What sparked your interest in science?

My father was a travelling salesman and as soon as I was two years old, he took my mother and me on the road with him. We travelled all over the eastern half of the United States until I was about six years old. During this time, my mother — who had trained as an elementary school teacher but fell pregnant before she could start teaching — got me interested in all sorts of things, including science. My mother was my steady companion; she talked to me all the time and showed me many interesting places during our road trips.


I later started building model airplanes and, when I was around 12 years old (in 1937), I developed a passionate interest in astronomy. I read all the books in the local library on the subject and, in an encyclopedia, I found instructions on how to build a telescope using magnifying glasses. I built one, but the images were very poor and blurry, and they had rainbows around the edges. I quickly determined that a better idea was to build a reflecting telescope; in other words, I had learned very early on to look critically at what I had read and done.

During the Second World War you worked on developing the atomic bomb. How did that period influence you?

When I went to Los Alamos, I was 18 years of age and had been in college for just over two years. I was one of the youngest people working there — although the whole effort consisted of young people. The director of the project, Robert Oppenheimer, was only in his mid-thirties, and he was one of the oldest. There were not many older scientists who were able to move out to that very remote location.

I was working on the problem of neutron diffusion, and while my position was a junior one, I found that I was able to do the same sort of work as other far more educated and experienced scientists. That gave me the sense that I could hold my own among more senior people, and that I could be a scientist who contributed something. That's an uncertainty that many kids start out with — the sooner they overcome it, the sooner they can contribute.

You were studying at Princeton at the same time that Albert Einstein was on the faculty. Did you have any interactions with him?

Einstein was far and away the most fascinating presence at the Institute for Advanced Studies in Princeton, where I spent a total of two years, from 1949 to 1951. But I had little to do with him. Einstein — already in his seventies — was not particularly active any more, and was critical of the developments that had taken place in quantum mechanics, which were upsetting his notion of causality. Despite being a pioneer of quantum theory, he had begun to have doubts about it. By the time I got to the Institute, he had really opted out of engagement.

Consequently he had nothing to do with people who were interested in quantum theory, as I was. That was very sad: we would have sacrificed a great deal to hear his criticisms or anything he had to say on the subject. But he wasn't available; he would sit in his office behind a closed door. I only encountered him when he was walking home. On one of these occasions I asked him whether I could take his photo, and he let me. I showed that photo for the first time in my Nobel lecture.

When you started working on quantum aspects of light — the work that would eventually earn you the Nobel Prize — did you have any idea that it would be so influential?

Anyone undertaking scientific work imagining that they are working for the Nobel Prize is out of their mind.

No. I thought it was a worthwhile pursuit but I did not see it as one of the great scientific questions of the age. It was a controversial topic at the time. But I was not thinking even remotely of the Nobel Prize, and I do not think that anyone else working in the field did either. After all, it took the Nobel committee more than 40 years to recognize the work. In fact, anyone undertaking scientific work imagining that they are working for the Nobel Prize is out of their mind. You should do what you know. If you think you have a fresh insight, you communicate it to the world and let the pieces fall where they may.

What is your advice to young people with an interest in science?

Find out what you think is really interesting and try to determine whether you have any skill at it. If you do, stick with it — the purpose is to generate new knowledge. I don't think that everyone should be a professional scientist, but many more kids should give it a try.