Michael Frayn: Copenhagen

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.

HeisenbergI 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.

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 …