First of all, I don’t think it is strange to be both novelist and playwright. I wonder why others don’t do both. I think the great difference is that in a novel it is possible for the writer to be inside the head of at least one of the characters. He doesn’t have to be, but if you think of most of the novels you’ve read, the author has known what all the characters’ thoughts and feelings and intentions were. If you read: She felt bitter resentment about what he had said. He intended to set off for Birmingham, but he changed his mind. She realized that he had not understood what she had said, etcetera—all these things seem absolutely natural, you don’t even notice that is the way most novels are written. In fact it is quite odd, because it implies that the author has absolute knowledge of what’s going on inside the head of his characters. Sometimes the author chooses not to exercise that right, and sometimes he exercises it in the case of one or two characters but not all. But it is the natural mode for the storyteller to know what’s happening inside his characters’ heads.
By contrast, in the play it is impossible to indicate directly what is going on inside people’s heads. All we know when we watch a play is what the characters are saying and what they are doing. Of course characters can say, I’m thinking so and so, or I’m feeling such and such, but this is not the same as knowing directly. You have to trust that the character is speaking truthfully, that he can understand himself—because characters often don’t.
Now, some stories require that you know what people are thinking, and some stories require that you don’t. In Copenhagen the whole point of the play is trying to find out what Heisenberg was thinking and what his intentions were in going to Copenhagen to see Niels Bohr. If I tried to write it as a novel the whole story would be told in one paragraph. I’d say, Heisenberg decided to go to Copenhagen in 1941 in order to talk to Niels Bohr about such and such, because he hoped that Bohr would say so and so . . . But I wanted to look at the difficulty of knowing that exists in life. So it seemed natural to be outside Heisenberg’s head and have to work out what was going on inside it.
When you got the story, did you know at once it would be a play rather than a novel?
Yes. Because that was what it was about—the difficulty of understanding people’s intentions, even one’s own intentions.
So it is the story that chooses the form, not you, the author?