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Hans Reichenbach (September 26, 1891, Hamburg, – April 9, 1953, Los Angeles) was a leading philosopher of science, educator and proponent of logical empiricism.

Life and work

Reichenbach is best known for founding the Berlin circle and for his logical empiricism.

After completing the secondary school in Hamburg, he studied civil engineering at the Technische Hochschule in Stuttgart, and physics, mathematics and philosophy at various universities, including Berlin, Erlangen, G�ttingen and Munich. Among his teachers were Ernst Cassirer, David Hilbert, Max Planck, Max Born and Arnold Sommerfeld. Reichenbach was active in youth movements and student organizations, and published articles about the university reform, the freedom of research, and against anti-Semitic infiltrations in student organizations.

Reichenbach received a degree in philosophy from the University of Erlangen in 1915 and his dissertation on the theory of probability, supervised by Paul Hensel and Emmy Noether, was published in 1916. Reichenbach served during World War I on the Russian front, in the German army radio troops. In 1917 he was removed from active duty, due to an illness, and returned in Berlin. While working as a physicist and engineer, Reichenbach attended Albert Einstein's lectures on the theory of relativity in Berlin from 1917 to 1920.

In 1920 Reichenbach began teaching at the Technische Hochschule at Stuttgart as Privatdozent. In the same year, he published his first book on the philosophical implications of the theory of relativity, The Theory of Relativity and A Priori Knowledge, which criticized the Kantian notion of synthetic a priori. He subsequently published Axiomatization of the Theory of Relativity (1924), From Copernicus to Einstein (1927) and The Philosophy of Space and Time (1928), the last stating the logical positivist view on the theory of relativity.

In 1926, with the help of Albert Einstein, Max Planck and Max von Laue, Reichenbach became assistant professor in the physics department of Berlin University.

He gained notice for his methods of teaching. Specifically, he was easily approached and his courses were open to discussion and debate. This was highly unusual at the time, although the practice is nowadays a common one.

In 1928, he founded the Berlin Circle (German: Die Gesellschaft f�r empirische Philosophie; English: "Society for Empirical Philosophy"). Among its members were Carl Gustav Hempel, Richard von Mises, David Hilbert and Kurt Grelling. In 1930 he and Rudolf Carnap began editing the journal Erkenntnis ("Knowledge").

In 1933, when Adolf Hitler became Chancellor of Germany, Reichenbach emigrated to Turkey, where he headed the Department of Philosophy at the University of Istanbul. He introduced interdisciplinary seminars and courses on scientific subjects, and in 1935 he published The Theory of Probability.

In 1938, with the help of Charles Morris, he moved to the United States to take up a professorship at the University of California, Los Angeles. His work on the philosophical foundations of quantum mechanics was published in 1944, followed by Elements of Symbolic Logic and The Rise of Scientific Philosophy. Hilary Putnam may have been his most prominent student. He helped establish UCLA as a leading philosophy department in the US in the post-war period.

He died on April 9, 1953 in Los Angeles while working on problems in the philosophy of time and on the nature of scientific laws. This work resulted in two books published posthumously: The Direction of Time and Nomological Statements and Admissible Operations.

Selected publications

• 1916. Der Begriff der Wahrscheinlichkeit f�r die mathematische Darstellung der Wirklichkeit. Ph.D. dissertation, Erlangen.
• 1920. Relativit�tstheorie und Erkenntnis apriori. English translation: 1965. The theory of relativity and a priori knowledge. University of California Press.
• 1922. "Der gegenw�rtige Stand der Relativit�tsdiskussion." English translation: "The present state of the discussion on relativity" in Reichenbach (1959).
• 1924. Axiomatik der relativistischen Raum-Zeit-Lehre. English translation: 1969. Axiomatization of the theory of relativity. University of California Press.
• 1924. "Die Bewegungslehre bei Newton, Leibniz und Huyghens." English translation: "The theory of motion according to Newton, Leibniz, and Huyghens" in Reichenbach (1959).
• 1927. Von Kopernikus bis Einstein. Der Wandel unseres Weltbildes. English translation: 1942, From Copernicus to Einstein. Alliance Book Co.
• 1928. Philosophie der Raum-Zeit-Lehre. English translation: Maria Reichenbach, 1957, The Philosophy of Space and Time. Dover. ISBN 0-486-60443-8
• 1930. Atom und Kosmos. Das physikalische Weltbild der Gegenwart. English translation: 1932, Atom and cosmos: the world of modern physics. G. Allen & Unwin, ltd.
• 1931. "Ziele und Wege der heutigen Naturphilosophie." English translation: "Aims and methods of modern philosophy of nature" in Reichenbach (1959).
• 1935. Wahrscheinlichkeitslehre�: eine Untersuchung �ber die logischen und mathematischen Grundlagen der Wahrscheinlichkeitsrechnung. English translation: 1948, The theory of probability, an inquiry into the logical and mathematical foundations of the calculus of probability. University of California Press.
• 1938. Experience and prediction: an analysis of the foundations and the structure of knowledge. University of Chicago Press.
• 1942. From Copernicus to Einstein Dover 1980: ISBN 0-486-23940-3
• 1944. Philosophic Foundations of Quantum Mechanics. University of California Press. Dover 1998: ISBN 0-486-40459-5
• 1947. Elements of Symbolic Logic. Macmillan Co. Dover 1980: ISBN 0-486-24004-5
• 1948. "Philosophy and physics" in Faculty research lectures, 1946. Univ. of California Press.
• 1949. "The philosophical significance of the theory of relativity" in Schilpp, P. A., ed., Albert Einstein: philosopher-scientist. Evanston�: The Library of Living Philosophers.
• 1951. The rise of scientific philosophy. University of California Press.
• 1954. Nomological statements and admissible operations. North Holland.
• 1956. The Direction of Time. University of California Press. Dover 1971: ISBN 0-486-40926-0
• 1959. Modern philosophy of science: Selected essays by Hans Reichenbach. Routledge & Kegan Paul. Greenwood Press 1981: ISBN 0-313-23274-1
• 1978. Selected writings, 1909-1953: with a selection of biographical and autobiographical sketches (Vienna circle collection). Dordrecht: Reidel. Springer paperback vol 1: ISBN 90-277-0292-6
• 1979. Hans Reichenbach, logical empiricist (Synthese library). Dordrecht�: Reidel.
• 1991. Erkenntnis Orientated: A Centennial volume for Rudolf Carnap and Hans Reichenbach. Kluwer. Springer 2003: ISBN 0-7923-1408-5
• 1991. Logic, language, and the structure of scientific theories�: proceedings of the Carnap-Reichenbach centennial, University of Konstanz, 21-24 May 1991. University of Pittsburgh Press.

References

• Gr�nbaum, A., 1963, Philosophical Problems of Space and Time. Chpt. 3.
• Carl Hempel, 1991, Hans Reichenbach remembered, Erkenntnis 35: 5-10.
• Wesley Salmon, 1977, "The philosophy of Hans Reichenbach," Synthese 34: 5-88.
• ------, 1991, "Hans Reichenbach's vindication of induction," Erkenntnis 35: 99-122.