Mathematics is really an art, not a science. You could say science also is an art. So I would say the difference is something you can't really describe - you can only recognize. You hear somebody playing the violin, and it was Fritz Kreisler or it was somebody else, and you can tell the difference. It is so in almost every art. We just don't understand why it is that there are just a few people who are just completely off the scale and the rest of them are just mediocre. And we don't know why. But I say it's certainly true of mathematics.

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.

If you want to have a program for moving out into the universe, you have to think in centuries not in decades.

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.

It is characteristic of all deep human problems that they are not to be approached without some humor and some bewilderment.

For any speculation which does not at first glance look crazy, there is no hope.

The brain, being analog, is able to grasp images so much better. The brain is just designed for comparing images and some patterns - patterns in space and patterns in time - which we do amazingly well. Computers can do it, too, but not in anything like the same kind of flexibility.