Men regard it as their right to return evil for evil and, if they cannot, feel they have lost their liberty.

Those who act receive the prizes.

Doubt is the beginning of wisdom

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).

To learn is a natural pleasure, not confined to philosophers, but common to all men.

We, on the other hand, must take for granted that the things that exist by nature are, either all or some of them, in motion.

Every rascal is not a thief, but every thief is a rascal.