Whatever we learn to do, we learn by actually doing it; men come to be builders, for instance, by building, and harp players by playing the harp. In the same way, by doing just acts we come to be just; by doing self-controlled acts, we come to be self-controlled ; and by doing brave acts, we become brave.
Happiness does not consist in amusement. In fact, it would be strange if our end were amusement, and if we were to labor and suffer hardships all our life long merely to amuse ourselves.... The happy life is regarded as a life in conformity with virtue. It is a life which involves effort and is not spent in amusement.
... the friendship of worthless people has a bad effect (because they take part, unstable as they are, in worthless pursuits, and actually become bad through each other's influence). But the friendship of the good is good, and increases in goodness because of their association. They seem even to become better men by exercising their friendship and improving each other; for the traits that they admire in each other get transferred to themselves.
All men by nature desire to know. An indication of this is the delight we take in our senses; for even apart from their usefulness they are loved for themselves...