The individual must not merely wait and criticize, he must defend the cause the best he can. The fate of the world will be such as the world deserves.

I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones.

I never think of the future. It comes soon enough.

The secret to creativity is knowing how to hide your sources.

No amount of experimentation can ever prove me right; a single experiment can prove me wrong.

The most beautiful thing we can experience is the mysterious. It is the source of all true art and all science. He to whom this emotion is a stranger, who can no longer pause to wonder and stand rapt in awe, is as good as dead: his eyes are closed.

Teaching should be such that what is offered is perceived as a valuable gift and not as a hard duty.