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 in some doubt.
Richard P. FeynmanNo! Not for a second! I immediately began to think how this could have happened. And I realized that the clock was old and was always breaking. That the clock probably stopped some time before and the nurse coming in to the room to record the time of death would have looked at the clock and jotted down the time from that. I never made any supernatural connection, not even for a second. I just wanted to figure out how it happened.
Richard P. FeynmanAny schemes - such as 'think of symmetry laws', or 'put the information in mathematical form', or 'guess equations'- are known to everybody now, and they are all tried all the time. When you are stuck, the answer cannot be one of these, because you will have tried these right away...The next scheme, the new discovery, is going to be made in a completely different way.
Richard P. Feynman