For as the eyes of bats are to the blaze of day, so is the reason in our soul to the things which are by nature most evident of all.

To attain any assured knowledge about the soul is one of the most difficult things in the world.

Every art and every inquiry, and similarly every action and choice, is thought to aim at some good; and for this reason the good has rightly been declared to be that at which all things aim.

He who can be, and therefore is, another's, and he who participates in reason enough to apprehend, but not to have, is a slave by nature.

Every action must be due to one or other of seven causes: chance, nature, compulsion, habit, reasoning, anger, or appetite.

The eyes of some persons are large, others small, and others of a moderate size; the last-mentioned are the best. And some eyes are projecting, some deep-set, and some moderate, and those which are deep-set have the most acute vision in all animals; the middle position is a sign of the best disposition.