Men who are unhappy, like men who sleep badly, are always proud of the fact.

Mathematics, rightly viewed, possesses not only truth, but supreme beauty a beauty cold and austere, like that of sculpture, without appeal to any part of our weaker nature, without the georgeous trappings of painting or music, yet sublimely pure, and capable of a stern perfection such as only the greatest art can show. The true spirit of delight, the exaltation, the sense of being more than Man, which is the touchstone of the highest excellence, is to be found in mathematics as surely as in poetry.

Conquer the world by intelligence, and not merely by being slavishly subdued by the terror that comes from it.

I must, before I die, find some way to say the essential thing that is in me, that I have never said yet -- a thing that is not love or hate or pity or scorn, but the very breath of life, fierce and coming from far away, bringing into human life the vastness and the fearful passionless force of non-human things.

All knowledge, we feel, must be built up upon our instinctive beliefs; and if these are rejected, nothing is left.

War grows out of ordinary human nature.

Whatever we know without inference is mental.