Of all the things which a man has, next to the gods his soul is the most divine and most truly his own.

The first step in learning is the destruction of human conceit.

Attention to health is life greatest hindrance.

If we are to keep our flock at the highest pitch of excellence, there should be as many unions of the best of both sexes, and as few of the inferior as possible, and that only the offspring of the better unions should be kept.

. . . Then anyone who leaves behind him a written manual, and likewise anyone who receives it, in the belief that such writing will be clear and certain, must be exceedingly simple-minded. . . .

A wise man speaks because he has something to say; a fool because he has to say something.

Those who have a natural talent for calculation are generally quick-witted at every other kind of knowledge; and even the dull, if they have had an arithmetical training, although they may derive no other advantage from it, always become much quicker than they would have been.