(Joan,1941) She wrote me a letter asking,"How can I read it?,Its so hard." I told her to start at the beginning and read as far as you can get until you're lost. Then start again at the beginning and keep working through until you can understand the whole book. And thats what she did

What is the fundamental hypothesis of science, the fundamental philosophy? We stated it in the first chapter: the sole test of the validity of any idea is experiment. ... If we are told that the same experiment will always produce the same result, that is all very well, but if when we try it, it does not, then it does not. We just have to take what we see, and then formulate all the rest of our ideas in terms of our actual experience.

There is no learning without having to pose a question. And a question requires doubt.

The real question of government versus private enterprise is argued on too philosophical and abstract a basis. Theoretically, planning may be good. But nobody has ever figured out the cause of government stupidity—and until they do (and find the cure), all ideal plans will fall into quicksand.

Turbulence is the most important unsolved problem of classical physics.

If you know that you are not sure, you have a chance to improve the situation. I want to demand this freedom for future generations.

The electron is a theory we use; it is so useful in understanding the way nature works that we can almost call it real.