The interview is based upon an email exchange with professor A. Ravi Prakash Rau, professor of physics at Louisiana State University in the United States. Professor Rau is a renowned atomic physicist, who has recently completed 50 years on the LSU faculty. His deep knowledge of the history of physics is one of his many accomplishments. He is also a frequent visitor to the Tata Institute of Fundamental Research and the Raman Research Institute. His most recent book, The Beauty of Physics: Patterns, Principles, and Perspectives, was published by Oxford University Press in 2014.
Below is a transcription of the interview, lightly edited for style and clarity, by Vijay Poduri.
Even though you belong to a later generation of physicists, did you have associations with the Manhattan Project scientists?
Robert Wilson was a close associate of Oppenheimer and was the person who climbed up the gantry to prime the first bomb the night of the first July 1945 test. Along with Leo Szilard and others, he later became the nucleus of the Union of Concerned Scientists, who advocated against military use in the waning days of the Manhattan Project. He was a very interesting guy, an artist as well, who personally designed the main building and layout of Fermilab. He was one of the five on my PhD Committee at the University of Chicago, having just joined the faculty (from Cornell) in 1966 as I entered the PhD programme when he came to build that high energy physics accelerator lab near Chicago.
He was a good friend of my advisor Ugo Fano, and when I asked him to be on my committee, he agreed. But within weeks, he had realised the magnitude of the job he had taken on to build that lab and so begged off classroom teaching and other duties. Three years down the line, he told me that mine was the only PhD Committee he was on, felt that having said yes, he would honour it to the end, but did not take on any others.
What do you think were the ethical responsibilities of the Manhattan Project physicists?
I have thought quite a bit about this question. First, I feel that after digesting all the arguments for its use, it was unjust and unnecessary to have dropped the two bombs on Japan. I think it was driven more by Truman and the US military and political high brass as the first shots of the confrontation with the USSR that was already clear by war’s end.
The USSR was about to declare war against Japan (had already announced it) and, as on the European front where it was mainly the Red Army’s grinding down of the Nazis that defeated them, they would have then claimed a big voice in the shape of post-war Japan/Pacific just as they did in Europe, something the US did not want to share. The two Japanese cities became pawns in this. Another was of course for the US government to justify to its own public the enormous investment in the A-bomb project besides the US military’s interest in being the sole (could not, and did not last long) possessors of these weapons.
It is on that last that I feel the scientists should not have abandoned all say in use of the weapon they had developed. In part, because of the logic of the terrible war they were in the midst of, the President and military were ceded sole authority on this. I am not sure how in a democracy any alternative precedents could have been established but it would have been good, given the unprecedented qualitative nature of these weapons of mass destruction, that it was not simply left to top elected leaders to assume that authority but find some mechanism of civilian and science voices at the war table along with Presidents and Generals to decide on whether and where to drop such bombs.
I do not know how true and rigorous in practice it is but I read a big book on India’s bomb which says that the physicists of the Bhabha Atomic Research Centre, such as Raja Ramanna, retained some say with the Indian military on these matters, and did not simply hand over the technology into their hands. Apparently, the pattern continues of DAE and DRDO, civilian agencies, controlling fissile material and bomb assembly while the military controls delivery, whether by aircraft or missile.
At least some voice for such civilian involvement should have been insisted on by the Manhattan Project physicists. There was a committee consisting of five men, including Enrico Fermi, that opposed the use against Japan, but it seems to have yielded easily, and in fact, wartime secrecy kept even that from widespread knowledge within the larger scientific community or public.
There was another unfortunate wrinkle that unlike a few US-born physicists – Oppenheimer, Wilson, Serber, Feynman, etc. – many key Manhattan Project scientists such as Fermi, Bethe, Wigner, Kistiakowsky, etc. were recent emigres fleeing Europe because of the Nazis and the war. They probably felt constrained from speaking up strongly on moral or other practical grounds arguing against military use. Oppenheimer, as head of the project, could also not join Szilard and Wilson openly, but clearly allowed that dissent to develop at Los Alamos.
Effects of bombing in Hiroshima. Credit: Wikimedia Commons
What are some other examples of science and technology research where you see scientists having ethical responsibilities?
In our own time, an issue with some parallels is in biology, when the first genetic tampering became evident a couple of decades ago. There was even some concern about completely catastrophic consequences and some top persons like Paul Berg called for a worldwide pause on certain research developments, in an Asilomar, CA, conference. Of course, the moratorium did not last long, that particular work was later seen as an unnecessary concern, but it was at least an example of scientists themselves worrying about such grave issues in their headlong pursuit of “the sweetness of the research” itself.
Perhaps today’s AI use in weather modification or military use pose similar parallels but, unfortunately, too often people give in too facilely to the default of continuing the development. There are always arguments to do so, it is the easier route. In January 2020, just before COVID, I was at an international workshop at the Raman Research Institute on quantum technologies. As in the US, the spectre of China has been used by some Indian scientists also to push for satellite-based quantum cryptography (a boondoggle, apart from anything else, since conventional cryptographies will adapt) and, because of where the money is, they have made alliances with the Indian military and its budget.
The Chinese contingent of Pan and his group (Mincius satellite) were there in full force. They are very impressive, also in their very reassuring insistence on the benign nature of these advances, good for the public, and such. But, questions of Orwellian control through broad surveillance by governments of their peoples and, of course, inevitable consequences of tie-ins with militaries for these rockets and satellites, were nowhere in the picture. I got up in one discussion session to raise this and how all international scientists involved in these future cryptographies should be having such discussions at least privately and how to retain some control on uses as Manhattan Project physicists should have insisted on (as I say, a few did have such concerns, but proved ineffective). Except for a response from one colleague later, it just fell flat.
Also read: The Many Sides and Dilemmas of ‘Oppenheimer’, Father of the Atomic Bomb
There was quite a bit of variation in the attitudes of various scientists to nuclear weapons. Can you elaborate on that?
Going back to the 1940s, Edward Teller was, of course, a true believer in having these weapons and unconstrained Hydrogen bombs, something others such as Fermi, Oppenheimer, Bethe, and Feynman were against, that very unconstrained nature making them morally reprehensible. But Teller and John von Neumann, also emigres, took no heed of any of this, even running roughshod over fellow physicists like Oppenheimer.
My advisor, Ugo Fano, who was not in the Manhattan Project, like Subrahmanyan Chandrasekhar (who did work on the US military’s Aberdeen Proving Grounds), kept his relationships with all of them and told me how nearly everyone else ostracised Teller and would cross the street to avoid shaking hands, even much later when he came on visits to the University of Chicago.
On Heisenberg and his “collaboration” with the Nazis, there are more nuanced considerations. He did stay on in Germany (as did a few others such as Max Planck), in part to have a bona fide claim to take care of German science post-war. He did head one of their bomb projects. There was another independent project in Berlin and part of his self-defence of participation is that he wanted to keep control and have a say. Others will dispute, and have, that he was slow-walking the German project but he seems to have put the energies into a working controlled fission-reactor. At least as a working first step, that also makes sense, just as Fermi and others built the first Pile in 1942 before the bomb project.
Chicago Pile One scientists at the University of Chicago on December 2, 1946. Photo: Wikimedia Commons
Incidentally, I have visited Heisenberg’s set-up inside a cave in a small village called Haigerloch near Tuebingen. It was a very small affair, unlikely to have ever achieved criticality, and was captured along with Heisenberg and his team in the last days of April 1945 by a team led by physicist Sam Goudsmit.
My own assessment is that Heisenberg was brilliant enough to know that achieving a weapon in a couple of years to be relevant to the war would have required the kind of multi-billion investment Germany could not make, only the US could and did. The brilliant and very clever play by Michael Frayn, Copenhagen, based on the famous visit by Heisenberg to Bohr during the war, touches on some of these aspects.
Many people think highly of the well-known physicists of the 20th century, but given their ethical blind spots, they were not necessarily admirable people. Your thoughts on this?
I did not meet Fermi or Heisenberg, but Fano knew both very well. He had spent six months in Fermi’s Rome group and three years as Heisenberg’s postdoctoral researcher in Leipzig. And Chandrasekhar had been a colleague and close friend of Fermi at the University of Chicago. In some of my conversations with him, he was critical of most of these top physicists as human beings (even Bohr) but spoke well of Heisenberg as a man.
You have avoided expressing opinions about the physicists we mentioned as human beings because you did not know them personally. But since these physicists are historical figures, shouldn’t we develop judgements about them as we do for other historical figures, based on their public actions?
I completely agree that many great scientists fall woefully short in many aspects. In part, this is also why we cannot simply say that scientists should decide because it could easily be a Teller or Von Neumann, both great physicists but complete extremists on using nuclear weapons.
What are your views on including scientists in societal decision-making?
There are two related matters that I feel strongly about. One is about deferring to expertise, in every area. This is where the current US discourse has gone completely off the tracks, whether on COVID vaccines or climate change, with social media influencers and politicians from Trump onwards, or even Supreme Court justices substituting their pronouncements for expert knowledge and advice.
I have also looked askance at how our societies are structured in that we let courts and lawyers and ultimately a few justices decide on major issues for the entire population. Even if all justices were all-wise Solomons and Solominas, leave alone the petty partisans many are, why should other expert advice not be part of these decisions? Courts seek expert advice but I mean more, that they be dominant in those domains of even the final decisions. I do not know how societies can design for this but, certainly, what we have now is ridiculous.
Going back to nuclear weapons, a Martian viewing from the outside would find incomprehensible that a single Trump-Kim [Jong-]Un pair can unleash hundreds of warheads that could destroy all 8 billion humans, billions of other life forms and leave a radioactively saturated atmosphere and soil of a planet in nuclear winter. That we have structured things with no others, scientists among them, even at the table, just Presidents and Generals, is what is absurd, similar to the primacy given to lawyers and judges in our societies and nations.
The second important thing is humility. This is the one thing I would emphasise most, also why I stress having several voices at the table, a simple substitution of Generals and politicians by some “top” scientists is also not the solution. In fact, I have always regarded The Copernican Principle in its broadest form as one of the most fundamental of all philosophy. We have no special status, not just Earth in the Solar System, or that System in our Galaxy, or that Galaxy…. This is why claims of “End of History” (Fukuyama), “End of Science,” “Theory of Everything” (even if held by many top physicists) all seem to me vacuous concepts. They only show a lack of humility, instead hubris, that somehow, in our limited 100 years in time and occupying a small insignificant part of the Universe, we will get to any of these. Humility, coupled with “many heads are better than one” argue for several, and varied, voices to decide consequential matters.
Also read: Homi Bhabha, Jawaharlal Nehru and the Bomb
What were your thoughts on seeing the movie Oppenheimer?
I have now seen Frayn’s Copenhagen (both play and movie), the opera Doctor Atomic, and movie Oppenheimer, all with the major theme of the bomb but with different items of emphasis. The first was on one encounter, that between Heisenberg and Bohr when the former visited occupied Denmark, and what might have transpired in their discussions that they remembered very differently later. Through several “revisits,” Frayn very cleverly plays on alternative representations, uncertainty, etc., and how difficult it is to penetrate to what “really” happened. This is, of course, now immortalised as one of our central metaphors in Kurosawa’s famous Rashomon.
My own reading is that Heisenberg, at great risk for being hauled up for treason by the Nazi authorities, nevertheless with his great regard and affection for Bohr who had become a father figure and looking ahead to implications of such a weapon (of course he did not want one dropped on Germany), made the trip and was trying to signal that physicists on both sides slow-walk the development of the A-bomb during that war, that Bohr might be able to use his great influence, including moral, on the Allied side. Bohr seems to have taken it amiss, also not surprising given Denmark’s brutal occupation and ongoing Nazi atrocities throughout Europe.
The 2005 John Adams opera Doctor Atomic, based partly on Durrenmatt’s play The Physicists, features only four characters, Oppenheimer, Bob Wilson, Kitty Oppenheimer, and Teller, and while telling some of the story of assembling that “Trinity gadget,” brings out the moral struggles the first two have on what they have wrought. It also features centrally the famous Oppenheimer quote from the Gita.
In a movie, Nolan can feature more characters and present broader pictures and perspectives. In many of them, the movie does this very well. The main lines of Oppenheimer’s life, his unhappiness with Blackett and Cambridge, his tortured relations with several women, his unique ability to juggle many topics and brilliant people while driving a mammoth project to success, his cavalier handling of some around him and destroying their lives (Bohm who had to go to Brazil, Haakon Chevalier, and Bernard Peters who had to leave the US and joined TIFR where he became an associate of ECG Sudarshan) but also deep moral scruples on the use of these weapons, are all as we read in many books and some from what I heard from people who knew him. The main concentration of Nolan, even while showing the Los Alamos project’s development, is on what ensued and the tussle with Lewis Strauss. That was tied up with the war’s aftermath of a drive to bigger H-bombs and rivalry with the Soviets in controlling the post-war world and he himself being shunted aside by the opposition within the US government.
Many physicists have very brief cameo appearances – Fermi, Bethe, Bohr, Heisenberg, Feynman reduced to being shown with bongo drums – but a few have more substantial roles. Isidor Rabi was always firmly on Oppenheimer’s side, but had reservations from the start on moral grounds. Unlike many of the others he did not move full-time to Los Alamos. Despite his reservations, he did later become a consultant and continued to be influential in the Atomic Energy Commission. In the security hearings, he speaks firmly for Oppenheimer. Edward Teller is, of course, shown as being relentless from the beginning on the “Super.” In the hearings, he does not question Oppenheimer being loyal to the US but adds those famous back-handed slap of words of wanting the nation’s security in other hands.
Even Groves (mutual respect of the two very different men is well shown), while acknowledging that the later AEC rules would have meant denying his security clearance, adds that his loyalty is unquestioned and that most others would not have also qualified for clearance. He could have added that there would then have been no Project/Bomb. In spite of the hearings being stacked by Strauss and others, the three person board finds no disloyalty but splits 2-1 to deny security clearance.
The movie also shows how Strauss too comes to a fall, his vaunted ambition to become a cabinet secretary finally denied him. Some justice in that. This was true, a crucial vote being Sen John Kennedy of Massachusetts, who later as President wanted to make amends by giving Oppenheimer the Fermi Award of the AEC though fate intervened through his own assassination and LBJ is shown handing the prize in 1964. As an aside, years later, I attended the function where Fano got the Fermi Award.
I was thinking of how these things seem to work when matters at high levels play out, the final verdict always “splitting the difference.” There seems to be some kind of internal logic to it, being compelled not to give a clean, unambiguous exoneration or denunciation. So, Oppenheimer is deemed loyal but security clearance taken away (2-1) which of course removes him from being able to influence decisions on bomb development and use, but Strauss is also denied his prize. It is a bit like Comey vindicating Hilary Clinton on her email server but with uncalled for comments on irresponsible handling, or the recent replay of this by Robert Hur with gratuitous pronouncements on Biden’s memory that was not in the purview of his investigation instead of just concluding that no criminal charges apply.
Strauss’s vendetta apparently went back to his feeling of public humiliation when Oppenheimer in Congressional hearings ridiculed his opposition to shipping medical isotopes abroad, saying that they could not be used as weapons. That too reminds me of in our own times that Trump was furious about Obama’s ribbing of him at a White House correspondents dinner and that deciding him to run against Obama’s policies and overturn them.
The two encounters with Einstein were completely fictitious, Nolan making them up for dramatic effect. Teller’s calculations on whether the atmosphere may be ignited were not taken to Einstein but to Compton to verify and then the consensus was that it was very unlikely. Nolan said this was one of the items that struck him and drove him to make such a movie, that even a slight chance of something of that enormity did not stop the relentless project once begun.
As an aside, when it was not yet clear that a bomb would be possible, Fermi had advanced the idea of using radioactive isotopes to poison Germany’s food, part of the debate becoming whether it could cross some threshold of a million casualties! Sounds shocking to us today.
The other thing of the Einstein encounter is used to end the movie, conflating Oppenheimer’s quote from the Gita (“I am become Death, destroyer/shatterer of worlds,” actually said said upon witnessing Trinity), that although it did not ignite the atmosphere on July 16, 1945, with today’s missiles and thousands of warheads, coupled with the refusal to stop worse and worse weapons, perhaps it marks the end of the world. Even as a totally irrational use of resources, the US is spending a trillion dollars to modernize its nuclear arsenal.
I found personally interesting the scene when Oppenheimer meets Fermi in Chicago and there is a brief shot of a big pile of graphite bricks under the football field, that graphite both outer shield and moderator inside to slow neutrons in that first 1942 demonstration. Some of that must have been stored away in the attic because, as I wrote, when I did my Grad Lab experiment on 14 MeV neutrons (there was a small accelerator producing them from deuteron+triton reactions), I used some of those bricks to shield what I was building for my measurements.
Szilard is shown as leading a group at Los Alamos after July 1945 to work against dropping the bomb on Japan. There were also groups elsewhere such as at the University of Chicago, one of the physicists being David Hill, who exposed Strauss at a congressional hearing.
Coming to Heisenberg, first an interesting story, touched on also in the movie, that in spite of the secrecy of the Manhattan Project, all physicists knew of the possibility once Fermi established that neutron-induced fission releases more neutrons. Leo Szilard, who got Einstein to write the letter to FDR that started the project, had already in the early 1930s patented the chain reaction should this turn out to be true. Fano told me of a meeting one evening over cocktails in a Chicago faculty house (Fermi’s or Compton’s?) where he and many physicists were present. So was Heisenberg, who was visiting the US in 1939 just before the declaration of war. There were whispers, pointing to Fermi and Heisenberg standing at one corner, that a war was coming and the two men would be on opposite sides and trying to make nuclear bombs.
Heisenberg’s motives are disputed, but as I noted, I saw his reactor experiment at Haigerloch and it was on much too small a scale to work and was using heavy water as moderator, something shown being mocked by a couple of physicists in the movie. As with Fermi, a reactor was the first step to show feasibility. I liked very much several times in the movie the words that experiment decides, otherwise theory is sterile, one of my own favourite lines over the years.
Whether Heisenberg saw early that a huge effort would be needed and deliberately slow-walked the project, knowing Germany could not put such an effort during that war, is disputed by some. But, after the war, in arguing against Germany developing the weapon (as France and the UK did), he was part of the Goettingen Manifesto in 1957, in which several West German nuclear scientists refused to work on nuclear weapons. A central paragraph of that Manifesto is unequivocal: “Our profession, that is, pure science and its application, through which we bring many young people into our fold, leaves us with the responsibility for the potential effects of these actions. Therefore, we cannot remain silent to all political issues.”
