Life and work
After completing secondary school in Hamburg, Hans studied civil engineering at the Hochschule für Technik 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. His older brother Bernhard Reichenbach shared in this activism and went on to become a member of the Communist Workers' Party of Germany, representing this organisation on the Executive Committee of the Communist International. He also worked with Alexander Schwab at this time.
Hans wrote the Platform of the
Socialist Student Party Berlin which was published in 1918. The party had remained clandestine until the November Revolution when it was formally founded with Hans as Chairman.
Reichenbach received a degree in philosophy from the University of Erlangen in 1915 and his Dr.phil. dissertation on the theory of probability, titled Der Begriff der Wahrscheinlichkeit für die mathematische Darstellung der Wirklichkeit (The Concept of Probability for the Mathematical Representation of Reality) and 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 Humboldt University of Berlin. 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. The Vienna Circle manifesto lists 30 of Reichenbach's publications in a bibliography of closely related authors. 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. Reichenbach himself did not practise Judaism, and his mother was a German Protestant, but he nevertheless suffered problems. 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.