The worst that happened to men of science was that Galileo suffered an honorable detention and a mild reproof, before dying peacefully in his bed.

The whole of mathematics consists in the organization of a series of aids to the imagination in the process of reasoning.

Ideas won't keep. Something must be done about them.

Education which is not modern share the fate of all organic things which are kept too long.

Order is not sufficient. What is required, is something much more complex. It is order entering upon novelty; so that the massiveness of order does not degenerate into mere repetition; and so that the novelty is always reflected upon a background of system.

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

The difference between ancients and moderns is that the ancients asked what have we experienced, and moderns asked what can we experience.