No one punishes the evil-doer under the notion, or for the reason, that he has done wrong -- only the unreasonable fury of a beast acts in that way. But he who desires to inflict rational punishment does not retaliate for a past wrong, for that which is done cannot be undone, but he has regard to the future, and is desirous that the man who is punished, and he who sees him punished, may be deterred from doing wrong again.
True opinions are a fine thing and do all sorts of good so long as they stay in their place; but they will not stay long. They run away from a man's mind, so they are not worth much until you tether them by working out the reason. Once they are tied down, they become knowledge, and are stable.
.. we shall not be properly educated ourselves, nor will the guardians whom we are training, until we can recognise the qualities of discipline, courage, generosity, greatness of mind, and others akin to them, as well as their opposites in all their manifestations.
Do you, like a skilful weigher, put into the balance the pleasures and the pains, near and distant, and weigh them, and then say which outweighs the other? If you weigh pleasures against pleasures, you of course take the more and greater; or if you weigh pains against pains, then you choose that course of action in which the painful is exceeded by the pleasant, whether the distant by the near or the near by the distant; and you avoid that course of action in which the pleasant is exceeded by the painful.
'That is the story. Do you think there is any way of making them believe it?'
' Not in the first generation', he said, 'but you might succeed with the second and later generations.'
And tell him it's quite true that the best of the philosophers are of no use to their fellows; but that he should blame, not the philosophers, but those who fail to make use of them.
Moderation, which consists in indifference about little things, and in a prudent and well-proportioned zeal about things of importance, can proceed from nothing but true knowledge, which has its foundation in self-acquaintance.
In things which we know, everyone will trust us ... and we may do as we please, and no one will like to interfere with us; and we are free, and masters of others; and these things will be really ours, for we shall turn them to our good.