Historical Perspective on "Copenhagen"
By Dr. David C. Cassidy,
© copyright, D.C. Cassidy, 2000
Copenhagen, a thought-provoking drama by Michael
Frayn that has played to sold-out audiences in London, has now opened
in New York with much well-deserved attention1. Despite the sparse
set, the three-person cast, and the technical nature of the subject
matter, this play appears to speak on some level to almost everyone.
One reason for this may be the confluence of past, present, and future
within the confines of this play, for as we rush headlong into a future
filled with the promise of potentially astonishing scientific and technological
advances, we are continually drawn back to the lingering questions
of the previous centuryquestions that are so profound in their
import that they, like the characters of Copenhagen, seem to transcend
time itself. How was it possible for the most advanced cultural and
scientific nation of the world to produce the genocidal killing machine
that was Nazi Germany? And a related question: How was it possible
that Werner Heisenberg, one of the most gifted of modern physicists,
a man educated in the finest tradition of Western culture, who was
neither a Nazi nor a Nazi supporterhow was it possible that such
a man would not only choose to remain in National Socialist Germany
for its entire twelve years of existence, but also actively seek a
prominent academic position in Berlin at the height of the wara
position that included the scientific directorship of nuclear fission
research for the German Army at war?
These are just two of the many difficult questions
that people have studied and debated ever since the end of World War
II. The often emotional debate continues at times even more intensely
than ever and it will no doubt continue at some level perhaps
ad infinitum, unless there is some new breakthrough, or perhaps some
fresh new perspective, such as the perspective of historical drama.
This was in fact my hope when I first heard about the play. I am delighted
that Copenhagen has succeeded so well in bringing these historical
issues (and even some of the science) to the public and in taking the
first steps toward resolving such difficult issues from the theatrical
perspective. But, as a historian, I must admit to some disappointment.
Despite the wide breadth of topics covered by
the playfrom nuclear fission and quantum mechanics to family
backgrounds and personal tragedywhat tends to disappoint me is
what is still missing from the play: a fuller sense of the larger historical
issues raised earlier, as well as a much broader appreciation of the
historical setting of this incident. I am speaking here solely as a
historian, not as a viewer or a playwright, for whom other considerations
must also enter. However, because of the absence of the broader historical
perspectives, the play seems to glide right past the most obvious answers
to the questions that the author does attempt to answer: What was Heisenberg
trying to tell Bohr during this meeting, and what did he want from
Bohr? Of course, since no one else was there to observe and record
the outdoor encounter between these two men, we cannot know for certain
what exactly was said or implied during their walk together, butto
use the metaphor of the Uncertainty Principle --one can narrow the
breadth of uncertainty somewhat regarding this visit, on the one hand,
by expanding the focus of the plays historical spotlight, on
the other hand.
The restricted focus, from the historians
viewpoint, is signaled early in the play when Heisenberg states: "...there
are only two things the world remembers about me. One is the uncertainty
principle, the other is my mysterious visit to Niels Bohr in Copenhagen
in 1941." It is difficult to know just what the world remembers
about Heisenberg. But I would suggest that what it remembers are his
many fundamental contributions to the creation of quantum mechanics--of
which the uncertainty principle is only one--and his leadership role
in German nuclear fission research during World War IIof which
the Copenhagen visit in 1941 was only one manifestation.
For instance, while emphasizing this one 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
* To German-occupied Budapest in 1941 and 1942.
* To Switzerland in 1942 and 1944
* To the occupied Netherlands in October 1943 just
after the last deportation of Dutch Jews to Auschwitz.
* To Cracow, Poland in Dec 1943 as a personal guest
of the infamous Dr. Hans Frank, General Governor of Poland, just months
after he and his murderous henchmen had annihilated the heroic Warsaw
* There were two more trips to Copenhagen in 1944
after Bohr had fled to England and America.
* And to Koenigsberg in East Prussianow Kaliningrad,
Russia--in Feb 1944.
Historian Mark Walker has pointed out in a study
of Heisenbergs war-time travels that Heisenberg undertook each
of these trips to occupied nations, including the trip to Copenhagen
in September 1941, as an explicit representative of the German office
for cultural propaganda2. On several of these trips Heisenberg is reported
to have made some very compromising and deeply painful statements to
his foreign colleagues. One of Heisenbergs 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.
The War Years
In fact, looking more broadly at Heisenbergs
attitude regarding Germanys war aims, especially in 1941, it seems
more likely that he did not. As I have developed at length in my biography
of the man.
Heisenbergs outlook throughout this period
was very much in line with the outlook of other patriotic non-Jewish
Germans among artistic, academic, and military circles. Out of nationalistic
and patriotic pride this social grouping eagerly supported the German
cause for the sake of the German nation. 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.
I hasten to add, however, that 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. They resigned themselves to support of
the Hitler regime for the sake of the nation, while clinging to the naive
belief that Hitler and his "ruffians" could be replaced somehow
as soon as they had won the war for the "real Germany"German
culture and tradition. When Germanys fortunes turned for the worse
as the war dragged on, these men turned against Hitler and the regime,
unleashing the failed assassination plot of June 1944 in the hope that
the world would recognize that "another Germany" had existed
along side Hitlers Germany.
That Heisenberg shared the ultimately fatal outlook
of his peers is evidenced not only by his close association in Berlin
with many of the members of the assassination plot,6 but also by his
participation from 1936 onward as a reserve corporal in a German mountain
infantry unit, despite his personal aversion to the Nazi cause. Although
all adult men under the age of 45 were required to participate in reserve
training, for Heisenberg it was more than a mere duty. For instance,
during the Sudeten Crisis of 1938,
Heisenberg expressed no regret as he and his unit
prepared to strike into neighboring Czechoslovakia. War was narrowly
averted at the last moment when the Western European nations appeased
Hitler at Munich by ceding the Sudetenland to Germany without a fight.
Heisenbergs only reaction afterwards was one of detached resignation
toward Hitlers war aims and toward the marching orders that he
well knew could end his life. Writing to his mother from the barracks
as his unit returned its weapons to storage for the time being he noted:
"It is strange to think how the fate of every
individual and the deaths of many hundreds of thousands can hang on the
decision of one man."7
In 1942 he seemed to display even greater resignation
toward the prosecution of the war when he wrote in a then-unpublished
"For us there remains nothing but to turn to
the simple things: we should conscientiously fulfill the duties and tasks
that life presents to us without asking too much about the why or the
wherefore...And then we should wait for whatever happens...reality is
transforming itself without our influence."8
Is there much doubt that Heisenberg would also have
accepted the required task of representing German war aims in his travels
abroad, even when traveling to German occupied Copenhagen in 1941?
Once again the answer grows more certainalthough
it never attains zero uncertainty (history is not an exact science)--
when we broaden the historical spotlight still further to examine why
Heisenberg chose to accept the position of scientific director of the
German nuclear project for the German Army at war.
First, I should point out that by the outbreak of
war in September 1939 Heisenberg had already lived through nearly seven
of the twelve years of the Third Reich. A lot had happened during those
seven years, and any questions for him about entering into the compromises
required to remain in Germany had already been long resolved. As the
regimes anti-Semitic programs came into place, many of Heisenbergs
students and colleagues were driven from Germany. Then in 1937 the SS
turned its attention on Heisenberg himself, accusing him in an SS publication
of teaching so-called "Jewish physics"that is, modern
theoretical physics.9 The SS article called Heisenberg a "white
Jew" and a "representative of the Einsteinian spirit in
the new Germany," implying that he was a traitor to the nation and
that a concentration camp was the suitable remedy. Finally, after a year-long
Gestapo investigation, Reichsführer-SS Heinrich Himmler personally exonerated
Heisenberg of all accusations of disloyalty to the regime. This protected
him from further such attacks, but the damage had been done.
Again as I attempted to develop in the biography,
Heisenberg now saw compromise in the face of dictatorship even more clearly
as the price required for remaining in Germany. His determination to
remain in Germany under such circumstances arose not only from his personal
attachment to the German nation and culture, but also from his misguided
belief that if he personally could survive in Germany until the end of
the war and the eventual removal of the Nazi regime, then so too would
decent German science survive until better times. With such an outlook,
the famed Nobel-Prize winner now interpreted every favor bestowed upon
himevery appointment to a prominent position, every permission
granted to travel to occupied countries, every invitation to address
a public audience as further evidence of rehabilitation of himself
and of contemporary theoretical physics in Germany.
The outbreak of war in Europe in 1939 suddenly provided
Heisenberg and his closest colleagues with an ideal opportunity to prove
their worth at last to their rulers by contributing their scientific
expertise to German war aims. And nuclear fission, the discovery and
development of which owed much to so-called "Jewish physics," provided
a splendid opportunity for the scientists to gain the protection of the
German Army through a sustained project that might perhaps produce a
new and more powerful weapon for the German arsenal--or at least a new
and more plentiful source of energy to power German ships and the German
economy. As Heisenberg later put it: "The official slogan of the
government was: We must make use of physics for warfare. We
turned it around for our slogan: We must make use of warfare for
By August 1941one month before the Copenhagen
visit--Heisenberg and his fission colleagues in Leipzig and Berlin suddenly
faced a new crisis: First, Heisenbergs Leipzig reactor research
team was nearing the worlds first evidence of neutron multiplication,
which they were able to confirm by the following spring. Not only was
the prospect of a nuclear weapon no longer just a theoretical possibility,
but the Germans were also convincedand they were rightthat
they were far ahead of Allied fission research at that timea lead,
however, which they soon lost. Second, Fritz Houtermans, working with
another group in Berlin, had shown theoretically that the element now
known as plutonium could be produced by a working reactor and could also
be used, in addition to uranium, to power a nuclear weapon. This discovery
suddenly blurred the distinction between work on a reactor and work on
a nuclear weapon.
Years later Heisenberg recalled: "It was from
September 1941 that we saw an open road ahead of us, leading to the atomic
bomb."11 With a visit to the cultural propaganda institute in Copenhagen
already planned, the open road to the atomic bombwhich Heisenberg
may or may have wanted--led straight to Niels Bohrs front door.
All of which brings us back to the questions raised by this play: What
was Heisenberg trying to tell Bohr during their meeting that September?
And what did he want from Bohr?
The morality issue
Heisenbergs own answer, which appeared in
several of his post-war writings, was published by the journalist Robert
Jungk in 1958 and has been accepted by many non-historians, popular writers,
and TV producers ever since.12 As Heisenberg put it in a 1948 document
and in other writings, as well as in the play, he wanted an answer from
Bohr to the question: "Does one as a physicist have the moral right
to work on the practical exploitation of atomic energy?"13
My problem with this explanation is that there is
no evidence in any other sources throughout the war, and especially in
1941, that moral issues regarding nuclear fission research were of particular
concern for Heisenbergnor for many other physicists, for that matter.
Of course, this does not rule out such a concern, but if it was so great
as to bring Heisenberg to Copenhagen under such difficult circumstances,
clues would have turned up in other sources from that period. I dont
know of any such clues.
It is true that Heisenberg did engage in an occasional
ethical discussion with Bohr in earlier years. But after Hitlers
rise to power and especially after the SS affair, Heisenberg turned for
any needed moral or ethical advice to his upright German colleagues,
Max Planck and Max von Laue, both of whom were still readily accessible
in Berlin in 1941. There is no indication that he ever consulted either
of them about the morality of nuclear-fission research.
If morality was really not the main concern, then
Heisenberg must have had another motive for seeking out Bohr in occupied
Denmark--a motive that more likely harkened back instead to their much
more frequent discussions in earlier days of international relations.
Indeed, it was during his earlier visits to Copenhagen and his encounters
with Bohr and his many other international guests during the 1920s that
Heisenberg first gained a real appreciation of the international community
of physics. He even learned to speak Danish and English as a result of
his extended visits to the international oasis that is still the Niels
Bohr Institute today.
By September 1941 the international situation looked
quite bleak for the world but quite positive for Germany. As is noted
in the play, by September 1941 the German Reich had reached its greatest
extent of the war. Most of continental Europe was under Nazi occupation,
German panzer divisions were plunging into Soviet Russia, and the United
States was still officially neutral. Heisenberg had learned from his
German co-workers that an atomic bomb was not just a theoretical possibility
but that it could indeed become a practical reality. If the war ended
with the German Army in place, or if it bogged down in a protracted conflict,
as had happened in World War I, it was easy to suppose that the United
States would have enough time and resources to catch up with German researchers
and to build a nuclear weapon, which they or other Allied forces might
well use or threaten to use on Germany. In a memoir of her late husband,
Mrs. Heisenberg wrote that throughout the war her husband "constantly
tortured himself" with the thought that the better equipped Allies
might build the bomb and use it on Germany.14 At the same time, Heisenberg
probably knew already or strongly suspected that Bohr was in contact
with Allied scientists through underground sources.
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 Heisenbergs outlook and relationship
to the war and to fission research-- all of which I could only briefly
outline here--strongly suggest that he wanted, first, to convince Bohr
that the seemingly inevitable German victory would not be so bad for
Europe after all. The alternative, as Heisenberg later noted to his horrified
Dutch colleagues,was a Europe ruled by the Soviet Union. Having witnessed
a traumatic Soviet revolution in Bavaria as a teenager, Heisenberg always
considered Soviet domination an even worse evil than Nazi domination.
Second, 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.
Bohr to his credit immediately sensed Heisenbergs
intentions and broke off the conversation. Heisenberg returned home to
Germany intent on continuingfission research. Heisenberg had already
resigned himself to the march of events, and events after the visit to
Bohr now appeared to be marching toward a possible nuclear war, regardless
of what he may or may not have wanted. In an unpublished letter written
to a Leipzig colleague, a historian of the middle ages, written just
one week after his return to Germany, Heisenberg alluded to a capability
to destroy the world that appears very much to be a veiled reference
to the inevitable possession of nuclear weaponry:
"I really liked the passage in your book
about the mind-set of the middle ages in contrast to our epoch. In
this connection it suddenly came to me that such a transformation could
occur once again in the near future. For perhaps we humans will recognize
one day that we actually possess the power to destroy the earth completely,
that we could very well bring upon ourselves the "end of the world" or
something closely related to it."15
Just three months later, the Army decided to abandon
its fission project on the recommendation of its closest advisors, choosing
to concentrate instead on rockets and jet aircraft. It was the beginning
of the end of any German hopes for sweeping success in fission research.
In the end, the spotlight of uncertainty reveals
Heisenberg as neither a hero nor a fiendish villain, but as a man who
appears to be not much different from what we might expect: a highly
gifted, cultured individual who was unfortunately caught up in the dreadful
circumstances of his time for which he, like most people, was totally
unprepared. For more on Heisenberg and Uncertainty, go to
1. Michael Frayn, Copenhagen (London: Methuen, 1998).
This paper was presented at the symposium "Creating
Copenhagen," held at
the Graduate Center of the City University of New
York on 27 March 2000.
2. Mark Walker, Nazi Science: Myth, Truth, and the
German Atomic Bomb (New
York: Plenum Press, 1995), chapters 6 and 7.
3. Quoted in a letter from G. P. Kuiper to a Major
Fischer, 30 June 1945
(University of Arizona Library, Kuiper Papers, Box
4. Uncertainty: The Life and Science of Werner Heisenberg
(New York: W. H.
5. Peter Hoffmann, The History of the German Resistance
Barry, transl. (Cambridge, Mass.: MIT Press, 1997).
A similar bifurcation of
reality is reported among German physicians by Robert
Jay Lifton, The Nazi
Doctors: Medical Killing and the Psychology of Genocide
(New York: Basic
6. See, for example, Klaus Scholder, ed., Die Mittwochsgeselleschaft:
Protokolle aus dem geistigen Deutschland 1932 bis
1944 (Munich: Siedler
7. Letter from Heisenberg to his mother, 18 September
family papers), quoted in Uncertainty, p. 396.
8. Heisenberg, typescript, ca. 1942, published as
Ordnung der Wirklichkeit
(Munich: Piper-Verlag, 1989), quote on pp. 171-172;
reprinted in Heisenberg,
Collected Works, volume C I, W. Blum et al., eds.
1984), pp. 217-306, on p. 304.
9. "Weisse Juden in der Wissenschaft," Das
Schwarze Korps (15 July 1937),
p. 6. The classic historical work on this episode
and the notion of "Jewish
physics" is Alan D. Beyerchen, Scientists under
Hitler: Politics and the
Physics Community in the Third Reich (New Haven:
Yale University Press,
10. Quoted in interview of Heisenberg by J. J. Ermenc,
Urfeld, Germany, 29
August 1967, transcript in Papers of Gen. Leslie
Groves, National Archives
and Records Administration, Gift Collection, Washington,
11. Quoted in Uncertainty, p. 435.
12. Robert Jungk, Brighter Than a Thousand Suns:
A Personal History of the
Atomic Scientists, James Cleugh, transl. (New York:
Jovanovich, 1958), pp. 102-104.
13. Heisenberg, affidavit on the Copenhagen visit,
typescript, ca. 1948 (Heisenberg Archive, Max Planck
Institute for Physics,
14. Elisabeth Heisenberg, Inner Exile: Recollections
of a Life with Werner
Heisenberg, S. Cappellari and C. Morris, transl.
(Boston: Birkhäuser, 1984),
15. Letter from Heisenberg to Hermann Heimpel, 1
October 1941, quoted by
Helmut Rechenberg, introduction to Heisenberg, Ordnung,
note 8, p. 17.