Carl Gustav Hempel (1905 – 1997)

One of the leading member of logical positivism, he was born in Orianenburg, Germany, in 1905.
Between March 17 and 24, 1982, Hempel gave an interview to Richard Nolan; the text of that interview was published for the first time in 1988 in Italian translation (Hempel, 'Autobiografia intellettuale' in Oltre il positivismo logico, Armando : Rome, Italy : 1988). This interview is the main source of the following biographical notes.

Hempel studied at the Realgymnasium at Berlin and, in 1923, he was admitted at the University of Gottingen where he studied mathematics with David Hilbert and Edmund Landau and symbolic logic with Heinrich Behmann. Hempel was very impressed with Hilbert's program of proving the consistency of mathematics by means of elementary methods; he also studied philosophy, but he found mathematical logic more interesting than traditional logic. The same year he moved to the University of Heidelberg, where he studied mathematics, physics and philosophy. From 1924 Hempel studied at Berlin, where he meet Reichenbach who introduced him to the Berlin Circle. Hempel attended Reichenbach's courses on mathematical logic, the philosophy of space and time, the theory of probability. He studied physics with Max Planck and logic with von Neumann. In 1929 Hempel took part in the first congress on scientific philosophy organized by logical positivists. He meet Carnap and — very impressed by Carnap — moved to Vienna where he attended three courses with Carnap, Schlick and Waismann, and took part to the meetings of the Vienna Circle. In the same years Hempel qualified as teacher in the secondary school and eventually, in 1934, he gained the doctorate in philosophy at Berlin, with a dissertation on the theory of probability. In the same year he emigrated to Belgium, with the help of a friend of Reichenbach, Paul Oppenheim (Reichenbach introduced Hempel to Oppenheim in 1930). Two years later Hempel and Oppenheim published the book Der Typusbegriff im Lichte der neuen Logik on the logical theory of classifier, comparative and metric scientific concepts. In 1937 Hempel was invited — with the help of Carnap — at the University of Chicago as Research Associate in Philosophy. After an another brief period in Belgium, Hempel emigrated to USA in 1939. He taught in New York, at the City College (1939-1940) and at the Queens College (1940-1948). In those years he was interested in the theory of confirmation and explanation, and published several articles on that subject — 'A purely syntactical definition of confirmation' in The Journal of Symbolic Logic, 8, 1943; 'Studies in the logic of confirmation' in Mind, 54, 1945; 'A definition of Degree of confirmation' (with P. Oppenheim) in Philosophy of science, 12, 1945; 'A note on the paradoxes of confirmation' in Mind, 55, 1946; 'Studies in the logic of explanation' (with P. Oppenheim) in Philosophy of science, 15, 1948. Between 1948 and 1955 Hempel taught at Yale University. His work Fundamentals of concept formation in empirical science was published in 1952 in the International Encyclopedia of Unified Science. From 1955 he taught at the University of Princeton. Aspects of scientific explanation and Philosophy of natural science were published in 1965 and 1966 respectively. After the pensionable age he continued in teaching at Berkley, Irvine, Jerusalem and, from 1976 to 1985, at Pittsburgh. In the meantime, his philosophical perspective was changing and he detached from logical positivism — 'The meaning of theoretical terms: a critique of the standard empiricist construal' in Logic, methodology and philosophy of science IV (ed. by Patrick Suppes), 1973; 'Valuation and objectivity in science' in Phisycs, philosophy and psychoanalysis (ed. by R.S. Cohen and L. Laudan), 1983; 'Provisoes: a problem concerning the inferential function of scientific theories' in Erkenntnis, 28, 1988. However, he remained affectionately joined to logical positivism: in 1975 he undertook the editorship (with W. Stegm