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Karl Giberson

Mr. Uncertainty: Part 2: The battle over Heisenberg.

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Otto Hahn wanted to kill himself, because it was he who discovered fission, and he can see the blood on his hands. Gerlach, our old Nazi coordinator, also wants to die, because his hands are so shamefully clean.

Heisenberg, in Copenhagen, Act One


Werner Heisenberg won the Nobel Prize in Physics for 1932 (received the following year). But this is certainly not adequate to explain the continuing interest in him and his work. Five years later Clinton Davisson and George Thomson won Nobel prizes, and who has heard of them? True, Heisenberg's prize was for work on the foundations of quantum mechanics, perhaps the most exciting theory in all of science, but he had collaborators in this effort who also made large contributions—Paul Dirac, Erwin Schrodinger, Niels Bohr—yet who, while far better known than Davisson and Thomson, certainly have not generated the kind of ongoing fascination that attends Heisenberg.

The first account of the Heisenberg Affair was an article written by Heisenberg himself that grew out of discussions with fellow internees at Farm Hall. Published first in German in 1946 and then in English in 1947 in the prestigious scientific journal Nature, the article argued that the German physicists knew very early on how to build an atomic bomb but, because of moral reservations about providing Hitler with such a terrible weapon, they deliberately did not work on the bomb and even interfered from time to time by falsifying results.

This account, in which Heisenberg portrayed himself in a favorable light, was quickly challenged by the first full-length treatment of the Heisenberg Affair: Alsos, by Samuel Goudsmit, published in 1947 and recently re released with a new introduction by Heisenberg's biographer, David Cassidy. "Alsos" was the code name for the Allied mission to capture the German nuclear physicists at the end of the war. Goudsmit, the discoverer of electron spin, had himself played an important role in the development of quantum mechanics and was a friend and colleague of Heisenberg before the war.

As the Allies were liberating Europe, Goudsmit was put in charge of gathering intelligence on the German bomb program. It was his job to evaluate the status of scientists and laboratories that may have been involved in the German war effort. The long-range Allied goal was to make sure that nothing of use would fall into Russian hands. If Goudsmit decided a scientist had played a meaningful role in the German bomb project then he would have him arrested. If laboratory equipment looked useful, he would have it confiscated.

Goudsmit was a Dutch Jew whose parents had been killed at Auschwitz just before the end of the war. He had tried to get Heisenberg to intervene on their behalf and never forgave him for what he thought was his rather feeble attempt to rescue his parents. Having seen the Farm Hall transcripts, which were so secret that even their existence could not be acknowledged at that time, Goudsmit was convinced that the "Heisenberg History" was self-serving propaganda and that his old friend was lying.

More than 50 years after its first publication, Goudsmit's book retains its power. In one passage he describes his arrival in the The Hague just after the liberation of Holland:

My trip gave me the chance to visit the house of my parents in The Hague, where I had been brought up . …I dreamed that I would find my aged parents at home waiting for me just as I had last seen them. Only I knew it was a dream. In March, 1943, I had received a farewell letter from my mother and father bearing the address of a Nazi concentration camp. …

Climbing into the little room where I had spent so many hours of my life, I found a few scattered papers, among them my high school report cards that my parents had saved so carefully through all these years.

The world has always admired the Germans so much for their orderliness. They are so systematic; they have such a sense of correctness. That is why they kept such precise records of their evil deeds, which we later found in their proper files in Germany. And that is why I know the precise date my father and my blind mother were put to death in the gas chamber. It was my father's seventieth birthday.

Goudsmit's book provided the first interpretation of Heisenberg's wartime work. It was a highly negative, even hostile, evaluation and drove a wedge between himself and Heisenberg that they were never able to eliminate entirely. Nevertheless, Goudsmit's attitude softened over the years until he was able to deliver the following as the closing paragraph of Heisenberg's obituary:

Heisenberg was a very great physicist, a deep thinker, a fine human being, and also a courageous person. He was one of the greatest physicists of our time, but he suffered severely under the unwarranted attacks by fanatical colleagues. In my opinion he must be considered to have been in some respects a victim of the Nazi regime.

One cannot help admiring Goudsmit's generous spirit of forgiveness.

Goudsmit's remarkable book was deeply resented by the repatriated German nuclear physicists, several of whom continued to proclaim publicly that they did not build a bomb for Hitler because of "moral scruples." The most aggressive proponent of this myth was Carl Friedrich von Weiszacker, a student of Heisenberg's who had also been interned at Farm Hall. Von Weiszacker was more political than Heisenberg and was eager to refurbish reputations tarnished by Goudsmit.

So, Heisenberg, why did you come to Copenhagen in 1941? It was right that you told us about all the fears you had. But you didn't really think I'd tell you whether the Americans were working on a bomb.

Niels Bohr, in Copenhagen, Act One


In 1949 Swiss journalist Robert Jungk, with the help of von Weiszacker, published Brighter Than a Thousand Suns, attempting to discredit Goudsmit's indictment by providing a very readable account of the German physicists' claims to have sabotaged Hitler's bomb project. Jungk later—much later—admitted that his influential account was bogus and apologized for the "spreading of the myth of passive resistance by the most important German physicists." He acknowledged that he had been "blinded by his esteem for those impressive personalities."1

In 1962, General Leslie Groves, who had been the military coordinator for the Manhattan project and who had seen the still-classified Farm Hall transcripts, provided his account in Now It Can Be Told. Groves covered the entire Manhattan Project; insofar as he dealt with the German counterpart, he echoed Goudsmit's earlier version. Groves's book was the first to mention the existence of the Farm Hall transcripts, a revelation that got historians clamoring for their declassification.

In the meantime, however, the Heisenberg History was steadily reinforced by ever more ingenious claims by the German physicists about how they had withheld the bomb from Hitler. Heisenberg carried the mystery with him to his death in 1976, but in 1980 Elizabeth Heisenberg published her account, Inner Exile, providing a tragic insider's perspective on her famous husband. Based less on the kind of documents that historians love, and more on the self-interested personal interpretations that arouse their suspicion, this memoir nevertheless provides a number of critical insights which, because of their great explanatory power, seem to ring true. Mrs. Heisenberg argues that her famous husband was never really confronted seriously with the prospects of building a bomb for Hitler. Initial estimates had indicated that the project had a time frame that was simply too long for leaders whose horizons were bounded entirely by the war.

This apparently benign claim is not without controversy. Historian Mark Walker, in his 1989 book, German National Socialism and the Quest for Nuclear Power, argued that the Germans were working on "bomb technology" although not actually on a bomb. (It is important to note what "working on a bomb" or "working on bomb physics" does and does not mean. There are many aspects to building bombs, and almost all of them involve scientific and technological problems that are interesting in their own right. For example, getting a sustained nuclear reaction to work is a very interesting scientific project, regardless of what use might be found for such an accomplishment.) Walker concludes that practical limitations based on economic and political considerations—rather than any moral or even scientific constraints—explain the pitiful German bomb effort.

Walker's argument was not original, but it was based on careful consideration of actual documents from the war and thus marked a significant advance in the Heisenberg controversy. Certainly Walker provides at least part of the answer to the "mystery," and maybe a large part. The Allied bomb project employed more than 100,000 people at one point, at several different locations. For example, there was a huge plant in Oak Ridge, Tennessee built to extract the fissionable uranium 235 from the 235/238 mixture in which it naturally occurs. The center at Oak Ridge had over 20,000 construction workers employed on it in August of 1943; almost 300 permanent buildings erected; and it had to run without interruption for more than a year simply to extract the requisite uranium 235 using a very inefficient method that exploited the small mass difference between the two isotopes of uranium. A similar center was built at Hanford, Washington, to try and make bomb material using another approach. And so on. The collective effort that went into the Manhattan Project was almost beyond comprehension.

Walker's argument, which also appears as a part of the German scientists' discussion at Farm Hall (to which he did not have access), was that the sheer magnitude of the technological effort required to build a bomb was simply not possible in wartime Germany. The Allies would have bombed any such strategic sites into oblivion. On November 16, 1943, for example, the Allies destroyed the Vemork power plant in Norway, effectively shutting down production of the heavy water the Germans were using in their nuclear research. On February 20, 1944, Allied commandos sank a ferry trying to transport 20 barrels of surviving heavy water from Norway to Germany. At one point Heisenberg was doing research in a cave, trying to prevent further destruction of his laboratories, which had already been bombed. Meanwhile, at Los Alamos, the families of the scientists and engineers racing toward the bomb were complaining that there was nothing for them to do.

We've been rounded up by the British—the whole team, everyone who worked on atomic research—and we've been spirited away. To Farm Hall, in Huntingdonshire, in the water-meadows of the River Ouse. Our families in Germany are starving, and there are we sitting down each evening to an excellent formal dinner with our charming host, the British officer in charge of us.

Heisenberg, in Copenhagen, Act One

Hitler's Uranium Club

On Feb 24, 1992, after decades of clamoring by historians, the Farm Hall transcripts were finally declassified. Surely the secretly recorded text of candid conversations among German scientists at the time of the bombing of Japan would lay the Heisenberg mystery to rest once and for all.

Goudsmit had argued that Heisenberg was immoral, a "hypocrite" and a "liar"; Jungk argued that he was heroic, a courageous member of the resistance; Elizabeth Heisenberg and Mark Walker had stressed practical issues that prevented the actual confrontation of the central moral question about building a bomb for Hitler. Who was right?

The first major book that was allowed to discuss the transcripts openly was Pulitzer Prize-winning journalist Thomas Powers's Heisenberg's War, published in 1993, a massive historical thriller which argues, once again, that Heisenberg was intentionally sabotaging the German bomb project. Powers's case is based on the following questions:

  1. Why did one of the other German nuclear physicists (Houtermans) complain that Heisenberg "tries to delay the work as much as possible?"
  2. Why did Heisenberg go to see Bohr in 1941? This remains a big mystery, probably never to be resolved. Heisenberg and Bohr tried to reconstruct their conversation after the war, but they differed on so many points that they gave up. They could not even agree on where the famous Copenhagen Conversation took place.
  3. Why did Heisenberg suggest that bombs required two tons of uranium 235, an amount that would take decades to extract from the 235/238 mix in which natural uranium occurred? There is some evidence, again not conclusive, that Heisenberg may have believed that the actual amount that was needed was much smaller.

Powers's answers to these questions led him to conclude that Goudsmit was so distraught by the death of his parents at Auschwitz that he could not read the Farm Hall transcripts objectively. Those sections of Goudsmit's seminal 1946 history Alsos that were based on statements made by the detainees at Farm Hall were carefully "selected" by Goudsmit, Powers charges, to portray the Germans in the worst possible light.

Powers's eminently readable book was widely reviewed and influential, especially among readers outside the science community. Unsurprisingly, however, not everyone agreed with Powers's own interpretation of the Farm Hall transcripts. In fact, some of the reviews of Heisenberg's War written by physicists who were able to interpret the Farm Hall transcripts for themselves were quite hostile.

The most complete analysis of the Farm Hall transcripts is Jeremy Bernstein's annotated account, Hitler's Uranium Club: The Secret Recordings at Farm Hall, which appeared in 1996. Bernstein, a professor of physics at Stevens Institute of Technology and longtime staff writer for The New Yorker, is well qualified to deal with this complex topic; he also worked for Goudsmit at Brookhaven National Laboratory in 1959 and witnessed two atomic bomb tests in 1957. He is a physics "insider," knows some of the principals personally, and has a sensitivity for how physicists think.

Bernstein's book—which takes its title from the name the German nuclear physicists gave to themselves—is a remarkable analysis of the Heisenberg question. An introduction by Cassidy and a 53-page prologue by Bernstein provide historical context, giving an overview of nuclear physics in Germany during the war.

As mentioned above, it was Groves's 1962 book, Now It Can Be Told, that first revealed the existence of the Farm Hall transcripts. In 1981 the eminent Harvard historian of science, Gerald Holton, asked to see the transcripts. He was told they were remaining classified beyond the normal 30 years because their release might cause "distress or embarrassment" to the immediate families or the descendants of the principals. Just who might be embarrassed by them was not clear, and this remains as a mystery to be solved. Bernstein speculates that the issue might have had something to do with Carl Friedrich von Weiszacker,2 Heisenberg's protege and fellow Farm Hall detainee, whose brother Richard had become the president of Germany.

No doubt the president of Germany had little enthusiasm for the release of transcripts that might embarrass his brother, who had become a leading figure in German culture, as well as remind the world that some of Germany's greatest scientists had tried to build a bomb for Hitler. In any event, after a 1991 appeal from the Royal Society, the transcripts were finally released to a general public still very much interested in Werner Heisenberg and what he was doing in Germany during the war.

The transcripts are a historical pearl of great price. The infamous internees were allowed to listen to the BBC reports of the bombs dropped on Japan. Initially suspecting a hoax, they eventually came to believe that the Americans had succeeded where they had failed; they then set about "constructing" a history to make their failure less embarrassing; at least this is how Bernstein interprets the proceedings. And all of this is caught on tape. The transcripts have been available now for almost a decade and several books have appeared to analyze them. Do they answer all the questions about what Heisenberg was doing in Germany during the war? No, or Powers and Bernstein would not be in such strong disagreement.

If Elizabeth Heisenberg is to be believed, the transcripts never will lay these historical questions to rest. She maintains her husband suspected they were being monitored and that some of what is on the transcripts was choreographed for the benefit of their British hosts. It may be significant that she wrote this years before the transcripts were declassified and she really had very little knowledge of exactly what the transcripts contained. Nevertheless, having read the transcripts myself, I find her suggestion highly unlikely. The tone that comes through very clearly is that of a spontaneous conversation recorded without knowledge of the participants.

The transcripts as presented in The Uranium Club go on for over three hundred pages with a running commentary by Bernstein. Many interesting things emerge in the course of the conversation—generally unflattering to the participants. The Germans appear not to have understood the significance of their losing the war. They complain endlessly about being detained without being charged with anything and threaten their hosts with breaking their parole and "running away." In their minds, as soon as the war is over, everything should go immediately back to normal. It is as if for them, World War II was just another European conflict, not unlike its countless predecessors.

Indeed, the German physicists display an extraordinary arrogance about their own importance. At one point von Weiszacker suggests that maybe the fate of the ten detainees was to be decided at Potsdam, as if Churchill, Stalin, and Roosevelt had nothing more important to discuss! The irony of this arrogant presumption has multiple layers. Heisenberg appears to have no clue how a bomb works, and Bernstein is particularly struck by what he calls the "intellectual thinness" of the group.

One of the most curious comments in the transcripts is made by von Weiszacker on August 7, upon hearing the news of the first atomic bomb: "History will record that the Americans and the English made a bomb, and that at the same time the Germans, under the Hitler regime, produced a workable engine.3 In other words, the peaceful development of the uranium engine was made in Germany under the Hitler regime, whereas the Americans and the English developed this ghastly weapon of war."

This is the birth of the Heisenberg Myth. This statement was repeated with variations again and again by von Weis zacker, Heisenberg, and those who told their tale. It plays a prominent role in Jungk's book; it forms the background to Powers's more recent treatment.

The extraordinary resilience of the Heisenberg Myth seems to have driven at least one scholar to assume a prosecutor's role. Penn State historian Paul Rose is the author of Heisenberg and the Nazi Atomic Bomb Project: A Study in German Culture, a massively documented yet strident polemic. Although Rose's book was published in 1998 it was written earlier, and Bernstein's book on the Farm Hall transcripts came out before it appeared. Bernstein, as we have seen, is himself sharply critical of the myth, but Rose attacks Heisenberg; in Rose's final analysis, the man is totally despicable.

That was the last and greatest demand that Heisenberg made on his friendship with you. To be understood when he couldn't understand himself. And that was the last and greatest act of friendship for Heisenberg that you performed in return. To leave him misunderstood.

Margrethe Bohr, in Copenhagen, Act Two

Why Did Heisenberg Do It?

If Rose has truly made his case then an interesting question emerges. How could a sophisticated, upright German scientist, mentored by the saintly Niels Bohr, working in a field whose central hero was the peace-loving Jew Albert Einstein, work on an atomic bomb for Adolf Hitler? Was Heisenberg a truly villainous character?

The most original part of Rose's book is his attempt to psychoanalyze the German psyche to see what it was about German culture that made so many "good" Germans so willing to do so many bad things. Seemingly upright people like Heisenberg and Hahn apparently thought it would be OK to deliver an atomic bomb to Hitler. Other, equally upright, people delivered Jews to concentration camps; some designed efficient poisons; we all know the story.

What was it about Germany that allowed this to happen? In Rose's words, "What explains the strange violation of common sense so often encountered in the postwar recollections and excuses offered by major cultural figures of the Nazi period?"

Rose answers this question in chapter 15, "The German Context," where he enlarges the ad hominem attack he has been making on Heisenberg to include all of Germany. Rose suggests that the untoward behavior of Germans like Heisenberg can be understood provided we "abandon our Western rationality and sensibility and being to think and feel 'German.'" We can do this, Rose suggests, by placing ourselves under the spell of a quartet of influential historical figures—Martin Luther, Immanuel Kant, G. F. W. Hegel, and Richard Wagner.

From Luther we learn that "freedom" is a purely internal state—salvation—that has nothing to do with one's outer political configuration. The Lutheran way, which became the German way, which became Heisenberg's way, was simply to obey the rules of the "State," no matter how morally corrupt it was, because, as Luther's translation of Romans 13:1 stated so clearly: "Let everyone be subject to the authority that has power … for all authority is ordained by God." In the meantime one should rejoice in one's inner freedom, which is separate from the state.

This was made even more explicit by Kant, whose categorical imperative—act only in a way that you would be comfortable generalizing into a rule for everybody—seemed to make it an unambiguously immoral act for an individual to go against the state. After all, imagine the un-German chaos that would ensue if every political malcontent engaged in acts of political subversion.

This German—actually Prussian—spirit of political subservience was taken one step further by Hegel, whom Rose interprets as claiming that "in the modern era the spirit of reason had reached its apogee in the Prussian state"—the "purest exemplar to date of reason and human freedom." And finally all of this was dressed up for cultural consumption by the great and profoundly anti-Semitic composer Richard Wagner.

Rose's analysis of the cultural context that nurtured figures like Heisenberg initially struck me as plausible, but I ran his historical scenario by a German colleague who teaches history of philosophy here at Eastern Nazarene College for her response. Her objections ran something like this: German anti-Semitism cannot be traced solely or even primarily to Luther; southern Germany was Catholic, taking no cues from Luther; the rest of Western Europe was also anti-Semitic and one can hardly imagine that the anti-Semitic riots in France were inspired in any way by Luther; as for Hegel, who hailed from Stuttgart, making him a Swabian, it apparently is inconceivable that a Swabian would have endorsed the Prussian state. This, it seems, is a common "American misreading" of Hegel.

Indeed, Rose's analysis, in my colleague's view, is a typical "American" misinterpretation of German politics. In America we expect the government to represent us, and become dissatisfied when it seems to go its own way; in prewar Germany, and even today to some degree, the government does not "represent" the people so much as "look after" them. The German view of war, my colleague said, is also radically different from the American view. "Wars come and go" in Germany, and historically many people have simply observed the arrival of a new war, or revolution of some sort, and waited for things to settle down.

Of course, none of this justifies Nazism in any way. But it does shed light on prominent Germans like Heisenberg who were enculturated to ignore the ethical shortcomings of their leaders, to be incomprehensibly disinterested in politics, to see wars as things that "come and go," to love their country for its past rather than its present.

Has Rose made his case? In an essay in Commentary (May 1999), Bernstein challenged a key piece of Rose's documentation. Rose makes much of a letter he claims was written by Heisenberg to Ruth Anshen in 1970. (Anshen was the power behind a series of books to which Heisenberg had contributed a volume.) In this letter Heisenberg writes with a clarity not found in any of his other statements where he suggests that he did not really want Hitler to get a bomb: "Dr. Hahn, Dr. Von Laue, and I falsified the mathematics in order to avoid the development of the atom bomb by German scientists."

This remarkable statement by Heisenberg is one of the reasons why Rose is so convinced that Heisenberg is a pathological liar, continuing along the immoral trajectory on which he embarked by remaining in Germany during the war. However, this letter is mysteriously missing and could not be found among Anshen's papers when she gave them to Columbia University. Nevertheless Rose is convinced "beyond doubt that the letter was genuine." Anshen's papers at Columbia do have three other letters from Heisenberg to Anshen, but there is nothing resembling this one.

The claim that Heisenberg allegedly made in this letter is unbelievable on a number of accounts, not the least of which is the tacit admission of treason. There is no way that Heisenberg would have indicted Hahn and von Laue as co-conspirators. Hahn was a chemist, not even close to being in Heisenberg's league in the area of mathematics. Whatever Hahn may have had to do with nuclear research in Germany it would most certainly not have been helping Heisenberg with mathematical calculations. As for von Laue, he simply did absolutely no research whatsoever on nuclear physics. He was not a member of the Uranium Club. His internment at Farm Hall was a puzzle to him and everyone else, and was probably due to Goudsmit's concern to keep him out of Russian hands. Furthermore, a claim that one might prevent the development of a bomb by "falsifying" mathematics is also very odd. The atomic bomb is an engineering problem, with countless small details that must be worked out. It is not based on an "equation" and, in fact, is not all that complicated from a mathematical perspective.

I agree with Bernstein that there is no way that Heisenberg could have written that letter. If the alleged document to which Rose refers exists at all, it could only be a forgery. Someone with limited knowledge of the German bomb project might have lumped Hahn, von Laue, and Heisenberg together since they were perhaps the most famous of the Farm Hall detainees, all three having won Nobel prizes.

The fact that Rose has so unequivocally embraced the authenticity of this letter and used it so prominently—in an argument that was overly aggressive and ad hominem to begin with—will probably discredit his work. It remains to be seen whether Bernstein will produce a more detailed treatment addressing this question.

In the meantime, there is Michael Frayn's play, Copenhagen, which recently opened in New York. Inspired by Frayn's reading of Powers's account of Heisenberg's controversial trip to Copenhagen in 1941 to talk to Bohr about physics, bombs, politics, war, and who knows what else, the play succeeds gloriously in capturing the unfathomable complexity of the Heisenberg controversy.

For two and a half hours, Niels Bohr, Margrethe Bohr, and Werner Heisenberg talk. Tense moments discussing the Nazi occupation of Denmark give way to scenes of great freedom as Heisenberg makes Margrethe sit on a chair and pretend to be a neutron with her husband an electron orbiting about her; Heisenberg plays the role of a photon, careening into the electron to show how observation influences measurement. In addition to serving as a sort of "conscience" for her great husband, Margrethe's presence provides a pretext for complex ideas from physics to be explained in layman's language, although Frayn has portrayed Margrethe as quite sophisticated scientifically and otherwise.

And sooner or later there will come a time when all our children are laid to dust, and all our children's children.

Margrethe Bohr, in Copenhagen, Act Two

Yes, But

In the course of writing this essay I found myself going back and forth between the Bernstein/Rose position and that of Powers, persuaded and yet dissatisfied by both.

Heisenberg was a great theoretical physicist, a powerhouse with abstraction. Experimental physicists like myself, whose training includes pedestrian things likes how to get vacuums to stop leaking, or how to polish laser mirrors, are not worthy to sharpen his pencils. He was Germany's greatest scientist and youngest full professor, a Nobel laureate; his stature made it inconceivable that anyone else could direct any major physics project in Germany.

On the other hand, he was a very poor experimentalist; he had failed that part of his doctoral exam, missing simple questions about batteries and telescopes. He knew nothing about engineering and even looked down his nose at that part of physics. If the physics problem could not be solved entirely in his head or on a piece of paper, then he wasn't very interested in the problem; nor was he particularly adept at solving it. Trying to turn Otto Hahn's 1938 discovery of nuclear fission into either a reactor or a bomb was not a job that could be done in Heisenberg's head. It required endless and sophisticated consideration of practical matters: shaping, polishing, fastening, cleaning, wiring, cooling. Building a bomb is more like building an airplane than inventing quantum mechanics.

Fission research, leading either to a reactor or a bomb, was held back in Germany because Heisenberg was simply not competent to direct such a project. His counterpart in the United States, J. Robert Oppenheimer, another powerful theoretician, insisted from the start that he have a close adviser who was an experimentalist so that he could be in constant dialog with that critical part of the project. Oppenheimer's respect for that part of physics certainly made a difference in the progress of the Manhattan project.

While simple incompetence is not the most exciting resolution to the Heisenberg mystery, it gains credibility from a leading Italian nuclear physicist named Edoardo Amaldi, who assured Moe Berg during the early days of Alsos that a theorist like Heisenberg would certainly not be able to direct a large experimental research program. Amaldi was more concerned about what Hahn and von Weiszacker might be able to do.

Simple incompetence, however, may not entirely explain the embarrassing state of the German nuclear program. Other factors came into play that had nothing to do with the skills of the principal scientists. A sense of gloom must have pervaded Heisenberg's inner world. Some of his colleagues had betrayed him; many of them had left, taking expertise, enthusiasm, and collegiality with them; the research infrastructure was gradually becoming populated with incompetents who got their positions through the Nazi party; it was tricky to use relativity theory, which was right at the heart of fission research. All of this contributed to a distracting intellectual lethargy that surely must have interfered with the kind of focused, clear-headed thinking that was occurring at Los Alamos.

There also had to be an uneasiness about the madman in charge of the German war effort. It has to be considered significant that Heisenberg was invited to participate in the plot to kill Hitler, and that some of his friends were executed for the attempt. There can be no doubt that Heisenberg saw Hitler as a temporary aberration. As long as Hitler was in charge, there must have been a "tentativeness" about fission research, or any research for that matter. Heisenberg and his colleagues must surely have worked with less than full enthusiasm.

But Werner Heisenberg did not stay in Germany to do nuclear physics; he knew before the war ever started that he could do better research in America, and he had no shortage of job offers there. Heisenberg stayed in Germany because he loved his country, a sentiment that may be difficult for some Americans to appreciate. Many of those who became his harshest critics were forced to leave Germany or countries occupied by the Germans. We must not trivialize their plight, nor minimize their suffering at the hands of the Nazis, but, when all is said and done, most of these refugees did not flee Germany for moral reasons; they fled to protect themselves or the lives of their family. Heisenberg had no Jewish family connections so he did not need to flee for practical reasons. We must be careful to place the comments of his critics in context—they were forced to flee and had good reasons to make their flight into a moral choice.

Heisenberg stayed in his beloved Germany so he would be there when the war ended. There is not a shred of evidence in any of the documentation to suggest that he stayed to help the Nazis win the war. His oft-quoted comment that "it would be nice if Germany won the war" certainly should not be interpreted to mean "it would be nice if Hitler won the war." (And perhaps such "off the cuff" remarks should not be so widely quoted. Who among us has not made the exceptional comment that would make us look untoward if it were widely disseminated?) Heisenberg believed that Europe would come to be dominated by either the Russians or the Germans. Once Hitler was gone from Germany the choice was clear as to which of these would be best. In fact Heisenberg found the prospects of a Russianized Europe so distasteful that, when it looked like Germany might be overrun by Russia, he actually did start making plans to leave.

Heisenberg is a tragic figure. I agree with the "Later Goudsmit," who eulogized Heisenberg by making him yet another victim of the Nazis, which is not to condone anything that he did or "to enlarge him in war beyond what he was in peace." There is great tragedy in a man who, had he been British or American, could have turned into a legendary figure like Einstein and spent his twilight years basking in the glow of an enduring achievement.

But this was not to be Heisenberg's story; until the end of his life he was haunted by the need to explain himself, something he was never able to do, even to his closest friends and colleagues. No doubt he struggled to explain things even to himself. After he died his widow continued the task. When she died Heisenberg's protege von Weiszacker carried on. Now Thomas Powers carries the tragic torch of deception, struggling to turn an ambiguous historical figure into a hero.

The enigma of a figure like Heisenberg working in Hitler's Germany will always be troubling. The great horror that was Nazism—images of which remain ever before us in movies and books—continues to remind us how uncomfortably close any of us may be to unfathomable evil. Heisenberg was not a Nazi. But it was possible to be less sympathetic to the Nazis than he was, and the jury of history demands nothing less than this. There is no "reasonable doubt" on the question of Heisenberg's innocence as a Nazi collaborator; but there is doubt, and that has been enough for those who would picture Heisenberg ensconced in his research lab while billows of smoke from the ovens at Dachau and Auschwitz rolled past his windows. And all he wanted to do was stay in Germany.4

But in the meanwhile, in this most precious meanwhile, there it is. … Our children and our children's children. Preserved, just possibly, by that one short moment in Copenhagen. By some event that will never quite be located or defined. By that final core of uncertainty at the heart of things.

Heisenberg, in Copenhagen, Act Two, closing commentary

This is the concluding installment of a two-part article.

Karl W. Giberson is professor of physics at Eastern Nazarene College.


1. The front cover of Jungk's book, still in print though he has disavowed its contents, features an endorsement from Bertrand Russell: "One of the most interesting books I have ever read. It is more exciting than any novel."

2. Carl von Weiszacker figures prominently in several crucial episodes that have contributed to the Heisenberg mystery. His role calls out for a fuller study by historians.

3. The Germans refer to a nuclear reactor as an "engine."

4. I would like to thank my colleagues Mark Yuly, John Free, and Paul Nyce for comments on an earlier draft of this manuscript. One of my students, Rebecca DiSante, tracked down some of the references and enthusiastically introduced me to Michael Frayn's Copenhagen. I would also like to especially thank my mother, for patiently proofreading the final version and making numerous helpful suggestions on grammar, style, and clarity.

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