Excellence is an art won by training and habituation. We do not act rightly because we have virtue or excellence, but we rather have those because we have acted rightly. We are what we repeatedly do. Excellence, then, is not an act but a habit.
And inasmuch as the great-souled man deserves most, he must be the best of men; for the better a man is the more he deserves, and he that is best deserves most. Therefore the truly great-souled man must be a good man. Indeed greatness in each of the virtues would seem to go with greatness of soul.
Now the goodness that we have to consider is clearly human goodness, since the good or happiness which we set out to seek was human good and human happiness. But human goodness means in our view excellence of soul, not excellence of body.
It is evident, then, that there is a sort of education in which parents should train their sons, not as being useful or necessary, but because it is liberal or noble.
It is clear that those constitutions which aim at the common good are right, as being in accord with absolute justice; while those which aim only at the good of the rulers are wrong.
The same things are best both for individuals and for states, and these are the things which the legislator ought to implant in the minds of his citizens.
There are, then, three states of mind ... two vices--that of excess, and that of defect; and one virtue--the mean; and all these are in a certain sense opposed to one another; for the extremes are not only opposed to the mean, but also to one another; and the mean is opposed to the extremes.