Hans Reichenbach - Life and Work

Life and Work

After completing the secondary school in Hamburg with his older brother Bernhard Reichenbach who would go on to be a member of the Communist Workers' Party of Germany, Hans studied civil engineering at the Technische Hochschule in Stuttgart, and physics, mathematics and philosophy at various universities, including Berlin, Erlangen, Göttingen 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 himself was of Jewish ancestry.

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 Max 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, as 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, Reichenbach founded the so-called "Berlin Circle" (German: Die Gesellschaft für 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").

When Adolf Hitler became Chancellor of Germany in 1933, Reichenbach was immediately dismissed from his appointment at the University of Berlin under the government's so called "Race Laws" due to his Jewish ancestry. He thereupon 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 W. Morris, Reichenbach moved to the United States to take up a professorship at the University of California, Los Angeles in its Philosophy Department. His work on the philosophical foundations of quantum mechanics was published in 1944, followed by Elements of Symbolic Logic in 1947, and The Rise of Scientific Philosophy — his most popular book — in 1951.

Reichenbach helped establish UCLA as a leading philosophy department in the United States in the post-war period. Carl Hempel, Hilary Putnam, and Wesley Salmon are perhaps his most prominent students.

Reichenbach died in Los Angeles on April 9, 1953, while working on problems in the philosophy of time and on the nature of scientific laws. As part of this he proposed a three part model of time in language, involving speech time, event time and - critically - reference time, which has been used by linguists since for describing tenses. This work resulted in two books published posthumously: The Direction of Time and Nomological Statements and Admissible Operations.