- The claim that mental types are multiply realizable has played an important role in supporting antireductionism in philosophy of mind. The multiple-realizability thesis implies that mental types and physical types are correlated one-many not one-one. A mental state such as pain might be correlated with one type of physical state in a human and another type of physical state in, say, a Martian or pain-capable robot. This has often been taken to imply that mental types are not identical to physical types since their identity would require one type of mental state to be correlated with only one type of physical state. The principal debate about multiple realizability in philosophy of mind concerns its compatibility or incompatibility with reductionism. On the assumption that reduction requires mental-physical type identities, the apparent multiple realizability of mental types, such as a pain being both a type of human brain state and a type of robot state, has been understood to support antireductionism. More recent work has challenged this understanding.
- The antireductionist argument depends on the following premises:
- 1. Mental types are multiply realizable;
- 2. If mental types are multiply realizable, then they are not identical to physical types;
- 3. If mental types are not identical to physical types, then psychological discourse (vernacular or scientific) is not reducible to physical theory.
- Among these claims, the most controversial has been Premise 1, the multiple-realizability thesis. Antireductionists have supported it both a priori by appeal to conceivability-possibility principles, and a posteriori by appeal to findings in biology, neuroscience, and artificial intelligence1 research. Reductionists have criticized these arguments, and they have also directly challenged the antireductionist premises.
- Reductionist challenges to Premises 1 and 2 claim that antireductionists dubiously assume that psychophysical relations must be reckoned relative to our current mental and physical typologies. Contrary to this assumption, some reductionists argue that future scientific investigation will result in the formulation of new mental and/or physical typologies which fail to support the antireductionist premises. Typology-based arguments of this sort have been among the most important and most widely discussed reductionist responses to the multiple-realizability argument. Responses that target Premise 3 have been less popular. They argue either that psychophysical reduction can be carried out without identity statements linking mental and physical types, or else that ontological issues concerning the identity or nonidentity of mental and physical types are completely orthogonal to the issue of reduction.
- The multiple-realizability thesis has also played an important role in recent discussions about nonreductive physicalism. The antireductionist argument has often been taken to recommend some type of nonreductive physicalism. Recently, however, Jaegwon Kim has effectively stood the argument on its head. He argues that physicalists who endorse multiple realizability are committed either to denying that mental types are genuine properties, ones that make a causal difference to their bearers, or else they are committed to endorsing some type of reductionism which identifies mental types with physical types.
- Multiple Realizability and the Antireductionist Argument
… a. Multiple Realizability and Multiple Correlatability
… b. Identity Theory, Functionalism and the Realization Relation
… c. Defining Multiple Realizability
… d. Multiple Realizability and Mental-Physical Type Identities
… e. Type Identities and Psychophysical Reductionism
- Arguments for the Multiple-Realizability Thesis
… a. Conceptual Arguments for the MRT
… b. Empirical Arguments for the MRT
- Responses to the Antireductionist Argument
… a. Typology-Based Responses
… … ai. New Mental Typologies: the Local Reduction Move
… … aii. New Physical Typologies I:
… … aiii. New Physical Typologies II: the Disjunctive Move
… … … aiii1. Law-Based Criticisms
… … … aiii2. Metaphysical Criticisms
… … aiv. Coordinate Typologies
… b. Reduction-Based Responses
- Multiple Realizability and Nonreductive Physicalism
- References and Further Reading
Recommended by "Lavelle (Suilin) - Minds, Brains and Computers". For the full text, see Link.
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