That's what I learned from World War II. Things are always more complicated than most people believe.

The marketplace judges technologies by their practical effectiveness, by whether they succeed or fail to do the job they are designed to do.

Science is not a collection of truths. It is a continuing exploration of mysteries.

The glory of science is to imagine more than we can prove.

I think that the artificial-intelligence people are making a lot of noise recently, claiming that artificial intelligence is making huge progress and we're going to be outstripped by the machines. But, in my view, this whole field is based on a misconception. I think the brain is analog, whereas the machines are digital. They really are different. So I think that what the machines can do, of course, is wonderful, but it's not the same as what the brain can do.

[On Richard P. Feynman's live demonstration of the rigidity of the O-rings when cold that doomed the space shuttle Challenger, killing seven astronauts:] The public saw with their own eyes how science is done, how a great scientist thinks with his hands, how nature gives a clear answer when a scientist asks her a clear question.

Plasma seems to have the kinds of properties one would like for life. It's somewhat like liquid water--unpredictable and thus able to behave in an enormously complex fashion. It could probably carry as much information as DNA does. It has at least the potential for organizing itself in interesting ways.