Logical Positivism and the Verification Principle

Logical positivism crystallized in Vienna in the 1920s around the Wiener Kreis, a discussion group that met regularly under the chairmanship of Moritz Schlick, who had held the chair of philosophy of the inductive sciences at the University of Vienna since 1922. Its core members included Rudolf Carnap, Otto Neurath, Hans Hahn, Friedrich Waismann, and Herbert Feigl, and its manifesto, "Wissenschaftliche Weltauffassung: Der Wiener Kreis" ("The Scientific Conception of the World"), was published in 1929, dedicated to Schlick and drafted principally by Neurath, Carnap, and Hahn. The group drew heavily on Ludwig Wittgenstein's Tractatus Logico-Philosophicus (1921), whose picture theory of meaning and rejection of metaphysical propositions as literally nonsensical shaped their central ambition: to reconstruct scientific knowledge on a rigorous logical and empirical foundation, purging it of what they saw as the meaningless speculation of traditional metaphysics, including much of German Idealism and Heideggerian ontology. A parallel Berlin group, the Gesellschaft für empirische Philosophie, led by Hans Reichenbach and including Carl Gustav Hempel, pursued closely related aims, and the movement as a whole is often labeled logical empiricism to capture this wider network beyond Vienna itself.