1941 – 2001
David Lewis (1941-2001) was an American analytic philosopher known for his systematic contributions to metaphysics, philosophy of language, and modal logic. He is best known for modal realism, the view that all possible worlds are as real as the actual world, and for influential work on counterfactuals, convention, and natural properties.
Developed modal realism in 'On the Plurality of Worlds'
Formulated the standard possible-worlds semantics for counterfactuals
Authored 'Convention: A Philosophical Study', foundational in philosophy of language
Advanced the theory of natural properties and Humean supervenience
Contributed to the causal theory of mind and functionalism