The fact that the climate is getting warmer doesn't scare me at all. There's no reason why one should be scared.

If you go to London now, not everything is beautiful, but it's amazingly better than it was. And the Thames is certainly a lot better: There are fish in the Thames.

I like people who are working on practical things and who are working in teams. It's not so important to get the glory. It's much more important to get something that works. It's a better way to live.

The public knows that human beings are fallible. Only people blinded by ideology fall into the trap of believing in their own infallibility.

A good cause can become bad if we fight for it with means that are indiscriminately murderous. A bad cause can become good if enough people fight for it in a spirit of comradeship and self-sacrifice. In the end it is how you fight, as much as why you fight, that makes your cause good or bad.

You have this world of mathematics, which is very real and which contains all kinds of wonderful stuff. And then we also have the world of nature, which is real, too. And that, by some miracle, the language that nature speaks is the same language that we invented for mathematics. That's just an amazing piece of luck, which we don't understand.

The question that will decide our destiny is not whether we shall expand into space. It is: shall we be one species or a million? A million species will not exhaust the ecological niches that are awaiting the arrival of intelligence.