That's the beautiful thing about science - that it's all about things we don't understand, not just the things we do understand.

We cannot hope to either understand or to manage the carbon in the atmosphere unless we understand and manage the trees and the soil too.

To me, mathematics is like playing the violin. Some people can do it - others can't. If you don't have it, then there's no point in pretending.

I'm a mathematician, basically. What I do is look around for problems where I can find useful applications for mathematics. All I do, really, is the math, and other people have the ideas.

You could say science also is an art.

Some of my friends like to keep science and religion together, but I certainly like to keep them separate.

It's amazing how much progress there's been in China, and also India. Those are the places that really matter - they're half of the world's population. They're the places where things are enormously better now than they were 50 years ago. And I don't see anything that's going to stop that.