Teenagers these days are out of control. They eat like pigs, they are disrespectful of adults, they interrupt and contradict their parents, and they terrorize their teachers.

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).

Our characters are the result of our conduct.

While most of those who hold that the whole heaven is finite say that the earth lies at the center, the philosophers of Italy, the so-called Pythagoreans, assert the contrary. They say that in the middle there is fire, and that the earth is one of the stars, and by its circular motion round the center produces night and day.

Democracy arose from men's thinking that if they are equal in any respect they are equal absolutely.

The excellence of a thing is related to its proper function.

Think as wise men do, but speak as the common people do.