"Kissing the hand of the Pope is not a sin, but to let him kiss your hand is a sin."

"The more you read and learn, the more you realize how little you know."

"The greatest fool is he who thinks he is wise."

"Faust complained about having two souls in his breast, but I harbor a whole legion."

"I grant that I am full of prejudices; I sucked them in with my mother's milk, and I cannot possibly argue them away."