Mental properties functionalization

When referring to Kim as a reductionsit, I do not mean to imply that Kim thinks that everything mental can be reduced to the physical. Kim clearly thinks that any mental properties, if they are to be scientifically respectable causal properties, must be functionally reduced to their underlying physical realization base. Kim does, however, seem to have doubts about whether things like qualia can be reduced. Thus, Kim seems to hold that qualia may be real in some sense of the word, but qualia are probably not functionally reducible and therefore caimot be causal. See e.g. Kim 1998 ch. 4 and 2005 ch. 6. 

This type of objection to nonreductive materialism is central to the work of Jaegwon Kim. Kim discusses this objection extensively in the various versions of his exclusion argument or supervenience argument. He holds that the only way to give mental properties a causal role is to functionally reduce them to physical properties, since physical causation will always rule out causation in virtue of irreducible mental... 

This type of solution is available to a type-identity materialist who holds that mental property M and physical property P are type identical. It is also available to Kim who now rejects the type identity of properties M and P, but holds that M is functionally reducible to P. 

Kim will attempt to do this by arguing that the exclusion principle forces us into one of two choices. Either we accept the causal impotence of higher-level properties, or we find a way to functionally reduce them. Kim will then argue that we have good reason to think that most higher-level scientific properties and many mental properties will turn out to be functionally definable and therefore fimctionally reducible. Thus, we are not left with the causal impotence of higher-level properties, nor are we forced to perform an all-encompassing type-identity reduction of these properties. Rather, we can functionally reduce them and retain their status as causal. 

Twin earth examples draw out the intuition that mental properties can be context-dependent properties. They show that it is possible for my doppelganger and me to have identical local lower level properties in our bodies and brains, but different higher-level mental properties due to differences in context Thus, mental properties do not just locally supervene on one s internal physical state, but rather globally supervene also on facts external to the person. If this is right, and mental properties can be context-dependent properties, then they too, along with many scientific properties, will resist functional reduction. 

Thus, we have good reason to think that both mental properties and many scientific properties will be context dependent and therefore resist functional definitions and functional reductions. The kind of trivial fimctional definition Kim gives for the concept of a gene is easy to come by. But this definition and reductive explanation does little explaining or illuminating, and we could easily find trivial fimctional definitions for... 

Once the exclusion principle has been rejected, then we no longer have any reason to reject nonreductive materialism on the grormds of exclusion. Furthermore, the most plausible alternative to nomeductive materialism - Kim s functional reduction - cannot be defended, since there is strong evidence in favor of the context dependence of scientific (and mental) properties. So at this point, nonreductive materialism seems to be the most viable option for a successful theory of mental causation. Let us now turn to some positive reasons for accepting a nomeductivist view of mental causation. 

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. 

The two big issues that are central in deciding who wins this debate are exclusion and context dependence. Anyone who buys the exclusion argument will have to reject nonreductive materialism. Anyone who believes that mental properties and other higher-level properties are context dependent will have to reject functional reduction. 

If we accept context dependence and realize that many higher-level properties will not be able to be functionally reduced, then that gives us even stronger reasons to reject the exclusion principle. Accepting context dependence not only rules out functional reduction as a viable theory of mind, but it also rules out functionally reducing many scientific properties. If we were to accept context dependence, then accepting the exclusion principle would not just have the result that epiphenomenalism about mental properties was true. It would also be the case that all context-dependent irreducible scientific properties were left epiphenomenal. Remember that the exclusion principle... 

If we are prepared to go for a functionalization of all mental properties, we will be embracing an all-encompassing reductionism about the mental, and this will solve the problem of mental causation. That s the good news. On a reductionist picture of this sort, however, the causal powers of mental properties turn out to be just those of their physical realizers, and there are no new causal powers brought into the world by mental properties. Many will consider that bad news. But the real bad news is that some mental properties, notably phenomenal properties of conscious experiences, seem to resist functionalization, and this means there is no way to account for their causal efficacy within a physicalist scheme. These properties are not able to overcome the supervenience argument, (pp. 118—19)... 

Our puzzle, the conundrum of the title, can now be restated in simple and familiar terms. The causal roles of our brain states are a function of the kinds of properties studied in neuroscience, but these kinds of properties are not mental properties — or so says the conventional wisdom that states that functionalism refuted the mind-brain identity theory understood as a type-type theory. It seems, therefore, that mental properties are causal idlers. 

Let s now see how similar points apply to mental properties. First, we need to outline the case for dualism about mental properties. We have seen that one class of mental properties - those we ascribe with the words pain, belief that snow is white, and so on those we believe a subject to instantiate when we use those words of them - cannot be neurological properties. They are some kind of functional property. But equally, as we also saw, it is a discovery of neuroscience that the causal roles played by mental properties are played by neurological properties. Moreover, the roles are those we take mental properties to play - what kind of state makes us wince pain This would seem to imply that mental properties are neurological properties, contrary to the conclusion reached earlier. What on earth is going on ... 

If a functional property is involved in a law, it is a G-property, and if it is involved in a natural science law, it counts as a P-property. The question is whether mental functional properties are also P-properties (i.e., appear in natural science laws), and it seems that they are not. The reason is that the various possible physical realizers of a mental property are heterogeneous. So, if there are mental properties that are functional G-properties, then RP is false. One response to this would be to broaden the conception of Ps to include configurations of G-property instantiations and arbitrary conjunctions and disjunctions of such configurations. But even then, functional properties of psychology may not be identical to any physical properties. The reason is that psychological functional properties may be realized by alien fundamental properties that conform to alien laws. 7 Suppose the fundamental individuals in our world are atoms or strings. It is at least prima facie plausible that there could be a world whose fundamental entities are fields and that at the macroscopic level is pretty much indiscernible from the actual world. In this world there are... 

A functional property as such will be defined by a role, even if it is claimed that it is only a posteriori that some mental property is that functional property. 

Of course, all functional properties are extrinsic properties, and if mental externalism is true for certain mental properties, then the functional properties with which the NRP theorist wishes to identify those mental properties will be very highly extrinsic. 

This point applies straightforwardly to the functionalist perspective on mentality. If we want a functional definition of mental property terms that apply to properties, the first-order variant will do. For example, the pain-property can be thought of as the property of jointly causing certain outputs together with certain other (mental) properties, being caused by certain inputs, and so forth. But if we want to ascribe those properties to people, we need second-order properties. What it is for a person to have pain, according to the functionalist, is for the person to have some property or other that has certain causal relations to other (mental) properties and to inputs and outputs. 

Kim (1992, 1998b) advocates a reductive physicalist approach to the mind that in effect rejects the metaphysical physicalist point of view. He takes mental properties to be merely nominal properties - indeed, hardly properties at all if ones criterion of reality for properties is causal efficacy. The idea is that the similarities among pain-feeling creatures that grounds their being in pain is not anything deep, but merely that they all instantiate a functional or even behavioral concept. The most fimdamental grounding is superficial. He says ... 

Judging from his (2005), Kim might agree about his earlier view. In the 2005 book, he poses the issue of reducibility starkly, saying, That a property is functionalizable, that is, it can be defined in terms of causal role -is necessary and sufficient for functional reducibility. It is only when we want to claim that the property has been reduced... that we need to have identified its physical realizer (p. 165). He then goes on to pose the question of whether mental properties are functionalizable. The answer... is yes and no. No for qualitative characters of experience, or qualia , and yes, or probably yes, for the rest (p. 165). No for qualitative characters of experience because of inverted-spectrum issues — it is metaphysically possible for functionally identical states to be different in qualitative character. The overall argument is that reductive physicalism fails for qualia — because they don t fit Kim s picture of reductive physicalism. However, there is another picture of reductive physicalism that has some merit, to which I turn in the next section. 

The way Smart s anonymous opponent conceives of the connection between identity statements and conceptual necessity is, to some extent, mimicked by a way of talking according to which kinds or types are more kin to concepts as conceived of here than to non-representational entities. The idea that there is a conceptual connection between the mental and the physical is tied to a fa on de parler that can be found in various parts of the debate on reductionism and type-identity theory, according to which we can analyze kinds, events or states in functional terms (cf. Block 1995 Kim 2005, 167 Jackson 2005). Type-identity theorists hold that mental types or kinds or properties are identical to physical types or kinds or properties. This suggests that mental kinds and physical kinds are non-representational objects - an interpretation that seems rather plausible given that type-identity theory is a metaphysical theory. Necessarily, there are no conceptual connections between kinds (or non-representational worldly entities), just because kinds are not the right sort of entities to instantiate conceptual relations in any nonderivative way. Kinds are the subject of ontological claims about mental properties. 

Up to now, we have reflected upon a family of partly competing and partly complementary theses about the metaphysics of the mind, and on how these theses can be illustrated by reference to the explication of reduction. These theses remain silent about the epistemic or procedural character of reductions (except for the highly implausible idea that the relevant identity-statements express a priori tmths) and about explanatory aspects of reduction. In the philosophy of mind, the dominant view about the link between reduction and explanation is that functional reduction somehow goes together with functional or mechanistic explanation. Functionalism also yields a theory of the metaphysics of mental properties and, contrary to ordinary type-identity theories, it explicitly employs the term reduction . 

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