Abstract

The Heisenberg microscope and its analysis by Weizsäcker are used by Grete Hermann in her 1935 essay on the foundations of quantum mechanics to argue her claims about causality in quantum mechanics. In this chapter, I wish to draw a comparison between Hermann’s use of the Heisenberg microscope and another famous use of a very similar thought experiment : Bohr’s analysis of the suspended single slit in his reply to EPR. I shall argue that Hermann’s use of different aspects of the classical pictures in the treatment of the Heisenberg microscope makes her treatment closer to Bohr’s discussion of the suspended slit than to Heisenberg’s own treatment of the microscope. This suggests that Hermann, who equally gave an extensive analysis of complementarity in her 1935 essay, may be an especially acute interpreter of Bohr’s views. I conclude by looking at Hermann’s approach in the context of more general examples of measurement and at possible limitations of the approach.