The material for this section was recorded by Ralph Leighton on May 15, 2009, at the California Institute of Technology. Leighton and Michael Gottlieb interviewed Rochus E. (Robbie) Vogt about Caltech in the early 1960s, and what it was like to teach Feynman’s physics. (Exclamation points usually indicate that Vogt was laughing about what he was saying at the time.)
Leighton: I’d like to ask you about your role in The Feynman Lectures on Physics. Take us back to those days, if you would.
Vogt: I came to Caltech in 1962, and the freshman course was given in ’61—so I came in the first year that Feynman’s freshman course had to be translated into something that common people could do—and it was quite a challenge! When Caltech hired me, I told Carl Anderson, the physics department chair, “I’ve got to finish up some important work in Chicago, and I cannot get away until mid-October.” He said, “No problem; somebody will take your class until mid-October, but as soon as you show up, you teach!” It was very different from the way it is today. I remember my wife, Micheline, and I arrived in Pasadena on a Saturday afternoon, and Monday morning, I was in a classroom—and I didn’t know what I was doing!
It was the second year of the course. Feynman gave the sophomore lectures, while your father [Robert Leighton] took over the freshman lectures. Leighton gave very good lectures, and it was very enjoyable to work on that team—and also it was great to see whether we mortals could teach Feynman, which many people doubted was possible! Under Bob Leighton, I was a Teaching Assistant (TA) teaching two recitation sections—a common one, and the honors section. The honors section was kind of neat; the common one wasn’t as neat, because it had biologists in it who didn’t want to learn physics! Nevertheless, it worked out. It was more of a challenge than the honors section—the honors section was so much easier to teach: they did it all on their own; they didn’t need me.
Leighton: It’s funny how you can think you’re a good teacher—when you have good students!
Vogt: That’s right. At that time there was a TQFR—a Teaching Quality Feedback Report—on all the faculty, which went on all the time, and I read my own. It said, “He’s doing a very good job, but of course anybody could do that with a good textbook like Feynman!” So they thought it was a good textbook at the time. In later years, people at Caltech said The Feynman Lectures are really not suitable as a textbook—but it’s amazing how many people read it in parallel with something they have been assigned—and that means The Lectures haven’t been lost. But at Caltech, it should still be the text, period!
It wasn’t easy, because none of us had the charm or allure of Feynman—nobody can imitate that. But in my second year, when I gave the freshman lectures (following Bob Leighton), I always gave this assignment: read the following chapter of Feynman, and then I will teach you what to do with it. That worked, because I did not parrot Feynman. In fact, I said to them, “There’s no sense in me trying to parrot the Bible—it stands on its own feet—but I can tell you how to work with it.” I gave them examples, applications, amplifications, and sometimes interpretations—because Feynman sometimes was on a pretty high level—and that seemed to work.
You might be amused how I took over the Feynman Lectures in my second year at Caltech. One day, in early October, Bob Leighton and I ran into each other, and he said, out of the blue, “Robbie, I want you to take over the class.”
“What’s going on, Bob?” I said with concern.
He says, “I need a sabbatical, and I’ve decided I’m going to go to Kitt Peak in Arizona, and I’ve decided you’ll take over the Feynman course.” So word got out that Bob Leighton was planning to pass The Feynman Lectures on to me.
Matt Sands, when he heard about it, went through the roof! I remember talking about it with Bob Leighton in his office, and outside Matt Sands was yelling in full voice at no one in particular, as far as I could tell, “Bob Leighton has gone insane! He’s crazy! He’s letting this inexperienced green assistant professor take over the Feynman course! This is an outrage! I protest!” He was really agitated, because he cared deeply. He trusted Bob Leighton, but he had never heard of me.
Anyway, I gave my first lecture for the Feynman course on the 21st of October, 1963. Several things had happened: I was going to a conference in India during quarter break in December, so had just gotten some yellow fever shots and some typhoid shots—and when I got the typhoid shots, I developed a high fever—and so on the 20th of October I had a high fever. On top of that, my wife, Micheline, brought our first daughter, Michele, into the world on that day, so I spent the night of October 20 in the hospital, waiting for things to happen! So I had only a couple of hours of sleep, I had a high fever, and I gave my first Feynman lecture—it was quite a start.
Incidentally, your mother, Alice, did something absolutely marvelous: she called us up and said, “I feel bad that Bob got you stuck with the Feynman course, and I know you kids are just getting going in life, so I have decided to subscribe you to a diaper service—this will give you some help,” which it was.
Anyway, as I said, I was very comfortable teaching Feynman physics, because these were very bright students: if you gave them a break, they would do something good with it. I think they were actually more able to do things under me than they were under Feynman, because in addition to Feynman, they got somebody who gave them applications of Feynman.
As you may know, more than half of the TAs were professors when Feynman was lecturing. But even when I was the lecturer, there were several professors with recitation sections—one of my TAs was Tommy Lauritsen. Tommy was very helpful. He came to each lecture and told me whether it was good, or whether it could be improved. Being a TA was considered necessary preparation to give The Feynman Lectures; after I gave The Lectures for two years, Tommy took over from me—he was the next Feynman lecturer.
When I was teaching the recitations under Bob Leighton, I got very familiar with the Feynman course. Otherwise, if I had walked in cold without that background, I couldn’t have done a good job. As a TA I had learned what the students needed—what worked with them, what didn’t work; even when I was the lecturer, I always taught a recitation in parallel with my lectures, because I wanted to find out how the students were doing, and what I could do better. When you are in a small class with ten to twenty students, you get very good feedback, whereas as a lecturer you get little feedback, because they’re so busy taking notes and listening. Sometimes you stay after class a little bit, but it’s not the same thing. But when you give them homework, and discuss it with them, you find out whether the students actually can do the physics.
I had a philosophy about homework that is in contrast to what they’re doing now—i.e., they print the solutions and hand them out to the students the day the homework is due, or use last year’s printout, because they often use the same problems again. I am totally opposed to that. It’s psychological: when you get stuck, and you absolutely don’t know what to do next, you naturally would like to look at the solution to get you over the hump. But pretty soon you begin to look at the solutions earlier and earlier. And so I made my philosophy very clear to the students. I said, “I expect you to try first to do your homework alone. But if you spend twenty minutes on a problem which I assign to you, and you still don’t know how to do it, then go and talk to others. Don’t feel bad about it. Sometimes you just don’t get it; you may have missed something critical. As soon as somebody gives you the word, you know how to do it. However, once you understand the problem, go back to your room and write up the solution on your own—don’t copy somebody else’s solution.”
There was a third phase: I said, “If as a group you can’t do it after half an hour, call me.” I had forgotten when students do their homework—thus I got phone calls at two or three o’clock in the morning: “We’re stuck! We have spent the last hour and we’re getting nowhere!”
Gottlieb: I would have given them another problem: “What is the latest hour that you think it is decent to call a professor?” [Laughter]
Vogt: Actually, I was grateful that they tried to do it. And when you’re young, it’s not a big deal to wake up at three in the morning, spend fifteen minutes talking to some students, and go back to sleep—especially when you’ve got a baby crying in the other room anyway! At least I knew what to do about the students’ problems; the baby’s crying, I had no idea!
Going back to your first question, Ralph, about my role in the Feynman course: I saw myself as an acolyte who was an interpreter, a go-between between Feynman and the students. Another role I had was coming up with exercises, along with Bob Leighton. He was very influential: I mean, he made me do it! He often said, when we created the A, B, and C problems, “We need a couple of more As, or a couple of more Bs.” Usually we had plenty of Cs, the hardest ones! He always knew what was missing. Sometimes he came up with a problem, but very often, he said, “Robbie, go think up a couple more problems—I know you can do it.” That was his style: he felt everybody was competent enough to do things; they just needed motivation to do it. He didn’t think he was imposing upon me; he just thought he’d help me to do the right thing!
One time years later I “cheated” and used someone else’s problem. There’s an important paper by one of my heroes, Val Telegdi, about the calculation of the g-factor of an electron. It was in Nuovo Cimento (the Italian physics publication), sixty-five pages I seem to remember, mostly mathematics above my head. I looked through the goddamn paper, and said to myself, “That’s so much hard work to go through it!” However, I remembered Feynman’s sophomore year lectures on quantum mechanics, and I knew that you could solve that same problem with Feynman Lectures physics. So I gave to my junior-year students this homework problem: “Calculate the g-factor of the electron.”
More than half the class was able to do it. Now, that was a little bit shifty, because you cannot use the style of quantum mechanics Feynman taught in the sophomore year for everything, but it has great applicability to certain physics problems like this one. You have no idea how proud the students were: in one and a half pages, they could do a piece of physics that took Telegdi sixty-five pages and a lot of math! And so they thought Feynman quantum mechanics was very elegant, which it is.
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Another thing I remember, coming back to my early years, when we taught the Feynman course: Every week, on Wednesdays, some six to ten physicists had lunch together (we brown-bagged it, or went to Mijares Mexican restaurant in Pasadena), which included Bob Leighton, Gerry Neugebauer, Tommy Lauritsen, and others. When we got together at those lunches, we talked about teaching: what worked, what didn’t work, what we could do better. There was so much mutual support that you could become a better teacher, because you had all that help—also on Friday afternoons at the Lauritsens, where a lot of us would unwind with martinis at the end of the week. We mostly talked about students and teaching. We talked about research at other times, since we were each doing different research areas, and we had different opinions on how fascinating things were that somebody else did—each of us thought our own research was the most fascinating, of course—but when it came to teaching, we were interested in what everybody else did, because we could learn from them. Nobody forced us to do that; it just happened spontaneously in the climate of Caltech in the early 1960s.
That’s how the Feynman course arose, I understand—at the Lauritsens over drinks. They were talking about how to do things better, and Matt Sands came up with the idea that they should rope in Feynman.
It was at such get-togethers that I saw how a university can be a very rewarding and warm place—because of the students: they form a link between the faculty. We got together because of the students, not because of our research. Of course, we also got together individually—Tommy often came to my lab and said, “Tell me what you’re doing,” and had good suggestions, but this was a one-on-one usually. This student business was a collegial activity. When I gave my lectures, there were usually three or four professors sitting in the back row, in 201 East Bridge, the big lecture hall—not because they didn’t trust me, or spied on me, but because they were curious how I was doing it, and what could be learned from it. Even Carl Anderson, the division chair, attended every other one of my lectures, and I got feedback from everybody. That was the Feynman spirit: you see, when Feynman taught the course, it was full of professors in the back row. They were so fascinated. And so they got in the habit even to come to the lecture of a common person—a boring person like me—because it had become a pattern. This is important. That’s what I regret: I don’t see that spirit today.
One last thing: in those days I was responsible for my lectures. I assigned all the homework, I made up all the quizzes, I made up all the final exams—personally—nobody else did it for me. I wouldn’t have asked somebody else, because I thought I knew better what to ask! In addition to that, I taught an honors section; in addition to that, I ran the freshman lab—that was a normal teaching assignment in those days. Today, I think it is one quarter of that. Most professors today teach one class for two quarters per year. Now, I am a fair person: I recognize that today, what we did then would no longer be possible, because today, professors have to spend so much time raising money for their research and defending their research—but that’s another story.