The strength of the Constitution lies entirely in the determination of each citizen to defend it. Only if every single citizen feels duty bound to do his share in this defense are the constitutional rights secure.

Subtle is the Lord. Malicious, He is not.

If you want to find out anything from the theoretical physicists about the methods they use, I advise you to stick closely to one principle: don't listen to their words, fix your attention on their deeds. To him who is a discoverer in this field the products of his imagination appear so necessary and natural that he regards them, and would like to have them regarded by others, not as creations of thought but as given realities.

Music has no effect on research work, but both are born of the same source and complement each other through the satisfaction they bestow

One cannot learn so well as by experiencing it oneself.

Germany had the misfortune of becoming poisoned, first because of plenty, and then because of want.

Do not grow old, no matter how long you live. Never cease to stand like curious children before the Great Mystery into which we were born.