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

The test of all knowledge is experiment.

Physics is like sex: sure, it may give some practical results, but that's not why we do it.

But see that the imagination of nature is far, far greater than the imagination of man.

Don't pay attention to "authorities," think for yourself.

There are all kinds of interesting questions that come from a knowledge of science, which only adds to the excitement and mystery and awe of a flower.

It does not matter who you are, or how smart you are, or what title you have, or how many of you there are, and certainly not how many papers your side has published, if your prediction is wrong then your hypothesis is wrong. Period.