Dogmatism is the anti-Christ of learning.

The paradox is now fully established that the utmost abstractions are the true weapons with which to control our thought of concrete fact.

I always feel that I have two duties to perform with a parting guest: one, to see that he doesn't forget anything that is his; the other, to see that he doesn't take anything that is mine.

All practical teachers know that education is a patient process of mastery of details, minute by minute, hour by hour, day by day.

After you understand about the sun and the stars and the rotation of the earth, you may still miss the radiance of the sunset.

Without adventure civilization is in full decay.

It is the business of the future to be dangerous.