There are two principles inherent in the very nature of things, recurring in some particular embodiments whatever field we explore - the spirit of change, and the spirit of conservation. There can be nothing real without both. Mere change without conservation is a passage from nothing to nothing. . . . Mere conservation without change cannot conserve. For after all, there is a flux of circumstance, and the freshness of being evaporates under mere repetition.

There is no nature at an instant.

I am also greatly indebted to Bergson, William James, and John Dewey. One of my preoccupations has been to rescue their type of thought from the charge of anti-intellectualism, which rightly or wrongly has been associated with it.

The real history does not get written, because it is not in people's brains but in their nerves and vitals.

Learning preserves the errors of the past as well as its wisdom.

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

Everything of importance has been said before by somebody who did not discover it.