The claim of the multiple realizability of mental states by brain states has been a major feature of the dominant philosophy of mind of the late 20th century. The claim is usually motivated by evidence that mental states are multiply realized, both within humans and between humans and other species. We challenge this contention by focusing on how neuroscientists differentiate brain areas. The fact that they rely centrally on psychological measures in mapping the brain and do so in (...) a comparative fashion undercuts the likelihood that, at least within organic life forms, we are likely to find cases of multiply realized psychological functions. (shrink)

Multiple realizability has been at the heart of debates about whether the mind reduces to the brain, or whether the items of a special science reduce to the items of a physical science. I analyze the two central notions implied by the concept of multiple realizability: "multiplicity," otherwise known as property variability, and "realizability." Beginning with the latter, I distinguish three broad conceptual traditions. The Mathematical Tradition equates realization with a form of mapping between objects. (...) Generally speaking, x realizes (or is the realization of) y because elements of y map onto elements of x. The Logico-Semantic Tradition translates realization into a kind of intentional or semantic notion. Generally speaking, x realizes (or is the realization of) a term or concept y because x can be interpreted to meet the conditions for satisfying y. The Metaphysical Tradition views realization as a species of determination between objects. Generally speaking, x realizes (or is the realization of) y because x brings about or determines y. I then turn to the subject of property variability and define it in a formal way. I then conclude by discussing some debates over property identity and scientific theory reduction where the resulting notion of multiple realizability has played a central role, for example, whether the nonreductive consequences of multiple realizability can be circumvented by scientific theories framed in terms of narrow domain-specific properties, or wide disjunctive properties. (shrink)

Reductionism is often understood to include two theses: (1) every singular occurrence that the special sciences can explain also can be explained by physics; (2) every law in a higher-level science can be explained by physics. These claims are widely supposed to have been refuted by the multiple realizability argument, formulated by Putnam (1967, 1975) and Fodor (1968, 1975). The present paper criticizes the argument and identifies a reductionistic thesis that follows from one of the argument's premises.

This paper concerns what Jerry Fodor calls a 'metaphysical mystery': How can there by macroregularities that are realized by wildly heterogeneous lower level mechanisms? But the answer to this question is not as mysterious as many, including Jaegwon Kim, Ned Block, and Jerry Fodor might think. The multiple realizability of the properties of the special sciences such as psychology is best understood as a kind of universality, where 'universality' is used in the technical sense one finds in the (...) physics literature. It is argued that the same explanatory strategy used by physicists to provide understanding of universal behavior in physics can be used to explain how special science properties can be heterogeneously multiply realized. (shrink)

Multiple realizability says that the same kind of mental states may be manifested by systems with very different physical constitutions. Putnam ( 1967 ) supposed it to be “overwhelmingly probable” that there exist psychological properties with different physical realizations in different creatures. But because function constrains possible physical realizers, this empirical bet is far less favorable than it might initially have seemed, especially when we take on board the richer picture of neural and brain function that neuroscience has (...) been uncovering over the past forty years, in which all sorts of brain activities play crucial roles beyond all-or-nothing electrical signaling. Because of its evolutionary history, the brain’s metabolic and informational processes are inextricably intertwined. The resulting complex integrated functions impose more constraints on possible realizers than the clean, single-purpose functions usually cited as examples in discussions of multiple realizability—with ramifications for the functionalist and computationalist foundations of cognitive science, artificial intelligence, and the philosophy of mind. (shrink)

Multiply realizable properties are those whose realizers are physically diverse. It is often argued that theories which contain them are ipso facto irreducible. These arguments assume that physical explanations are restricted to the most specific descriptions possible of physical entities. This assumption is descriptively false, and philosophically unmotivated. I argue that it is a holdover from the late positivist axiomatic view of theories. A semantic view of theories, by contrast, correctly allows scientific explanations to be couched in the most perspicuous, (...) powerful language available. On a semantic view, traditional notions of multiple realizability are thus very hard to motivate. At best, one must abandon either the idea that multiple realizability is an interesting scientific notion, or else admit that multiply realizable properties do not automatically block scientific reductions. (shrink)

This article examines the multiple realizability thesis within a causal framework. The beginnings of this framework are found in Elliott Sober’s “Multiple Realizability Argument against Reduction,”...

We critically analyze Alexander Rosenberg’s argument based on the multiple realizability of biological properties that there are no biological laws. The argument is intuitive and suggestive. Nevertheless, a closer analysis reveals that the argument rests on dubious assumptions about the nature of natural selection, laws of nature, and multiple realizability. We also argue that the argument is limited in scope, since it applies to an outmoded account of laws and the applicability of the argument to other (...) more promising accounts of laws is questionable. Another concern of ours is that the relation between multiple realizability and natural selection is more complex than Rosenberg acknowledges. Finally, we claim that an explanation for why Rosenberg’s argument appears persuasive and appealing is that the argument is based on an inflated concept of multiple realizability that rests on unreliable intuitions concerning what counts as a different realization of the same property. Consequently, we argue that the argument is at best inconclusive and at worst false insofar as its implications for the existence of biological laws are concerned. (shrink)

In the literature on multiple realizability and the identity theory, cases of neural plasticity have enjoyed a very limited role. The present article attempts to remedy this small influence by arguing that clinical and experimental evidence of quite extensive neural reorganization offers compelling support for the claim that psychological kinds are multiply realized in neurological kinds, thus undermining the identity theory. In particular, cases are presented where subjects with no measurable psychological deficits also have vast, though gradually received, (...) neurological damage. Common objections and concerns are also discussed and rejected. 1 Introduction2 The GRP, Serial Lesion Effect, and Multiple Realizability2.1 A case study of the serial lesion effect2.2 Evaluating the case study’s evidence for multiple realizability3 The GRP More Generally4 Objections to the GRP as Evidence for Multiple Realizability4.1 Small plastic effects and neurological taxonomies4.2 But do neural regions and locations even matter at all?4.3 But are there not other options besides location?5 Conclusion. (shrink)

b>: This article explains the concept of multiple realizability and its role in the philosophy of mind. In particular, I consider what is required for the multiple realizability of psychological kinds, the relevance of multiple realizability to the reducibility and autonomy of psychology, as well as further refinements of the concept that would prove helpful.

Biological theory demands a clear organism concept, but at present biologists cannot agree on one. They know that counting particular units, and not counting others, allows them to generate explanatory and predictive descriptions of evolutionary processes. Yet they lack a unified theory telling them which units to count. In this paper, I offer a novel account of biological individuality, which reconciles conflicting definitions of ‘organism’ by interpreting them as describing alternative realisers of a common functional role, and then defines individual (...) organisms as essentially possessing some mechanisms that play this role. (shrink)

The multiple-realizability argument has been the mainstay ofanti-reductionist consensus in philosophy of mind for the past thirty years. Reductionist opposition to it has sometimes taken the form of the Disjunctive Move: If mental types are multiply-realizable, they are not coextensive with physical types; they might nevertheless be coextensive with disjunctionsof physical types, and those disjunctions could still underwrite psychophysical reduction. Among anti-reductionists, confidence is high that the Disjunctive Move fails; arguments to this effect, however, often leave something to (...) be desired. I raise difficulties for one anti-reductionist response to the DisjunctiveMove, the Explanatory Response. (shrink)

The claim of the multiple realizability of mental states by brain states has been a major feature of the dominant philosophy of mind of the late 20th century. The claim is usually motivated by evidence that mental states are multiply realized, both within humans and between humans and other species. We challenge this contention by focusing on how neuroscientists differentiate brain areas. The fact that they rely centrally on psychological measures in mapping the brain and do so in (...) a comparative fashion undercuts the likelihood that, at least within organic life forms, we are likely to find cases of multiply realized psychological functions. (shrink)

Framed within the dialectic of the causal exclusion argument (Kim 2005), this paper does two things. One, it clarifies some properties of multiple realizability based on its true origin (Turing 1950). And two, it challenges a form of argument Noordhof (1997), Clarke (1999), and Whittle (2007) employ to support the idea that the mental has causal powers not had by its physical realization base (Novel). The paper challenges Novel with ideas derived from multiple realizability, among others.

Must a theory of quantum gravity have some truth to it if it can recover general relativity in some limit of the theory? This paper answers this question in the negative by indicating that general relativity is multiply realizable in quantum gravity. The argument is inspired by spacetime functionalism—multiple realizability being a central tenet of functionalism—and proceeds via three case studies: induced gravity, thermodynamic gravity, and entanglement gravity. In these, general relativity in the form of the Einstein field (...) equations can be recovered from elements that are either manifestly multiply realizable or at least of the generic nature that is suggestive of functions. If general relativity, as argued here, can inherit this multiple realizability, then a theory of quantum gravity can recover general relativity while being completely wrong about the posited microstructure. As a consequence, the recovery of general relativity cannot serve as the ultimate arbiter that decides which theory of quantum gravity that is worthy of pursuit, even though it is of course not irrelevant either qua quantum gravity. Thus, the recovery of general relativity in string theory, for instance, does not guarantee that the stringy account of the world is on the right track; despite sentiments to the contrary among string theorists. (shrink)

In recent decades, a number of authors have relied on the multiple realizability argument to reject methodological individualism. In this article, I argue that this strategy results in serious difficulties and makes it impossible to identify social entities and phenomena.

Critics of multiple realizability have recently argued that we should concentrate solely on actual here-and-now realizations that are found in nature. The possibility of alternative, but unactualized, realizations is regarded as uninteresting because it is taken to be a question of pure logic or an unverifiable scenario of science fiction. However, in the biological context only a contingent set of realizations is actualized. Drawing on recent work on the theory of neutral biological spaces, the paper shows that we (...) can have ways of assessing the modal dimension of multiple realizability that do not have to rely on mere conceivability. (shrink)

The argument from multiple realizability is that, because quite diverse physical systems are capable of giving rise to identical psychological phenomena, mental states cannot be reduced to physical states. This influential argument depends upon a theory of reduction that has been defunct in the philosophy of science for at least fifteen years. Better theories are now available.

Bechtel and Mundale (1999) argue that multiple realizability is not plausible. They point out that neuroscientists assume that psychological traits are realized similarly in homologous brain structures and contend that a biological aspect of the brain that is relevant to neuropsychological state individuation provides evidence against multiple realizability. I argue that Bechtel and Mundale adduce the wrong sort of evidence against multiple realizability. Homologous traits do not provide relevant evidence. It is homoplasious traits of (...) brains that can provide evidence for or against multiple realizability. (shrink)

Multiple realizability (MR) is traditionally conceived of as the feature of computational systems, and has been used to argue for irreducibility of higher-level theories. I will show that there are several ways a computational system may be seen to display MR. These ways correspond to (at least) five ways one can conceive of the function of the physical computational system. However, they do not match common intuitions about MR. I show that MR is deeply interest-related, and for this (...) reason, difficult to pin down exactly. I claim that MR is of little importance for defending computationalism, and argue that it should rather appeal to organizational invariance or substrate neutrality of computation, which are much more intuitive but cannot support strong antireductionist arguments. (shrink)

Recently, several critics of the multiple realizability thesis have argued that philosophers have tended to accept the thesis on too weak grounds. On the one hand, the analytic challenge has problematized how philosophers have treated the multiple realization relation itself, claiming that assessment of the sameness of function and the relevant difference of realizers has been uncritical. On the other hand, it is argued that the purported evidence of the thesis is often left empirically unverified. This paper (...) provides a novel strategy to answer these worries by introducing a role for multiple realizability in the context of biological engineering. In the field of synthetic biology, bioengineers redesign the evolutionary realizations of biological functions, even constructing artificial chemical surrogates in the laboratory. I show how in the rational design approach to biological engineering, multiple realizability can function as a design heuristic in which the sameness of function and difference of realizers can be controlled. Although practically motivated, this engineering approach has also a theoretical, exploratory component that can be used to study the empirical limitations of multiple realizability. Successful realization of the engineering designs would amount to a concrete demonstration of multiple realizability, taking evidence for MRT beyond what is readily found in nature. (shrink)

The multiple-realizability argument has been the mainstay of anti-reductionist consensus in philosophy of mind for the past thirty years. Reductionist opposition to it has sometimes taken the form of the Disjunctive Move: If mental types are multiply-realizable, they are not coextensive with physical types; they might nevertheless be coextensive with disjunctions of physical types, and those disjunctions could still underwrite psychophysical reduction. Among anti-reductionists, confidence is high that the Disjunctive Move fails; arguments to this effect, however, often leave (...) something to be desired. I raise difficulties for one anti-reductionist response to the Disjunctive Move, the Explanatory Response. (shrink)

A popular argument supporting functionalism has been what is commonly called the “multiple realizability” argument. One version of this argument uses thought experiments designed to show that minds could be composed of different types of material. This article offers a metaphilosophical analysis of this argument and shows that it fails to provide a strong case for functionalism. The multiple realizability argument is best understood as an inference‐to‐the‐best‐explanation argument, whereby a functionalist account of our mental concepts serves (...) to explain our multiple realizability intuitions. I show that the argument is inadequate because alternative accounts of our mental concepts exist that provide equally plausible explanations for these intuitions. Moreover, in the case of our qualia concepts, a nonfunctionalist account explains several other intuitions that functionalism cannot explain. Thus, despite its popularity, the intuition‐based version of the multiple realizability argument is a poor reason for accepting functionalism. (shrink)

I will discuss two possible options how a defender of the type identity-theory with respect to mental properties can avoid the conclusion of Putnam's Multiple Realizability Argument. I begin by offering a rigorous formulation of Putnam's argument, which has been lacking so far in the literature (section 2). This rigorous formulation shows that there are basically two possible options for avoiding the argument's conclusion. Contrary to current mainstream, I reject the first option?Kim's 'local reductionism'?as untenable (section 3). I (...) endorse the second option, which has been brought into discredit by being too closely associated with disjunctive properties. I first show that many of the criticisms of disjunctive properties miss their target or beg the question against their opponent view (sections 4 & 5). Then I argue that it is not necessary to tie the second option closely to disjunctive properties. Hence, even if we deny the legitimacy of disjunctive properties, the identity-theorist still need not accept the conclusion of the Multiple Realizability Argument since there is an alternative, though related, way to spell out the second response (section 6). (shrink)

It has been debated what implications multiple realizability has for reductionism. I claim that more explicit attention needs to be paid to the distinction between multiple realizations of kinds and diverse implementations of laws. In this paper, I distinguish two different theses on the relations between multiple realization and diverse implementation: one thesis states that multiple realizations imply diverse implementations and the other states the converse. I claim that although antireductionism might turn out to be (...) false if the first thesis is accepted, this “realization‐based” antireductionism is not the only option for antireductionism. For the antireductionists who accept the second thesis, multiple realizations only provide evidence for diverse implementations. I defend this “implementation‐based” antireductionism again Shapiro's dilemma. I argue that one horn of the dilemma does not pose any problem and that the other horn simply begs the question. (shrink)

It is widely held that psychological theories cannot be reduced to those of the natural sciences. Perhaps the most common reason for rejecting psycho-physical reduction is the belief that mental properties are multiply realizable--i.e., that events of different physical types might realize the same mental property. While the multiple realizability argument has had its share of criticism, its major flaw has been overlooked. I aim to show the real reason why the argument fails and why multiple (...) class='Hi'>realizability is compatible with even the strongest varieties of reduction. (shrink)

Multiple Realizability (MR) must still be regarded as one of the principal arguments against type reductionist accounts of higher-order properties and their special laws. Against this I argue that there is no unique MR but rather a multitude of MR categories. In a slogan: MR is itself “multi-realized”. If this is true then we cannot expect one unique reductionist strategy against MR as an anti-reductionist argument. The main task is rather to develop a taxonomy of the wide variety (...) of MR cases and to sketch possible reductionist answers for each class of cases. The paper outlines some first steps in this direction. (shrink)

In this paper it is argued that the multiple realizability argument and Kripke's argument are based on schemas of identifications rather than identification. In fact, "heat = molecular motion" includes a term "molecular motion" that does not capture a natural kind, nor has a unique referent. If properly framed, this schema suits also for the type identity theory of mind. Some consequences of this point are evaluated.

Anti-reductionists hold that special science explanations of some phenomena are objectively better than physical explanations of those phenomena. Prominent defenses of this claim appeal to the multiple realizability of special science properties. I argue that special science explanations can be shown to be better, in one respect, than physical explanations in a way that does not depend on multiple realizability. Namely, I discuss a way in which a special science explanation may be more abstract than a (...) competing physical explanation, even if it is not multiply realizable, and I argue that this kind of abstraction can be used to support the idea that that special science explanation omits explanatorily irrelevant detail. (shrink)

The idea of reduction has appeared in different forms throughout the history of science and philosophy. Thales took water to be the fundamental principle of all things; Leucippus and Democritus argued that everything is composed of small, indivisible atoms; Galileo and Newton tried to explain all motion with a few basic laws; 17th century mechanism conceived of everything in terms of the motions and collisions of particles of matter; British Empiricism held that all knowledge is, at root, experiential knowledge; current (...) physicists are searching for the GUT, the “grand unified theory,” that will show that at very high energies the electromagnetic and the weak and strong nuclear forces are fused into a single unified field. Some of these projects are clearly ontological in nature (Leucippus and Democritus), others are more methodological (mechanism), and still others strive for theoretical simplification (the projects of Galileo and Newton or the search for a GUT). Nevertheless, as they all aim at revealing some kind of unity or simplicity behind the appearance of plurality or complexity, they may all be regarded as (attempted) reductions. (shrink)

A close examination of Kim's argument in "Multiple Realization and the Metaphysics of Reduction" for the claim that if a kind is multiply realizable in a way that blocks identification with more fundamental properties it is also a kind unlikely to appear as an appropriate kind in a theory in the first place. Ultimately, I argue that there is one reasonably promising argument of this sort, but its success turns on explanatory questions the answers to which are far from (...) obvious. (shrink)

Functionalism argues that since any mental state can be realized by different physical systems, it is therefore wrong to define or identify a mental state of an organism by the corresponding physical-chemical state of its body . In this paper, I argue that since a single mental state can also be realized in different functional patterns, multiple realizability creates the same problem for functionalism. This means that it is wrong to implicitly define a mental state by its causal (...) role in an interconnected network of inputs, outputs and internal states. It is discussed that the functionalists’ responses to this criticism are as plausible as the physicalists’ responses to the problem. It is concluded that in dealing with the multiple realizability problem, functionalism has no advantage over its rival, type physicalism. (shrink)

Shapiro has argued that the multiple realizability thesis for psychology, despite its broad acceptance, is far from being a well-established thesis. He suggests that not only do many of the standard examples of multiple realizability fail to be clearly examples but a competing thesis (“the mental constraint thesis”) that human-like minds are severely constrained in their physical realization is the more likely thesis. I will argue, however, that Shapiro’s mental constraint thesis is not a competing thesis (...) with the multiple realizability thesis. Once it is understood how these theses are compatible, the widespread acceptance of multiple realizability looks entirely reasonable. (shrink)

Shapiro has suggested that the empirical plausibility of the multiple realizability of human-like minds is dubious, because a contrary thesis, the Mental Constraint Thesis, enjoys positive empirical evidence. The Mental Constraint Thesis states that, given the actual physical laws, there is only one way to realize a human-like mind. I will suggest, however, that the Mental Constraint Thesis is not a contrary to the empirical multiple realizability thesis relevant to psychological reduction or autonomy and, as a (...) consequence, has no bearing on those classificatory issues. (shrink)

It has been debated what implications multiple realizability has for reductionism. I claim that more explicit attention needs to be paid to the distinction between multiple realizations of kinds and diverse implementations of laws. In this paper, I distinguish two different theses on the relations between multiple realization and diverse implementation: one thesis states that multiple realizations imply diverse implementations and the other states the converse. I claim that although antireductionism might turn out to be (...) false if the first thesis is accepted, this "realization-based" antireductionism is not the only option for antireductionism. For the antireductionists who accept the second thesis, multiple realizations only provide evidence for diverse implementations. I defend this "implementation-based" antireductionism again Shapiro's dilemma. I argue that one horn of the dilemma does not pose any problem and that the other horn simply begs the question. (shrink)

Metaphysical semantics is supposed to connect the nonfundamental to the fundamental in a distinctively “linguistic” way, explaining how nonfundamental truths can be grounded in fundamental facts , and so inducing a radically eliminative vision of the nonfundamental as mere talk. I wonder how the story goes when a single nonfundamental truth can be grounded in many different fundamental facts. For instance, the truth that Moore has hands can presumably be grounded in many different distributions of fields, arrangements of particles, vibrations (...) of strings, or whatnot. I am asking how metaphysical semantics can accommodate this sort of multiple realizability. (shrink)

A critical analysis of recent interventionist responses to the causal exclusion problem is presented. It is argued that the response can indeed offer a solution to the problem, but one that is based on renouncing the multiple realizability thesis. The account amounts to the rejection of nonreductive physicalism and would thus be unacceptable to many. It is further shown that if the multiple realizability thesis is brought back in and conjoined with the interventionist notion of causation, (...) inter-level causation is ruled out altogether. (shrink)

Are qualia natural kinds? In order to give this question slightly more focus, and to show why it might be an interesting question, let me begin by saying a little about what I take qualia to be, and what natural kinds. For the purposes of this paper, I shall be assuming a fairly full-blooded kind of phenomenal realism about qualia: qualia, thus, include the qualitative painfulness of pain (rather than merely the functional specification of pain states), the qualitative redness in (...) the visual field that typically accompanies red discriminations, the taste of lemon (independently of the fact that such states are normally caused by lemons and give rise to puckering of the lips, etc.), and so on. In other words, I am assuming the falsity of functionalism with respect to qualia, though I am not for a moment assuming dualism. (shrink)

While the concept of multiple realizability is widely used, it is seldom rigorously characterized. This paper defends a liberal conception of multiple realizability as sameness of type through _any_ differences in the (lower-level) conditions that give rise to instances of that type. This kind of “sameness through difference” is contrasted with another type of asymmetric dependency relation between properties, multiple _specification_. This liberal conception is then defended from objections, and it is augmented by a concept (...) of relativized multiple realizability. The last section presents a survey of the ontological, explanatory, and methodological consequences of this analysis of multiple realizability. (shrink)

Pluralism about truth is the view that there is more than one way for a proposition to be true. When taken to imply that there is more than one concept and property of truth, this position faces a number of troubling objections. I argue that we can overcome these objections, and yet retain pluralism's key insight, by taking truth to be a multiply realizable property of propositions.

Jaegwon Kim attempts to pose a dilemma for anyone who would deny mind/body reductionism, namely that one must either advocate the wholesale reduction of psychology to physical science or the sundering of psychology into distinct fields each one of which is reducible to physical science. Supposedly, the denial of mind/body reduction is not an option. My aim is to show that this is not a genuine dilemma, and that antireductionism is an option, if one recognizes that natural-kind individuation is not (...) wholly a matter of metaphysics but is, at least to some degree, a matter of convention as well. The central point is that physical sciences and mental sciences have somewhat different criteria for individuating kinds. (shrink)