One of the memorable moments of my life was when Willard Libby came to Princeton with a little jar full of crystals of barium xenate. A stable compound, looking like common salt, but much heavier. This was the magic of chemistry, to see xenon trapped into a crystal.

The world is just - it's wonderful when you look at all the detail. It's just amazing. Nothing is boring if you look at it carefully.

Have felt it myself. The glitter of nuclear weapons. It is irresistible if you come to them as a scientist. To feel it's there in your hands, to release this energy that fuels the stars, to let it do your bidding. To perform these miracles, to lift a million tons of rock into the sky. It is something that gives people an illusion of illimitable power and it is, in some ways, responsible for all our troubles - this, what you might call technical arrogance, that overcomes people when they see what they can do with their minds.

The universe in some sense must have known that we were coming.

Sometimes we talked about the nature of the human soul and about the Cosmic Unity of souls that I had believed in so firmly when I was 15 years old. My mother did not like the phrase Cosmic Unity. It was too pretentious. She preferred to call it a world soul.

I think the biggest misconception about mathematics is that everybody has to learn it. That seems to be a complete mistake. All the time worrying about pushing the children and getting them to be mathematically literate and all that stuff. It's terribly hard on the kids. It's also hard on the teachers. And I think it's totally useless. 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.

We must be careful not to discourage our twelve-year-olds by making them waste the best years of their lives preparing for examinations.