A theory is the more impressive the greater is the simplicity of its premises, the more different are the kinds of things it relates and the more extended the range of its applicability.

The truth isn't always a blinding light. Sometimes it's a deep and dazzling darkness, that illuminates - and burns - just as surely.

Never let yourself be seduced by any problem, no matter how difficult.

Everything is determined, the beginning as well as the end, by forces over which we have no control. It is determined for the insect, as well as for the star. Human beings, vegetables, or cosmic dust, we all dance to a mysterious tune, intoned in the distance by an invisible piper.

I don't know what weapons will be used in the Third World War. But I can tell you what they'll use in the Fourth - rocks!

I assert that the cosmic religious experience is the strongest and the noblest driving force behind scientific research.

Concepts that have proven useful in ordering things easily achieve such authority over us that we forget their earthly origins and accept them as unalterable givens.