Without adventure civilization is in full decay.

Seek simplicity, and distrust it.

It is more important that a proposition be interesting than that it be true.

For successful education there must always be a certain freshness in the knowledge dealt with. It must be either new in itself or invested with some novelty of application to the new world of new times. Knowledge does not keep any better than fish. You may be dealing with knowledge of the old species, with some old truth; but somehow it must come to the students, as it were, just drawn out of the sea and with the freshness of its immediate importance.

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

Religion is what a person does in his solitariness.

Religion will not regain its old power until it can face change in the same spirit as does science.