Good breeding in cattle depends on physical health, but in men on a well-formed character.

Life unexamined, is not worth living.

No power and no treasure can outweigh the extension of our knowledge.

Everything existing in the universe is the fruit of chance and necessity.

One should practice much sense, not much learning.

Medicine heals diseases of the body, wisdom frees the soul from passions.

Nothing exists except atoms and empty space; everything else is opinion.