Carl Gustav Hempel was born in 1905 in Oranienburg, Germany. He studied mathematics, physics, and philosophy at the Universities of Göttingen, Heidelberg, Berlin, and Vienna. In 1929, he participated in a congress on scientific philosophy where he met Rudolf Carnap. Inspired by Carnap’s work, Hempel moved to Vienna during the winter semester of 1929-1930 and joined in the meetings of the Vienna Circle. After returning to Berlin, he earned his Ph.D. in 1934 for his work on probability under Hans Reichenbach, himself a major figure in the field of logical empiricism. The same year, Hempel and his first wife Eva left the increasingly repressive Germany and emigrated to Belgium, with the help of Paul Oppenheim, with whom he co-authored the book Der Typusbegriff im Lichte der neuen Logik in 1936. After three years of private research and writing, Hempel emigrated to the U.S. in 1937, accepting a position as Carnap’s research assistant in philosophy at the University of Chicago. Subsequently, he held positions at the City College of New York, Queens College, and Yale University, where he was promoted to the rank of Professor in 1953. During his Yale period, Hempel also spent a semester as a Visiting Professor at Columbia University in the fall of 1950, as a Hibben Research Fellow at Princeton in the spring of 1953, and a year as a Visiting Professor at Harvard University in 1953-1954. In 1955, Hempel joined the Princeton faculty as a Stuart Professor of Philosophy. He came to the University of Pittsburgh in 1976 as a University Professor of Philosophy and stayed until 1985, when he returned to Princeton. On November 9, 1997, Hempel died at age 92 near his home in Princeton Township, New Jersey.
Hempel was a philosopher of science who played a central role in the development of logical positivism or logical empiricism. In his early years, he was a member of the so called Berlin Circle ("Gesellschaft für wissenschaftliche Philosophie"), a Berlin counterpart to the Vienna Circle. Hempel’s work is mainly associated with the concept of deductive-nomological explanation and with the Raven paradox. In 1948, Hempel developed with Paul Oppenheim a logically precise theory known as the Deductive-Nomological, or Covering Law, Model of Explanation, which sees scientific laws and theories as systematizing otherwise unwieldy bodies of particular empirical claims. To deal with probabilistic explanation, Hempel articulated an Inductive-Statistical Model in 1962. He also developed models of historical and functional explanation in the biological and social sciences, as well as of historical explanation. Those models shaped all subsequent work on scientific explanation.
Hempel also sought to describe the conditions under which particular reports of observation may be said to confirm general hypothesis. His famous Raven Paradox exemplifies the logical challenge: Since the hypothesis (1) "All ravens are black" can be reformulated equivalently as (2) "All non-black things are non-ravens," the report of non-black non-ravens (e.g., white shoes) would seem to confirm (1) just as would the report of black ravens. Hempel then proposed a quantitative method for determining the degree of confirmation of any hypothesis by particular statements of evidence.
Hempel was author of the influential books Aspects of Scientific Explanation and Other Essays in the Philosophy of Science and Philosophy of Natural Science, which have been translated into ten languages. He held Guggenheim and Fulbright fellowships and served as a fellow at the Center for Advanced Study in the Behavioral Sciences at Stanford and as an honorary research fellow in philosophy at University College, London. He also was a fellow of the American Academy of Arts and Sciences, a member of the Académie Internationale de Philosophie des Sciences and American Philosophical Society, and a corresponding fellow of the British Academy.