"The modern world is so organized that if you are a decent human being, you are bound to be unhappy."

"What men want is not knowledge but certainty."

"If a man is to be happy, he must not only be free from the fear of death, but from the fear of life."

"I am not interested in the universe as a mere collection of facts, but as a system of relations."

"The child thus comes to the conclusion that parents are apt to lie to him. If they lie in one matter, they may lie in another, so that their moral and intellectual authority is destroyed."