David Kellogg Lewis was born in Oberlin, Ohio, on 28 September 1941 and died in Princeton, New Jersey, on 14 October 2001. During an undergraduate year at Oxford he heard J. L. Austin’s last lecture series and was tutored by Iris Murdoch. He took his doctorate at Harvard (1967) under W. V. O. Quine; the dissertation became his first book, Convention (1969). He taught at UCLA from 1966 and, from 1970 until the end of his life, at Princeton University. He should not be confused with C. I. Lewis (1883–1964), another American philosopher. His thought is among the most influential systematic constructions of late twentieth-century analytic metaphysics, distinguished by bold ontological theses defended with rigorous argument and by a demonstration of the explanatory power of the notion of a possible world.
Key Concepts
- Convention — in Convention: A Philosophical Study (1969), Lewis analyzes conventions, linguistic ones included, as regularities of behaviour that solve coordination problems and are sustained by common knowledge among participants. The book engages Thomas Schelling’s game theory and Hume’s account of convention, and answers Quine’s scepticism about explaining language through conventions. It received the first Franklin Matchette Prize of the American Philosophical Association.
- Modal realism — in On the Plurality of Worlds (1986), Lewis argues that possible worlds are as concrete as our own, spatiotemporally isolated from one another; “actual” is an indexical term, like “here” or “now,” rather than an absolute property. Lewis himself acknowledged that the thesis meets what he called the “incredulous stare” and defended it by the theoretical benefits it brings.
- Counterpart theory — formulated in “Counterpart Theory and Quantified Modal Logic” (1968): an individual exists in only one world, and modal claims about it concern its counterparts, similar to it, in other worlds. Saul Kripke criticized this approach in Naming and Necessity.
- Counterfactuals — in Counterfactuals (1973), he proposes a semantics on which a counterfactual conditional “if A were the case, C would be the case” is true when C holds in the closest worlds to the actual one in which A holds, according to a similarity relation among worlds. In “Causation” (1973), he uses counterfactual dependence to analyze causation. Robert Stalnaker independently proposed a rival semantics.
- Humean supervenience — the thesis that everything in the world supervenes on a “mosaic” of local particular facts, with no necessary connections among them, stated in the introduction to the second volume of the Philosophical Papers (1986).
- Principal Principle — in “A Subjectivist’s Guide to Objective Chance” (1980), it links rational credence to objective chances.
- Epistemic contextualism — “Elusive Knowledge” (1996) argues that the truth of knowledge attributions varies with the attributor’s context.
- Ability hypothesis — in “What Experience Teaches” (1988), he answers Frank Jackson’s knowledge argument by holding that knowing what an experience is like consists in acquiring abilities, a know-how in Gilbert Ryle’s sense.
Influenced by
- W. V. O. Quine — his doctoral supervisor, whose logical rigour and naturalism shaped his training, even though Lewis disagreed with him on central points (modality, ontology)
- Rudolf Carnap — the semantics of intensions and the logical analysis of language
- Leibniz — the tradition of possible worlds
- David Hume — the idea of convention and the picture of the world as a mosaic of distinct facts
- J. J. C. Smart and D. M. Armstrong — Australian materialism, with whom he engaged in the philosophy of mind
Influenced
- Contemporary analytic metaphysics (modality, causation, laws of nature, universals, mereology)
- The formal semantics of conditionals and the literature on counterfactuals
- Philosophy of language and game-theoretic approaches to convention
- The debate on causation, objective probability and contextualist epistemology
Works
Convention: A Philosophical Study (1969); Counterfactuals (1973); Philosophical Papers, vols. I (1983) and II (1986); On the Plurality of Worlds (1986); Parts of Classes (1991); Papers in Metaphysics and Epistemology (1999).
See also
Quine, Saul Kripke, Rudolf Carnap, Leibniz, Hume, Donald Davidson, Gilbert Ryle, J.L. Austin, C. I. Lewis