The soul should concentrate itself by itself.

But of the heaven which is above the heavens, what earthly poet ever did or ever will sing worthily?

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.

Better a good enemy than a bad friend.

Mathematics is the language in which the gods talk to people.

May I do to others as I would that they should do unto me.

It behooves those who take the young to task to leave them room for excuse, lest they drive them to be hardened by too much rebuke.