Virtue is the desire of things honourable and the power of attaining them.

The essence of knowledge is self-knowledge.

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.

Arithmetic is a kind of knowledge in which the best natures should be trained, and which must not be given up.

Those wretches who never have experienced the sweets of wisdom and virtue, but spend all their time in revels and debauches, sink downward day after day, and make their whole life one continued series of errors.

Ignorance is the root cause of all difficulties.

... the community suffers nothing very terrible if its cobblers are bad and become degenerate and pretentious; but if the Guardians of its laws and constitution, who alone have the opportunity to bring it good government and prosperity, become a mere sham, then clearly it is completely ruined.