When physicists don’t see eye to eye

When Michael Frayn wrote Copenhagen, he could surely scarcely have imagined the interest it would generate and the furore it would cause. A play that consists almost entirely of erudite conversations between two eminent physicists (Niels Bohr and Werner Heisenberg) about the development of quantum theory and the moral responsibilities of nuclear scientists is not obviously a crowd-puller. And yet, five years after its première, the play is still being performed and is still the subject of hotly contested academic debates at conferences throughout the world. Apart from the concern of scientists and historians in getting the facts right about Heisenberg’s visit to Copenhagen in 1941, the interest roused by the play centres on the question of who is morally more culpable: those German scientists, like Heisenberg, who co-operated with the Nazi regime to the extent of taking part in the (failed) Nazi atomic bomb project or those allied scientists, like Bohr, who contributed to the success of the Manhattan Project, which led to the deaths of hundreds of thousands of Japanese civilians?

The genesis of John Cornwell’s stimulating, engaging and accessible new book lies in a symposium held at Jesus College, Cambridge (where Cornwell directs the Science and Human Dimension Project) in November 2002 to discuss Frayn’s play. Listening to the passionate disagreements among historians and scientists regarding Heisenberg’s wartime activities evidently aroused in Cornwell the desire to think through the issues raised by the debate and to steer his own course through the competing views. Rejecting both the vehemently anti-Heisenberg stance of the historian, Paul Lawrence Rose, and the determinedly pro-Heisenberg position put forward by Thomas Powers in Heisenberg’s War (upon which Frayn seems to have been somewhat over-reliant), Cornwell comes down in favour of the measured and informed analysis of the physicist Jeremy Bernstein, who argues that Heisenberg, though no Nazi, was genuinely trying to build an atomic bomb and that the project failed, not because it was sabotaged from within, but because it was inadequately funded, inefficiently run and hampered by Heisenberg’s own confusions about the physics of nuclear fission.