Out of the crooked timber of humanity, no straight thing was ever made.

Out of timber so crooked as that from which man is made nothing entirely straight can be carved.

What can I know? What ought I to do? What can I hope?

By a lie, a man... annihilates his dignity as a man.

Morality is not the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.

Always recognize that human individuals are ends, and do not use them as means to your end.