A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty.

Mathematicians are like Frenchmen: whatever you say to them they translate into their own language and forthwith it is something entirely different.

If something cannot go on forever, it will stop.

Mathematics requires a small dose, not of genius, but of an imaginative freedom which, in a larger dose, would be insanity.

Chess is not only a game — it is a battle of characters!