Copenhagen - Michael Frayn [41]
But he goes further, and argues that Heisenberg ‘did not simply withhold himself, stand aside, let the project die. He killed it.’ He tries to show that at every point Heisenberg was careful to hold out enough hope to the authorities to ensure that he and and his team were left in charge of the project, but never enough to attract the total commitment and huge investment that would have offered the only real hope of success. ‘Heisenberg’s caution saved him. He was free to do what he could to guide the German atomic research effort into a broom closet, where scientists tinkered until the war ended.’
Cassidy, reviewing the book in Nature, described it as a good story, but insisted that ‘as history it is incredible.’ Rose dismisses it as ‘entirely bogus’ and ‘a scholarly disaster’. Powers acknowledged ruefully, in a recent letter to the Times Literary Supplement, that he had failed to convince any historian who had pronounced upon the matter.
The play is not an attempt to adjudicate between these differing views of Heisenberg’s personality, or these differing accounts of his activities. But it would have been impossible to write it without taking some view of Powers’ version of events, so here, for what it is worth, is a brief summary of the case, and of my own hesitant view of it. The evidence is confused and contradictory, and making any sense of it involves balancing probabilities and possibilities almost as indeterminable as Heisenberg found events inside the atom.
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Some of the evidence undoubtedly appears to support Powers’s thesis in its stronger form, that Heisenberg deliberately sabotaged the project.
In the first place there are two scraps of direct testimony. One is a message brought to America in 1941 by a departing German Jewish academic called Fritz Reiche. It was from Fritz Houtermans, the German physicist who had just realised that if they could get a reactor going it would produce plutonium, and that plutonium would be a fissile alternative to the U235 that they could not separate. Reiche testified later that he had passed it on to a group of scientists working at Princeton, including Wolfgang Pauli, John von Neumann, and Hans Bethe. As Rudolf Ladenburg, the physicist who arranged the meeting, recorded it afterwards, Houtermans wanted it to be known that ‘a large number of German physicists are working intensively on the problem of the uranium bomb under the direction of Heisenberg,’ and that ‘Heisenberg himself tries to delay the work as much as possible, fearing the catastrophic results of a success.’
Rose dismisses Houtermans as a proven liar, and records that Reiche later appeared to withdraw his belief in Heisenberg’s opposition to the project. But neither of these objections seems immediately relevant to the consistency of Reiche’s and Ladenburg’s testimony.
The second scrap of evidence is even more direct, but much more dubious. Heisenberg’s American editor, Ruth Nanda Anshen, records receiving a letter from him in 1970 in which he claimed that, ‘Dr Hahn, Dr von Laue and I falsified the mathematics in order to avoid the development of the atom bomb by German scientists.’
The letter itself has apparently vanished from the record. Rose nonetheless accepts it as beyond doubt genuine, and sees it as a yet more blatant attempt at self-justification. It is not, however, called into evidence by Powers, even though it would appear to support his case, and he mentions it only in his notes, and with the greatest reserve. Jeremy Bernstein, who seems to me the best-informed and most fair-minded of all Heisenberg’s critics, and whose book Hitler’s Uranium Club will be relied upon in understanding the scientific considerations that follow, dismisses it as ‘incredible’ and ‘a chimera’. It is entirely at odds with Heisenberg’s careful moderation in all his other references to the matter, and the inclusion of Hahn and von Laue in the plot is nonsensical. Hahn was a chemist, not a physicist, and, as will be plain from what comes later, had no knowledge whatosever of the relevant mathematics, while von Laue