Authors: Michael Frayn
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
Hebenberg, 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, in spite of all attempts at reform. Particularly the foreign service. 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 Germany 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.
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 No! 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.
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 skiing going on here, I think.
Heisenberg
Your skiing 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
And 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.