The highest form of pure thought is in mathematics.

Let us describe the education of our men. What then is the education to be? Perhaps we could hardly find a better than that which the experience of the past has already discovered, which consists, I believe, in gymnastic, for the body, and music for the mind.

Until philosophers rule as kings or those who are now called kings and leading men genuinely and adequately philosophise, that is, until political power and philosophy entirely coincide, while the many natures who at present pursue either one exclusively are forcibly prevented from doing so, cities will have no rest from evils,... nor, I think, will the human race.

It gives me great pleasure to converse with the aged. They have been over the road that all of us must travel, and know where it is rough and difficult and where it is level and easy.

Madness, provided it comes as the gift of heaven, is the channel by which we receive the greatest blessings... the men of old who gave things their names saw no disgrace or reproach in madness; otherwise they would not have connected it with the name of the noblest of arts, the art of discerning the future, and called it the manic art... So, according to the evidence provided by our ancestors, madness is a nobler thing than sober sense... madness comes from God, whereas sober sense is merely human.

You may be sure, dear Crito, that inaccurate language is not only in itself a mistake: it implants evil in men's souls.

And all knowledge, when separated from justice and virtue, is seen to be cunning and not wisdom; wherefore make this your first and last and constant and all-absorbing aim, to exceed, if possible, not only us but all your ancestors in virtue; and know that to excel you in virtue only brings us shame, but that to be excelled by you is a source of happiness to us.