Canguilhem Georges (1904–96), French historian and philosopher of science. Canguilhem succeeded Gaston Bachelard as director of the Institut d’Histoire des Sciences et des Techniques at the University of Paris. He developed and sometimes revised Bachelard’s view of science, extending it to issues in the biological and medical sciences, where he focused particularly on the concepts of the normal and the pathological (The Normal and the Pathological, 1966). On his account norms are not objective in the sense of being derived from value-neutral scientific inquiry, but are rooted in the biological reality of the organisms that they regulate. Canguilhem also introduced an important methodological distinction between concepts and theories. Rejecting the common view that scientific concepts are simply functions of the theories in which they are embedded, he argued that the use of concepts to interpret data is quite distinct from the use of theories to explain the data. Consequently, the same concepts may occur in very different theoretical contexts. Canguilhem made particularly effective use of this distinction in tracing the origin of the concept of reflex action. See also BACHELARD , PHILOSOPHY OF THE SOCIAL SCIENCES , PSYCHOPATHOLOGY. G.G.