While I am describing to you how Nature works, you won't understand why Nature works that way. But you see, nobody understands that.

Our freedom to doubt was born out of a struggle against authority in the early days of science. It was a very deep and strong struggle: permit us to question - to doubt - to not be sure. I think that it is important that we do not forget this struggle and thus perhaps lose what we have gained.

This attitude of mind - this attitude of uncertainty - is vital to the scientist, and it is this attitude of mind which the student must first acquire. It becomes a habit of thought. Once acquired, we cannot retreat from it anymore.

It is scientific only to say what is more likely and what less likely, and not to be proving all the time the possible and impossible.

Ordinarily it would take me about fifteen minutes to get a hallucination going," wrote Feynman, "but on a few occasions, when I smoked some marijuana beforehand, it came very quickly.

The problem of creating something new, but which is consistent with everything which has been seen before, is one of extreme difficulty.

Ordinary fools are all right; you can talk to them, and try to help them out. But pompous fools-guys who are fools and are covering it all over and impressing people as to how wonderful they are with all this hocus pocus-THAT, I CANNOT STAND! An ordinary fool isn't a faker; an honest fool is all right. But a dishonest fool is terrible!