Imagination is not to be divorced from the facts. It is a way of illuminating the facts.

Common sense is genius in homespun.

We must produce a great age, or see the collapse of the upward striving of our race.

Mathematics as a science, commenced when first someone, probably a Greek, proved propositions about "any" things or about "some" things, without specifications of definite particular things.

Nature is probably quite indifferent to the aesthetic preferences of mathematicians.

The vigor of civilized societies is preserved by the widespread sense that high aims are worth-while.

It does not matter what men say in words, so long as their activities are controlled by settled instincts. The words may ultimately destroy the instincts; but until this has occurred, words do not count.