Drama around a Wartime Heisenberg Letter

A recently published letter written by Werner Heisenberg in October 1943 has been interpreted as reporting on a sudden chasm in a close relationship between Heisenberg and Carl Friedrich von Weizsäcker. The interpretation is interesting because (as will be argued) it is counterintuitive. There are alternatives; for example, it could be an afterthought following extended nightly small talk, not to be taken seriously. I argue, with reference to other sources, that the long-standing friendship was complex and incongruent in many ways, yet solid. It is unlikely that this relation should be vulnerable to destruction by a single irrational incident, that did not even touch on personal commitments. The incident seems rather to be an atypical expression of frustration, with little consequence. The letter can even be interpreted as a unique expression of its author’s resentment of phraseology with roots in Nazi rhetoric.