Last week, AIP opened to the public three interviews with Robert Oppenheimer from our collections. While researchers have previously been able to consult these with permission from the Oppenheimer family, we have worked with the family to update the terms of use so that the interviews can be included in our online oral history collection. There are relatively few extended first-hand remarks by Oppenheimer that can be readily accessed, and now anyone can freely examine this expansive trove of them.

1960: Scanned transcript | Formatted transcript

1963: Scanned transcript | Formatted transcript | Audio

1966: Scanned transcript | Formatted transcript | Video

The first interview was conducted in 1960 by journalist Robert Cahn as background for an article he wrote for the Saturday Evening Post. The transcript appears to be a near-verbatim summary of their conversation, but unfortunately we do not have the original tape recording. The second interview was with philosopher Thomas Kuhn in 1963 as part of the Sources for History of Quantum Physics project, and the audio of it is also available (though the sound quality is uneven). The third interview was conducted by Charles Weiner, then the head of AIP’s history program, for the Harvard Project Physics film The World of Enrico Fermi, and we have posted the full interview footage.

For scholars, the interviews will not offer any startling revelations, but readers who know Oppenheimer’s biography well enough to contextualize his remarks will find significant insights. To offer a sense of how at least one expert would see the interviews, we asked nuclear historian and former AIP postdoc Alex Wellerstein for his impressions. His reading focuses both on little details that the interviews add to existing knowledge as well as Oppenheimer’s personal perspective on the history he inhabited.

The 1960 interview: The Manhattan Project

Wellerstein: This is full of interesting stories and anecdotes, but the most charming of them of course have already been known for a while. I think his description of implosion work at Los Alamos is particularly good in that it does not completely tell the narrative from the known outcomes, as is often done. One gets a sense of the searching quality of it, of the number of unknowns, of the false starts and directions. The parts of most interest to me personally are his discussions of the pressures of time.

Oppenheimer: “I remember that we sometimes tried to say, suppose it doesn’t work, what will we do. And we could never answer that, because we felt that from where we stood we didn’t know enough to imagine what we would do unless we also found out why it didn’t work. … We could, of course, have tried to make implosion uranium bombs, and I proposed to [Manhattan Project head Gen. Leslie] Groves we make something that would be a little more efficient use of the material. But he, and I think probably rightly, felt that it was a time to be sure and to be fast, and that delay might be more serious. … I tended to think that there would be more trouble if I painted a glowing picture to Groves and then we welshed on it, than if I made a fairly conservative estimate and then we did a little better. I thought that if he presented a fairly optimistic picture and then things started slipping, the whole confidence in the operation might get lost. Perhaps I was wrong.”

Wellerstein: I thought the discussion of Joseph Hirschfelder starting the study of fallout was interesting, both because it is an anti-compartmentalization argument of sorts, but also because one gets a real sense of how idiosyncratic the approach to bomb problems could be. Fallout of course became a major issue, but the ways in which it was only somewhat understood at the time are interesting.

Oppenheimer: [asked for an example of non-compartmentalization] “There was a physical chemist called Hirschfelder (now at Wisconsin), he helped with explosives. But he wasn’t playing a very central part. But we came up with one very big thing. He understood there would be fallout and predicted it, explained what one could and couldn’t do to reduce it, and prepared us for it, so that we could at least measure it, take some precautions. He was doing something like studying the effects of the explosion on the atmosphere (there were all sorts of complicated things), but this [was] one point for which no one had any responsibility, which of course has had quite a history since then.”

Wellerstein: Niels Bohr is known to have been given a lot of credit in the initiator discussions, but what exactly his contributions were has never been all that clear. I haven’t seen it described this way before. Things about the initiator work are still redacted in most accounts, so this is helpful in understanding Bohr’s role, even though it doesn’t give a lot of details.

Oppenheimer: “I for a long time felt that maybe we were not taking the initiator problem seriously enough, but that was cleared up and Bohr played a large part in giving a general argument that it was much harder to misdesign than to design an initiator, that is that almost anything you put together would work. We did overdesign it. But the notion that this thing would fly together and fly apart without there being a neutron to start the chain reaction was not very attractive.”

Wellerstein: I don’t recall reading that Oppenheimer had received tritium-deuterium cross sections right after the Trinity test—perhaps it has been noted before, but I didn’t remember it. It’s interesting and highlights the sense that the Super was always lurking on Oppenheimer’s mind (as well as others’) as the ultimate example of what they were building could lead to, eventually.

Oppenheimer: “There was a dramatic small point. When I got back to Los Alamos there was a report on my desk giving an account of the enormously high reaction cross-section [of the] tritium–deuterium reaction. It was very relevant for the thermonuclear. [Robert] Bacher had been working on it. It was very favorable—or ominous.”

The 1963 interview: Quantum mechanics and early experiences

Wellerstein: A lot of these early stories are nice—they’ve been used in biographies before, though. It is interesting to see Kuhn trying to impose his own categories of thinking on Oppenheimer at times. I think Oppenheimer’s description of himself at California in the last two pages is probably the most interesting. One gets a real “feel” for him here: it’s not “Oppenheimer the brilliant scientist,” it is “Oppenheimer the junior professor,” and it is at times remarkably self-deprecating.

Oppenheimer: “I found myself—entirely in Berkeley and almost entirely at Cal Tech—as the only one who understood what [quantum mechanics] was all about, and the gift which my high school teacher of English had noted for explaining technical things came into action. … I started really as a propagator of the theory which I loved, about which I continued to learn more, and which was not well understood, but which was very rich. …

I think, from all I hear, that I was a very difficult lecturer. .... I remember [Linus] Pauling’s advice, almost certainly in ‘28. He said, ‘If you want to give a seminar or lecture, decide what it is you want to talk about, and then find some agreeable subject of contemplation not remotely related to your lecture, and then interrupt that from time to time to say a few words.’ So, you can see how bad it must have been. …

In Berkeley I gave what was … in practice usually a second-year graduate course, which had not been given before, on quantum theory and quantum mechanics. ... I usually gave a seminar on one other aspect of theoretical physics, typically statistical mechanics and relativity, both things which I loved very much. But these were all with people who didn’t have to learn these things, but [rather] wanted to. .... It was very rarely and only in quite different contexts that I ever worked with undergraduates. I think they didn’t think I’d be any good for them, and it didn’t occur to me to ask to teach freshman physics or anything like that.”

The 1966 interview: Enrico Fermi and the state of physics

Wellerstein: I am not sure whether Oppenheimer’s reflections on Fermi tell us much more than we know, but there are parts that seem quite personal, quite probing. I thought the parts on Fermi’s changing attitudes towards the military/government were interesting.

Oppenheimer: “He had a good deal of trust that when the military said they had a requirement, they must know what they were talking about. And he had a tendency to suppose that those who in some vague sense were the government must be quite expert at that, as he was expert at physics. I think he lost this confidence, not in himself, but in the fact that other people were just like him in different areas of human activity. … I know that he was discontented, and spoke to me later, of the casualness with which we had dealt with the so-called hydrogen bomb question.”

Wellerstein: I think the bit about Fermi saying he was most proud of his work on the first reactor is interesting, as well as Oppenheimer’s admission that this seems odd to many physicists.

Oppenheimer: “Fermi sometimes said, and I think deeply meant, that that was the thing that he was proudest of. This strikes people who have contempt for practice as a rather odd thing for a physicist to say. But it was very much in character.”

Wellerstein: I also thought there were some good lines in Oppenheimer’s reflections on what physics had become by the final years of his life, as opposed to what it was in his youth.

Oppenheimer: “The number of physicists is very much larger. The ways in which they can occupy themselves, earn a living, play a useful part, are very much more varied than 50 years ago. The number of truly gifted men, who by their gifts and by character come somewhere near the phrase “great physicists, great scientists, great men,” is obviously not going to be very much bigger today than it was in 1910. And it’s pretty hard to beat Einstein, Rutherford, and Bohr, who were all on the scene at that time.

And so if you look with a dull eye, you think it’s a much less distinguished company, because it’s much more diluted. But if you look with some attention to what people are doing, I think you see the opposite, namely that gifted and imaginative and technically enormously resourceful work is very much more widespread than it was 50 years ago.

I believe that it is just for a man to decide whether to rejoice or to weep about this. But he mustn’t get mixed up about it. It’s not the same world.”

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William Thomas
American Institute of Physics
wthomas@aip.org

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