Algebra is the intellectual instrument which has been created for rendering clear the quantitative aspects of the world.

I regret that it has been necessary for me in this lecture to administer a large dose of four-dimensional geometry. I do not apologize, because I am really not responsible for the fact that nature in its most fundamental aspect is four-dimensional. Things are what they are.

The safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato.

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.

In all education the main cause of failure is staleness.

Identification of rhythm as the casual counterpart of life; wherever there is some life, only perceptible to us when the analogies are sufficiently close.

Learning is often spoken of as if we are watching the open pages of all the books which we have ever read, and then, when occasion arises, we select the right page to read aloud to the universe.