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.

As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality.

The man of science is a poor philosopher.

Nonsense, seems to sum up everything.

The years of searching in the dark for a truth that one feels but cannot express, the intense desire and the alternations of confidence and misgiving until one breaks through to clarity and understanding, are known only to him who has experienced them himself.

Only the Catholic Church protested against the Hitlerian onslaught on liberty. Up till then I had not been interested in the Church, but today I feel a great admiration for the Church, which alone has had the courage to struggle for spiritual truth and moral liberty

In my personal experience I have hardly come to know the wretchedness of mankind better than as a result of the general theory of relativity and everything connected to it. But it doesn't bother me.