 Feyerabend’s principal intellectual engagement in the late 1940s and early 1950s was in his capacity as student leader of the “Kraft Circle”. Viktor Kraft was a former member of the Vienna Circle, and became Feyerabend’s dissertation supervisor. The Kraft Circle was a philosophy club centred around Kraft, which constituted another part of the Austrian College Society. Bela Juhos, Walter Hollitscher, Georg Henrik von Wright, Elizabeth Anscombe and Wittgenstein were all visiting speakers. Feyerabend reports that the Circle held meetings from 1949 to 1952 or 1953 (SFS, p. 109), that they set themselves the task of “considering philosophical problems in a nonmetaphysical manner and with special reference to the findings of the sciences” (“Herbert Feigl: A Biographical Sketch”, in P. K.Feyerabend &amp; G.Maxwell (eds.), Mind, Matter, and Method: Essays in Philosophy and Science in Honor of Herbert Feigl, (Minneapolis: University of Minnesota Press, 1966), pp. 1–2) and that their main topics of discussion were the questions of the reality of theoretical entities and of the “external world”. About Wittgenstein’s lecture, Feyerabend recalls the following: 