But logic is not all, one needs one's heart to follow an idea.

The electron is a theory. But the theory is so good we can almost consider them real.

The basis of action on love, the brotherhood of all men, the value of the individual... the humility of the spirit.

The present situation in physics is as if we know chess, but we don't know one or two rules.

I'm trying to find out NOT how Nature could be, but how Nature IS.

I don't feel frightened by not knowing things.

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.