The Vienna Circle (German: Wiener Kreis) was an association of philosophers gathered around the University of Vienna in 1922, chaired by Moritz Schlick, also known as the Ernst Mach Society (Verein Ernst Mach) in honour of Ernst Mach. Among its members were Gustav Bergmann, Rudolf Carnap, Philipp Frank, Hans Hahn, Tscha Hung, Victor Kraft, Karl Menger, Richard von Mises, Marcel Natkin, Otto Neurath, Olga Hahn-Neurath, Theodor Radakovic, Rose Rand and Friedrich Waismann.
Herbert Feigl and Kurt Gödel were two eminent students at the University of Vienna at this time. They were allowed to participate in the meetings, but were not members of the Vienna Circle. Members of the Vienna Circle had a common attitude towards philosophy, consisting of an applied logical positivism drawn from Ludwig Wittgenstein, whose Tractatus Logico-Philosophicus formed the basis for the group's philosophy (although Wittgenstein himself insisted that logical positivism was a gross misreading of his thinking, and took to reading poetry during meetings of the Vienna Circle). The Vienna Circle's influence on 20th century philosophy was immense, and much later work, such as that of Willard Van Orman Quine, was in response to the Circle's thought.