While I am a convinced pacifist there are circumstances in which I believe the use of force is appropriate - namely, in the face of an enemy unconditionally bent on destroying me and my people.

Imagination is more powerful than knowledge.

My interest in science was always essentially limited to the study of principles.... That I have published so little is due to this same circumstance, as the great need to grasp principles has caused me to spend most of my time on fruitless pursuits.

I believe that Gandhi’s views were the most enlightened of all the political men in our time. We should strive to do things in his spirit: not to use violence in fighting for our cause, but by non-participation in anything you believe is evil.

A clever person solves a problem. A wise person avoids it.

As far as I'm concerned, I prefer silent vice to ostentatious virtue.

Knowledge of what is does not open the door directly to what should be.