Observe that open loves are held to be more honourable than secret ones, and that the love of the noblest and highest, even if their persons are less beautiful than others, is especially honourable.

The essence of knowledge is self-knowledge.

Let no one destitute of geometry enter my doors.

He who is gracious to his lover under the impression that he is rich, and is disappointed of his gains because he turns out to be poor, is disgraced all the same: for he has done his best to show that he would give himself up to any one's "uses base" for the sake of money; but this is not honourable.

Beauty of style and harmony and grace and good rhythm depend on simplicity - I mean the true simplicity of a rightly and nobly ordered mind and character, not that other simplicity which is only a euphemism for folly.

For just as poets love their own works, and fathers their own children, in the same way those who have created a fortune value their money, not merely for its uses, like other persons, but because it is their own production. This makes them moreover disagreeable companions, because they will praise nothing but riches.

The cause of all sins in every case lies in the person's excessive love of self.