Nothing happens until something moves.

We owe a lot to the Indians, who taught us how to count, without which no worthwhile scientific discovery could have been made.

If you do the same thing over and over again you cannot ever expect a different outcome.

It seems to me an utterly futile task to prescribe rules and limitations for the conduct of war. War is not a game; hence one cannot wage war by rules as one would in playing games. Our fight must be against war itself. The masses of people can most effectively fight the institution of war by establishing an organization for the absolute refusal of military service.

It is humankind's duty to respect all life, not only animals have feelings but even also trees and plants.

The theoretical idea ... does not arise apart from and independent of experience; nor can it be derived from experience by a purely logical procedure. It is produced by a creative act. Once a theoretical idea has been acquired, one does well to hold fast to it until it leads to an untenable conclusion.

Measured objectively, what a man can wrest from Truth by passionate striving is utterly infinitesimal. But the striving frees us from the bonds of the self and makes us comrades of those who are the best and the greatest.