Steven Chu Interview: Conversations with History; Institute of International Studies, UC Berkeley

A Scientist's Random Walk: Conversation with Steven Chu, Nobel Laureate, Physics; Geballe Professor of Physics and Applied Physics, Stanford University; February 13, 2004, by Harry Kreisler
Photo by Jane Scherr

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Being a Scientist

Why is it that the public understanding of science doesn't proceed at a higher pace? Is it because there are not enough scientists who are doing the writing?

That's a difficult question. As I give more public talks, as I get exposed to these issues more and more, I think that there are two things: One is, unfortunately, there is a public fear of science, especially physics. They think, "Oh, my gosh, physics ... it's hard. It has math in it. It's going to be very difficult for me to understand what's really going on." That, I think, is something that might have happened in grade school or high school.

If you didn't have the right teacher ...

Yes. And the trouble with learning physical science and mathematics is, once you slip behind a little bit, and you just didn't get this concept, or it's not quite firm in your mind about this mathematical thing that you have to know, well then, next week you're on to something else. But they really expect you to know something about last week. And so that's one of the issues.

The other issue is that the ideas are complex. Now, if you step back and if you spend some serious time thinking about it, the kernel of the ideas are clearly not complex. The essence of an idea is what we try to work with most. As a professor with my graduate students, we would read a paper and look at the paper and say, "What's the essence of the idea? What's something new? Forget about the equations. Forget about the complicated argument and try to identify the kernel of the idea." That can be communicated, but it takes effort.

You did your graduate work here at Berkeley. So in a way, you're coming back to deliver the Hitchcock Lectures.


What contribution did your Berkeley education make overall? I'm sure you could go through a long list. Who was your mentor here?

My mentor was Eugene Commins. He was a wonderful professor. He has a history of having many graduate students who have gone on and done wonderful thing. He's revered as a classroom teacher as well, and, also, in the way he does things, the way he goes about life. In every respect that I can think of he was a mentor, not only in terms of the science but how you handle yourself in situations and in the world.

He had one remarkable quality that I wish I could copy, and that is, he made all of his students feel special, and that they could do something. He got all of us to live up to the highest we could do, without saying, "You must do this," or without making us feel pressured or guilty, or something like that. He would work side by side with us, often late into the night, as a colleague more than as a professor. That was a remarkable experience to grow up in that environment.

The other thing I learned here is to try to think of things to do that would be important in science. There are many things you can study in science; some focus on big questions. Try to identify the correct questions. It was not only my advisor but the Berkeley professors around here at that time; there were six or seven Nobel Laureates in the physics department who were active, and you could watch they way they approached problems. This would come out not in a formal lecture or something, but in casual conversations when they're maybe giving a colloquium -- how they approach it, and how they thought about it. This enters in a very subconscious way. That is probably why there are so many distinguish graduates in Berkeley.

Help us understand what the prerequisites are for doing science well. If a student or students were to watch this, what should they know about this way of life and what they need to bring to it -- training and so on?

The first thing is, they have to be interested in it. They have to be genuinely interested. They have to have curiosity. Science is really about describing the way the universe works in one aspect or another in all branches of science -- how a life form works, how this works, how that works. You're really trying to understand what's around you. You have to have a natural curiosity for that.

In certain types of science, there might be prerequisites. In physics, you should have some mathematical ability. Otherwise, I think it would be very hard. But beyond those prerequisites that a lot of people do have, you need to have, first, this curiosity, a driven curiosity. You want to know the answer. With that curiosity comes a certain doggedness, because there are going to be setbacks, you're going to be discouraged. Things aren't going to work. You're going to have trouble understanding them. Things are going to be hard to understand, especially the first time. Science doesn't come naturally to people.

I had the hardest time in my first few years as a freshman/sophomore, and also in high school, understanding physics in a really deep sense. I could do well in exams, but to get it inside your stomach and to say, "Okay, I have a real feel for it"; it took a while to develop that intuition. But there were other drivers for that. It seemed like a beautiful way of understanding the world.

But I'll go back to the other thing -- this doggedness, this saying, "I'm not going to quit. I really want to find out." It enters in other walks of life. If you think of an athlete who wants to become a good athlete, well, there's going to be a lot of training involved. Sometimes you don't feel like getting up early in the morning or staying late in the afternoon and spending the hours training.

That turns out to be one of the most important things that separate [students] in graduate school. At graduate school at Stanford, you have some of the best students in the world, who you can see are going to go on and become world-class scientists, and who are very smart and are going to be good. But the thing that really differentiates [among them] is this passion to find out what the answer is: "I'm not going to quit." After those prerequisites, the thing that separates the people who are going to excel from people who are good and not, is that internal drive.

In a joking "aside" yesterday in your lecture you said that in science, once you announce something, first, everybody tells you you're wrong; then they tell you it's trivial; and then that you are not the first to discover it. It emphasizes what you just said, that there has to be an inner drive. But also it suggests an element of courage, that you're going to stand up to people and say, "This is what I think," and then keep on going even if you're proven wrong. And then try to adjust what your experiment has shown.

That's right. When you make something that's unexpected, and it's a little bit out of people's expectations, they're first going to reject it. And, actually, that's one of the strengths of science. You have to say, "No, it's not [just] because I said it is"; you're going to have to convince them. And by convincing them, it's really through discussion and additional experiments, because in the end the experiment is going to be the final arbitrator. There's no high priest or priestess of science that says, "You're right; you're wrong." You go back and you do more experiments. So the reaction, if you're a little bit off center or a lot off center, is, "No, that's preposterous. You've got to be wrong." The more outlandish you are, the more unexpected the finding, the more you're going to get that reaction.

Now. in the end, after one understands what's going on -- and it goes back to understanding the science -- then you say, "No, no, no, it's all right. Yes, we could have foreseen that." That's where it becomes trivial. It's sort of, "Well, sure." It wasn't trivial at the beginning, but after you see it, then it becomes easy. But that's actually a mark of really understanding something, to then say, "Of course."

The final one is, "You're not the first to discover this." That is also true. There are always precursors. There's always someone before you who had a glimmer of this and a glimmer of that. Science is based upon a lot of rediscovery.

But going back to your point, namely you're going to be rebuffed and oftentimes rejected, and it's not a personal issue. You've just got to stand up to it and go back; now, you could be wrong, but you're going to go back and convince yourself you're right. The rule I tell myself and my students is, we have to be our worst critics, and once we convince ourselves that we're right, then we should have no problem convincing everybody else we're right. Good scientists are their own worst critics. They're always trying to prove themselves wrong, which is hard, because sometimes you've got an idea and you think you're right and you have to force yourself [to ask], "Where are the weak points of this argument, or the weak points of my experiment?"

One of the points that came out in your lecture for me, a non-scientist, was the importance of collaboration, not only with your own students but with other scientists, and even other scientists who are in subgroups within physics, but even beyond that, to scientists in other fields of science, that those sets of communications working together are important to push this process along.

Yes. That's another misconception that many people have about scientists, or doing science and learning science. The misconception is you go to school, you take classes, you study -- years and years of study. You learn everything there is to know in a certain sub-field, a very narrow sub-field, and then you do work in that area. That is the form, but it's rarely taken. It's especially not true the way I do it.

Maybe it goes back to my high school days, when I was not such a good student. In actual fact, if one wants to go into a new area beyond your school days, you can pick up a classic textbook and begin to read, and begin to read in the literature; but it's not as much fun. When I was going into biology maybe a dozen years ago, I did try that. I picked up a big, fat tome called Biochemistry, a classic textbook. I started reading; it was 1,500 pages. I got to page 150, and I was deciding, "Well, it's beginning to slip out of my head as fast as it's going in now." I reached a "steady state!"

So I said, "Well, this isn't going to work." So I would look around, and I had some [knowledge] from reading newspapers and magazines such as Science, Science Times, The New York Times, Scientific American, things of that nature. I had an interest in these biological problems, and I would pick something that I was interested in. But, of course, since I wasn't an expert in biology, I didn't know, "Is this a stupid question? Is this a deep question? What?" I would say, "Well, I think I can do something here and I have some interest." So I'd trot over to the biology department or medical school and say, "Is this something we're studying? I think I want to do this." And they would tell me sometimes, "No, no, it's silly," or "It's been done before." Or sometimes they'd say, "This is a central problem in biology." That rarely happened.

But what happened is then I would start to collaborate with these people who spent their career in this specialty, and who grew up in this culture. They would say, "You should read this article, and that article, and that article." We would talk, and it was wonderful to learn that way. So you could sort of leapfrog over the years of school. Now to be sure, I'm not pretending I have as broad or deep as knowledge of that. But you start with a little, thin sliver of a particular problem, and you start to build knowledge around that thin sliver. By the time you've done the experiment and you're starting to write the paper, you better have some knowledge of what's around, because you won't even get to publish in the paper if you haven't referenced the right people or the precursors before you. But it's learning in that way.

Then you go back to the books, but now you use the index. You say, "I want to learn about this." So now I've begun to teach my students -- many of my students are physicists wanting to go into biology. I say, "Okay, we'll use the index. This is the problem. Why don't you look here, read these five pages in this book, and these ten pages here, and these fifteen pages here." By the time you read this review article, within a month, you're reading the primary literature.

In biology.

In biology, without the three years of courses. Within a few months to a few years, you're beginning to get a feel for it. It's very important that you get this feel, because you have to ask the right questions. One of the most important things that a scientist does is ask a question that's important and that has a chance of being solved. You can ask important questions like, "How does a brain work?" but that's not sufficient. You have to pick a part of that question where you can make you a contribution, a serious contribution, and something that others would be interested in.

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