David Lewis

Agora

David Lewis

1941–2001

A first way ina deliberate simplification – the portrait says more

Every possible world is just as real as ours – and talking about possibilities is talking about what happens in those other worlds.

Placement

Analytic Philosophy · North America · Metaphysics, Language

Modal realism: all possible worlds exist just as really as our own.

Key ideas

Modal realism
Conventions
Humean supervenience

Teachers: W. V. O. Quine

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Influence

Influenced by 5

Gottfried Wilhelm Leibniz

influenced by
Lewis took up Leibniz’s possible worlds but as concrete, real worlds; his world-bound individuals with counterparts are often compared to Leibniz’s view (On the Plurality of Worlds, 1986). D. Lewis, “Counterpart Theory and Quantified Modal Logic”, Journal of Philosophy 65 (1968); On the Plurality of Worlds (1986); SEP “David Lewis”
Evidence: also in InPhO · InPhO
Gottfried Wilhelm Leibniz › 1646–1716
David Hume

influenced by
Lewis named his thesis of ‘Humean supervenience’ after Hume, the denier of necessary connections: everything supervenes on the local distribution of particular qualities (Philosophical Papers II, 1986). D. Lewis, Philosophical Papers, vol. II (1986), introduction; “Humean Supervenience Debugged”, Mind 103 (1994); SEP “David Lewis”
Evidence: also in InPhO · InPhO
David Hume › 1711–1776
Rudolf Carnap

influenced by
Lewis adapted the Ramsey–Carnap method for theoretical terms to define mental states by their causal roles (‘How to Define Theoretical Terms’, 1970; ‘Psychophysical and Theoretical Identifications’, 1972). D. Lewis, “How to Define Theoretical Terms”, Journal of Philosophy 67 (1970); “Psychophysical and Theoretical Identifications”, Australasian Journal of Philosophy 50 (1972); SEP “David Lewis”
Evidence: also in InPhO · InPhO
Rudolf Carnap › 1891–1970
W. V. O. Quine studied with

studied with
Lewis wrote his Harvard dissertation (1967) under Quine; it became Convention (1969), which answers Quine’s doubts about whether language can rest on convention. D. Lewis, Convention (1969), preface
Evidence: AI draft
W. V. O. Quine › 1908–2000
J. J. C. Smart

influenced by
Lewis gave Smart’s identity of experiences and brain processes a new argument: experiences are defined by their causal roles, and the occupants of these roles are physical (1966). D. Lewis, “An Argument for the Identity Theory”, Journal of Philosophy 63 (1966); J. J. C. Smart, “Sensations and Brain Processes” (1959); SEP “The Mind/Brain Identity Theory”
Evidence: AI draft
J. J. C. Smart › 1920–2012

Criticism

Criticized by 1

Sally Haslanger

criticised by
Haslanger defended endurance against Lewis’s argument from temporary intrinsics: things can change their intrinsic properties without having temporal parts (‘Endurance and Temporary Intrinsics’, Analysis, 1989). S. Haslanger, “Endurance and Temporary Intrinsics”, Analysis 49 (1989), 119–125; D. Lewis, On the Plurality of Worlds (1986), 202–204
Evidence: AI draft
Sally Haslanger › b. 1955

Criticizes 2

Saul Kripke

criticised
Lewis rejected Kripke’s view that possible worlds are stipulated and share individuals, defending counterpart theory against the ‘Humphrey objection’ (On the Plurality of Worlds, 1986, ch. 4). D. Lewis, On the Plurality of Worlds (1986), ch. 4; “Counterpart Theory and Quantified Modal Logic”, Journal of Philosophy 65 (1968); S. Kripke, Naming and Necessity (1980)
Evidence: AI draft
Saul Kripke › 1940–2022
Frank Jackson

criticised
Lewis answered Jackson’s knowledge argument with the ability hypothesis: on seeing red, Mary gains abilities to recognise, imagine and remember, not new information (‘What Experience Teaches’, 1988). D. Lewis, “What Experience Teaches”, Proceedings of the Russellian Society 13 (1988); F. Jackson, “What Mary Didn’t Know”, Journal of Philosophy 83 (1986)
Evidence: AI draft
Frank Jackson › b. 1943

Works

1986On the Plurality of Worlds
Possible worlds are as real as ours – counterpart relations instead of identity.

Position

Lewis built a systematic metaphysics of unusual clarity. His best-known and most controversial thesis is modal realism: talk of what is possible or necessary refers to other possible worlds that exist just as concretely as ours, only spatiotemporally separate from it. Things in other worlds are not identical with us but our “counterparts.” Lewis defended this view not out of eccentricity but because it explains modality, counterfactual conditionals, properties and content more economically than its rivals. He also gave an analysis of conventions in game-theoretic terms, a theory of counterfactuals and causation, and the programme of “Humean supervenience,” according to which everything depends on the local distribution of physical qualities.

Life & context

Lewis was born in Oberlin, Ohio, in 1941 and wrote his dissertation at Harvard under Quine. After teaching at UCLA he spent the rest of his career at Princeton from 1970, with frequent stays in Australia, which he regarded as a second philosophical home. He died in 2001; his papers, collected in several volumes, are among the most cited in analytic philosophy.