The proof that you know something is that you are able to teach it

...virtue is not merely a state in conformity with the right principle, but one that implies the right principle; and the right principle in moral conduct is prudence.

Where the laws are not supreme, there demagogues spring up.

All food must be capable of being digested, and that what produces digestion is warmth; that is why everything that has soul in it possesses warmth.

A man's happiness consists in the free exercise of his highest faculties.

It is possible to fail in many ways . . . while to succeed is possible only in one way (for which reason also one is easy and the other difficult - to miss the mark easy, to hit it difficult).

Learning is not child's play; we cannot learn without pain.