thus contains two constituents, reason and appetite. Both must be
present. There must be passions, if they are to be controlled. Hence
the ascetic ideal of rooting out the passions altogether is
fundamentally wrong. It overlooks the fact that the higher form does
not exclude the lower--that were contrary to the conception of
evolution--it includes and transcends it. It forgets that the passions
are an organic part of man, and that to destroy them is to do injury
to his {318} nature by destroying one of its essential members. The
passions and appetites are, in fact, the matter of virtue, reason its
form, and the mistake of asceticism is that it destroys the matter of
virtue, and supposes that the form can subsist by itself. Virtue means
that the appetites must be brought under control, not that they must
be eradicated. Hence there are two extremes to be avoided. It is
extreme, on the one hand, to attempt to uproot the passions; and it is
extreme, on the other, to allow them to run riot. Virtue means
moderation. It consists in hitting the happy mean as regards the
passions, in not allowing them to get the upper hand of reason, and
yet in not being quite passionless and apathetic. From this follows
the famous Aristotelian doctrine of virtue as the mean between two
extremes. Every virtue lies between two vices, which are the excess
and defect of appetite respectively.

What is the criterion here? Who is to judge? How are we to know what
is the proper mean in any matter? Mathematical analogies will not help
us. It is not a case of drawing a straight line from one extreme to
the other, and finding the middle point by bisection. And Aristotle
refuses to lay down any rule of thumb in the matter. There is no
golden rule by virtue of which we can tell where the proper mean is.
It all depends on circumstances, and on the person involved. What is
the proper mean in one case is not the proper mean in another. What is
moderate for one man is immoderate for his neighbour. Hence the matter
must be left to the good judgment of the individual. A sort of fine
tact, good sense, is required to know the mean, which Aristotle calls
"insight." This insight is both the cause and the {319} effect of
virtue. It is the cause, because he who has it knows what he ought to
do. It is the effect, because it is only developed by practice. Virtue
renders virtue easy. Each time a man, by use of his insight, rightly
decides upon the mean, it becomes easie