Lewis Edwin Hahn joined the department in 1949 and served as head from then until l963. He received his Ph.D. in 1939 from the University of California at Berkeley with a dissertation titled A Contextualistic Theory of Perception, directed by Paul Marhenke. Professor Hahn was a Member of the Committee to Promote Original Work in Philosophy, 1954-1960; President of the Southwestern Philosophical Society, 1955; President of the Southern Society for Philosophy and Psychology, 1958-1959; Chairman of the Western Conference on the Teaching of Philosophy, 1958-1960; Secretary-Treasurer of the Western Division of the American Philosophical Association, 1959-1961; Secretary-Treasurer of the Association of Graduate Schools of the American Associations of Universities, 1962-1963; Chairman of the Conference of Secretaries of Constituent Societies of the American Council of Learned Societies, 1962-1966; and Co-Chairman of the Special Planning Committee for the XIIIth World Congress of Philosophy in Mexico City, 1963. Professor Hahn initiated the Ph.D. program, the first graduate of which was Ronald John Glossop in 1960. Professor Hahn served as Associate Dean of the Washington University Graduate School of Arts and Sciences, 1953-1954; Dean of the Graduate School of Arts and Sciences, 1954-1963; and as Acting Dean of Faculties, Summer 1954. In 1963, Professor Hahn moved to Southern Illinois University at Carbondale as Research Professor in Philosophy. While at Washington University, Professor Hahn was co-author (with Ray Lepley, John Dewey, et al.) of Value: A Cooperative Inquiry and published numerous articles.