
healthy and vigorous—using these words to mean not productive of health and
vigor but resulting from them: we are not rendered any more capable of healthy and
vigorous action by knowing the science of medicine or of physical training.
If on the other hand we are to say that Prudence is useful not in helping us to act
virtuously but in helping us to become virtuous, then it is of no use to those who are
virtuous already. Nor is it of any use either to those who are not, since we may just as
well take the advice of others who possess Prudence as possess Prudence ourselves. We may
be content to do as we do in regard to our health; we want to be healthy, yet we do not
Moreover it would seem strange if Prudence, which is inferior to Wisdom, is nevertheless
to have greater authority than Wisdom: yet the faculty that creates a thing1
governs and gives orders to it.
Let us now therefore discuss these difficulties, which so far have only been stated.
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 part2
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 Virtue4
; 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 spoke5
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.