physicalism, non-reductive
The claim that functional properties cannot be reduced to physical properties, but that nevertheless all causality is physical. See physicalism, multiple realizability, functionalism.

Kim Against Non-reductive Physicalism
Jaegwon Kim sees Donald Davidson's theory of anomalous monism to be a kind of non-reductive physicalism, as well as Fred Dretske's distinction between reasons and causes. Kim claims that one can be either a physicalist, or non-reductive, but not both. In Kim 1993 (p. 351-2), he describes the problem using the following diagram.
       M causes M*
       P causes P*
In this diagram, a single mental event M is seen as causing another mental event M*. This mental event is physically realized (for example in a brain state) by a physical event P, which causes P* i.e. the physical realization of M* . Kim's argument against the existence of mental causation is that the top layer does no real work. P can cause P* all by itself, with no help from M, and there is no coherent way in which M can cause M* without P's help, or without causing P*. Thus it seems that physical causality is all we've got, and mental descriptions are somewhere between being shallow and being outright falsehoods. Kim claims that the only coherent alternatives are:
       1) Dualism, which says that M and M* are independent of P and P*;
       2) Reductionism, which says that physical events are identical with mental events; and
       2a) Eliminativism, which says that mental events do not exist at all.
Clearly, position 1) is non-reductive, without being materialist and 2) and 2a) are materialist, without being non-reductive.
There is also another alternative: Mental Epiphenomenalism, which says that M exists but has no causal powers. Because Kim (1993, p. 348) accepts Samuel Alexander's (1927) dictum that "to be is to have causal powers", he sees this position as fundamentally self-contradictory.
Problems with Kim's Position
Kim's arguments against non-reductive materialism's attempt to have it both ways are valid, and have had a profound impact. But he has been less successful with his attempts at a positive account of the relationship between functional properties and physical properties. Part of the reason his accounts are less convincing is that he is not afraid to bite whatever bullets are necessary in order to remain consistent. For example, he claims that a genuinely physical explanation would have to deny causal powers not only to beliefs and desires, but to everything except the elementary particles of physical theory.
"all causal relations involving observable phenomena-all causal relations from daily experience--are cases of epiphenomenal causation" (ibid. p.96)
Kim defines epiphenomenal causation as a relationship between two events which appears to be a cause and effect relationship, but in fact is merely a reflection of some other underlying causal process. If we are to be consistent in our denial of emergent processes, we must claim that strictly speaking the rock thrown at the chair did not cause the chair to fall over. Rather the relationship between the thrown rock and the chair is an epiphenomenon that supervenes on the genuine causal processes of subatomic particles, in essentially the same way that mental states supervene upon physical states. For if we granted the existence of emergent macroscopic causal properties within physics, there would be no reason to deny their existence in the mental realm.
Kim admits that the causality of tables and chairs is every bit as epiphenomenal as that of mental states, because both are dependent on more fundamental laws of physics. But strictly speaking, Kim's position would also require us to claim that all of the laws of chemistry are epiphenomenal, because the behavior of the elements is really causally dependent on the behavior of protons, neutrons and electrons. The behavior of these subatomic particles would also be epiphenomenal, because they are causally dependent on the behavior of quarks. And now that we recognize that scientific revolutions are a natural part of the growth of sciences, we cannot discount the possibility that further research could reveal (if it hasn't already) that quarks have parts. If this happened, then the behavior of quarks would be epiphenomenal. Paul Churchland (1989) also suggests that metaphysically there is no reason to be certain that this reductive process ever stops:
. . .consider the possibility that for any level of order discovered in the universe, there always exists a deeper taxonomy of kinds and a deeper level of order in terms of which the lawful order can be explained. It is, as far as I can see, a wholly empirical question whether or not the universe is like this, like an "explanatory onion" with an infinite number of explanatory skins. If it is like this, then there are no basic or ultimate laws to which all investigators must inevitably led (pp. 293-4).
If this suggestion turns out to be correct, then quarks would be as bereft of causal powers as beliefs and desires. If every causal effect is dependent on the behavior of its parts, and the division of parts into parts goes on forever, there would be no principled reason to stop the regress at one place rather than another. For Kim, this is true even if there is no multiple realizability involved. The macroproperty would be epiphenomenal even if it constantly conjoined with some microproperty, for the microproperty would be doing the real work, and the macroproperty would be only an epiphenomenon of some set of microproperties. But something like multiple realizability does emerge unless it is possible to establish what are called "bridge laws" i.e. equivalencies between terms used at both the macro and micro levels.
Kim also repeatedly asserts that the special sciences must be connected to physics by bridge laws, and considers this to be the main reason for dismissing the possibility of emergent causality (see especially chapter 6 of Kim, 1993). For example, he claims: "each supervenient property necessarily has a coextensive property in the base family" (Kim 1993 p.72); and "The reduction of one theory to another is thought to be accomplished when the laws of the reduced theory are shown to be derived from the laws of the reducer theory, with the help of 'bridge principles'" (ibid. p. 150). Kim admits in an accompanying footnote that "whether this is the most appropriate model. . . could be debated." But apparently he feels that the bridge law model is good enough for him, for he continues to work with it for the rest of the chapter (see also p. 248 and p. 260).

Bridge Laws
Kim's arguments are consistent given the assumption that science produces bridge laws. But they can also serve as a two-edged sword if we question that assumption. If the sciences are not connected by bridge laws, then Kim's arguments imply that there is no longer any reason to deny the existence of emergent causality. And as it turns out, bridge laws are simply not to be found when we look at the most successful reductions in the history of science. There is clearly some relationship that is established when one theory reduces another, but almost all modern philosophers of science acknowledge that in most cases this relationship is more like an isomorphism or a similarity than an identity (see Bickle 1998, Hooker 1981, Churchland 1975). And these kinds of loose relationships will not yield necessary causal connections between the two realms, only probable ones. If A = B, then one can infer from this that if A is F , then B is F. But if A is only similar to B, the only thing we can conclude from "A is F" is that "B is probably F". The connection will only incline, not necessitate -- to quote Leibniz. If there is any blurring at all between the entities referred to in macrodiscourse and those referred to in microdiscourse, the laws that govern the entities in one domain cannot necessitate the behavior of entities in the other.
Kim (1993) considers the possibility that the macroscopic supervenes only loosely on the microscopic in chapter 5, section 5 (Global Supervenience Strengthened: Similarity vs. Indiscernability). Although he doesn't explain in any detail what is meant by loose supervenience, he surprisingly seems quite comfortable with this idea. However, for the reasons given above, any such looseness would leave open the possibility of emergent macroscopic causality.
One alternative to both dualism and physicalism that Kim does not consider is pluralism. Suppose that there were certain patterns that emerged in what we call physical processes which had genuine causal powers? This kind of emergence would not necessarily imply a dualistic universe, but rather a pluralistic one; what Nancy Cartwright (1999) has called a "dappled world." There could be a variety of macroscopic patterns having an impact on such a world, some of which would be able to control the particles they were made of, rather than exclusively the other way around. In such a pluralistic universe , there would be no principled reason for denying the possibility of mental causality. Mental processes could be one kind of emergent phenomenon, but not the only one. One could flippantly say that when one asks a pluralist "are you a dualist" the correct answer is "yes, at the very least". Such a view would save mental causation from having to rely on finding something ontologically unique about the mental, and from being tarred with the brush of Cartesian dualism. In a post-Darwinian world, any attempt to grant special abilities to consciousness (especially to human consciousness) is bound to look like special pleading motivated by wishful thinking. If we can get the same result by seeing our mental processes as one of many different kinds of emergent properties, then mental properties would be much more plausible result of evolutionary processes.
Kim admits that the claim that physical causality has no emergent properties is an empirical one. He claims that "modern theoretical science treats macrocausation as reducible epiphenomenal causation and . . . this has proven to be an extremely successful explanatory and predictive research strategy." He describes this claim as an "observation" (Kim 1993 p. 96). However, evidence from the history of science shows that we have not discovered the bridge laws that would be necessary to maintain deterministic links between micro and macrocausation, and thus we have no real decisive evidence from science that there is no emergent physical causality. Kim has shown us that if we are willing to say that causal properties emerge anywhere between quarks and minds, we have no reason to deny causal powers to minds. Perhaps Kim is biting the wrong bullet.
Teed Rockwell