《哥本哈根》是迈克尔·弗雷恩创作的戏剧，基于1941年在哥本哈根发生的一次事件——物理学家尼尔斯·玻尔和他的学生维尔纳·海森堡之间的会面。该剧于1998年在伦敦国家剧院首演，并上演了超过300场

版权归属为迈克尔·弗雷恩，如有侵权，联系作者处理

关于话剧哥本哈根：

天堂，或许是地狱。三个灵魂聚在了这里。

他们谈1941年的战争，哥本哈根9月的那个雨夜，挪威滑雪场的比赛，纳粹德国的核反应堆，同盟国正在研制的原子弹；他们谈量子、粒子、铀裂变和测不准原理，还谈贝多芬、巴赫的钢琴曲；他们谈战争时期个人为自己祖国竭尽全力的权利，炸弹扔下后城市里狼藉扭曲的尸体。

他们谈这谈那，最想说清的却是两个影响了世界物理学进程的诺贝尔获奖者沃纳·海森堡和尼尔斯·波尔在1941年的哥本哈根会面——谜一样的会面。

有关角色详情：

尼尔斯·玻尔（Niels Bohr）

身份：丹麦物理学家，量子力学奠基人之一，诺贝尔物理学奖得主。性格与特质：

理性与包容：以深邃的哲学思考和科学直觉著称，善于在争论中调和矛盾（如提出“互补性原理”）。矛盾与挣扎：在战时面对旧友海森堡的来访时，既试图保持科学家的客观性，又因国家立场与个人情感陷入冲突。父性形象：被海森堡视为学术导师和精神父亲，但战后因理念分歧渐行渐远。剧中核心冲突：试图理解海森堡1941年神秘访问的真实动机，同时反思科学伦理在战争中的边界。

玛格丽特·玻尔（Margrethe Bohr）

身份：尼尔斯·玻尔的妻子，敏锐的观察者和家庭情感的核心。性格与特质：

警觉与怀疑：对海森堡的敌意贯穿始终，质疑其在德国占领下的忠诚度（“他是德国人，我们是丹麦人”）。情感纽带：作为玻尔思想的倾听者与记录者，以局外人视角揭示对话的潜台词。历史见证者：通过回忆（如儿子克里斯蒂安的死亡）隐喻战争对个人与家庭的创伤。剧中核心冲突：在科学讨论与政治猜忌之间，成为道德与情感的“第三视角”，推动真相的探寻。

维尔纳·海森堡（Werner Heisenberg）

身份：德国物理学家，量子力学先驱，“不确定性原理”提出者。性格与特质：

天才与争议：科学上激进创新（如“量子力学”的突破），政治上因纳粹德国背景背负道德质疑。矛盾与自辩：坚称战时研究仅用于核能开发，却因未能明确拒绝武器化可能遭历史诟病（“我一生都在解释”）。孤独与挣扎：渴望玻尔的认可（“你是我精神的父亲”），又因立场的对立陷入永恒的误解。剧中核心冲突：试图向玻尔夫妇证明1941年访问的“善意”（传递德国核计划信息？寻求道德赦免？），却成为科学伦理的永恒谜题。

这是关于科学和道德的撕扯，三人对话重现了二战中科学家如何在国家忠诚、人性良知与学术理想间抉择。记忆的不可靠性：通过多重回忆视角（如“十月还是九月？”），暗示历史真相的模糊性与叙事的权力。量子隐喻：角色互动宛如“不确定性原理”的具象化——动机、语言与记忆的交叠构成无法观测的“叠加态”。

ACT ONE

Margrethe: But why?

Bohr: You’re still thinking about it?

Margrethe: Why did he come to Copenhagen?

Bohr: Does it matter, my love, now we’re all three of us dead and gone?

Margrethe: Some questions remain long after their owners have died. Lingering like ghosts. Looking for the answers they never found in life.

Bohr: Some questions have no answers to find.

Margrethe: Why did he come? What was he trying to tell you?

Bohr: He did explain later.

Margrethe: He explained over and over again. Each time he explained it became more obscure.

Bohr: It was probably very simple, when you come right down to it: he wanted to have a talk.

Margrethe: A talk? To the enemy? In the middle of a war?

Bohr: Margrethe, my love, we were scarcely the enemy.

Margrethe: It was 1941!

Bohr: Heisenberg was one of our oldest friends.

Margrethe: Heisenberg was German. We were Danes. We were under German occupation.

Bohr: It put us in a difficult position, certainly.

Margrethe: I’ve never seen you as angry with anyone as you were with Heisenberg that night.

Bohr: Not to disagree, but I believe I remained remarkably calm.

Margrethe: I know when you’re angry.

Bohr: It was as difficult for him as it was for us.

Margrethe: So why did he do it? Now no one can be hurt, now no one can be betrayed.

Bohr: I doubt if he ever really knew himself.

Margrethe: And he wasn’t a friend. Not after that visit. That was the end of the famous friendship between Niels Bohr and Werner Heisenberg.

Heisenberg: Now we’re all dead and gone, yes, and there are only two things the world remembers about me. One is the uncertainty principle, and the other is my mysterious visit to Niels Bohr in Copenhagen in 1941. Everyone understands uncertainty. Or thinks he does. No one understands my trip to Copenhagen. Time and time again I’ve explained it. To Bohr himself, and Margrethe. To interrogators and intelligence officers, to journalists and historians. The more I’ve explained, the deeper the uncertainty has become. Well, I shall be happy to make one more attempt. Now we’re all dead and gone. Now no one can be hurt, now no one can be betrayed.

Margrethe: I never entirely liked him, you know. Perhaps I can say that to you now.

Bohr: Yes, you did. When he was first here in the twenties? Of course you did. On the beach at Tisvilde with us and the boys? He was one of the family.

Margrethe: Something alien about him, even then.

Bohr: So quick and eager.

Margrethe: Too quick. Too eager.

Bohr: Those bright watchful eyes.

Margrethe: Too bright. Too watchful.

Bohr: Well, he was a very great physicist. I never changed my mind about that.

Margrethe: They were all good, all the people who came to Copenhagen to work with you. You had most of the great pioneers in atomic theory here at one time or another.

Bohr: And the more I look back on it, the more I think Heisenberg was the greatest of them all.

Heisenberg: So what was Bohr? He was the first of us all, the father of us all. Modern atomic physics began when Bohr realised that quantum theory applied to matter as well as to energy. 1913. Everything we did was based on that great insight of his.

Bohr: When you think that he first came here as my assistant in 1924…

Heisenberg: I’d only just finished my doctorate, and Bohr was the most famous atomic physicist in the world.

Bohr: … and in just over a year he’d invented quantum mechanics.

Margrethe: It came out of his work with you.

Bohr: Within three he’d got uncertainty.

Margrethe: And you’d done complementarily.

Bohr: We argued them both out together.

Heisenberg: We did most of our best work together.

Bohr: Heisenberg usually led the way.

Heisenberg: Bohr made sense of it all.

Bohr: We operated like a business.

Heisenberg: Chairman and managing director.

Margrethe: Father and son.

Heisenberg: A family business.

Margrethe: Even though we had sons of our own.

Bohr: And we went on working together long after he ceased to be my assistant.

Heisenberg: Long after I’d left Copenhagen in 1927 and gone back to Germany. Long after I had a chair and a family of my own.

Margrethe: Then the Nazis came to power…

Bohr: And it got more and more difficult. When the war broke out - impossible. Until that day in 1941.

Margrethe: When it finished forever.

Bohr: Yes, why did he do it?

Heisenberg: September, 1941. For years I had it down in my memory as October.

Margrethe: September. The end of September.

Bohr: A curious sort of diary memory is.

Heisenberg: You open the pages, and all the neat headings and tidy jottings dissolve around you.

Bohr: You step through the pages into the months and days themselves.

Margrethe: The past becomes the present inside your head.

Heisenberg: September, 1941, Copenhagen… And at once here I am, getting off the night train from Berlin with my colleague Carl von Weizsacker. Two plain civilian suits and raincoats among all the field.grey Wehrmacht uniforms arriving with us, all the naval gold braid, all the well-tailored black of the SS. In my bag I have the text of the lecture I’m giving. In my head is another communication that has to be delivered. The lecture is on astrophysics. The text inside my head is a more difficult one.

Bohr: We obviously can’t go to the lecture.

Margrethe: Not if he’s giving it at the German Cultural Institute - it’s a Nazi propaganda organisation.

Bohr: He must know what we feel about that.

Heisenberg: Weizsacker has been my John the Baptist. and written to warn Bohr of my arrival.

Margrethe: He wants to see you?

Bohr: I assume that’s why he’s come.

Heisenberg: But how can the actual meeting with Bohr be arranged?

Margrethe: He must have something remarkably important to say.

Heisenberg: It has to seem natural. It has to be private.

Margrethe: You’re not really thinking of inviting him to the house?

Bohr: That’s obviously what he’s hoping.

Margrethe: Niels! They’ve occupied our country!

Bohr: He is not they.

Margrethe: He’s one of them.

Heisenberg: First of all there’s an official visit to Bohr’s workplace, the Institute for Theoretical Physics, with an awkward lunch in the old familiar canteen. No chance to talk to Bohr, of course. Is he even present? There’s Rozental… Petersen, I think… Christian M?ller, almost certainly… It’s like being in a dream. You can never quite focus the precise details of the scene around you. At the head of the table .Is that Bohr? I turn to look, and it’s Bohr, it’s Rozental, it’s M?ller it’s whoever I appoint to be there… A difficult occasion, though I remember that clearly enough.

Bohr: It was a disaster. He made a very bad impression. Occupation of Denmark unfortunate. Occupation of Poland, however, perfectly acceptable. Germany now certain to win the war.

Heisenberg: Our tanks are almost at Moscow. What can stop us? Well, one thing, perhaps. One thing.

Bohr: He knows he’s being watched, of course. One must remember that. He has to be careful about what he says.

Margrethe: Or he won’t be allowed to travel abroad again.

Bohr: My love, the Gestapo planted microphones in his house. He told Goudsmit when he was in America. The SS brought him in for interrogation in the basement at the Prinz-Albert-Strasse.

Margrethe: And then they let him go again.

Heisenberg: I wonder if they suspect for one moment how painful it was to get permission for this trip. The humiliating appeals to the Party, the demeaning efforts to have strings pulled by our friends in the Foreign Office.

Margrethe: How did he seem? Is he greatly changed?

Bohr: A little older.

Margrethe: I still think of him as a boy.

Bohr: He’s nearly forty. A middle-aged professor, fast catching up with the rest of us.

Margrethe: You still want to invite him here?

Bohr: Let’s add up the arguments on either side in a reasonably scientific way. Firstly, Heisenberg is a friend…

Margrethe: Firstly, Heisenberg is a German.

Bohr: A White Jew. That’s what the Nazis called him. He taught so-called Jewish physics. And refused to stop. He stuck with Einstein and relativity, in spite of the most terrible attacks.

Margrethe: All the real Jews have lost their jobs. He’s still teaching.

Bohr: He’s still teaching relativity.

Margrethe: Still a professor at Leipzig.

Bohr: At Leipzig, yes. Not at Munich. They kept him out of the chair at Munich.

Margrethe: He could have been at Columbia.

Bohr: Or Chicago. He had offers from both.

Margrethe: He wouldn’t leave Germany.

Bohr: He wants to be there to rebuild German science when Hitler goes. He told Goudsmit.

Margrethe: And if he’s being watched it will all be reported upon. Who he sees. What he says to them. What they say to him.

Heisenberg: I carry my surveillance around like an infectious disease. But then I happen to know that Bohr is also under surveillance.

Margrethe: And you know you’re being watched yourself.

Bohr: By the Gestapo?

Heisenberg: Does he realise?

Bohr: I’ve nothing to hide.

Margrethe: By our fellow-Danes. It would be a terrible betrayal of all their trust in you if they thought you were collaborating.

Bohr: Inviting an old friend to dinner is hardly collaborating.

Margrethe: It might appear to be collaborating.

Bohr: Yes. He’s put us in a difficult position.

Margrethe: I shall never forgive him.

Bohr: He must have good reason. He must have very good reason.

Heisenberg: This is going to be a deeply awkward occasion.

Margrethe: You won’t talk about politics?

Bohr: We’ll stick to physics. I assume it’s physics he wants to talk to me about.

Margrethe: I think you must also assume that you and I aren’t the only people who hear what’s said in this house. If you want to speak privately you’d better go out in the open air.

Bohr: I shan’t want to speak privately.

Margrethe: You could go for another of your walks together.

Heisenberg: Shall I be able to suggest a walk?

Bohr: I don’t think we shall be going for any walks. Whatever he has to say he can say where everyone can hear it.

Margrethe: Some new idea he wants to try out on you, perhaps.

Bohr: What can it be, though? Where are we off to next?

Margrethe: So now of course your curiosity’s aroused…, in spite of everything.

Heisenberg: So now here I am, walking out through the autumn twilight to the Bohrs' house at Ny-Carlsberg. Followed, presumably, by my invisible shadow. What am I feeling? Fear, certainly - the touch of fear that one always feels for a teacher, for an employer, for a parent. Much worse fear about what I have to say. About how to express it. How to broach it in the first place. Worse fear still about what happens if I fail.

Margrethe: It’s not something to do with the war?

Bohr: Heisenberg is a theoretical physicist. I don’t think anyone has yet discovered a way you can use theoretical physics to kill people.

Margrethe: It couldn’t be something about fission?

Bohr: Fission? Why would he want to talk to me about fission?

Margrethe: Because you’re working on it.

Bohr: Heisenberg isn’t.

Margrethe: Isn’t he? Everybody else in the world seems to be. And you’re the acknowledged authority.

Bohr: He hasn’t published on fission.

Margrethe: It was Heisenberg who did all the original work on the physics of the nucleus. And he consulted you then, he consulted you at every step.

Bohr: That was back in 1932. Fission’s only been around for the last three years.

Margrethe: But if the Germans were developing some kind of weapon based on nuclear fission…

Bohr: My love, no one is going to develop a weapon based on nuclear fission.

Margrethe: But if the Germans were trying to, Heisenberg would be involved.

Bohr: There’s no shortage of good German physicists.

Margrethe: There’s no shortage of good German physicists in America or Britain.

Bohr: The Jews have gone, obviously.

Heisenberg: Einstein, Wolfgang Pauli, Max Born… Otto Frisch, Lise Meitner… We led the world in theoretical physics! Once.

Margrethe: So who is there still working in Germany?

Bohr: Sommerfeld, of course. Von Laue.

Margrethe: Old men.

Bohr: Wirtz. Harteck.

Margrethe: Heisenberg is head and shoulders above all of them.

Bohr: Otto Hahn - he's still there. He discovered fission, after all.

Margrethe: Hahn's a chemist. I thought that what Hahn discovered…

Bohr: …was that Enrico Fermi had discovered it in Rome four years earlier. Yes - he just didn’t realize it was fission. It didn’t occur to anyone that the uranium atom might have split, and turned into two atoms of barium. Not until Hahn and Strassmann did the analysis, and detected the barium.

Margrethe: Fermi's in Chicago.

Bohr: His wife’s Jewish.

Margrethe: So Heisenberg would be in charge of the work?

Bohr: Margrethe, there is no work! John Wheeler and I did it all in 1939. One of the implications of our paper is that there’s no way in the foreseeable future in which fission can be used to produce any kind of weapon.

Margrethe: Then why is everyone still working on it?

Bohr: Because there’s an element of magic in it. You fire a neutron at the nucleus of a uranium atom and it splits into two atoms of barium. It’s what the alchemists were trying to do - to turn one element into another.

Margrethe: So why is he coming?

Bohr: Now your curiosity’s aroused.

Margrethe: My forebodings.

Heisenberg: I crunch over the familiar gravel to the Bohrs' front door, and tug at the familiar bell-pull. Fear, yes. And another sensation, that's become painfully familiar over the past year. A mixture of self-importance and sheer helpless absurdity - that of all the 2,000 million people in this world, I'm the one who's been charged with this impossible responsibility… The heavy door swings open.

Bohr: My dear Heisenberg!

Heisenberg: My dear Bohr!

Bohr: Come in, come in…

Margrethe: And of course as soon as they catch sight of each other, all their caution disappears. The old flames leap up from the ashes. If we can just negotiate all the treacherous little opening civilities…

Heisenberg: I'm so touched you felt able to ask me.

Bohr: We must try to go on behaving like human beings.

Heisenberg: I realise how awkward it is.

Bohr: We scarcely had a chance to do more than shake hands at lunch the other day.

Heisenberg: And Margrethe, I haven't seen…

Bohr: Since you were here four years ago.

Margrethe: Niels is right. You look older.

Heisenberg: I had been hoping to see you both in 1938, at the congress in Warsaw…

Bohr: I believe you had some personal trouble.

Heisenberg: A little business in Berlin.

Margrethe: In the Prinz-Albert-Strasse?

Heisenberg: A slight misunderstanding.

Bohr: We heard, yes. I'm so sorry.

Heisenberg: These things happen. The question is now resolved. Happily resolved. Entirely resolved… We should all have met in Zurich…

Bohr: In September 1939.

Heisenberg: And of course, sadly…

Bohr: Sadly for us as well.

Margrethe: A lot more sadly still for many people.

Heisenberg: Yes. Indeed.

Bohr: Well, there it is.

Heisenberg: What can I say?

Margrethe: What can any of us say, in the present circumstances?

Heisenberg: No. And your sons?

Margrethe: Are well, thank you. Elisabeth? The children?

Heisenberg: Very well. They send their love, of course.

Bohr：Sailing?

Margrethe：Not a good start.

Bohr：No, no sailing.

Heisenberg：The Sound is . . . ?

Bohr：Mined.

Heisenberg：Of course.

Margrethe：I assume he won't ask if Niels has been skiing.

Heisenberg：You've managed to get some skiing?

Bohr：Skiing? In Denmark?

Heisenberg：In Norway. You used to go to Norway.

Bohr：I did, yes.

Heisenberg：But since Norway is also. . . well. . .

Bohr：Also occupied? Yes, that might make it easier. In fact, I suppose we could now holiday almost anywhere in Europe.

Heisenberg：I'm sorry. I hadn't thought of it quite in those terms.

Bohr：Perhaps I'm being a little oversensitive.

Heisenberg：Of course not. I should have thought.

Margrethe：He must almost be starting to wish he was back in the Prinz-Albert-Strasse.

Heisenberg：I don't suppose you feel you could ever come to Germany. . .

Margrethe：The boy's an idiot.

Bohr：My dear Heisenberg, it would be an easy mistake to make, to think that the citizens of a small nation, of a small nation overrun, wantonly and cruelly overrun, by its more powerful neighbour, don't have exactly the same feelings of national pride as their conquerors, exactly the same love of their country.

Margrethe：Niels, we agreed.

Bohr：To talk about physics, yes.

Margrethe：Not about politics.

Bohr：I'm sorry.

Heisenberg：No, no.I was simply going to say that I still have my old skihut at Bayrischzell. So if by any chance . . . at any time . . . for any reason. . .

Bohr：Most kind of you. 

Heisenberg：Frau Schumacher in the bakery - you remember her?

Bohr：I remember Frau Schumacher.

Heisenberg：She still has the key.

Bohr：Perhaps Margrethe would be kind enough to sew a yellow star on my ski-jacket.

Heisenberg：Yes. Yes. Stupid of me.

Margrethe：Silence again. Those first brief sparks have disappeared, and the ashes have become very cold indeed. So now of course I'm starting to feel almost sorry for him. Sitting here all on his own in the midst of people who hate him, all on his own against the two of us. He looks younger again, like the boy who first came here in 1924. Younger than Christian would have been now. Shy and arrogant and anxious to be loved. Homesick and pleased to be away from home at last. And, yes, it's sad, because Niels loved him, he was a father to him.

Heisenberg：So . . . what are you working on?

Margrethe：And all he can do is press forward.

Bohr：Fission, mostly.

Heisenberg：I saw a couple of papers in the Physical Review. The velocity-range relations of fission fragments . . . ?

Bohr：And something about the interactions of nuclei with deuterons. And you?

Heisenberg：Various things.

Margrethe: Fission?

Heisenberg: I sometimes feel very envious of your cyclotron.

Margrethe: Why? Are you working on fission yourself?

Heisenberg: There are over thirty in the United States. Whereas in the whole of Germany… Well… You still get to your country place, at any rate?

Bohr: We still go to Tisvilde, yes.

Margrethe: In the whole of Germany, you were going to say…

Bohr: …there is not one single cyclotron.

Heisenberg: So beautiful at this time of year. Tisvilde.

Bohr: You haven't come to borrow the cyclotron, have you? That's not why you've come to Copenhagen?

Heisenberg: That's not why I've come to Copenhagen.

Bohr: I'm sorry. We mustn't jump to conclusions.

Heisenberg: No, we must none of us jump to conclusions of any sort.

Margrethe: We must wait patiently to be told.

Heisenberg: It's not always easy to explain things to the world at large.

Bohr: I realise that we must always be conscious of the wider audience our words may have. But the lack of cyclotrons in Germany is surely not a military secret.

Heisenberg: I've no idea what's a secret and what isn't.

Bohr: No secret, either, about why there aren't any. You can't say it, but I can. It's because the Nazis have systematically undermined theoretical physics. Why? Because so many people working in the field were Jews. And why were so many of them Jews? Because theoretical physics, the sort of physics done by Einstein, by Schrödinger and Pauli, by Born and Sommerfeld, by you and me, was always regarded in Germany as inferior to experimental physics, and the theoretical chairs and lectureships were the only ones that Jews could get.

Margrethe: Physics, yes? Physics.

Bohr: This is physics.

Margrethe: It's also politics.

Heisenberg: The two are sometimes painfully difficult to keep apart.

Bohr: So, you saw those two papers. I haven't seen anything by you recently.

Heisenberg: No.

Bohr: Not like you. Too much teaching?

Heisenberg: I'm not teaching. Not at the moment.

Bohr: My dear Heisenberg - they haven't pushed you out of your chair at Leipzig? That's not what you've come to tell us?

Heisenberg: No, I'm still at Leipzig. For part of each week.

Bohr: And for the rest of the week?

Heisenberg: Elsewhere. The problem is more work, not less.

Bohr: I see. Do I?

Heisenberg: Are you in touch with any of our friends in England? Born? Chadwick?

Bohr: Heisenberg, we're under German occupation. Germany's at war with Britain.

Heisenberg: I thought you might still have contacts of some sort. Or people in America? We're not at war with America.

Margrethe: Yet.

Heisenberg: You've heard nothing from Pauli, in Princeton? Goudsmit? Fermi?

Bohr: What do you want to know?

Heisenberg: I was simply curious… I was thinking about Robert Oppenheimer the other day. I had a great set-to with him in Chicago in 1939.

Bohr: About mesons.

Heisenberg: Is he still working on mesons?

Bohr: I'm quite out of touch.

Margrethe: The only foreign visitor we've had was from Germany. Your friend Weizsäcker was here in March.

Heisenberg: My friend? Your friend, too. I hope. You know he's come back to Copenhagen with me? He's very much hoping to see you again.

Margrethe: When he came here in March he brought the head of the German Cultural Institute with him.

Heisenberg: I'm sorry about that. He did it with the best of intentions. He may not have explained to you that the Institute is run by the Cultural Division of the Foreign Office. We have good friends in the foreign service. Particularly at the Embassy here.

Bohr: Of course. I knew his father when he was Ambassador in Copenhagen in the twenties.

Heisenberg: It hasn't changed so much since then, you know, the German foreign service.

Bohr: It's a department of the Nazi government.

Heisenberg: Germany is more complex than it may perhaps appear from the outside. The different organs of state have quite different traditions. Some departments remain stubbornly idiosyncratic, in spite of all attempts at reform. Particularly the foreign service. You know how attached diplomats are to outmoded conventions. Our people in the Embassy here are quite old-fashioned in the way they use their influence. They would certainly be trying to see that distinguished local citizens were able to work undisturbed.

Bohr: Are you telling me that I'm being protected by your friends in the Embassy?

Heisenberg: What I'm saying, in case Weizsäcker failed to make it clear, is that you would find congenial company there. I know people would be very honoured if you felt able to accept an occasional invitation.

Bohr: To cocktail parties at the German Embassy? To coffee and cakes with the Nazi plenipotentiary?

Heisenberg: To lectures, perhaps. To discussion groups. Social contacts of any sort could be helpful.

Bohr: I'm sure they could.

Heisenberg: Essential, perhaps, in certain circumstances.

Bohr: In what circumstances?

Heisenberg: I think we both know.

Bohr: Because I'm half-Jewish?

Heisenberg: We all at one time or another may need the help of our friends.

Bohr: Is this why you've come to Copenhagen? To invite me to watch the deportation of my fellow-Danes from a grandstand seat in the windows of the German Embassy?

Heisenberg: Bohr, please! Please! What else can I do? How else can I help? It's an impossibly difficult situation for you, I understand that. It's also an impossibly difficult one for me.

Bohr: Yes. I'm sorry. I'm sure you also have the best of intentions.

Heisenberg: Forget what I said. Unless…

Bohr: Unless I need to remember it.

Heisenberg: In any case, it's not why I've come.

Margrethe: Perhaps you should simply say what it is you want to say.

Heisenberg: What you and I often used to do in the old days was to take an evening stroll.

Bohr: Often. Yes. In the old days.

Heisenberg: You don't feel like a stroll this evening, for old times' sake?

Bohr: A little chilly tonight, perhaps, for strolling.

停掉BGM

Heisenberg: This is so difficult. You remember where we first met?

Bohr: Of course. At Göttingen in 1922.

Heisenberg: At a lecture festival held in your honour.

Bohr: It was a high honour. I was very conscious of it.

Heisenberg: You were being honoured for two reasons. Firstly because you were a great physicist…

Bohr: Yes, yes.

Heisenberg: …and secondly because you were one of the very few people in Europe who were prepared to have dealings with Germany. The war had been over for four years, and we were still lepers. You held out your hand to us. You've always inspired love, you know that. Wherever you've been, wherever you've worked. Here in Denmark. In England, in America. But in Germany we worshipped you. Because you held out your hand to us.

Bohr: Germany's changed.

Heisenberg: Yes. Then we were down. And you could be generous.

Margrethe: And now you're up.

Heisenberg: And generosity's harder. But you held out your hand to us then, and we took it.

Bohr: Yes…! Not you. As a matter of fact. You bit it.

Heisenberg: Bit it?

Bohr: Bit my hand! You did! I held it out, in my most statesmanlike and reconciliatory way, and you gave it a very nasty nip.

Heisenberg: I did?

Bohr: The first time I ever set eyes on you. At one of those lectures I was giving in Göttingen.

Heisenberg: What are you talking about?

Bohr: You stood up and laid into me.

Heisenberg: Oh. I offered a few comments.

Bohr: Beautiful summer's day. The scent of roses drifting in from the gardens. Rows of eminent physicists and mathematicians, all nodding approval of my benevolence and wisdom. Suddenly, up jumps a cheeky young pup and tells me that my mathematics are wrong.

Heisenberg: They were wrong.

Bohr: How old were you?

Heisenberg: Twenty.

Bohr: Two years younger than the century.  

Heisenberg: Not quite.  

Bohr: December 5th, yes?  

Heisenberg: 1. 93 years younger than the century.  

Bohr: To be precise.  

Heisenberg: No - to two places of decimals. To be precise, 1. 928 . . . 7 . . . 6 . . . 7 . . . 1. . .

Bohr: I can always keep track of you, all the same. And the century.  

Heisenberg和Bohr 两人笑

Margrethe: And Niels has suddenly decided to love him again, in spite of everything. Why? What happened? Was it the recollection of that summer's day in Göttingen? Or everything? Or nothing at all? Whatever it was, by the time we've sat down to dinner the cold ashes have started into flame once again.  

Bohr: You were always so combative! It was the same when we played table-tennis at Tisvilde. You looked as if you were trying to kill me.  

Heisenberg: I wanted to win. Of course I wanted to win. You wanted to win.  

Bohr: I wanted an agreeable game of table-tennis.  

Heisenberg: You couldn't see the expression on your face.  

Bohr: I could see the expression on yours.  

Heisenberg: What about those games of poker in the ski hut at Bayrischzell, then? You once cleaned us all out! You remember that? With a non-existent straight! We're all mathematicians .we're all counting the cards. we're 90 per cent certain he hasn't got anything. But on he goes, raising us, raising us. This insane confidence. Until our faith in mathematical probability begins to waver, and one by one we all throw in.  

Bohr: I thought I had a straight! I misread the cards! I bluffed myself!  

Margrethe: Poor Niels.  

Heisenberg: Poor Niels? He won! He bankrupted us! You were insanely competitive! He got us all playing poker once with imaginary cards!  

Bohr: You played chess with Weizsäcker on an imaginary board!  

Margrethe: Who won?  

Bohr: Need you ask? At Bayrischzell we'd ski down from the hut to get provisions, and he'd make even that into some kind of race! You remember? When we were there with Weizsäcker and someone? You got out a stop-watch.  

Heisenberg: It took poor Weizsäcker eighteen minutes.  

Bohr: You were down there in ten, of course.  

Heisenberg: Eight.  

Bohr: I don't recall how long I took.  

Heisenberg: Forty-five minutes.  

Bohr: Thank you.  

Margrethe: Some rather swift ski-ing going on here, I think.  

Heisenberg: Your ski-ing was like your science. What were you waiting for? Me and Weizsäcker to come back and suggest some slight change of emphasis?  

Bohr: Probably.  

Heisenberg: You were doing seventeen drafts of each slalom?  

Margrethe: Without me there to type them out.  

Bohr: At least I knew where I was. At the speed you were going you were up against the uncertainty relationship. If you knew where you were when you were down you didn't know how fast you'd got there. If you knew how fast you'd been going you didn't know you were down.  

Heisenberg: I certainly didn't stop to think about it.  

Bohr: Not to criticise, but that's what might be criticised with some of your science.  

Heisenberg: I usually got there, all the same.  

Bohr: You never cared what got destroyed on the way, though. As long as the mathematics worked out you were satisfied.  

Heisenberg: If something works it works.  

Bohr: But the question is always, What does the mathematics mean, in plain language? What are the philosophical implications?  

Heisenberg: I always knew you'd be picking your way step by step down the slope behind me, digging all the capsized meanings and implications out of the snow.  

Margrethe: The faster you ski the sooner you're across the cracks and crevasses.  

Heisenberg: The faster you ski the better you think.  

Bohr: Not to disagree, but that is most . . . most interesting.  

Heisenberg: By which you mean it's nonsense. But it's not nonsense. Decisions make themselves when you're coming downhill at seventy kilometres an hour. Suddenly there's the edge of nothingness in front of you. Swerve left? Swerve right? Or think about it and die? In your head you swerve both ways. . .  

Margrethe: Like that particle.  

Heisenberg: What particle?  

Margrethe: The one that you said goes through two different slits at the same time.  

Heisenberg: Oh, in our old thought-experiment. Yes. Yes!  

Margrethe: Or Schrödinger's wretched cat.  

Heisenberg: That's alive and dead at the same time.  

Margrethe: Poor beast.  

Bohr: My love, it was an imaginary cat.  

Margrethe: I know.  

Bohr: Locked away with an imaginary phial of cyanide.  

Margrethe: I know, I know.  

Heisenberg: So the particle's here, the particle's there.  

Bohr: The cat's alive, the cat's dead.  

Margrethe: You've swerved left, you've swerved right.  

Heisenberg: Until the experiment is over, this is the point, until the sealed chamber is opened, the abyss detoured; and it turns out that the particle has met itself again, the cat's dead.  

Margrethe: And you're alive.  

Bohr: Not so fast, Heisenberg.  

Heisenberg: The swerve itself was the decision.  

Bohr: Not so fast, not so fast!  

Heisenberg: Isn't that how you shot Hendrik Casimir dead?  

Bohr: Hendrik Casimir?  

Heisenberg: When he was working here at the Institute.  

Bohr: I never shot Hendrik Casimir.  

Heisenberg: You told me you did.  

Bohr: It was George Gamow. I shot George Gamow. You don't know - it was long after your time.  

Heisenberg: Bohr, you shot Hendrik Casimir.  

Bohr: Gamow, Gamow. Because he insisted that it was always quicker to act than to react. To make a decision to do something rather than respond to someone else's doing it.  

Heisenberg: And for that you shot him?  

Bohr: It was him! He went out and bought a pair of pistols! He puts one in his pocket, I put one in mine, and we get on with the day's work. Hours go by, and we're arguing ferociously about....I can't remember .....our problems with the nitrogen nucleus, I expect - when suddenly Gamow reaches into his pocket. . .  

Heisenberg: Cap-pistols.  

Bohr: Cap-pistols, yes. Of course.  

Heisenberg: Margrethe was looking a little worried.  

Margrethe: No - a little surprised. At the turn of events.  

Bohr: Now you remember how quick he was.  

Heisenberg: Casimir?  

Bohr: Gamow.  

Heisenberg: Not as quick as me.  

Bohr: Of course not. But compared with me.  

Heisenberg: A fast neutron. However, or so you're going to tell me. . .  

Bohr: However, yes, before his gun is even out of his pocket . . .  

Heisenberg: You've drafted your reply.  

Margrethe: I've typed it out.  

Heisenberg: You've checked it with Klein.  

Margrethe: I've retyped it.  

Heisenberg: You've submitted it to Pauli in Hamburg.  

Margrethe: I've retyped it again.  

Bohr: Before his gun is even out of his pocket, mine is in my hand.  

Heisenberg: And poor Casimir has been blasted out of existence.  

Bohr: Except that it was Gamow.  

Heisenberg: It was Casimir! He told me!  

Bohr: Yes, well, one of the two.  

Heisenberg: Both of them simultaneously alive and dead in our memories.  

Bohr: Like a pair of Schrödinger cats. Where were we?  

Heisenberg: Ski-ing. Or music. That's another thing that decides everything for you. I play the piano and the way seems to open in front of me.all I have to do is follow. That's how I had my one success with women. At a musical evening at the Bückings in Leipzig .we've assembled a piano trio. 1937, just when all my troubles with the . . . when my troubles are coming to a head. We're playing the Beethoven G major. We finish the scherzo, and I look up from the piano to see if the others are ready to start the final presto. And in that instant I catch a glimpse of a young woman sitting at the side of the room. Just the briefest glimpse, but of course at once I've carried her off to Bayrischzell, we're engaged, we're married, etc.the usual hopeless romantic fantasies. Then off we go into the presto, and it's terrifyingly fast .so fast there's no time to be afraid. And suddenly everything in the world seems easy. We reach the end and I just carry on ski-ing. Get myself introduced to the young woman see her home and, yes, a week later I've carried her off to Bayrischzell .another week and we're engaged three months and we're married. All on the sheer momentum of that presto!  

Bohr: You were saying you felt isolated. But you do have a companion, after all.  

Heisenberg: Music?  

Bohr: Elisabeth!  

Heisenberg: Oh. Yes. Though, what with the children, and so on. . . I've always envied the way you and Margrethe manage to talk about everything. Your work. Your problems. Me, no doubt.  

Bohr: I was formed by nature to be a mathematically curious entity: not one but half of two.  

Heisenberg: Mathematics becomes very odd when you apply it to people. One plus one can add up to so many different sums . . .  

Margrethe: Silence. What's he thinking about now? His life? Or ours?  

Bohr: So many things we think about at the same time. Our lives and our physics.  

Margrethe: All the things that come into our heads out of nowhere.  

Bohr: Our private consolations. Our private agonies.  

Heisenberg: Silence. And of course they're thinking about their children again.  

Margrethe: The same bright things. The same dark things. Back and back they come.  

Heisenberg: Their four children living, and their two children dead.  

Margrethe: Harald. Lying alone in that ward.  

Bohr: She's thinking about Christian and Harald.  

Heisenberg: The two lost boys. Harald. . . .  

Bohr: All those years alone in that terrible ward.  

Heisenberg: And Christian. The firstborn. The eldest son.  

Bohr: And once again I see those same few moments that I see every day.  

Heisenberg: Those short moments on the boat, when the tiller slams over in the heavy sea, and Christian is falling.  

Bohr: If I hadn't let him take the helm. . .  

Heisenberg: Those long moments in the water.  

Bohr: Those endless moments in the water.  

Heisenberg: When he's struggling towards the lifebuoy.  

Bohr: So near to touching it.  

Margrethe: I'm at Tisvilde. I look up from my work. There's Niels in the doorway, silently watching me. He turns his head away, and I know at once what's happened.  

Bohr: So near, so near! So slight a thing!  

Heisenberg: Again and again the tiller slams over. Again and again. . .  

Margrethe: Niels turns his head away . .  

Bohr: Christian reaches for the lifebuoy. . .  

Heisenberg: But about some things even they never speak.  

Bohr: About some things even we only think.  

Margrethe: Because there's nothing to be said.  

Bohr: Well . . . perhaps we should be warm enough. You suggested a stroll.  

Heisenberg: In fact the weather is remarkably warm.  

Bohr: We shan't be long.  

Heisenberg: A week at most.  

Bohr: What - our great hike through Zealand?  

Heisenberg: We went to Elsinore. I often think about what you said there.  

Bohr: You don't mind, my love? Half-an-hour?  

Heisenberg: An hour, perhaps. No, the whole appearance of Elsinore, you said, was changed by our knowing that Hamlet had lived there. Every dark corner there reminds us of the darkness inside the human soul. . .  

Margrethe: So, they're walking again. He's done it. And if they're walking they're talking. Talking in a rather different way, no doubt......I've typed out so much in my time about how differently particles behave when they're unobserved . . . I knew Niels would never hold out if they could just get through the first few minutes. If only out of curiosity. . . . Now they're started an hour will mean two, of course, perhaps three. . . The first thing they ever did was to go for a walk together. At Göttingen, after that lecture. Niels immediately went to look for the presumptuous young man who'd queried his mathematics, and swept him off for a tramp in the country. Walk..... talk.......make his acquaintance. And when Heisenberg arrived here to work for him, off they go again, on their great tour of Zealand. A lot of this century's physics they did in the open air. Strolling around the forest paths at Tisvilde. Going down to the beach with the children. Heisenberg holding Christian's hand. They talked on the boat a lot. Was Christian ever on the boat with them? No, he was too young for sailing then. . . . Yes, and every evening in Copenhagen, after dinner, they'd walk round Faelled Park behind the Institute, or out along Langelinie into the harbour. Walk, and talk. Long, long before watts had ears . . . But this time, in 1941, their walk takes a different course. Ten minutes after they set out . . . they're back! I've scarcely had the table cleared when there's Niels in the doorway. I see at once how upset he is ..........he can't look me in the eye.  

Bohr: Heisenberg wants to say goodbye. He's leaving.  

Margrethe: He won't look at me, either.  

Heisenberg: Thank you. A delightful evening. Almost like old times. So kind of you.  

Margrethe: You'll have some coffee? A glass of something?  

Heisenberg: I have to get back and prepare for my lecture.  

Margrethe: But you'll come and see us again before you leave?  

Bohr: He has a great deal to do.  

Margrethe: It's like the worst moments of 1927 all over again, when Niels came back from Norway and first read Heisenberg's uncertainty paper. Something they both seemed to have forgotten about earlier in the evening, though I hadn't. Perhaps they've both suddenly remembered that time. Only from the look on their faces something even worse has happened.  

Heisenberg: Forgive me if I've done or said anything that . . .  

Bohr: Yes, yes.  

Heisenberg: It meant a great deal to me, being here with you both again. More perhaps than you realise.  

Margrethe: It was a pleasure for us. Our love to Elisabeth.  

Bohr: Of course.  

Margrethe: And the children.  

Heisenberg: Perhaps, when this war is over. . . . If we're all spared. . . . Goodbye.  

Margrethe: Politics?  

Bohr: Physics. He's not right, though. How can he be right? John Wheeler and I . . .  

Margrethe: A breath of air as we talk, why not?  

Bohr: A breath of air?  

Margrethe: A turn around the garden. Healthier than staying indoors, perhaps.  

Bohr: Oh. Yes.  

Margrethe: For everyone concerned.  

Bohr: Yes. Thank you. . . . How can he possibly be right? Wheeler and I went through the whole thing in 1939.  

Margrethe: What did he say?  

Bohr: Nothing. I don't know. I was too angry to take it in.  

Margrethe: Something about fission?  

Bohr: What happens in fission? You fire a neutron at a uranium nucleus, it splits, and it releases energy.  

Margrethe: A huge amount of energy. Yes?  

Bohr: About enough to move a speck of dust. But it also releases two or three more neutrons. Each of which has the chance of splitting another nucleus.  

Margrethe: So then those two or three split nuclei each release energy in their turn?  

Bohr: And two or three more neutrons.  

Heisenberg: You start a trickle of snow sliding as you ski. The trickle becomes a snowball. . .  

Bohr: An ever-widening chain of split nuclei forks through the uranium, doubling and quadrupling in millionths of a second from one generation to the next. First two splits, let's say for simplicity. Then two squared, two cubed, two to the fourth, two to the fifth, two to the sixth. . .  

Heisenberg: The thunder of the gathering avalanche echoes from all the surrounding mountains. . .  

Bohr: Until eventually, after, let's say, eighty generations, 280 specks of dust have been moved. 280 is a number with 24 noughts. Enough specks of dust to constitute a city, and all who live in it.  

Heisenberg: But there is a catch.  

Bohr: There is a catch, thank God. Natural uranium consists of two different isotopes, U-238 and U-235. Less than one per cent of it is U-235, and this tiny fraction is the only part of it that's fissionable by fast neutrons.  

Heisenberg: This was Bohr's great insight. Another of his amazing intuitions. It came to him when he was at Princeton in 1939, walking across the campus with Wheeler. A characteristic Bohr moment. I wish I'd been there to enjoy it. Five minutes deep silence as they walked, then: 'Now hear this . I have understood everything.'  

Bohr: In fact it's a double catch. 238 is not only impossible to fission by fast neutrons - it also absorbs them. So, very soon after the chain reaction starts, there aren't enough fast neutrons left to fission the 235.  

Heisenberg: And the chain stops.  

Bohr: Now, you can fission the 235 with slow neutrons as well. But then the chain reaction occurs more slowly than the uranium blows itself apart.  

Heisenberg: So again the chain stops.  

Bohr: What all this means is that an explosive chain reaction will never occur in natural uranium. To make an explosion you will have to separate out pure 235. And to make the chain long enough for a large explosion. . .  

Heisenberg: Eighty generations, let's say. . .  

Bohr: . . . you would need many tons of it. And it's extremely difficult to separate.  

Heisenberg: Tantalisingly difficult.  

Bohr: Mercifully difficult. . . The best estimates, when I was in America in 1939, were that to produce even one gram of U-235 would take 26,000 years. By which time, surely, this war will be over. So he's wrong, you see, he's wrong! Or could I be wrong? Could I have miscalculated? Let me see. . . . What are the absorption rates for fast neutrons in 238? What's the mean free path of slow neutrons in 235. . . ?  

Margrethe: But what exactly had Heisenberg said? That's what everyone wanted to know, then and forever after.  

Bohr: It's what the British wanted to know, as soon as Chadwick managed to get in touch with me. What exactly did Heisenberg say?  

Heisenberg: And what exactly did Bohr reply? That was of course the first thing my colleagues asked me when I got back to Germany.  

Margrethe: What did Heisenberg tell Niels - what did Niels reply? The person who wanted to know most of all was Heisenberg himself.  

Bohr: You mean when he came back to Copenhagen after the war, in 1947?  

Margrethe: Escorted this time not by unseen agents of the Gestapo, but by a very conspicuous minder from British intelligence.  

Bohr: I think he wanted various things.  

Margrethe: Two things. Food-parcels. . .  

Bohr: For his family in Germany. They were on the verge of starvation.  

Margrethe: And for you to agree what you'd said to each other in 1941.  

Bohr: The conversation went wrong almost as fast as it did before.  

Margrethe: You couldn't even agree where you'd walked that night.  

Heisenberg: Where we walked? Faelled Park, of course. Where we went so often in the old days.  

Margrethe: But Faelled Park is behind the Institute, eight or nine kilometres away from where we live!  

Heisenberg: I can see the drift of autumn leaves under the street-lamps next to the bandstand.  

Bohr: Yes, because you remember it as October!  

Margrethe: And it was September.  

Bohr: No fallen leaves!  

Margrethe: And it was 1941. No street-lamps!  

Bohr: I thought we hadn't got any further than my study. What I can see is the drift of papers under the reading-lamp on my desk.  

Heisenberg: We must have been outside! What I was going to say was treasonable. If I'd been overheard I'd have been executed.  

Margrethe: So what was this mysterious thing you said?  

Heisenberg: There's no mystery about it. There never was any mystery. I remember it absolutely clearly, because my life was at stake, and I chose my words very carefully. I simply asked you if as a physicist one had the moral right to work on the practical exploitation of atomic energy. Yes?  

Bohr: I don't recall.  

Heisenberg: You don’t recall, no, because you immediately became alarmed. You stopped dead in your tracks.  

Bohr: I was horrified.  

Heisenberg: Horrified. Good, you remember that. You stood there gazing at me, horrified.  

Bohr: Because the implication was obvious. That you were working on it.  

Heisenberg: And you jumped to the conclusion that I was trying to provide Hitler with nuclear weapons.  

Bohr: And you were!  

Heisenberg: No! A reactor! That’s what we were trying to build! A machine to produce power! To generate electricity, to drive ships!  

Bohr: You didn’t say anything about a reactor.  

Heisenberg: I didn’t say anything about anything! Not in so many words. I couldn’t! I’d no idea how much could be overheard. How much you’d repeat to others.  

Bohr: But then I asked you if you actually thought that uranium fission could be used for the construction of weapons.  

Heisenberg: Ah! It’s coming back!  

Bohr: And I clearly remember what you replied.  

Heisenberg: I said I now knew that it could be.  

Bohr: This is what really horrified me.  

Heisenberg: Because you’d always been confident that weapons would need 235, and that we could never separate enough of it.  

Bohr: A reactor - yes, maybe, because there it’s not going to blow itself apart. You can keep the chain reaction going with slow neutrons in natural uranium.  

Heisenberg: What we’d realised, though, was that if we could once get the reactor going. . .  

Bohr: The 238 in the natural uranium would absorb the fast neutrons. . .  

Heisenberg: Exactly as you predicted in 1939 - everything we were doing was based on that fundamental insight of yours. The 238 would absorb the fast neutrons. And would be transformed by them into a new element altogether.  

Bohr: Neptunium. Which would decay in its turn into another new element. . .  

Heisenberg: At least as fissile as the 235 that we couldn’t separate . . .  

Margrethe: Plutonium.  

Heisenberg: Plutonium.  

Bohr: I should have worked it out for myself.  

Heisenberg: If we could build a reactor we could build bombs. That’s what had brought me to Copenhagen. But none of this could I say. And at this point you stopped listening. The bomb had already gone off inside your head. I realised we were heading back towards the house. Our walk was over. Our one chance to talk had gone forever.  

Bohr: Because I’d grasped the central point already. That one way or another you saw the possibility of supplying Hitler with nuclear weapons.  

Heisenberg: You grasped at least four different central points, all of them wrong. You told Rozental that I’d tried to pick your brains about fission. You told Weisskopf that I’d asked you what you knew about the Allied nuclear programme. Chadwick thought I was hoping to persuade you that there was no German programme. But then you seem to have told some people that I’d tried to recruit you to work on it!  

Bohr: Very well. Let’s start all over again from the beginning. No Gestapo in the shadows this time. No British intelligence officer. No one watching us at all.  

Margrethe: Only me.  

Bohr: Only Margrethe. We’re going to make the whole thing clear to Margrethe. You know how strongly I believe that we don’t do science for ourselves, that we do it so we can explain to others. . .  

Heisenberg: In plain language.  

Bohr: In plain language. Not your view, I know.you’d be happy to describe what you were up to purely in differential equations if you could

but for Margrethe’s sake . . .  

Heisenberg: Plain language.  

Bohr: Plain language. All right, so here we are, walking along the street once more. And this time I’m absolutely calm, I’m listening intently. What is it you want to say?  

Heisenberg: It’s not just what I want to say! The whole German nuclear team in Berlin! Not Diebner, of course, not the Nazis.....but Weizsäcker, Hahn, Wirtz, Jensen, Houtermanns ..........they all wanted me to come and discuss it with you. We all see you as a kind of spiritual father.  

Margrethe: The Pope. That’s what you used to call Niels behind his back. And now you want him to give you absolution.  

Heisenberg: Absolution? No!  

Margrethe: According to your colleague Jensen.  

Heisenberg: Absolution is the last thing I want!  

Margrethe: You told one historian that Jensen had expressed it perfectly.  

Heisenberg: Did I? Absolution. . . . Is that what I’ve come for? It’s like trying to remember who was at that lunch you gave me at the Institute. Around the table sit all the different explanations for everything I did. I turn to look. . . Petersen, Rozental, and . . . yes . . . now the word absolution is taking its place among them all. . .  

Margrethe: Though I thought absolution was granted for sins past and repented, not for sins intended and yet to be committed.  

Heisenberg: Exactly! That’s why I was so shocked!  

Bohr: You were shocked?  

Heisenberg: Because you did give me absolution! That’s exactly what you did! As we were hurrying back to the house. You muttered something about everyone in wartime being obliged to do his best for his own country. Yes?  

Bohr: Heaven knows what I said. But now here I am, profoundly calm and conscious, weighing my words. You don’t want absolution. I understand. You want me to tell you not to do it? All right. I put my hand on your arm. I look you in the eye in my most papal way. Go back to Germany, Heisenberg. Gather your colleagues together in the laboratory. The whole team - Weizsäcker, Hahn, Wirtz, Jensen, Houtermanns, all the assistants and technicians. Get up on a table and tell them 'Niels Bohr says that in his considered judgment supplying a homicidal maniac with an improved instrument of mass murder is . . . ' What shall I say? ' . . . an interesting idea.' No, not even an interesting idea. ' . . . a really rather seriously uninteresting idea.' What happens? You all fling down your Geiger counters?  

Heisenberg: Obviously not.  

Bohr: Because they’ll arrest you.  

Heisenberg: Whether they arrest us or not it won’t make any difference. In fact it will make things worse. I’m running my programme for the Kaiser Wilhelm Institute. But there’s a rival one at Army Ordnance, run by Kurt Diebner, and he’s a party member. If I go they’ll simply get Diebner to take over my programme as well. He should be running it anyway. Wirtz and the rest of them only smuggled me in to keep Diebner and the Nazis out of it. My one hope is to remain in control.  

Bohr: So you don’t want me to say yes and you don’t want me to say no.  

Heisenberg: What I want is for you to listen carefully to what I’m going on to say next, instead of running off down the street like a madman.  

Bohr: Very well. Here I am, walking very slowly and popishly. And I listen most carefully as you tell me. . .  

Heisenberg: That nuclear weapons will require an enormous technical effort.  

Bohr: True.  

Heisenberg: That they will suck up huge resources.  

Bohr: Huge resources. Certainly.  

Heisenberg: That sooner or later governments will have to turn to scientists and ask whether it’s worth committing those resources - whether there’s any hope of producing the weapons in time for them to be used.  

Bohr: Of course, but. . .  

Heisenberg: Wait. So they will have to come to you and me. We are the ones who will have to advise them whether to go ahead or not. In the end the decision will be in our hands, whether we like it or not.  

Bohr: And that’s what you want to tell me?  

Heisenberg: That’s what I want to tell you.  

Bohr: That’s why you have come all this way, with so much difficulty? That’s why you have thrown away nearly twenty years of friendship? Simply to tell me that?  

Heisenberg: Simply to tell you that.  

Bohr: But, Heisenberg, this is more mysterious than ever! What are you telling it me for? What am I supposed to do about it? The government of occupied Denmark isn’t going to come to me and ask me whether we should produce nuclear weapons!  

Heisenberg: No, but sooner or later, if I manage to remain in control of our programme, the German government is going to come to me! They will ask me whether to continue or not! I will have to decide what to tell them!  

Bohr: Then you have an easy way out of your difficulties. You tell them the simple truth that you’ve just told me. You tell them how difficult it will be. And perhaps they’ll be discouraged. Perhaps they’ll lose interest.  

Heisenberg: But, Bohr, where will that lead? What will be the consequences if we manage to fail?  

Bohr: What can I possibly tell you that you can’t tell yourself?  

Heisenberg: There was a report in a Stockholm paper that the Americans are working on an atomic bomb.  

Bohr: Ah. Now it comes, now it comes. Now I understand everything. You think I have contacts with the Americans?  

Heisenberg: You may. It’s just conceivable. If anyone in Occupied Europe does it will be you.  

Bohr: So you do want to know about the Allied nuclear programme.  

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 programme. . .  

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? You said it would be easy to imagine that one might have less love for one’s country if it’s small and defenceless. Yes, and it would be another easy mistake to make, to think that one loved one’s country less because it happened to be in the wrong. Germany is where I was born. Germany is where I became what I am. Germany is all the faces of my childhood, all the hands that picked me up when I fell, all the voices that encouraged me and set me on my way, all the hearts that speak to my heart. Germany is my widowed mother and my impossible brother. Germany is my wife. Germany is our children. I have to know what I’m deciding for them! Is it another defeat? Another nightmare like the nightmare I grew up with? Bohr, my childhood in Munich came to an end in anarchy and civil war. Are more children going to starve, as we did? Are they going to have to spend winter nights as I did when I was a schoolboy, crawling on my hands and knees through the enemy lines, creeping out into the country under cover of darkness in the snow to find food for my family? Are they going to sit up all night, as I did at the age of seventeen, guarding some terrified prisoner, talking to him and talking to him through the small hours, because he’s going to be executed in the morning?  

Bohr: But, my dear Heisenberg, there’s nothing I can tell you. I’ve no idea whether there’s an Allied nuclear programme.  

Heisenberg: It’s just getting under way even as you and I are talking. And maybe I’m choosing something worse even than defeat. Because the bomb they’re building is to be used on us. On the evening of Hiroshima Oppenheimer said it was his one regret. That they hadn’t produced the bomb in time to use on Germany.  

Bohr: He tormented himself afterwards.  

Heisenberg: Afterwards, yes. At least we tormented ourselves a little beforehand. Did a single one of them stop to think, even for one brief moment, about what they were doing? Did Oppenheimer? Did Fermi, or Teller, or Szilard? Did Einstein, when he wrote to Roosevelt in 1939 and urged him to finance research on the bomb? Did you, when you escaped from Copenhagen two years later, and went to Los Alamos?  

Bohr: My dear, good Heisenberg, we weren’t supplying the bomb to Hitler!  

Heisenberg: You weren’t dropping it on Hitler, either. You were dropping it on anyone who was in reach. On old men and women in the street, on mothers and their children. And if you’d produced it in time they would have been my fellow-countrymen. My wife. My children. That was the intention. Yes?  

Bohr: That was the intention.  

Heisenberg: You never had the slightest conception of what happens when bombs are dropped on cities. Even conventional bombs. None of you ever experienced it. Not a single one of you. I walked back from the centre of Berlin to the suburbs one night, after one of the big raids. No transport moving, of course. The whole city on fire. Even the puddles in the streets are burning. They’re puddles of molten phosphorus. It gets on your shoes like some kind of incandescent dog-muck.I have to keep scraping it off as if the streets have been fouled by the hounds of hell. It would have made you laugh - my shoes keep bursting into flame. All around me, I suppose, there are people trapped, people in various stages of burning to death. And all I can think is, How will I ever get hold of another pair of shoes in times like these?  

Bohr: You know why Allied scientists worked on the bomb.  

Heisenberg: Of course. Fear.  

Bohr: The same fear that was consuming you. Because they were afraid that you were working on it.  

Heisenberg: Bohr, you could have told them!  

Bohr: Told them what?  

Heisenberg: What I told you in 1941! That the choice is in our hands! In mine - in Oppenheimer’s! That if I can tell them the simple truth when they ask me, the simple discouraging truth, so can he!  

Bohr: This is what you want from me? Not to tell you what the Americans are doing but to stop them?  

Heisenberg: To tell them that we can stop it together.  

Bohr: I had no contact with the Americans!  

Heisenberg: You did with the British.  

Bohr: Only later.  

Heisenberg: The Gestapo intercepted the message you sent them about our meeting.  

Margrethe: And passed it to you?  

Heisenberg: Why not? They’d begun to trust me. This is what gave me the possibility of remaining in control of events.  

Bohr: Not to criticise, Heisenberg, but if this is your plan in coming to Copenhagen, it’s . . . what can I say? It’s most interesting.  

Heisenberg: It’s not a plan. It’s a hope. Not even a hope. A microscopically fine thread of possibility. A wild improbability. Worth trying, though, Bohr! Worth trying, surely! But already you’re too angry to understand what I’m saying.  

Margrethe: No - why he’s angry is because he is beginning to understand! The Germans drive out most of their best physicists because they’re Jews. America and Britain give them sanctuary. Now it turns out that this might offer the Allies a hope of salvation. And at once you come howling to Niels begging him to persuade them to give it up.  

Bohr: Margrethe, my love, perhaps we should try to express ourselves a little more temperately.  

Margrethe: But the gall of it! The sheer, breathtaking gall of it!  

Bohr: Bold ski-ing, I have to say.  

Heisenberg: But, Bohr, we’re not ski-ing now! We’re not playing table-tennis! We’re not juggling with cap-pistols and non-existent cards! I refused to believe it, when I first heard the news of Hiroshima. I thought that it was just one of the strange dreams we were living in at the time. They’d got stranger and stranger, God knows, as Germany fell into ruins in those last months of the war. But by then we were living in the strangest of them all. The ruins had suddenly vanished just the way things do in dreams and all at once we’re in a stately home in the middle of the English countryside. 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. It’s like a pre-war house-party......one of those house.......parties in a play, that’s cut off from any contact with the outside world, where you know the guests have all been invited for some secret sinister purpose. No one knows we’re there..... no one in England, no one in Germany, not even our families. But the war’s over. What’s happening? Perhaps, as in a play, we’re going to be quietly murdered, one by one. In the meanwhile it’s all delightfully civilised. I entertain the party with Beethoven piano sonatas. Major Rittner, our hospitable gaoler, reads Dickens to us, to improve our English. . . . Did these things really happen to me . . . ? We wait for the point of it all to be revealed to us. Then one evening it is. And it’s even more grotesque than the one we were fearing. It’s on the radio: you have actually done the deed that we were tormenting ourselves about. That’s why we’re there, dining with our gracious host, listening to our Dickens. We’ve been kept locked up to stop us discussing the subject with anyone until it’s too late. When Major Rittner tells us I simply refuse to believe it until I hear it with my own ears on the nine o’clock news. We’d no idea how far ahead you’d got. I can’t describe the effect it has on us. You play happily with your toy cap pistol. Then someone else picks it up and pulls the trigger . . . and all at once there’s blood everywhere and people screaming, because it wasn’t a toy at all. . . . We sit up half the night, talking about it, trying to take it in. We’re all literally in shock.  

Margrethe: Because it had been done? Or because it wasn’t you who’d done it?  

Heisenberg: Both. Both. Otto Hahn wants to kill himself, because it was he who discovered fission, and he can see the blood on his hands. Gerlach, our old Nazi co-ordinator, also wants to die, because his hands are so shamefully clean. You’ve done it, though. You’ve built the bomb.  

Bohr: Yes.  

Heisenberg: And you’ve used it on a living target.  

Bohr: On a living target.  

Margrethe: You’re not suggesting that Niels did anything wrong in working at Los Alamos?  

Heisenberg: Of course not. Bohr has never done anything wrong.  

Margrethe: The decision had been taken long before Niels arrived. The bomb would have been built whether Niels had gone or not.  

Bohr: In any case, my part was very small.  

Heisenberg: Oppenheimer described you as the team’s father-confessor.  

Bohr: It seems to be my role in life.  

Heisenberg: He said you made a great contribution.  

Bohr: Spiritual, possibly. Not practical.  

Heisenberg: Fermi says it was you who worked out how to trigger the Nagasaki bomb.  

Bohr: I put forward an idea.  

Margrethe: You’re not implying that there’s anything that Niels needs to explain or defend?  

Heisenberg: No one has ever expected him to explain or defend anything. He’s a profoundly good man.  

Bohr: It’s not a question of goodness. I was spared the decision.  

Heisenberg: Yes, and I was not. So explaining and defending myself was how I spent the last thirty years of my life. When I went to America in 1949 a lot of physicists wouldn’t even shake my hand. Hands that had actually built the bomb wouldn’t touch mine.  

Margrethe: And let me tell you, if you think you’re making it any clearer to me now, you’re not.  

Bohr: Margrethe, I understand his feelings. . .  

Margrethe: I don’t. I’m as angry as you were before! It’s so easy to make you feel conscience-stricken. Why should he transfer his burden to you? Because what does he do after his great consultation with you? He goes back to Berlin and tells the Nazis that he can produce atomic bombs!  

Heisenberg: But what I stress is the difficulty of separating 235.  

Margrethe: You tell them about plutonium.  

Heisenberg: I tell some of the minor officials. I have to keep people’s hopes alive!  

Margrethe: Otherwise they’ll send for the other one.  

Heisenberg: Diebner. Very possibly.  

Margrethe: There’s always a Diebner at hand ready to take over our crimes.  

Heisenberg: Diebner might manage to get a little further than me.  

Bohr: Diebner?  

Heisenberg: Might. Just possibly might.  

Bohr: He hasn’t a quarter of your ability!  

Heisenberg: Not a tenth of it. But he has ten times the eagerness to do it. It might be a very different story if it’s Diebner who puts the case at our meeting with Albert Speer, instead of me.  

Margrethe: The famous meeting with Speer.  

Heisenberg: But this is when it counts. This is the real moment of decision. It’s June 1942. Nine months after my trip to Copenhagen. All research cancelled by Hitler unless it produces immediate results.....and Speer is the sole arbiter of what will qualify. Now, we’ve just got the first sign that our reactor’s going to work. Our first increase in neutrons. Not much ..... thirteen per cent - but it’s a start.  

Bohr: June 1942? You’re slightly ahead of Fermi in Chicago.  

Heisenberg: Only we don’t know that. But the RAF have begun terror-bombing. They’ve obliterated half of Lübeck, and the whole centre of Rostock and Cologne. We’re desperate for new weapons to strike back with. If ever there’s a moment to make our case, this is it.  

Margrethe: You don’t ask him for the funding to continue?  

Heisenberg: To continue with the reactor? Of course I do. But I ask for so little that he doesn’t take the programme seriously.  

Margrethe: Do you tell him the reactor will produce plutonium?  

Heisenberg: I don’t tell him the reactor will produce plutonium. Not Speer, no. I don’t tell him the reactor will produce plutonium.  

Bohr: A striking omission, I have to admit.  

Heisenberg: And what happens? It works! He gives us barely enough money to keep the reactor programme ticking over. And that is the end of the German atomic bomb. That is the end of it.  

Margrethe: You go on with the reactor, though.  

Heisenberg: We go on with the reactor. Of course. Because now there’s no risk of getting it running in time to produce enough plutonium for a bomb. No, we go on with the reactor all right. We work like madmen on the reactor. We have to drag it all the way across Germany, from east to west, from Berlin to Swabia, to get it away from the bombing, to keep it out of the hands of the Russians. Diebner tries to hijack it on the way. We get it away from him, and we set it up in a little village in the Swabian Jura.  

Bohr: This is Haigerloch?  

Heisenberg: There’s a natural shelter there. the village inn has a wine cellar cut into the base of a cliff. We dig a hole in the floor for the reactor, and I keep that programme going, I keep it under my control, until the bitter end.  

Bohr: But, Heisenberg, with respect now, with the greatest respect, you couldn’t even keep the reactor under your control. That reactor was going to kill you.  

Heisenberg: It wasn’t put to the test. It never went critical.  

Bohr: Thank God. Hambro and Perrin examined it after the Allied troops took over. They said it had no cadmium control rods. There was nothing to absorb any excess of neutrons, to slow the reaction down when it overheated.  

Heisenberg: No rods, no.  

Bohr: You believed the reaction would be self-limiting.  

Heisenberg: That’s what I originally believed.  

Bohr: Heisenberg, the reaction would not have been self-limiting.  

Heisenberg: By 1945 I understood that.  

Bohr: So if you ever had got it to go critical, it would have melted down, and vanished into the centre of the earth!  

Heisenberg: Not at all. We had a lump of cadmium to hand.  

Bohr: A lump of cadmium? What were you proposing to do with a lump of cadmium?  

Heisenberg: Throw it into the water.  

Bohr: What water?  

Heisenberg: The heavy water. The moderator that the uranium was immersed in.  

Bohr: My dear good Heisenberg, not to criticise, but you’d all gone mad!  

Heisenberg: We were almost there! We had this fantastic neutron growth! We had 670 per cent growth!  

Bohr: You’d lost all contact with reality down in that hole!  

Heisenberg: Another week. Another fortnight. That’s all we needed!  

Bohr: It was only the arrival of the Allies that saved you!  

Heisenberg: We’d almost reached the critical mass! A tiny bit bigger and the chain would sustain itself indefinitely. All we need is a little more uranium. I set off with Weizsäcker to try and get our hands on Diebner’s. Another hair-raising journey all the way back across Germany. Constant air raids.....no trains ......we try bicycles - we never make it! We end up stuck in a little inn somewhere in the middle of nowhere, listening to the thump of bombs falling all round us. And the Beethoven G minor cello sonata on the radio. . .  

Bohr: And everything was still under your control?  

Heisenberg: Under my control - yes! That’s the point! Under my control!  

Bohr: Nothing was under anyone’s control by that time!  

Heisenberg: Yes, because at last we were free of all constraints! The nearer the end came the faster we could work!  

Bohr: You were no longer running that programme, Heisenberg. The programme was running you.  

Heisenberg: Two more weeks, two more blocks of uranium, and it would have been German physics that achieved the world’s first self-sustaining chain reaction.  

Bohr: Except that Fermi had already done it in Chicago, two years earlier.  

Heisenberg: We didn’t know that.  

Bohr: You didn’t know anything down in that cave. You were as blind as moles in a hole. Perrin said that there wasn’t even anything to protect you all from the radiation.  

Heisenberg: We didn’t have time to think about it.  

Bohr: So if it had gone critical . . .  

Margrethe: You’d all have died of radiation sickness.  

Bohr: My dear Heisenberg! My dear boy!  

Heisenberg: Yes, but by then the reactor would have been running.  

Bohr: I should have been there to look after you.  

Heisenberg: That’s all we could think of at the time. To get the reactor running, to get the reactor running.  

Bohr: You always needed me there to slow you down a little. Your own walking lump of cadmium.  

Heisenberg: If I had died then, what should I have missed? Thirty years of attempting to explain. Thirty years of reproach and hostility. Even you turned your back on me.  

Margrethe: You came to Copenhagen again. You came to Tisvilde.  

Heisenberg: It was never the same.  

Bohr: No. It was never the same.  

Heisenberg: I sometimes think that those final few weeks at Haigerloch were the last happy time in my life. In a strange way it was very peaceful. Suddenly we were out of all the politics of Berlin. Out of the bombing. The war was coming to an end. There was nothing to think about except the reactor. And we didn’t go mad, in fact. We didn’t work all the time. There was a monastery on top of the rock above our cave. I used to retire to the organ-loft in the church, and play Bach fugues.  

Margrethe: Look at him. He’s lost. He’s like a lost child. He’s been out in the woods all day, running here, running there. He’s shown off, he’s been brave, he’s been cowardly. He’s done wrong, he’s done right. And now the evening’s come, and all he wants is to go home, and he’s lost.  

Heisenberg: Silence.  

Bohr: Silence.  

Margrethe: Silence.  

Heisenberg: And once again the tiller slams over, and Christian is falling.  

Bohr: Once again he’s struggling towards the lifebuoy.  

Margrethe: Once again I look up from my work, and there’s Niels in the doorway, silently watching me. . .  

Bohr: 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.  

Heisenberg: No.  

Bohr: You didn’t seriously hope that I’d stop them.  

Heisenberg: No.  

Bohr: You were going back to work on that reactor whatever I said.  

Heisenberg: Yes.  

Bohr: So, Heisenberg, why did you come?  

Heisenberg: Why did I come?  

Bohr: Tell us once again. Another draft of the paper. And this time we shall get it right. This time we shall understand.  

Margrethe: Maybe you’ll even understand yourself.  

Bohr: After all, the workings of the atom were difficult to explain. We made many attempts. Each time we tried they became more obscure. We got there in the end, however. So - another draft, another draft.  

Heisenberg: Why did I come? And once again I go through that evening in 1941. I crunch over the familiar gravel, and tug at the familiar bell-pull. What’s in my head? Fear, certainly, and the absurd and horrible importance of someone bearing bad news. But . . . yes . . . something else as well. Here it comes again. I can almost see its face. Something good. Something bright and eager and hopeful.  

Bohr: I open the door. . .  

Heisenberg: And there he is. I see his eyes light up at the sight of me.  

Bohr: He’s smiling his wary schoolboy smile.  

Heisenberg: And I feel a moment of such consolation.  

Bohr: A flash of such pure gladness.  

Heisenberg: As if I’d come home after a long journey.  

Bohr: As if a long-lost child had appeared on the doorstep.  

Heisenberg: Suddenly I’m free of all the dark tangled currents in the water.  

Bohr: Christian is alive, Harald still unborn.  

Heisenberg: The world is at peace again.  

Margrethe: Look at them. Father and son still. Just for a moment. Even now we’re all dead.  

Bohr: For a moment, yes, it’s the twenties again.  

Heisenberg: And we shall speak to each other and understand each other in the way we did before.  

Margrethe: And from those two heads the future will emerge. Which cities will be destroyed, and which survive. Who will die, and who will live. Which world will go down to obliteration, and which will triumph.  

Bohr: My dear Heisenberg!  

Heisenberg: My dear Bohr!  

Bohr: Come in, come in. . .  

ACT ONE 结束