The Complete Aristotle (eng.)

self-indulgent relatively to the insensible
man, insensible relatively to the self-indulgent, and the liberal
man prodigal relatively to the mean man, mean relatively to the
prodigal. Hence also the people at the extremes push the
intermediate man each over to the other, and the brave man is
called rash by the coward, cowardly by the rash man, and
correspondingly in the other cases.
    These states being thus opposed to one another, the greatest
contrariety is that of the extremes to each other, rather than to
the intermediate; for these are further from each other than from
the intermediate, as the great is further from the small and the
small from the great than both are from the equal. Again, to the
intermediate some extremes show a certain likeness, as that of
rashness to courage and that of prodigality to liberality; but the
extremes show the greatest unlikeness to each other; now contraries
are defined as the things that are furthest from each other, so
that things that are further apart are more contrary.
    To the mean in some cases the deficiency, in some the excess is
more opposed; e.g. it is not rashness, which is an excess, but
cowardice, which is a deficiency, that is more opposed to courage,
and not insensibility, which is a deficiency, but self-indulgence,
which is an excess, that is more opposed to temperance. This
happens from two reasons, one being drawn from the thing itself;
for because one extreme is nearer and liker to the intermediate, we
oppose not this but rather its contrary to the intermediate. E.g.
since rashness is thought liker and nearer to courage, and
cowardice more unlike, we oppose rather the latter to courage; for
things that are further from the intermediate are thought more
contrary to it. This, then, is one cause, drawn from the thing
itself; another is drawn from ourselves; for the things to which we
ourselves more naturally tend seem more contrary to the
intermediate. For instance, we ourselves tend more naturally to
pleasures, and hence are more easily carried away towards
self-indulgence than towards propriety. We describe as contrary to
the mean, then, rather the directions in which we more often go to
great lengths; and therefore self-indulgence, which is an excess,
is the more contrary to temperance.
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9
    That moral virtue is a mean, then, and in what sense it is so,
and that it is a mean between two vices, the one involving excess,
the other deficiency, and that it is such because its character is
to aim at what is intermediate in passions and in actions, has been
sufficiently stated. Hence also it is no easy task to be good. For
in everything it is no easy task to find the middle, e.g. to find
the middle of a circle is not for every one but for him who knows;
so, too, any one can get angry—that is easy—or give or spend money;
but to do this to the right person, to the right extent, at the
right time, with the right motive, and in the right way, that is
not for every one, nor is it easy; wherefore goodness is both rare
and laudable and noble.
    Hence he who aims at the intermediate must first depart from
what is the more contrary to it, as Calypso advises
Hold the ship out beyond that surf and spray.
    For of the extremes one is more erroneous, one less so;
therefore, since to hit the mean is hard in the extreme, we must as
a second best, as people say, take the least of the evils; and this
will be done best in the way we describe. But we must consider the
things towards which we ourselves also are easily carried away; for
some of us tend to one thing, some to another; and this will be
recognizable from the pleasure and the pain we feel. We must drag
ourselves away to the contrary extreme; for we shall get into the
intermediate state by drawing well away from error, as people do in
straightening sticks that are bent.
    Now in everything the pleasant or pleasure is most to be guarded
against; for we do not judge it impartially. We ought, then, to
feel towards pleasure as the elders of the people felt towards
Helen, and in all circumstances repeat their saying; for if we
dismiss pleasure thus we are less likely to go astray. It is by
doing this, then, (to sum the matter up) that we shall best be able
to hit the mean.
    But this is no doubt difficult, and especially in individual
cases; for or is not easy to determine both how and with whom and
on what provocation and how long one should be angry; for we too
sometimes praise those who fall short