A country cannot simultaneously prepare and prevent war.

Laws alone can not secure freedom of expression; in order that every man present his views without penalty there must be spirit of tolerance in the entire population.

Only six men in the world know about relativity. I am not one of them. When I ask them to explain, they confused me.

He who finds though that lets us penetrate even a little deeper into the eternal mystery of nature has been granted great grace. He who, in addition, experiences the recognition, sympathy, and help of the best minds of his times, had been given almost more happiness than one man can bear.

Once we accept our limits, we go beyond them.

Gradually the conviction gained recognition that all knowledge about things is exclusively a working-over of the raw material furnished by the senses. ... Galileo and Hume first upheld this principle with full clarity and decisiveness.

In matters of truth and justice, there is no difference between large and small problems, for issues concerning the treatment of people are all the same.