David Lewis (philosopher)

David Lewis (philosopher)

David Kellogg Lewis (September 28, 1941 – October 14, 2001) was an American philosopher. Lewis taught briefly at UCLA and then at Princeton from 1970 until his death. He is also closely associated with Australia, whose philosophical community he visited almost annually for more than thirty years. He has made contributions in philosophy of language, philosophy of mind, metaphysics, epistemology, and philosophical logic. He is probably best known for his controversial modal realist stance: that (i) possible worlds exist, (ii) every possible world is a concrete entity, (iii) any possible world is causally and spatiotemporally isolated from any other possible world, and (iv) our world is among the possible worlds. This view has a wide variety of uses in providing a framework for philosophical thought, including providing a non-modal analysis of necessity and possibility. A recent poll conducted among philosophers ranked Lewis the thirteenth most important philosopher of the past 200 years, and another ranked him as the third most important philosopher of the twentieth century.