Clarence Irving (C.I.) Lewis

(American philosopher, 1883–1964). The founder of "conceptualist pragmatism", C.I. Lewis was the most influential American philosopher active in the 1930s and 1940s. Lewis was instrumental in the rise of analytic philosophy in the United States and many of his graduate students at Harvard went on to become the leading figures in the field. He made major contributions to logic and epistemology, and to a lesser extent, ethics. He is the author of Mind and World Order: Outline of a Theory of Knowledge, Symbolic Logic, and An Analysis of Knowledge and Valuation.