No endeavor that is worthwhile is simple in prospect; if it is right, it will be simple in retrospect.

Physics without mathematics is meaningless.

A fact is a simple statement that everyone believes. It is innocent, unless found guilty. A hypothesis is a novel suggestion that no one wants to believe. It is guilty, until found effective.

Had we not pursued the hydrogen bomb, there is a very real threat that we would now all be speaking Russian. I have no regrets.

The extinction of the human race will come from its inability to EMOTIONALLY comprehend the exponential function.

Secrecy, once accepted, becomes an addiction.

[Chemistry] laboratory work was my first challenge. ... I still carry the scars of my first discovery-that test-tubes are fragile.