Do not read so much, look about you and think of what you see there. - Richard Feynman

In physics the truth is rarely perfectly clear, and that is certainly universally the case in human affairs. Hence, what is not surrounded by uncertainty cannot be the truth.

I've always been rather very one-sided about the science, and when I was younger, I concentrated almost all my effort on it. I didn't have time to learn, and I didn't have much patience for what's called the humanities; even though in the university there were humanities that you had to take, I tried my best to avoid somehow to learn anything and to work on it. It's only afterwards, when I've gotten older and more relaxed that I've spread out a little bit — I've learned to draw, and I read a little bit, but I'm really still a very one-sided person and don't know a great deal. I have a limited intelligence and I've used it in a particular direction.

It is important to realize that in physics today, we have no knowledge what energy is. We do not have a picture that energy comes in little blobs of a definite amount. It is not that way.