Authors: Michael Frayn
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 relativity, and they said it was Jewish physics. He couldn’t mention Einstein by name, but he stuck with 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 Goucdsmit.
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 realise it was fission. It didn’t occur to anyone that the uranium atom might have split, and turned into an atom of barium and an atom of krypton. 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 other elements. 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-Albrecht-Strasse?
Heisenberg
A slight misunderstanding.
Bohr
We heard, yes. I’m so sorry.
Heisenberg
These things happen. The question is now resolved. Happily resolved. We should all have met in Zürich …
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.
Margrethe
They so much wanted to see each other, in spite of everything! But now the moment has come they’re so busy avoiding each other’s eye that they can scarcely see each other at all.
Heisenberg
I wonder if you realise how much it means to me to be back here in Copenhagen. In this house. I have become rather isolated in these last few years.
Bohr
I can imagine.
Margrethe
Me he scarcely notices. I watch him discreetly from behind my expression of polite interest as he struggles on.
Heisenberg
Have things here been difficult?
Bohr
Difficult?
Margrethe
Of course. He has to ask. He has to get it out of the way.
Bohr
Difficult What can I say? We’ve not so far been treated to the gross abuses that have occurred elsewhere. The race laws have not been enforced.
Margrethe
Yet.
Bohr
A few months ago they started deporting
Communists and other anti-German elements.
Heisenberg
But you personally …?
Bohr
Have been left strictly alone.
Heisenberg
I’ve been anxious about you.
Bohr
Kind of you. No call for sleepless nights in Leipzig so far, though.
Margrethe
Another silence. He’s done his duty. Now he can begin to steer the conversation round to pleasanter subjects.
Heisenberg
Are you still sailing?
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-Albrecht-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 ski-hut at Bayrischzell. So if by any chance … at any time … for any reason …
Bohr
Perhaps Margrethe would be kind enough to sew a yellow star on my ski-jacket.