"Not to be absolutely certain is, I think, one of the essential things in rationality."

"Everything is vague to a degree you do not realize till you have tried to make it precise."

"Patriots always talk of dying for their country and never of killing for their country."

"Sin is geographical."

"The human race may well become extinct before the end of the century."

"We have, in fact, two kinds of morality side by side: one which we preach but do not practice, and another which we practice but seldom preach."

"Nothing endures but personal qualities."

"I know of no way to judge the future but by the past."

"The revolution is not an apple that falls when it is ripe. You have to make it fall."

"The cowards never start and the weak die along the way."

"His mother should have thrown him away and kept the stork."

"Show me a man who has enjoyed his school days and I'll show you a bully and a bore."