In September 1941, Werner Heisenberg, at the time Germany's pre-eminent scientist and the head of its atom bomb program, traveled to Nazi-occupied Copenhagen to visit his old friend and mentor, Niels Bohr. Both were Nobel laureates; both were among the giants of modern theoretical physics. Eighteen months later, Bohr would escape and work on the Manhattan Project, helping to build a bomb for the Allies. But what happened at that meeting is still pretty much a mystery: Did Heisenberg come to pump Bohr about what he might know from his overseas contacts about any Allied bomb program? Was he there to talk about the morality of scientists engaging in work on terror weapons and thus, perhaps, to dissuade his Western counterparts from engaging in such an undertaking? Was he trying to recruit Bohr for the German bomb?
Behind those questions lurks a much larger mystery that may always bedevil historians: Why did Heisenberg and the Germans never even come close to producing a bomb for Hitler? Did he try and fail, or was he, in effect, a subtle saboteur empowered with scientific knowledge that no one could challenge? In his massive book Heisenberg's War: The Secret History of the German Bomb, Thomas Powers says that Heisenberg, who never became a Nazi and balked at the immorality of building a bomb for Hitler, did what he could to guide "the German atomic bomb effort into a broom closet." But Powers also knows that the evidence is not conclusive and that Heisenberg, who lived until 1976, did little to clear things up. "Frustrated by Heisenberg's silence," he writes at the very end of his book, "something in the historian wants to lecture his shade and say: Your history is incomplete. No one can fairly complain of the way things turned out, but you shirked your final duty--to accept responsibility for what you did and tell us about it. No one else can clear up the confusion... ."
Michael Frayn has tried to do almost precisely that. He's conjured up Heisenberg's shade, along with those of Bohr and Bohr's wife Margrethe, to recreate the meeting in Copenhagen--to imagine it from all of its many uncertain perspectives--and, in the process, produce a riveting piece of theater. Both in text and as staged--first in London, where it played for two years, and now in New York--Copenhagen is a metaphor for uncertainty, an echo of Heisenberg's own great scientific work. He theorized that the process of observing subatomic particles itself affects their behavior. The more precise the measurement of the position of a particle, the less precise the measurement of its momentum. Beginning with Einstein, the new physics, as Bohr declares in the play, turned the old deterministic world "inside out... . We put man back at the center of the universe." But if Copenhagen's brilliance lies partially in its intellectual and rhetorical elegance, even in its ability to elucidate some difficult theoretical physics, its real power is in its dramatic plumbing of human uncertainty--its portrayal of people entangled in some of life's most vexing mysteries and in moral dilemmas of Talmudic dimensions.
On the bare circular stage conceived by director Michael Blakemore and designed by Peter J. Davison, the players move about each other, like particles in a nuclear experiment, observer and observed changing positions, the observer subtly becoming the observed, the observed the observer. Together and separately--never quite certain of the details--they recall the lovely days of collegiality and affection of the long-gone past, the silly moments of play, and the long walks and intellectual controversies out of which the great insights of quantum mechanics were forged: uncertainty, complementarity, the great compromise of the Copenhagen Interpretation that light can be both wave and particle. The play shifts seamlessly from flashback to the posthumous present, then back again, as Bohr and Heisenberg seek each other out, and moment gives to dazzling moment. When I saw Copenhagen in London in March, with David Baron as Bohr, Corinna Marlowe as Margrethe, and William Brand as Heisenberg, it was hard to imagine that it could be played with greater intellectual subtlety and crispness. But the New York production, with Philip Bosco, Blair Brown, and Michael Cumpsty, has an emotional depth and sense of loss that make the drama all the more compelling.
The nucleus of reality in this search for the truth, if there is one, is Bohr's wife Margrethe, who seems to know both of these once-close colleagues and friends better than they know each other or themselves, and who's not loath to remind Heisenberg of his flaws, and especially of his wartime approval of Germany's early conquests and his apparent failure to understand the horrors his country had imposed on others.
Bohr, ever the Danish patriot, despite his affection for his old friend, angrily broke off the Copenhagen meeting when Heisenberg raised the issue of ... what? ... a bomb, a reactor? And so the questions still revolve: What really were Heisenberg's intentions? How does one reconcile loyalty to family, colleagues, friends, country with the monstrosity of a regime run by homicidal maniacs? Bohr always seemed too embarrassed, or perhaps too hurt, to speak of it afterward. But why did Heisenberg never fully explain himself? Could he have done so either without looking like a traitor who had lost the war for the Germans or appearing to be an incompetent collaborator in Hitler's war?
In raising those questions, Frayn, following Powers's lead, lifts Heisenberg from the shadows into which he fell after the war--suspicion on the one hand, outright contempt on the other--and makes him a moral agent on a plane with the incorruptible and universally respected Bohr.
Bohr: So you do want to know about the Allied nuclear program?
Heisenberg: I simply want to know if there is one. Some hint, some clue. I've just betrayed my country and risked my life to warn you of the German program... .
Bohr: And now, I'm to return the compliment?
Heisenberg: Bohr, I have to know! I'm the one who has to decide! If the Allies are building a bomb, what am I choosing for my country? [It would be] an easy mistake to make, to think that one loved one's country less because it happened to be in the wrong.
In the end, Frayn's Heisenberg even absolves Bohr for his role in building the Allied bomb, to which Bohr responds, "Whereas you, my dear Heisenberg, never managed to contribute to the death of one single solitary person in all your life." Frayn gives Heisenberg the last lines, allows him a benediction:
Margrethe: And when all our eyes are closed, when even the ghosts have gone, what will be left of our beloved world? Our ruined and dishonored and beloved world?
Heisenberg: 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.
Given the doubts about Heisenberg's wartime role, not to mention the genocide practiced by the country that he claims to love, it's not surprising that this dramatic tour de force has regenerated controversy. In a recent piece in The Chronicle of Higher Education, Paul Lawrence Rose, a historian of science at Penn State who in 1998 published a very different assessment of Heisenberg's role in the Nazi bomb program (Heisenberg and the Nazi Atom Bomb Project: A Study in German Culture), accuses Frayn of equating the two sides in the war, of suggesting that Jews were the real inventors of the bomb, and of making everyone seem guilty "so everyone is blameless." What's clear, both in the play and as historical fact, is that Heisenberg radically overestimated the amount of the U-235 isotope that would be necessary to sustain a chain reaction and thus never believed a bomb could be built with the resources available--hardly believed it even when, interned at war's end by the British at a rural retreat in England, he heard the news of Hiroshima. Bohr, in Frayn's dialogue of shades, is astounded that Heisenberg never did the calculation. To this day, that oversight is the key to arguments of historians like Rose that Heisenberg, "a brilliant but weak man, whose shallow moral character allowed him to be easily corrupted by his nationalist German sympathies into colluding with Nazism," failed simply because he screwed up his physics.
But here the play has a persuasiveness that critics like Rose can't muster. "Please don't try to tell us you are a hero of the resistance," says the clear-eyed Margrethe to Heisenberg. "Your talent is for skiing too fast for anyone to see where you are. For always being in more than one position at a time, like one of your particles." But did the brilliant, impulsive Heisenberg fail to calculate the necessary diffusion equation because he didn't think of it, or was it because the impossibly high amounts of U-235 that Bohr himself had once believed necessary allowed Heisenberg to avoid the moral quandary that might have faced him if the project had seemed technically more feasible? He never had to confront the moral question, Heisenberg said after the war; he could honestly tell his masters that producing a bomb would be hard to do. "In my view," says Frayn in an essay accompanying the play, he "kept the knowledge of ... how little of it would be needed, not to himself but from himself."
None of that is conclusive. The play has already generated a round of conferences and symposia, and the debate will no doubt go on. Yet right or wrong, Copenhagen's very power seems to create an implicit moral equivalence between the bomb makers, Allied and German, that the circumstances of the war don't begin to justify. Although we're reminded that the Nazis hunted down Jews and that Germany lost most of her best scientists as a result, we hear a lot more about German children dying than about the Holocaust, are subtly invited to forget that it was not the Allies but the Nazis who waged a genocidal war (and that Bohr thus had far more of an ethical foundation for building a bomb).
"Thanks to the play's chic postmodernism, as well as the complexity of its ideas," says Rose, "the subtle revisionism of Copenhagen has been received with a respect denied such cruder revisionisms as that of David Irving's Holocaust denial. Revision it is, nonetheless, and Copenhagen is more destructive than Irving's self-evidently ridiculous assertions... ." That seems far over the top. This is a play--a piece of fiction, as Frayn reminds us--focused on one event and one discrete set of questions without clear answers. And yet, like Shakespeare's historically questionable Richard III, it may ultimately shape our perception, if not our understanding, of those events far more than all the histories of science put together. Its power to do so is the measure of its brilliance. ¤