Michael Frayn's play "Copenhagen" has now reached Broadway after its production in London two years ago. It has received an unusual measure of attention and respectable reviews that--allow me to state this at the very beginning of this essay--it deserved. "Copenhagen" deals with a significant episode--or, rather, with the human drama inherent within it--that happened in September 1941, in the middle of World War II. This episode has been treated by various writers and historians since that time, while it was also described (or, more precisely: attempted to be explained) by at least one of its protagonists, Werner Heisenberg, and also in his biography, written by his wife, Elisabeth. What happened was not simple. "Copenhagen" is not the first example of sensitive writers being attracted to the deeper moral implications of the acts and ideas of physicists in the 20th century, as in the play, "The Physicists" by the Swiss Friedrich Duerrenmatt. Michael Frayn attributes to this particular episode of September 1941, a philosophical, rather than a historical, explanation; but his concern with history, too, is such that he appended a long postscript to his two-act play in which, among other things, he stated with commendable modesty: "I am acutely aware how over-simplified my version is." I do not really think that his version is "over-simplified," except perhaps for his last philosophical conclusion; but my interest in this episode is even more historical than it is philosophical, which is why I am compelled to sum up the antecedents and the events of September 1941 as briefly as I can.
Heisenberg and Niels Bohr were, perhaps, the two greatest physicists of the 20th century. Surely they were the two leaders during the brief Golden Age of Physics, 1924 to 1927, when Heisenberg's Indeterminacy Theory and Bohr's Copenhagen Complementarity Interpretation superseded Einstein's still largely deterministic concept of physical reality. (Frayn does not attribute special significance to this conflict with Einstein; indeed, on one or two occasions he has his two protagonists refer to Einstein as "God" and to Bohr as "Pope.") In any event, Heisenberg and Bohr were close allies at the time, even though the first was much younger than the second and the latter's protege. Soon Heisenberg (who was to receive the Nobel Prize for physics) became much more than a protege. That they regarded each other with a mutual high degree of esteem is unquestionable. Heisenberg was German, Bohr Danish; Heisenberg was a German patriot, Bohr was half-Jewish. This did not matter--surely not for some time. In 1933 Hitler came to power in Germany; but their relations remained uncompromised--again, at least for some time. Heisenberg was neither a committed nor a convinced Nazi. Then in April 1940, Hitler's army and navy occupied Denmark. For various reasons, Hitler and his government treated Denmark as a model protectorate, allowing its king and its democratically elected government to function, albeit of course with grave restrictions; Jewish people in Denmark, too, were unharmed and largely unrestricted, including Bohr. In September 1941, Heisenberg went to Denmark, with the ostensible purpose of giving a lecture. There and then he visited his old friend Bohr. There occurred a long and unhappy conversation between them, during which evidently Bohr and Heisenberg were talking past each other. Their subject was the world situation in September 1941, including--very cautiously, and by no means directly--the potentiality of the construction of an atomic reactor and, perhaps consequently, of an atomic bomb. Their conversation not only did not dispel but strengthened their reciprocal suspicions, especially Bohr's (and his wife's) as to what Heisenberg's real purposes were. Heisenberg returned to Germany; Bohr stayed in Denmark until 1943, when he was spirited out to Sweden and thereafter to England and then to the United States. In 1947 Heisenberg went to Denmark to see Bohr again; but their earlier friendship was not restored.
Their reciprocal misunderstandings--in Frayn's formulation the Uncertainty Principle, the uncertainty of each one's assumption of the other's intentions or of the attribution of each other's motives--is the essence of his play, to the construction of which I must now turn.
Frayn's "Copenhagen" is an imaginative attempt to represent the personalities involved and the philosophical meaning of what happened in September 1941. It is the reconstitution of a retrospect. There is nothing wrong with this because, as the great Dane Soren Kierkegaard once wrote, we live forward but we can only think backward. In "Copenhagen," Heisenberg, Bohr and his wife, Margrethe, surely think backward but they no longer live forward; they are now met in another world, where the three of them try to reconstruct what exactly happened with them in September 1941: In sum, they try to explain themselves. Hence the differences between the play and the actual events nearly 60 years earlier. The crucial, and perhaps tragically useless, conversation between Heisenberg and Bohr in 1941 occurred not in Bohr's house but during a walk they took in a neighboring park (it had been their custom to take such walks together in the past). The play, on the other hand, takes place entirely in the living room of the Bohr house, with all three of them standing or walking around in a circle.
More significant is Frayn's portraiture of the three persons, which differs, at least to a considerable extent, from what we know of their inclinations and attitudes in 1941. Of course he has every right to do this, being a playwright and not a historian; but there is more to this, too. Heisenberg and the Bohrs are dead; in Frayn's play they live in or, rather, come back from another world; World War II is long past; and they have become older, mellower and wiser. In September 1941 Bohr was--with every reason--worried, suspicious and rigid; in "Copenhagen" he is avuncular and forgiving and only some of his suspicions appear. There is little evidence that in September 1941 Bohr's wife Margrethe talked much; in "Copenhagen" she has a fair amount to say. Unlike her husband's, her doubts and criticism of Heisenberg are sharp and often bitter. Of the three protagonists it is her portrait in "Copenhagen" that may come closest to how she may have thought in September 1941, but an exaggeration of her role in the play is well within the artistic province of Frayn's composition.
But the main problem--both in "Copenhagen" and of what we know about what "actually" happened in September 1941 --involves Heisenberg. In this play his portrait is not very different from the young Heisenberg of 10 or even 15 years before; young, energetic, attractive, full of respect for his older mentor, on occasion even charming. He and Bohr reminisce a lot about their earlier comradeship. In the play Margrethe accuses Heisenberg of failing to understand their situation under a German occupation; of being willing to work for Hitler; of working on a German nuclear reactor that could be employed for the construction of a bomb; of trying to show off.
Margrethe: And if you want to know why you came to Copenhagen in 1941 I'll tell you that as well. You're right--there's no great mystery about it. You came to show yourself to us.
Bohr: Margrethe! Margrethe! No!
Margrethe: When he first came in 1924 he was a humble assistant lecturer from a humiliated nation, grateful to have a job. Now here you are, back in triumph--the leading scientist of a nation that's conquered most of Europe. You've come to show us how well you've done in life.
Bohr: This is so unlike you!
Margrethe: I'm sorry . . . but isn't that really why he's here? Because he's burning to let us know that he's in charge of some vital piece of secret research. And that even so he's preserved a lofty moral independence, preserved it so famously that he's being watched by the Gestapo.
This attribution of Heisenberg's motives sounds exaggerated; but it is Frayn's purpose to portray a triangular relationship, with Margrethe differing not only from Heisenberg but also from Bohr. At the very end of the play Margrethe relents somewhat. We emerge from the play with a considerable respect for Heisenberg, who is (and was) not a villain. In their last agonized and philosophic conversation, all three of them accept uncertainty and talk about themselves having turned to dust, and perhaps the world laid to dust, though in the last words of the play Heisenberg appears as the vitalist and perhaps even optimist.
Yet the problem--the historical problem--about Heisenberg's mission
in September 1941 is still extant, "Copenhagen" notwithstanding; and now
allow me to propose a, perhaps plausible, historical hypothesis about
By September 1939, when World War II in Europe began, many of the top physicists of the world already knew that the making of an atom bomb was possible, principally because of a successful fission experiment that had been produced in Berlin a year and a half before. That was why, barely a fortnight after Germany invaded Poland and more than two years before Pearl Harbor, President Franklin D. Roosevelt was advised of the necessity of exploring the construction of an atomic explosive, because refugee physicists in the United States feared and believed that German physicists would be working on it. What Heisenberg and other German physicists were working on (among other things) was a nuclear reactor, though not a nuclear bomb, for many reasons, including Heisenberg's belief that a reactor producing nuclear energy was a more important achievement than a bomb; that the construction of a bomb, a potentiality only after the completion of a reactor, besides having its horrific portents, would take many, many years and unimaginable amounts of monies; in sum that the making of an atom bomb would not only be horribly expensive but also expensively horrible. It could be built--eventually: but why? And this was his crucial suggestion to Bohr in Copenhagen; and this was what froze Bohr and damaged their relationship, perhaps forever. Bohr seems to have thought that Heisenberg brought up this topic, the suggestion that the making of a nuclear bomb was, yes, a possibility, with the intention of frightening him. Heisenberg seems to have thought that Bohr (perhaps mostly because of Denmark's unique situation under German occupation) still had some contact with physicists in the Allied countries, whereby it would be worthwhile to attempt some kind of a tacit agreement, so that physicists on either side would refrain from promoting the building of atom bombs or perhaps even refrain from stating such a practical possibility to their governments. In one of his anxious and cautious responses to Heisenberg, Bohr said that the possibility of such a secret international agreement across a world war was nonsense; in this Bohr was right. He also thought that Heisenberg was somehow blackmailing him with the suggestion that the making of such a bomb was after all possible, obviously in Germany too; in this Bohr was wrong.
All of this is dealt with, in detail, in Frayn's "Copenhagen"--yet it is arguable whether the crux of the matter was technical; the crux of their misunderstanding was political; more precisely, national. What is missing in "Copenhagen"--again, let me repeat: this is a play written by a playwright, not a reconstruction researched and composed by a historian--is the devolution of the Heisenberg-Bohr relationship well before that evening in September 1941. Bohr knew that Heisenberg was not a Nazi Party member; he knew that Heisenberg had gotten into some trouble with radical Nazis in the 1930s because of his assistance to some of his Jewish colleagues and because of his refusal to dismiss the validity of Einstein's relativity theory (the importance of this is perhaps exaggerated by Frayn); he knew that during his visit to the United States Heisenberg met and talked with some of his former German Jewish physicist colleagues who were by then living and working in America. But Bohr knew, too, that Heisenberg was a German patriot or perhaps even a nationalist; that he refused to listen to suggestions that he, too, remain in the United States in 1939; and that he was, among other things, a convinced anti-communist. We must also consider--and neither Frayn nor any of the other writers and historians who have written about Heisenberg have paid attention to this--that Heisenberg's relationship to Bohr had demonstrably lessened and thinned at least two years before their meeting in 1941. In April 1940, the Germans subdued and occupied Denmark brutally and swiftly. As far as we know there was no sympathetic or friendly signal from Heisenberg to Bohr at that time or afterward. It is true that Bohr was allowed to live physically and materially and professionally a largely untouched life in Germany's model Danish protectorate; he even wrote and published scientific papers and kept working in his Physics Institute in Copenhagen. To Heisenberg it may have seemed that, under the circumstances, this was perhaps enough. Most probably he did not adequately, or even properly, understand the tremendously depressing psychic conditions of Bohr's life, of a half-Jewish scientist in German-occupied Denmark. Had he understood that better, he might have approached Bohr in a different way.
The essence of their misunderstanding was, I repeat, national and political. When they met in Bohr's house (they had actually met a day or so before, in Bohr's institute), it was inevitable that they would talk, no matter how briefly, about the world situation, that is, politics. (One of the charms of their earlier relationships was their custom of talking about many things besides physics.) Some of Heisenberg's remarks shocked Bohr and his wife, for example his defense of the German invasion of Poland: This and a few other instances at the very beginning of their talk only served to congeal Bohr's suspicions.
But there was more than that. This was September 1941, when the German armies were surging fast eastward in Russia, corralling millions of Russian prisoners, soon within sight of Moscow. Heisenberg made a remark about that. And this remark was not only another tic, or jump, in Bohr's suspicious mind--or another nail in the coffin of Heisenberg's great but essentially naive expectations. It also suggests something about Heisenberg at the time that has not hitherto evoked interest. This was Heisenberg's inclination to what I call the Two-War Idea.
What was--and still is--the German Two-War Idea? It is that Germany fought two wars; one against the Western democracies, the Anglo-American side; the other against Russia, the representative of International Communism; that the first war was regrettable and avoidable, while the second war was not; and that regrettable, too, was the fact that Germany's Anglo-American opponents did not understand this. Appearances and attractions of the Two-War Idea persist even now. They were at the bottom of the German Historikerstreit, the Historians' Controversy in 1986; and they are, openly rather than indirectly, stated and promoted by certain Germans (and also by certain British "revisionists") to this day. And there is plenty of evidence that the Two-War Idea accorded with much of German sentiment, as well as with German political calculations, in 1941. It was there in the incredibly different treatment of Western and Russian prisoners of war, 1 million of the latter starved to death in German prisoner compounds in 1941. It was there among respectable non-Nazis, the most startling example being that of Archbishop (later Cardinal) Clemens August von Galen who, from his pulpit in Munster in August 1941, openly assailed the Nazi program of euthanasia and who, in the same sermon, praised the German invasion of Russia as a crusade against Atheistic Communism. (Hitler chose to leave Galen alone.) And it was there in Heisenberg's mind, too. In his early youth he had some bitter experiences during the short-lived and ludicrous Soviet experiment in Munich in 1919; in the United States in 1939 he said on one occasion that if war came, only Russia would profit from it; and to Bohr in September 1941, he made at least one reference to the German armies approaching Moscow. He seemed to have had every reason to believe that the war against Russia was going well and that perhaps it was close to its end. Why then should the war between Germany and the Anglo-American world go on, with the prospect of ever more frightening weaponry? In this respect Heisenberg's wishes were not very different from those of Rudolf Hess, who, a few months before September 1941, had taken upon himself the task of flying to Britain to attempt to persuade the British to make peace or at least an armistice in the West with a Germany whose main task was the eradication of communism in the East.
Heisenberg's mission was not to Scotland but to Denmark; he was not
attempting to contact a British duke but an old friend, a Danish
physicist; and there was both naivete and idealism in his attempt. At the
same time his attempt was not devoid of political considerations and
perhaps even of calculations; and Bohr understood that perhaps only too
The history of science is the history of scientists. It is history, not science, that explains both how and why the atomic bomb was made in America--and how and why it was not made in Germany. Both the sources of Heisenberg's failure to come even close to a meeting of minds with Bohr and his preference for building a German nuclear reactor rather than a bomb were complicated matters: complicated because of the intricacies of the human mind, which is, after all, the most complex organism in the entire universe known to us. The "causes" of the atom bomb were historical and, ultimately, personal, they were scientific and technical only on a secondary level of "causes."
It is here that I must depart from the "Copenhagen" interpretation--not from Bohr's famous 1927 Copenhagen Interpretation of Quantum Mechanics but from Frayn's philosophical "Copenhagen" interpretation of 2000. The core of Frayn's philosophical argument is Uncertainty: that Heisenberg's discovery of the inevitable uncertainty relations in our measurements of atomic particles and electrons inevitably corresponds to the uncertainty that exists in the relationships of human beings--as in this dramatic instance in the relationship of Heisenberg and Bohr and Margrethe; and Frayn, very aptly, suggests this correspondence to the audience through the very staging of his play. But this is too simple. Physical and mental uncertainty are not the same things. Because of the complexity of the human mind (and heart), certainty in human relationships cannot completely exist: No human being can and will know another human being entirely; indeed what A says to B is never exactly what B hears him say. This uncertainty--or, rather, incompleteness--is no reason to despair; the very charm of human relationships is inherent therein because in such relationships, understanding is even more important (and fundamental) than is accuracy. But when it comes to physical matter--or rather, to our measurement and management of matter, very much including sub-atomic matter--uncertainty exists not within matter itself but because of the limitations of the human mind (the recognition of which, contrary to material or unattenuated logic, enriches rather than impoverishes it). The functions of the human mind are not identical with the functions of physics.
However, there is an important passage in "Copenhagen" that does credit to its author's intellect. It is a statement that Frayn puts into Bohr's mouth:
Bohr: Because you see what we did in those three years, Heisenberg? Not to exaggerate, but we turned the world inside out! Yes, listen, now it comes, now it comes. . . . We put man back at the center of the universe. Throughout history we keep finding ourselves displaced. We keep exiling ourselves to the periphery of things. First we turn ourselves into a mere adjunct of God's unknowable purposes, tiny figures kneeling in the great cathedral of creation. And no sooner have we recovered ourselves in the Renaissance, no sooner has man become, as Protagoras proclaimed him, the measure of all things, than we're pushed aside again by the products of our own reasoning! We're dwarfed again as physicists built the great new cathedrals for us to wonder at--the laws of classical mechanics that predate us from the beginning of eternity, that will survive us to eternity's end whether we exist or not. Until we come to the beginning of the twentieth century, and we're suddenly forced to rise from our knees again.
Bohr did not say this; but Frayn does. Yes, man is back at the center of the universe--the recognition of which opens up prospects and vistas that are both unimaginable and unpredictable.
Heisenberg: It starts with Einstein.
Yes, and no: because Einstein denied Heisenberg and Bohr. To him,
physical reality was entirely and absolutely independent of human
John Lukacs Is the author of "A Thread of Years" and, most recently, "Five Days in London" (Yale University Press).
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