You have to change from doubter to believer.

Everything I did, and I think everything Martin Luther King did, was because we allowed our lives to be in tune with what we felt to be a divine purpose. And it didn’t matter whether we lived or died. It didn’t matter how much money we made, or what we accomplished.

They encouraged me, the way I do others now, that if you really have something that you like to do, that’s what you probably should do. Despite what everybody says, that you can’t make a living, or that’s not practical, or a thousand reasons why you may not do this or this or this. If that’s what your heart says you should do, chances are that you ought to listen.

Only the disciplined ones are free in life. If you are undisciplined, you are a slave to your moods. You are a slave to your passions.

It is necessary, I believe, to accept this idea, not only for science, but also for other things; it is of great value to acknowledge ignorance.  It is a fact that when we make decisions in our life we don't necessarily know that we are making them correctly; we only think that we are doing the best we can – and that is what we should do.

Then there was Von Neumann, the great mathemati-cian. We used to go for walks on Sunday. We'd walk in the canyons, and we'd often walk with Bethe, and Von Neumann, and Bacher. It was a great pleasure. And Von Neumann gave me an interesting idea; that you don't have to be responsible for the world that you're in.

I would like to add something that’s not essential to the science, but something I kind of believe, which is that you should not fool the layman when you’re talking as a scientist.

The questions of the students are often the source of new research.  They often ask profound questions that I’ve thought about at times and then given up on, so to speak, for a while.  It wouldn’t do me any harm to think about them again and see if I can go any further now.  The students may not be able to see the thing I want to answer, or the subtleties I want to think about, but they remind me of a problem by asking questions in the neighborhood of that problem.  It’s not so easy to remind yourself of these things.

the colonel said I shouldn't tell them how the neutrons work and all the details because we want to keep things separate, so just tell them what to do to keep it safe.

It's made me a very happy man ever since.