But although all our knowledge begins with experience, it does not follow that it arises from experience.

For how is it possible, says that acute man, that when a concept is given me, I can go beyond it and connect with it another which is not contained in it, in such a manner as if that latter necessarily belonged to the former?

Always treat people as ends in themselves, never as means to an end.

It is by his activities and not by enjoyment that man feels he is alive. In idleness we not only feel that life is fleeting, but we also feel lifeless.

Two things strike me dumb: the infinite starry heavens, and the sense of right and wrong in man.

All trades, arts, and handiworks have gained by division of labor... Where the different kinds of work are not distinguished and divided, where everyone is a jack-of-all-trades, there manufactures remain still in the greatest barbarism.

Rules for Happiness: something to do, someone to love, something to hope for.