The recent publication of the lectures given by the University of Vienna Philosophical Society from 1888 to 1922 has apparently stimulated increased interest among many scholars. 2 The primary reason, of course, is that the Vienna background of many of the best-known philosophers of the 20th century has raised the distinct possibility that the Philosophical Society was a significant or even principal incubator for this remarkable development. Mach, Wittgenstein, Boltzmann, Neurath, Popper, von Hayek, and Feyerabend were all Viennese. The first four thinkers were clearly influenced by lectures and discussions given in the Society, the father of Sir Karl Popper was a member, 3 Friedrich von Hayek alleges that most philosophical discussion revolved around Mach’s ideas at that time, 4 and concerning Feyerabend’s attraction to philosophy, one might suspect a source in Boltzmann’s Populare Schriften. 5 Some of the groups which appear to have been ‘spun off from the Society include Schlick’s Circle, Reininger’s Circle, and Heinrich Gomperz’s Circle. 6