Heisenberg’s message to Bohr: Who knows?

David C. Cassidy states that “there is no evidence in any other sources … that moral issues regarding nuclear fission research were of particular concern for Heisenberg—nor for many other physicists, for that matter.”

This statement gives the false impression that the physicists who were working on the US Manhattan Project had no concern for the moral issues related to their research. I was a physicist working at Argonne National Laboratory during 1943 and 1944. I know from experience that a majority of physicists there were very concerned about the moral issues related to the development and use of the atomic bomb.

There were many informal discussions among the physicists at Argonne concerning these issues. Most of the discussions ended with the conclusion: We must be first! Few of us had access to information about how far along the Germans were in their nuclear research. However, we knew that if the Germans were to develop the bomb first, the results would be disastrous for the free world.