I have only two rules which I regard as principles of conduct. The first is: Have no rules. The second is: Be independent of the opinion of others.

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.

When you sit with a nice girl for two hours, it seems like two minutes; when you sit on a hot stove for two minutes, it seems like two hours. That's relativity.

Every serious scientific worker is painfully conscious of this involuntary relegation to an ever-narrowing sphere of knowledge, which threatens to deprive the investigator of his broad horizon and degrades him to the level of a mechanic.

When I study philosophical works I feel I am swallowing something which I don't have in my mouth.

Nothing will end war unless the peoples themselves refuse to go to war.

The woman who follows the crowd will usually believe that I said this.