121st anniversary of Grete Hermann's birthday

Summary

Grete Hermann: from physics to politics

Grete Hermann (1901-1984), a well-trained mathematician and philosopher, was a doctoral student of Emmy Noether in Göttingen, who later worked together with Werner Heisenberg and Niels Bohr in Leipzig.

In her talk about Grete’s remarkable life and work Dr. Reichenberger will focus on her discussions with the physicist Adolf Kratzer and the mathematician Paul Bernays about the measurement problem, which illuminate a deep interdependence between philosophy and physics. In the second part of her talk, she will highlight Hermann's work on the intersection of science, politics, and ethics, and its astonishing relevance in the light of the current pandemic crisis, by reconsidering Hermann's concept of "objective knowledge".

Grete Hermann and the question of the completeness of quantum theory

The completeness of quantum theory is a problem which has been addressed by many physicists in the 1930s (and later). In her 1935 article, Grete Hermann systematically investigates the main arguments which were put forward against an extension of quantum mechanics by hidden variables in order to explain the indeterminism in quantum systems. She comes to the conclusion that hidden variables cannot be ruled out in principle. The most famous of her refusals is the critique of John von Neumann’s proof claiming that an extension by hidden variables is not possible without changing the predictions of quantum mechanics. On the other hand, by giving a careful analysis of a thought experiment proposed by Werner Heisenberg and investigated by Carl Friedrich von Weizsäcker, she argues that quantum theory is already complete and does not need an extension.

In his talk Prof. Filk will give a brief review of her argumentation, in particular her critique of von Neumann and her way to look at von Weiszäcker’s model. And he would like to emphasize why it is still worthwhile reading her article.