Civilizations can only be understood by those who are civilized.

No one who achieves success does so without acknowledging the help of others. The wise and confident acknowledge this help with gratitude.

A Unitarian is a person who believes in at most one God.

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.

You think the world is what it looks like in fine weather at noon day; I think it is what it seems like in the early morning when one first wakes from deep sleep.

It must be admitted that there is a degree of instability which is inconsistent with civilization. But, on the whole, the great ages have been unstable ages.

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