When a scientist doesn't know the answer to a problem, he is ignorant. When he has a hunch as to what the result is, he is uncertain. And when he is pretty darn sure of what the result is going to be, he is still in some doubt. We have found it of paramount importance that in order to progress we must recognize our ignorance and leave room for doubt. Scientific knowledge is a body of statements of varying degrees of certainty - some most unsure, some nearly sure, but none absolutely certain.

If I could explain it to the average person, I wouldn't have been worth the Nobel Prize.

We absolutely must leave room for doubt or there is no progress and there is no learning. There is no learning without having to pose a question. And a question requires doubt. People search for certainty. But there is no certainty. People are terrified — how can you live and not know? It is not odd at all. You only think you know, as a matter of fact. And most of your actions are based on incomplete knowledge and you really don’t know what it is all about, or what the purpose of the world is, or know a great deal of other things. It is possible to live and not know.

But the real glory of science is that we can find a way of thinking such that the law is evident.

I, a universe of atoms, an atom in the universe.

Thank you very Much, I enjoyed myself

There was a time when the newspapers said that only twelve men understood the theory of relativity. I do not believe there ever was such a time ... On the other hand, I think I can safely say that nobody understands quantum mechanics.