Authors: Michael Frayn
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 …
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
Skiing. 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. 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 walls 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?