The German physicist and philosopher Friedrich Albert Moritz Schlick (1882-1936) revived positivism as a leading force in 20th-century thought and was the founding spirit of the Vienna Circle.

Moritz Schlick was born in Berlin on Feb. 28, 1833, and educated there. His secondary school training was largely focused on mathematics and physics, and he pursued these subjects further in his university studies at Heidelberg, Lausanne, and Berlin. His doctoral thesis at Berlin, written under Max Planck, was Reflection of Light (1904).

By 1910 Schlick's interests had shifted from physics proper to epistemology and the philosophy of science. With his inaugural dissertation, "The Nature of Truth in the Light of Modern Physics," he began his teaching career at Rostock. There he continued to follow developments in physics, partly through his friendship with Planck and Albert Einstein; and he wrote the first interpretation of the latter's relativity theory in 1917. Also during this period, Schlick worked out his fundamental ideas on scientific knowing and published them as The General Theory of Knowledge (1918). This earned him wide attention and a call to a professorship, first at Kiel in 1921 and a year later at Vienna.

At Vienna, Schlick quickly became the center of a group of men interested in scientific philosophy, logic, and mathematics. The group included among others Otto Neurath, Rudolf Carnap, Herbert Feigl, Friedrich Waismann, and Kurt Gödel and later the English philosophers Alfred Ayer and Susan Stebbing and an American, Charles Morris. There were weekly meetings to discuss fundamental questions in logic and the philosophy of science. Setting very exact (critics would say "narrow") criteria for knowledge, the group rejected metaphysical propositions as meaningless and severely limited the range of significant speech in ethics and esthetics. In 1929, on the occasion of Schlick's return from a guest lectureship at Stanford, Calif., he was presented with a pamphlet describing the history, membership, orientation, and goals of the group. It was called "The Scientific View of the World: The Vienna Circle."

The reading of Ludwig Wittgenstein's Tractatus in 1921 fundamentally altered Schlick's conception of the task of philosophy. He now held that philosophy's task was the analysis of the concepts used in science and the language spoken in everyday life. Widely propagated by members of the Vienna Circle, this is the dominant view in English and American philosophy today.

Schlick was shot by a deranged former student while on his way to lecture at the University of Vienna on June 22, 1936. Owing to his death and to the hostility of the Nazi regime after the Anschluss, the members of the Circle were widely dispersed to Scandinavia, England, and the United States.

Further Reading

• There is no major work on Schlick. Victor Kraft, The Vienna Circle: The Origin of Neo-positivism (1953), gives an account of the history and central doctrines of the group.