I knew that whatever I did, however much I read or studied, I would not be able to catch the manner of being of Heisenberg and Bohr, let alone Margrethe who is much less well recorded in historical record.
I was inhibited when I began to write... it was the first time I based fictitious characters on real people.
But after a time the characters do what fictitious characters always do, they begin to take on a life of their own.
One of the more chastening, and also one of the most intelligent things that was said about the play, happened the first night in New York. I went backstage and I met a very tall, very charming young man who said, I am Werner Heisenberg's son.
'Of course your Heisenberg is nothing like my father,' he said, 'I never saw my father express emotion about anything except music.' Well that was quite a chastening reminder that I was not actually going to have hit the real characters.
But then he continued, 'But in a play, I recognize you have to have characters who are rather more forthcoming than that.'
And I thought that this was a terrific understanding of what plays are doing. They are not just recording the historical record... but trying to find the truth that never quite got expressed in life.