The science of pure mathematics, in its modern developments, may claim to be the most original creation of the human spirit.

But you can catch yourself entertaining habitually certain ideas and setting others aside; and that, I think, is where our personal destinies are largely decided.

You cannot be wise without some basis of knowledge, but you may easily acquire knowledge and remain bare of wisdom.

War can protect; it cannot create.

Religion is what the individual does with his own solitariness.

Art flourishes where there is a sense of adventure.

Fundamental progress has to do with the reinterpretation of basic ideas.