All professional men are handicapped by not being allowed to ignore things which are useless.

Thought expands, but paralyzes; action animates, but narrows.

The thinking person has the strange characteristic to like to create a fantasy in the place of the unsolved problem, a fantasy that stays with the person even when the problem has been solved and truth made its appearance.

One lives but once in the world.

I have heard myself accused of being an opponent, an enemy of mathematics, which no one can value more highly than I, for it accomplishes the very thing whose achievement has been denied me.

The sea is flowing ever, The land retains it never.

God could cause us considerable embarrassment by revealing all the secrets of nature to us: we should not know what to do for sheer apathy and boredom.