Multiple realizability properties

My criticisms might not apply to a view that is less reductive than Kim s. Kim s view seems to have an advantage over more reductive type-identity materialist views, because Kim s functional reduction seems to be able to account for the multiple-realizability of higher-level properties in a way that type-identity materialism cannot. However, Kim s theory of functional reduction ultimately fails, because it cannot account for the context dependence of many higher-level properties. If there were some version of reductive materialism that could somehow account for the context dependence of higher-level properties, then this view might be immune to many of my criticisms. However, we might wonder how a view that allows for context dependence could even be considered reductionist at all. 

The lower-level-higher-level distinction is really just about multiple realizability. To say a property is a higher-level property just means that it is multiply realizable with respect to its lower-level instantiation. So, for instance, macroproperties like size can be higher-level properties, since size is multiply realizable. We could, for instance, have five balls that are the exact same size, but each ball could have an entirely different microstructure (e.g., one is made of plastic, one of metal, one of wood, etc.). 

Because of the difficulties associated with Nagel s bridge-law model of reduction and the success of multiple realization arguments against type-identity materialism, Kim has come to reject type-identity materialism in favor of what he ealls functional reduction. The functional reduction of a property requires three steps ... 

Ron McClamrock (1995a, ch. 3) has argued that we can use the ideas of multiple realizability and context dependence to pick out preferred levels of causation and explanation. When we have token identity at different levels, we can use the ideas of multiple realizability and context dependence to hold properties at one level fixed while varying properties at other levels, in order to try to see at which level the causal mechanism occurs. In the ball-sorter case, we see that the causation occurs in virtue of size and that the macro-level of size is the right level of explanation. 

We can use multiple realizability and context dependence to help us try to isolate the properties in virtue of which the event is caused without being forced to exclude properties at other levels as also causal. 

I have argued that if we take a closer look at causation, we see that there is no plausible reason for accepting the exclusion principle. We can use the ideas of multiple realizability and context dependence to help us isolate which properties are causal properties. When we do this, we can see that there is nothing about causation that ought to lead us to think that sufficiency at one level will rule out causation at other levels. 

Aecepting nonreductive materialism gets us what we want and need out of a theory of mental causation. We can have sufficient causation at the physical level and causation in virtue of irreducible mental properties, without any sort of problematic overdetermination. We can account for both the multiple realizability and the context dependence of many mental properties. And we can account for why mental explanations often seem to offer us better predictive and explanatory power than lower level physical ones. Mental explanations work because menial properties are causal properties. 

It is clear that mental properties are multiply realizable, and there also seem to be good reasons to think that they are context dependent as well. For this reason, it seems that nonreductive materialism has the most initial plausibility, because it can account for the multiple realizability and context dependence of mental properties. Although we can argue over whether mental properties are context dependent, we can t deny that they are multiply realizable. Since type-identity materialism has a hard time dealing with multiple realizability, it seems to be at a clear disadvantage. Kim s theory of ftmctional reduction has an advantage over type-identity materialism because it does have a way of accounting for the multiple realizability of mental properties. So the real debate here, as I see it, is between nonreductive materialism and functional reduction. 

With the distinction between economical and loose reduction in mind, let s turn to Kim s treatment of multiply realizable properties in chapter 4 of MIPW. We may suppose, with Kim, that the exclusion argument provides a strong reason to seek a reduction of mental properties to physical properties we may also note — though Kim does not — that the reduction will afford a solution only if it is an economical one. The ostensible problem with multiply realizable mental properties is that their multiplicity of realizers apparently precludes strong type reductions pain cannot be identified with the firing of C fibers if some creatures realize... 

We could introduce the additional condition that the property structures involved here should be property structures that mimic the structure of multiple realization, reflecting, for example, the intuition that every mental token (that is one object presented as an instance of mental kind M) reduces to a physical token (that is the same object presented as instantiating a physical kind, where this kind is one of the realizers of M). This nicely fits the idea that the realization relation is an explanatory relation to give an example, on this view, a pain token is a pain token in virtue of being a token of C-fiber stimulation. 

Does multiple realizability really attack type-identity theory It seems obvious that many innocent properties are multiply realizable. For example, a specific mean kinetic energy of an entity can be realized by infinitely many spatial states of the entity s constituents (Kisfler 1999). This does not affect its being a basic kind. Thus, multiple realizability does not seem to threaten identity-theories per se. The trick is to introduce a distinction between heterogeneous multiple realization and homogeneous multiple realization. The former is bad for the identity-theorist,... 

Among philosophers of mind, it is common to assume that at least some mental properties are functional in nature (Putnam 1975 Jacob 1997 Kim 1992,1998 van Gulick 2001 Block 1997,2007, forthcoming). Basically, a functional property is a property that is to be characterized, or that is characterizable in functional terms. The idea that functional properties are functional in nature, or that they are role-properties raises subtle issues about the nature of dispositional properties, their connection to multiple realizability and to functionalism. Suffice it to say that on all these views, a functional characterization is, to some extent, transparent with respect to the so described property s nature (for a discussion, see van Riel 2012). Here are two ways to conceive of characterizations in functional terms. The first is obtained from Lewis (1972), the second can be found in Block (2007), building on Putnam (1975). To give an idea of how to conceive of functional properties, it will prove useful to talk freely about theoretical terms. Theoretical terms are conceived of as terms that can be defined by the Ramsey-sentence of the theory in which they occur. A functional characterization of a property is, then, a characterization of a property in terms of the relevant Ramsey-sentence, obtained from a psychological theory. 

Clapp, Leonard. 2001. Disjunctive properties and multiple realizations. The Journal of Philosophy 98 111-136. 

Kistler, Max. 1999. Multiple realization, reduction and mental properties. International Studies in the Philosophy of Science 13 135-149. 

---