Introduction: Josef Schächter and the Vienna Circle

The Vienna Circle is the name given to a regular discussion group of some 20 members around the physicist and philosopher Moritz Schlick (1882–1936). In this so-called “Schlick-Circle” the reform of traditional philosophy, its foundations and methods were discussed between 1924 and 1936 against the background of relativity theory, quantum physics, symbolic logic and language analysis. It endeavored to redefine the currents of rationalism and empiricism and combine them into “logical empiricism”. The task of philosophy was to clarify the language of science by determining the meaning of statements. An encyclopedia of unified science challenged philosophy’s claim to leadership in the sciences (Stadler 2015).