Physics professor and historian of science Silvan “Sam” Schweber has worked at Brandeis for more than sixty years, and has served Brandeis under every one of its presidents, beginning with the university’s founding president Abraham Sachar.
Schweber trained at Princeton during the 1940s, where he studied with Robert Oppenheimer, the father of the atomic bomb. During the early 1950s he studied at Cornell with Hans Bethe, who has been called the midwife of the hydrogen bomb. Schweber’s book In the Shadow of the Bomb: Bethe, Oppenheimer, and the Moral Responsibility of the Scientist describes the very different personalities of Oppenheimer and Bethe and the different ways in which they responded to the scientific, political and ethical challenges of the early Cold War period.
This book is just one of Professor Schweber’s many books on science in the 20th century; his understanding of the role that physics and technology played in that dangerous century is seemingly comprehensive. I recently sat down with Professor Schweber to discuss physics, physicists, and the development and production of weapons of mass destruction.
WR: Your book, In the Shadow of the Bomb: Bethe, Oppenheimer, and the Moral Responsibility of the Scientist focuses on the lives and decisions of the two physicists who played major roles in the development of the nuclear arsenal of the United States. You knew both men. If I may start with Bethe, what was the context for your interaction with him?
SS: I was trained as a physicist, first at the University of Pennsylvania, and then from there I went to Princeton in 1949. In 1952 I went to Cornell on a National Science Foundation postdoctoral fellowship, and that’s when I was introduced to Bethe. Bethe was the main theorist at Cornell University. Actually, it turned out that between 1952 and 1953 he wasn’t there that much because he was working on the hydrogen bomb. The person who was the dominant figure when I first was there in 1952 was Freeman Dyson.
Contact with Oppenheimer comes before that, because Oppenheimer had come to Princeton in 1947 as the director of the Institute for Advanced Study, and every Wednesday there would be a joint theoretical seminar between the Princeton University physics department and Oppenheimer’s Institute, so that all of the theorists, and every graduate student, would go out to the Institute and meet Oppenheimer. He was the chair of the seminar.
My first personal contact with Oppenheimer, which in many ways colored my view of him, was at the beginning of the Korean War. Earlier than that, you had the action of the House Un-American Activities Committee (HUAC) and David Bohm had been called up. David Bohm had been a student of Oppenheimer’s, and was an assistant professor at Princeton University, and I actually had shared an office with him the first year I came there. In the spring of 1950 I took a course with him.
In early 1951 he had appeared before HUAC and essentially took the 5th Amendment on being asked names of other people, or even asked whether he was a communist. As a result of this, in early 1951 he was held in contempt of Congress by virtue of not answering these questions.
Then the President of Princeton University essentially decided that Bohm was not allowed to have access to the university. So two of us went up to see Oppenheimer and told him of the plight of Bohm. And Oppenheimer said, by all means, he should have a desk at the Institute for Advanced Study whenever he wants. He never went back to Princeton. That was my first contact with Oppenheimer
WR: And Oppenheimer, in this case, was willing to protect Bohm?
SS: Yes, his student. In this case he was protecting his student. A big event in spring of 1954, when I was at Cornell, was when Oppenheimer’s Q clearance had been revoked by the Atomic Energy Commission. This really sent a shock through the entire physics community. At the time, Bethe was the president of the Physical Society, and organized efforts to help Oppenheimer. Again, these paths cross.
WR: In a different context, in the context of his student Bernard Peters, I understand that Oppenheimer did not stand up to protect a colleague.
SS: It’s complicated. I don’t know all the details. In part, the problem was with Oppenheimer’s brother Frank Oppenheimer, who had been a communist, as undoubtedly David Bohm and a number of other people were. And there was nothing wrong with being a communist at the time, in the sense that you could still work at Los Alamos at the time. There was no reason at the time you were not allowed to work there. The Soviet Union was our ally.
But somehow by the time after World War Two, you have the McCarthy era, the Cold War had started, so the tenor had changed considerably. Anti-communism was really rampant. The Soviet Union became nominally our enemy, and that really colored and polarized both the culture and the political attitudes.
Frank Oppenheimer at one stage had been asked by a radio station in Minnesota, where he was an assistant professor, they called him up and they asked him if he had ever been a communist. He answered no. And then he was called in front of the House Un-American Activities Committee and it came out that he had been a member. So he had lied, and was dismissed by the University of Minnesota by virtue of having lied.
WR: Having lied to a radio station?
SS: To a radio station. And essentially the further developments made it clear than he had been a communist, and he had lied. And it was clear that Robert Oppenheimer was vulnerable. It was well-known that he had associated with left-wing organizations, and many of his students were left wing. There was an effort to reduce his influence within the Atomic Energy Commission. Reduce his influence.
The crucial year was after August 1949, when the Soviet Union detonated their bomb, and the question was: what is the response of the United States? Already then Mr. Teller and lots of other people, for example the head of the Berkeley Radiation Lab, wanted to go full speed ahead. The advisory committee to the Atomic Energy Commission, with Oppenheimer as its chair, was opposed to that. They said “investigate, but no crash program to develop a hydrogen bomb – a bomb of a magnitude that is unnecessary.”
So there was a concerted effort on the part of many people to get rid of Oppenheimer – remove him from such an influential position.
WR: Because he resisted the development of the hydrogen bomb?
SS: He said we should go ahead, investigate. But not a crash program.
WR: What role was Bethe playing?
SS: He was opposed to the hydrogen bomb, too. Already then, Teller was recruiting people to come to Los Alamos to work on a hydrogen bomb. Bethe went back, as he went back every summer. But his intent was to prove that you can’t make a hydrogen bomb. That the technicalities are such that you can’t create a weapon like that.
In 1951, after Teller and Ulam had proposed their mechanism, Bethe changed his mind. And he thought “if we can do it, they can do it too.” And then it became an issue of deterrence. If they can have it, we should have it in order to prevent either side from using it.
WR: As I understand Bethe and Oppenheimer both viewed the hydrogen bomb as a tool with no conceivable military purpose.
SS: No conceivable use.
WR: So it seems that for this brief window in 1951, Bethe played what turns out to have been a key role in the development of the hydrogen bomb.
SS: Yes. There is no question. There is one other interesting development within that time period that Bethe is associated with. That is that Vannevar Bush, who was the head of the entire World War Two scientific effort, likewise was opposed to the hydrogen bomb. He made a proposal, and this is now looking back at Los Alamos, the uranium bomb was totally designed by the theoretical division at Los Alamos. It was never tested. It was used – they were so convinced that it would work.
The plutonium bomb, on the other hand, with its implosion technique, is a much more complicated design. And the Trinity Test is a test to see whether it would work.
A hydrogen bomb is even more complicated. So Vannevar Bush came up with the idea of trying to figure out how it worked – even after Teller-Ulam – try to design it and so on. But then don’t test it. Make a proposal to the Soviet Union that they work on it, we work on it, theoretically, in terms of design. But we commit ourselves not to test the weapon. If the other side does test it, then we can easily detect the test and easily catch up.
That proposal was made to the Secretary of State, but the proposal stopped there. It never reached Truman’s desk.
WR: What would have been the impact if that proposal had worked?
SS: A deceleration of the arms race, no question. The big turning point in all of this was, again, the formation of the PSAC – the President’s Scientific Advisory Committee. In 1957, after Sputnik, Mr. Edwin Land became a member. He was a wizard in photography, lensing, and various things like that. He is the one who developed the lenses that would allow you to photograph from 40 or 50 thousand feet in the air. You could get pictures and see whether the person on the ground was drinking Coca Cola or not.
That’s when the U2 flights started. At that point we realized that the Soviet Union was far behind in the development of nuclear weapons. This is 1957, we recognized that the Soviet Union was far behind in terms of the numbers of atomic weapons, and all of this talk about us being behind is just wrong. That’s when Eisenhower changed his mind, and Eisenhower was president at the time. He eventually came out and, at the end of his presidency gave the speech warning about the military-industrial complex. So he was willing to see the world differently by virtue of this new information.
WR: The information that in fact the Soviets were far behind us in the development of nuclear weapons
SS: Not so much the development as much as the numbers. The number of missiles, the number of atomic bombs. We knew how much was involved, in terms of separation of materials, whether it’s plutonium, whether it’s tritium. Whatever. And so it was clear that all of the claim that there was a gap between the Soviet Union and the United States was just myth. Maybe not myth, more statements that were used for political purposes.
WR: Around this period, I understand that Bethe was proposing a test ban.
SS: Bethe was constantly playing a role. Let me put it this way. Bethe stayed at Los Alamos, was an advisor to any number of committees. He was involved in developments here in Boston in terms of missiles. He was involved, in part, in order to have a mastery of the technical developments, so that he could bring some forms of sanity to the government.
His goal was to counteract the kind of advice that the government was getting from Teller. If you want a harrowing experience, here is one: George Kistiakowsky was the science advisor to President Eisenhower at the time. Kistiakowsky is born in Russia, has a thick accent. A very tall fellow. And Eisenhower sent him out to Omaha, Nebraska, which was the heart of the Air Force’s Strategic Air Command. He came there, so you can imagine this man, with a heavy Russian accent, talking to the general, and coming back to Washington totally terrified, in terms of what Strategic Air Command had in mind.
WR: In the sense that they were not prepared for the responsibility of the power of the weapons entrusted to them?
SS: You have seen the famous movie?
WR: Dr. Strangelove?
SS: Exactly. If you read Kistiakowsky’s memoirs, you get this sense of the problem. We had bombers constantly up in the air, 24 hours a day, et cetera.
WR: And during this period, the end of the Eisenhower Administration, you were already at Brandeis?
SS: I am here.
WR: As these events were occurring, and as physics was playing such an important role in national security, what did physicists know about what was going on with respect to the development of our arsenal?
SS: Let me phrase it this way. Again, I am an historian, and in fact, I am writing something on Bethe after World War Two. Bethe comes back to Cornell after the war, and he sets up a laboratory. His colleague then become the Atomic Energy Commissioner, so in 1957, 1958, Robert Wilson comes in and becomes the head of the Nuclear Lab. Bethe and Wilson share all decisions. There is a secretary, they have an office setup with two open doors between them, so there is very little written record between them, except when they were apart.
So in the spring of 1950, Wilson is away, I believe in Washington, and they write to one another. The Korean War breaks out. And it was clear as a graduate student that the physics faculty took the Korean War exceedingly seriously. The Korean War shook people. And there are letters between Bethe and Wilson where they really believed the Soviet Union was behind it, they thought it might be the beginning of World War Three. So it reinforces this notion of the Cold War turning into World War Three. The Soviet Union was looked at more and more as a potential enemy with whom we may come to blows.
So the Cold War is taken very seriously among the physics community. When I am here at Brandeis, certainly MIT and Lincoln Labs were deeply involved in defense activities. Any number of things. In every possible way, the community was involved.
WR: What are the lessons from this period for scientists working today?
SS: The lesson was that scientists are on tap, but not on top. That was really clear at Los Alamos. There was this sense, which I call it – it’s more than a hope – they really believed that they would be involved in the decision making with respect to whether or not to use the bomb. And I think when they come out, I think Oppenheimer better than almost anyone else, it is clear that it’s not the case. It was a military enterprise, it was clear from the beginning that the decisions were in the hands of the government and the military. So in response, the scientists create the FAS – the Federation of American Scientists – go out to the public. What they do achieve is that control over atomic energy is in civilian hands, not in military hands.
Basically, at most, they can give advice. But the decision lies elsewhere. And, let me put it this way. I spoke to enough physicists in high enough places. They really felt they were used, and they would not have done the same thing again if they could have done it over. But to give you an idea of how serious the situation was. The Korean War, somebody like Robert Wilson, after 1945, decides he will have nothing to do with atomic energy. With bombs or anything like that.
In 1950, the Korean War, new developments in accelerator physics, and he sees enough indication of the potential to create an electron beam as a weapon to shoot down atomic bombs as they fall. At the time, atomic bombs would come down in a parachute, detonate when the airplane dropping it was far enough away.
So he gets back and is willing to design such a piece of military equipment again. And that’s how he gets involved. Not with electrons, but with protons with huge applications to radiation treatment of cancer. What I am trying to point out is how the Korean War seemed at the time. How it changed the context.
WR: The fear of the Soviet Union?
SS: Yes. Well, I mean Korea is a real war. Period. The question was “should we use atomic weapons?” MacArthur wanted to use them, and was only stopped at the highest level.
WR: I want to ask about the backgrounds of Oppenheimer and Bethe. Oppenheimer came from an Ethical Culture environment, which may be less familiar for some folks. Bethe came from a very specific part of German culture and society. They each came from specific moral and intellectual backgrounds that affected the roles they played in the context of physics in the postwar period.
SS: Oppenheimer was somewhat shaped by the people at Harvard. But he goes to Germany, and he is there at the time that quantum mechanics develops, and in that sense the two of them share a background, Bethe a little bit more so; he was a student of Arnold Sommerfeld, so he was molded that way from the word “go.” So in terms of the molding, it is how to look at physics. I think that there are differences. Bethe is clearer about his capacities, what is it that he can do, what can he not do. He realizes that his power is in solving problems given the general outlines.
Oppenheimer was possibly more ambitious. So in terms of science, it’s that kind of difference. In the 1930s, Oppenheimer trains most of the American physicists and does a very good job. Oppenheimer’s orientation is going toward more and more fundamental things. He gets deeply involved in meson theory, trying to understand the next step.
Bethe stops at nuclear physics, which is likewise the next step, but which you can still do phenomenologically, and go very far that way. And he’s successful at it. So in terms of physics, these are different temperaments. With Bethe undoubtedly the more powerful calculator.
Their difference in backgrounds, qua human beings? The big difference is really, in some sense, Bethe is not Jewish. He comes from a non-Jewish background. His mother had been Jewish, but converted when she was fairly young, and having been Jewish never came up, and it only came up vaguely, in terms of meeting some of his family. So it is only 1933 that Bethe recognizes that his mother had been Jewish, et cetera. But he never became Jewish. Bethe marries a woman whose mother is Jewish, but who never converted. His wife, Rose Ewald, had more connection to being Jewish.
Whereas Oppenheimer, it is clear, it is part of his background, and escaping from it. Whatever you want to call it, maybe not escaping. But not being Jewish. One thing which everybody knows, is the difficulty that Jewish people had in getting professorial appointments at any American universities in the 1930s. So he is certainly aware of what it means to be Jewish, all of these things.
WR: Even though he came from a position of great privilege?
SS: Well, his parents certainly remained Jews, culturally and more. But became members of the Ethical Culture Society, which Felix Adler who created it, was essentially a step away from being Jewish. Let me phrase it this way, one way of characterizing the Jewish faith. Judaism is not a proselytizing religion, in contrast to Christianity and Islam. The Reform Jews, and in particular Felix Adler, had a vision of what the message of what the prophetic path was, in the contrast: the prophet versus the priest. There is a famous division within Judaism, with the prophetic being much more worldly, cosmopolitan.
Think of the prophet Amos, I believe, who said “walk justly and humbly”. And so there is an element of proselytizing which you can’t do in Judaism, and Ethical Culture has that. It is for, partly, the rich Jewish community, with very much a sense of improving the social condition of the world around them. Ethical Culture does that. They start by opening an elementary school for the workers of the Ladies’ Garment Union. It expands and is very successful in terms of what it does.
They had some very good teachers, and there is a sense of noblesse oblige which comes with the Ethical Culture environment, going through that school. Doing the right thing, doing the noble thing, all of that, in the best of sense. And Oppenheimer had that.
Then he goes to the West Coast, becomes very socially liberal. With the left wing being something, seeing, reading correctly what’s happening in Spain, in terms of totalitarianism versus democracy. Because now we are clear in terms of the role that Stalin played with Spain – it is different from what they say it as.
For the most part, it was not that Bethe was oblivious during the 1930s. He was very happy doing his physics, he was very successful at Cornell. It was his association with his wife Rose that made him more conscious of all the issues. It was a joint decision on the part of Bethe and his wife to go out to Los Alamos. That was something characteristic of the Europeans, which tells you something about American marriages as opposed to European marriages. Every one of the Europeans, whether Jewish or not – Teller, Smith, Bethe – when they get asked by Oppenheimer to come to Los Alamos, they talk it over with their wives. It becomes a joint decision.
None of the Americans, when they are asked by Oppenheimer to come – they are told “you can’t talk to anyone about this.” None of them ever told their wives.
WR: I have a counterexample from later in 1945, 1946. My grandfather was an American chemist who went to Los Alamos.
SS: The chemists are different. The chemists are not directly involved, nor do they have this sense of Los Alamos being a utopia.
WR: No, I think my grandfather, who was a PhD chemist there, viewed it very much as a job.
SS: Yes. Technically. He was called upon professionally.
WR: As I think about their marriage, I think that my grandfather would have preferred to be a chemistry professor, but my grandmother felt like a stable government job was a good thing, even if you were making nuclear weapons.
I want to transition and ask some questions about Brandeis. You arrived here sixty years ago. How is it the same? How is it different?
SS: Let me start by saying that starting in the late 1970s, when I became an historian of science, my intellectual world shifted to being more primarily rooted at Harvard, with the community of people working on the history of science. I was a visiting professor there in the history of science, and have been an associate over there since 1980. So I know less about Brandeis.
But there is an interesting sociological fact, which may be strange, but I will say it. When I came to Brandeis in 1956, and developed the physics department, it was predominantly Jewish. The faculty members were Jewish, as a reflection of the physics community at large, certainly in theoretical physics. It turned out that for experimental physicists Brandeis was attractive if you were Jewish because it was creating something, giving to the Jewish community an equivalent to a Princeton or any of the Ivy League schools.
WR: Was that part of the draw for you to come to Brandeis?
SS: Definitely, no question. My background is such that, I was born in France. I only came to the United States in 1942. And so from 1942 to roughly, until I went to graduate school, even later, the issue was would I emigrate to Israel. So, yes, building a Jewish institution – secular, but Jewish-sponsored – meant a great deal. No question. As it did to many of the people who came here. And Abraham Sachar was exceedingly smart in attracting many of the people, not just in the sciences, also in the humanities, whether in English, in history, in music. Getting all of these people to start Brandeis.
So, at the present time in physics, the only colleague who is not Jewish is a colleague who came in the 1960s who is now retired. But go downstairs now and look in the “rogue’s gallery”, now it is a reflection of science in general. There are very few Americans. And I don’t know whether there are any people in the graduate school who are Jewish. It’s a reflection on the Jewish community, and likewise on Brandeis.
WR: Theoretical physics is no longer…
SS: Physics in general, and the sciences in general, are no longer a ladder for the Jewish population. Jewish people can now succeed in any number of places.
What is the other big difference? And again I am making a sociological point, and this is reflected both at Harvard and here. We live in post-modernity. We live in neoliberalism. And if I look at the graduate students in the sciences, and the young faculty being appointed. Certainly at Harvard, in history, history of sciences, being a university professor is a profession.
But, let me put it this way. Theoretical physicists, the only ones who really ask ultimate questions are the people who do astrophysics, who do high energy physics. For the rest of the community, it’s not relevant what happens in astrophysics. The way physics is formulated at the present time, the level of precision at which you operate, it’s not relevant, the subatomic level, quarks anything down there. You can see it at Harvard, at MIT, at the colloquia, if it is a talk on high-energy physics, unless it is clear that it is relevant to the condensed matter physicists, you don’t see them.
If it’s a talk on biophysics, the high-energy physics people don’t come. The pressure is too great – to know what is happening in your own subdiscipline. How does it resolve when somebody retires? Do you hire a new person in a specific subfield? So the character of a university, what a university is like, is very different from what it was when I first came to Brandeis.
WR: Different how?
SS: The great difference is this. As difficult as the context was, the cold war. Nonetheless, until the Vietnam War, it was a hopeful time. There was a sense that you could improve the world. At least you could improve this country.
Several of us, a colleague, me, during the sixties, went down during the summers and taught physics at Black colleges in the South. It’s part of what happens in the 60s. There is less of that now.
WR: Because of the pressure?
SS: No, because the world has changed. Whether it’s globalization, neoliberalism, all of these things. The world is very different. Partly, indeed by virtue of the technical advances that physics has provided. Better in terms of your iPhone. There is a totally different texture to the world because of all of that.
WR: What are you most optimistic about right now as you look at the world in 2016?
SS: My grandchildren. I have a granddaughter who is graduating from high school. She’s 16 or 17. She went on a State Department trip with a number of other people. Went to southern India. They were in Bangalore, Tamil Nadu. She stayed with a family and got a sense of the difference, and also the poverty. The conditions under which people in India live. Not different from a lot of other places.
She comes back. Her father and mother are both academics, and she is trying to choose, what kind of college, and what kind of profession she wants. But the one thing she knows is that whatever she chooses she wants to improve the world.
WR: Thank you so much for your time!
(Image: 1954 thermonuclear weapon test Romeo on Bikini Atoll. (Photo: United States Department of Energy, via Wikimedia Commons))
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