People do not naturally become morally excellent or practically wise. They become so, if at all, only as the result of lifelong personal and community effort.
Most men appear to think that the art of despotic government is statesmanship, and what men affirm to be unjust and inexpedient in their own case they are not ashamed of practicing towards others; they demand just rule for themselves, but where other men are concerned they care nothing about it. Such behavior is irrational; unless the one party is, and the other is not, born to serve, in which case men have a right to command, not indeed all their fellows, but only those who are intended to be subjects; just as we ought not to hunt mankind, whether for food or sacrifice . .
When you have thrown a stone, you cannot afterwards bring it back again, but nevertheless you are responsible for having taken up the stone and flung it, for the origin of the act was within you. Similarly the unjust and profligate might at the outset have avoided becoming so, and therefore they are so voluntarily, although when they have become unjust and profligate it is no longer open to them not to be so.
But the virtues we get by first exercising them, as also happens in the case of the arts as well. For the things we have to learn before we can do them, we learn by doing them, e.g. men become builders by building and lyre players by playing the lyre; so too we become just by doing just acts, temperate by doing temperate acts, brave by doing brave acts.
The investigation of the truth is in one way hard, in another easy. An indication of this is found in the fact that no one is able to attain the truth adequately, while, on the other hand, no one fails entirely, but everyone says something true about the nature of all things, and while individually they contribute little or nothing to the truth, by the union of all a considerable amount is amassed.
Friends hold a mirror up to each other; through that mirror they can see each other in ways that would not otherwise be accessible to them, and it is this mirroring that helps them improve themselves as persons.