Cassidy’s Heisenberg

When I was asked to replace David Cassidy, because he decided not to come as a consequence of the horrible events in New York, I was very hesitant at first, because David is the expert on Heisenberg and my own contribution to the Heisenberg and Copenhagen debate is rather marginal. But I agreed finally, because I think I know David well enough—since about twenty years now—to have a feel for his work.

I am not going to read his paper word by word. Instead, I would like to highlight some of his arguments, in particular about the political stance of the historical Heisenberg. Michael Frayn’s Heisenberg and David Cassidy’s Heisenberg, in my opinion, diverge in particular in this regard. Despite this divergence, however, David is full of praise about the play. He said:

“drama can add a new and fertile dimension to history,”

and he is aware of the different aims of drama and history:

“... while enhancing our perception of the past, drama can—and often must—also distort the past in order to succeed in the pursuit of its own aims and methods. Drama, as we know, is not history, nor should it be regarded as such.”

In the concrete case of Frayn’s Heisenberg, David finds that

“the real interplay between fact and fiction occurs, not on the plane of externals, but in the realm of Heisenberg's internal intentions, thoughts, and motives during his Copenhagen visit. This is precisely where the direct evidence is weakest or non-existent, and this is precisely the stage on which the play unfolds its greatest dramatic effects.”

Nevertheless, there is no room for arbitrary imagination, because

“we do have the advantage of familiarity with the person, which we can gain by observing him acting and reacting in different situations throughout his entire life. Depending upon our diligence, we can achieve fairly good insights into his attitudes, decisions, and personality leading up to and surrounding important historical events. The September 1941 meeting in Copenhagen did not occur in a historical or biographical vacuum.”

David, in his present text, does not provide the details concerning these “important historical events,” but he did this in an earlier paper, to which he refers in footnote 2. Rather than reading David’s present paper to the end, I would like to make this historical context of Heisenberg’s Copenhagen visit more transparent, by quoting from David’s earlier paper. First, it seems necessary to clarify Heisenberg’s political stance. This is how David summarized this attitude:[1]

“Heisenberg's outlook throughout this period was very much in line with that of other patriotic non-Jewish Germans among artistic, academic, and military circles... As the German army blitzed across Europe during the early years of the war, these circles welcomed the news of victories on all fronts. Final victory, they believed, was close at hand in September 1941.

However, while this cultural and military elite wanted Germany to win the war, this did not mean that they wanted Hitler or the Nazi regime to win. They were not Nazis but proud, upstanding nationalists.”

From this perspective, Heisenberg’s Copenhagen visit appears in a different context, a context which is not mirrored in Michael Frayn’s play:

“While emphasizing the single episode—perhaps for good dramatic reasons—the play leaves out at least ten other equally controversial visits that Heisenberg made to Nazi-occupied countries and to German-speaking Switzerland during the war. Among these travels were trips

To German-occupied Budapest in 1941 and 1942.

To Switzerland in 1942 and 1944.

To the occupied Netherlands in October 1943, just after the deportation of many Dutch Jews to Auschwitz.

To Krakow, Poland, in December 1943 as a guest of the infamous Dr. Hans Frank, general governor of Poland, just months after he and his murderous henchmen had annihilated the heroic inhabitants of the Warsaw ghetto.

To Copenhagen twice in 1944 after Bohr had fled to England and America.

To Königsberg in East Prussia (now Kaliningrad, Russia) in February 1944.

Historian Mark Walker has pointed out, in a study of Heisenberg's war-time travels, that Heisenberg undertook each of these trips to occupied nations, including his trip to Copenhagen in 1941, as an explicit representative of the German office for cultural propaganda. On several of these trips, Heisenberg is reported to have made compromising and deeply painful statements to his foreign colleagues. One of Heisenberg's Dutch colleagues later attributed the following statement to him during his visit to the occupied Netherlands in October 1943:

Democracy cannot develop sufficient energy to rule Europe. There are, therefore, only two alternatives: Germany and Russia. And then a Europe under German leadership would be the lesser evil.

One wonders if Heisenberg really had anything different to say in Copenhagen two years earlier.”

To me, this addresses a crucial aspect of the entire Copenhagen visit. Although the details of the conversation between Heisenberg and Bohr are not known, do we really have to speculate about other reasons for the dispute or “misunderstanding,” as Heisenberg later put it? Heisenberg, a representative of the German cultural elite, visiting a Nazi occupied country and arguing for a Europe under German leadership!? How could Bohr react other than with dismay? I have compared this situation elsewhere[2] with a situation described in a novel by Lion Feuchtwanger,[3] in which two former friends meet in Paris in the late 1930s: The one lives there in exile, the other comes as a visitor. Like Heisenberg, the visitor belongs to the German cultural elite, like Heisenberg he is no Nazi, but has made compromises with the Nazi regime for the sake of his career. I do not want to strain this comparison, I just want to emphasize that one must not seek hidden causes, such as controversial opinions with respect to nuclear bombs, in order to understand why the friendship between Heisenberg and Bohr ended in Copenhagen in 1941.

I do not know whether David would share this opinion. He argues that the bomb question might have been a second cause.

“So, what was Heisenberg trying to tell Bohr during this meeting, and what did he want from Bohr? The broader historical setting and a fuller appreciation of Heisenberg's outlook and relationship to the war and to fission research strongly suggest that he wanted to convince Bohr that the seemingly inevitable German victory would not be so bad for Europe after all. (...) What he apparently wanted from Bohr was for Bohr to use his influence to prevent Allied scientists, who were surely far behind the Germans, from working toward building a bomb that could be used against Germany.”

I think that we have not enough historical evidence in support of such a far-reaching statement. To me, the second cause seems speculative, and the first one sufficient to explain Bohr’s dismay. David Cassidy is careful enough to admit some degree of historical uncertainty, although a smaller one than to allow for as much imagination as in the play. Let me conclude with his own words:

“The challenge then becomes to create a successful drama of these events in which the uncertainty, or Unbestimmtheit, in the situation is greatly reduced and in which there is no longer any significant need to resort to pure imagination. But, then, that would be a wholly different play, and one probably much less enjoyable than Michael's extraordinary "Copenhagen."”