Since the branch of philosophy on which we are at present engaged differs from the others in not being a subject of merely intellectual interest — I mean we are not concerned to know what goodness essentially is, but how we are to become good men, for this alone gives the study its practical value — we must apply our minds to the solution of the problems of conduct.
A state is an association of similar persons whose aim is the best life possible. What is best is happiness, and to be happy is an active exercise of virtue and a complete employment of it.
Happiness is essentially perfect; so that the happy man requires in addition the goods of the body, external goods and the gifts of fortune, in order that his activity may not be impeded through lack of them.
The soul consists of two parts, one irrational and the other capable of reason. (Whether these two parts are really distinct in the sense that the parts of the body or of any other divisible whole are distinct, or whether though distinguishable in thought as two they are inseparable in reality, like the convex and concave of a curve, is a question of no importance for the matter in hand.)
Excellence, then, is a state concerned with choice, lying in a mean, relative to us, this being determined by reason and in the way in which the man of practical wisdom would determine it.
The Life of the intellect is the best and pleasantest for man, because the intellect more than anything else is the man. Thus it will be the happiest life as well.
When we look at the matter from another point of view, great caution would seem to be required. For the habit of lightly changing the laws is an evil, and, when the advantage is small, some errors both of lawgivers and rulers had better be left; the citizen will not gain so much by making the change as he will lose by the habit of disobedience.