This paper introduces and reproduces a document from Feyerabend’s Nachlass including: (i) Feyerabend’s 1967 tentative translation into English of an original German typescript reporting the lecture notes of an academic course on magnetic monopoles delivered by physicist Felix Ehrenhaft (1879-1952) at the University of Vienna in the 1947 summer semester; and (ii) Feyerabend’s memoir focusing on Ehrenhaft in postwar Vienna.In addition to making available to a larger audience Ehrenhaft’s lectures on a highly controversial topic, the publication of Feyerabend’s typescript offers (...) the opportunity to reconsider, delve deeper into and cast a brighter light on a rather neglected aspect in the growing literature on Feyerabend’s thought: the significance of Ehrenhaft for the development of Feyerabend’s intellectual biography. (shrink)

Karl Popper and Paul Feyerabend were among the most influential philosophers of science of the twentieth century. Extensive studies have been dedicated to the development of their controversial relationship, which saw Feyerabend turning from a student and supporter of Popper to one of his harshest critics. Yet, it is not as well known that the rift between Popper and Feyerabend arose mainly in the context of their studies on the foundations of quantum mechanics, which has been the main subject of (...) their discussions for about two decades. This paper reconstructs in detail their diatribe over the foundations of quantum mechanics, emphasising also the major role that their personal relationship played in their distancing. (shrink)