But nature did not deem it her business to make the discovery of her laws easy for us.

The creative principle [of science] resides in mathematics.

Imagination encircles the world.

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.

The man who regards his own life and that of his fellow-creatures as meaningless is not merely unfortunate but almost disqualified for life.

The difference between what the most and the least learned people know is inexpressibly trivial in relation to that which is unknown.

I shall never believe that God plays dice with the world.