I know what it's like to see one's mother go through the agony of death and be unable to help; there is no consolation. We all have to bear such heavy burdens, for they are unalterably linked to life.

Man owes his strength in the struggle for existence to the fact that he is a social animal.

A country cannot simultaneously prepare and prevent war. I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones. The distinctions separating the social classes are false; in the last analysis they rest on force.

Intelligent life on other planets? I'm not even sure there is on earth!

This is a question too difficult for a mathematician. It should be asked of a philosopher"(when asked about completing his income tax form)

The most difficult part about understanding something is that we understand it all.

Outer changes always begin with an inner change of attitude.