The mere formulation of a problem is far more essential than its solution, which may be merely a matter of mathematical or experimental skills. To raise new questions, new possibilities, to regard old problems from a new angle requires creative imagination and marks real advances in science.

One feels the insignificance of the individual, and it makes one happy.

You cannot simultaneously prevent and prepare for war.

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.

Marvellous, what ideas the young people have these days. But I don't believe a word of it.

The faster you go, the shorter you are.

I have come to know the mutability of all human relationships and have learned to insulate myself against both heat and cold so that a temperature balance is fairly well assured.