Published online by Cambridge University Press: 01 January 2020
According to a prominent line of thought, we can be physicalists, but not reductive physicalists, by holding that mental and other ‘higher-level’ or ‘nonbasic’ properties — properties that are not obviously physical properties — are all physically realized. Spelling this out requires an account of realization, an account of what it is for one property to realize another. And while several accounts of realization have been advanced in recent years, my interest here is in the ‘subset view,’ which has often been invoked explicitly in defense of nonreductive physicalist positions.
1 See Gillett, Carl ‘The Dimensions of Realization,’ Analysis 62 (2002): 316–23;CrossRefGoogle Scholar Kim, Jaegwon Mind in a Physical World (Cambridge, MA: The MIT Press 1998);CrossRefGoogle Scholar Melnyk, Andrew A Physicalist Manifesto (Cambridge: Cambridge University Press 2003);CrossRefGoogle Scholar Polger, Thomas ‘Realization and the Metaphysics of Mind,’ Australasian Journal of Philosophy 85 (2007): 233–59.CrossRefGoogle Scholar The significance of the notion of realization for physicalism is emphasized in Poland, Jeffery Physicalism: The Philosophical Foundations (New York: Oxford University Press 1994)CrossRefGoogle Scholar and in my ‘Guidelines for Theorizing About Realization,’ The Southern Journal of Philosophy 48 (2010): 393-416.
2 See Shoemaker, Sydney ‘Realization and Mental Causation,’ reprinted in Shoe maker, Identity, Cause, and Mind, expanded edition (New York: Oxford University Press 2003);Google Scholar Shoemaker, Physical Realization (New York: Oxford University Press 2007);CrossRefGoogle Scholar Wilson, Jessica ‘How Superduper Does a Physicalist Supervenience Need To Be?’ The Philosophical Quarterly 49 (1999):CrossRefGoogle Scholar 3352; Wilson, ‘Non-reductive Realization and the Powers-based Subset Strategy,’ The Monist 94 (2011);CrossRefGoogle Scholar Clapp, Lenny ‘Disjunctive Properties: Multiple Realizations,’ The Journal of Philosophy 98 (2001): 111–36.Google Scholar
3 Powers so understood thus correspond to what Shoemaker calls ‘conditional causal powerS.’ For instance, the property of being knife-shaped has the ‘conditional power’ to cut bread, since it has this power conditional, in part, on the knife-shaped object also having the property of being made of steel. This amounts to the claim that an instance of being knife-shaped will cause the cutting of bread if certain conditions obtain (for instance, the knife-shaped object is pressed against bread) and certain further properties are instantiated by the knife-shaped object (for instance, being made of steel). See Shoemaker, ‘Causality and properties,’ in Time and Cause, P. van Inwagen, ed. (Dordrecht: D.Reidel 1980), reprinted in Shoemaker, Identity, Cause, and Mind.
4 See Shoemaker, ‘Realization and Mental Causation’; Shoemaker, Physical Realization; see also Clapp, ‘Disjunctive Properties…’; Wilson, ‘How Superduper…’; Wilson, ‘Non-reductive Realization…’. Shoemaker, ‘Realization and Mental Causation,’ officially defines property realization not only in terms of powers, but also ‘backward-looking causal features,’ where backward-looking causal features consist in what brings about the instantiation of a property. While the notion of a backward-looking causal feature raises a number of issues (see Brian McLaughlin, ‘Mental Causation and Shoemaker-Realization,’ Erkenntnis 67 (2007): 149-72), I will work with the simpler formulation. For one, Shoemaker expresses doubts about the need for building the notion of a backward-looking causal feature into the definition of subset realization (Physical Realization, 12). Second, other definitions of subset realization have been formulated in terms of powers (see, for example, Clapp, ‘Disjunctive Properties…’; Wilson, ‘How Superduper…’).
5 See, for instance, Clapp, ‘Disjunctive Properties…’; Wilson, ‘How Superduper…’.
6 See, for instance, Shoemaker, Physical Realization, 6, 14. For a dissenting opinion, see McLaughlin, ‘Mental Causation and Shoemaker-Realization.’
7 Shoemaker, ‘Realization and Mental Causation,’ 435-6; Shoemaker, Physical Realization, 13–4 and Wilson,Google Scholar ‘How Superduper…,’ 51.
8 Shoemaker, ‘Realization and Mental Causation.’ Similar ideas can be found in Stephen Yablo, ‘Mental Causation,’ The Philosophical Review 101 (1992): 245-80.Google Scholar See my ‘Subset Realization, Parthood, and Causal Overdetermination,’ Pacific Philosophical Quarterly (forthcoming) for an extended discussion and critique of this strategy.
9 See Shoemaker, ‘Realization and Mental Causation,’ 434;Google Scholar Shoemaker, Physical Realization, 17;Google Scholar Wilson, ‘How Superduper …,’ 45.Google Scholar Defenders of the subset view motivate the claim that the causal powers of subset-realized properties are typically a proper subset of those of realizers primarily by appealing to our intuitions about causation and causal relevance. Shoemaker and Wilson, for instance, consider the case of Alice, a pigeon conditioned to peck at scarlet things but not at shades of red other than scarlet. Intuitively, they argue, scarlet, but not red, thus has the power to bring about a pecking response in Alice: when Alice is presented with a scarlet patch of an appropriate size and pecks at the patch, intuitively it is the patch's being scarlet, rather than its being red, that causes Alice to peck. If scarlet is a realizer of red, it follows that realizer properties may have powers beyond those of realized properties (see Shoemaker, ‘Realization and Mental Causation,’ 431-2; Shoemaker, Physical Realization, 14;Google Scholar Wilson, ‘How Superduper …,’ 1999, 48;Google Scholar this case is also discussed in Yablo, ‘Mental Causation’).
13 It can be noted that this line of thought is at least prima facie distinct from the idea that we may reject the identification of realized properties with physical properties by insisting that realized properties are ‘second-order’ properties — properties the having of which consists in having some other property that meets a certain condition — and that second-order properties are not identical with first-order physical properties; see, for example, Ned Block, ‘Introduction: What is Functionalism?’ in Readings in Philosophy of Psychology, Vol. 1, ed. N. Block (Cambridge, MA: Harvard University Press 1980); Hilary Putnam, ‘Logical Positivism and the Philosophy of Mind,’ in The Legacy of Logical Positivism, Achinstein, P. and Barker, S. edş (Baltimore: Johns Hopkins Press 1969).Google Scholar Whether such an appeal to second-order properties is successful is a matter of dispute; see Kim, Mind in a Physical World, for some doubtş Shoemaker, Physical Realization, discusses the extent to which the subset view involves a second-order conception of realized propertieS.
14 See Clapp, ‘Disjunctive Properties….’; Shoemaker ‘Realization and Mental Causation’; Shoemaker, Physical Realization. Shoemaker, ‘Causality and Properties,’ provides a prominent defense of the ‘causal view of propertieS.’ Wilson, ‘Nonreductive Realization…,’ argues that the subset view of realization does not require that properties are individuated by causal powerS. While I will not dwell on this issue, and will discuss some related issues in §IV, I believe that much of the motivation for the subset view is lost if we do not suppose that there is an important connection between properties and powers (see, for example, Brian McLaughlin, ‘Review of Sydney Shoemaker's Physical Realization,’ Notre Dame Philosophical Reviews (2009); available at: <http://ndpr.nd.edu/review.cfm?id=16607>).
15 I will return to this issue in §IV. Note also that while there is a sense in which this formulation of a physical property in terms of physical powers is circular, it is not clear that this circularity threatens the attempt to tie the kind of property we have to the kind of powers associated with it. Rather, the circularity present here would seem to just be the general circularity that arises for attempts to characterize properties in terms of powers, since the notion of a power will itself involve reference to properties; such a worry about the causal view of properties is discussed in Shoemaker, ‘Causality and PropertieS.’
16 See n. 14.
20 Kim, ‘Phenomenal Properties, Psychophysical Laws, and the Identity Theory,’ The Monist 56 (1972): 177–92,CrossRefGoogle Scholar notes that multiple realization may not rule out physical identifications, since systems that are physically diverse in some respects might be physically similar in other respectş On the present line of thought, the subset view provides one way in which Kim's suggestion might be spelled out.
21 See Kim, Mind in a Physical World, for discussions of this strategy. McLaughlin, ‘Review of Sydney Shoemaker's Physical Realization,’ discusses the disjunctive strategy in the context of the subset view; see also Clapp, ‘Disjunctive Properties…’
24 In the quoted passage, Shoemaker could be read as saying that powers realize other powers — that physical powers realize mental powerS. But the surrounding text suggests that this is not what he has in mind and, moreover, he never offers an independent account of what it would be for a power to realize another power.
25 See my ‘Guidelines for Theorizing about Realization’ for a defense of this idea.
26 McLaughlin, ‘Mental Causation and Shoemaker-Realization,’ makes a similar point about attempts to combine a subset approach to realization with the kind of ‘proportionality’ view of causation advanced in Yablo, ‘Mental Causation,’ and suggested by Shoemaker in ‘Realization and Mental Causation.’
28 Wilson, ‘Non-reductive Realization…’
29 See, for example, Shoemaker, ‘Realization and Mental Causation’; Shoemaker, Physical Realization.
30 For example, for the strategy to succeed, it will have to hold that the ‘merely physicalistically acceptable properties’ have powers that are not distinctively physical powers (causal powers that can be characterized in distinctively physical terms); yet in this case, it may face the problems that arose in §III regarding the distinction between mental powers and physical powers.
31 Some of the ideas in this paper were originally presented at the 2008 meeting of the International Symposium of the Austrian Ludwig Wittgenstein Society and at the 2008 ‘PhilMiLCog’ Graduate Conference at the University of Western Ontario. I am grateful to the audience members on these occasions for helpful comments and advice. I am also grateful to Christopher Hill, Jaegwon Kim, Bernard Kobes, and Douglas Kutach for written comments on related material.