Online research in philosophy

In this note, I will discuss one issue concerning the main argument of Mind in a Physical World (Kim, 1998), the Causal Exclusion Argument. The issue is whether it is a consequence of the Causal Exclusion Argument that all macro level causation (that is, causation above the level of fundamental physics) is an illusion, with all of the apparent causal powers of mental and other macro properties draining into the bottom level of physics. I will argue that such a consequence would give us reason to reject the Causal Exclusion Argument. But there is also a stronger challenge, the charge that, if there is no bottom level of physics, the Causal Exclusion Argument has the consequence that “causal powers would drain away into a bottomless pit and there wouldn’t be any causation anywhere.” (81--page numbers that are not attributed to other works are to Kim, 1998).

An analysis and rebuttal of Jaegwon Kim's reasons for taking nonreductive physicalism to entail the causal irrelevance of mental features to physical phenomena, particularly the behaviour of human bodies.

In numerous papers Jaegwon Kim argues that nonreductive materialists (i.e., those philosophers who believe that there are no irreducible non-physical objects in the universe, and yet there are irreducible psychological properties which are indispensable in intentional psychological explanations) face two problems. One is that intentional mental properties are not causally relevant; the other is that explanations appealing to these properties are excluded by explanations appealing to physical, in particular, microphysical, properties.1 The first problem can be called the problem of epiphenomenalism. The second problem is what Kim calls the problem of explanatory/causal exclusion. Epiphenomenalism is not just a problem for nonreductive materialists, but a problem for psychology (as a science of psychological explanation), and for anyone who believes that our thought is the cause of our action. Kim argues that the exclusion problem, on the other hand, is especially a problem for nonreductive materialists. Nonreductive materialists typically buy into the principle of the causal closure of the physical domain, according to which "any physical event that has a cause at time t has a physical cause at t..... [I]f we trace the causal ancestry of a physical event, we need never go outside the physical domain." [Kim 1989b, p. 280] One cannot reject this principle unless one is willing to go back to Cartesian dualism. But the problem is, if all causation is done at the physical level, then there is no causal work left for mental kinds. If mental kinds do not play any causal role, then intentional psychological explanations that appeal to mental properties are not warranted. Therefore, Kim concludes, nonreductive materialism is an untenable position. Some nonreductionists (Davidson, Dretske, LePore & Loewer, Jackson & Pettit, for example) have tried to argue for the causal relevancy of mental properties from an..

Kim argues that we can never have more than one complete and independent explanation for a single event. The existence of both mental and physical explanations for behavior would seem to violate this principle. We can avoid violating it only if we suppose that mental causal relationships supervene on physical causal relationships. I argue that although his solution is attractive in many respects, it will not do as it stands. I propose an alternate understanding of supervenient causation which preserves the advantages of Kim's account while avoiding the problems. My analysis involves appeal to counterfactuals. Any counterfactual analysis must confront the problem that mental states appear to be screened off from causal relevance by physical states. I argue that screening off is not a problem, because cases in which mental states appear to be screened off are cases in which background conditions are not held constant.

It is quite obvious why the antireductionist picture of mental causation that rests on supervenience is an attractive theory. On the one hand, it secures uniqueness of the mental; on the other hand, it tries to place the mental in our world in a way that is compatible with the physicalist view. However, Kim reminds us that anti-reductionists face the following dilemma: either mental properties have causal powers or they do not. If they have them, we risk a violation of the causal closure of the physical domain; if they do not have them, we embrace epiphenomenalism, which denies any sort of causal powers to the mental. So, either we violate the causal closure of physics, or we end up with epiphenomenalism. The first two sections of the article describe the problem of causal exclusion and Kim’s causal dilemma. The last two introduce Horgan’s antireductionist answer and my objection to that answer.

Jaegwon Kim’s causal exclusion argument says that if all physical effects have sufficient physical causes, and no physical effects are caused twice over by distinct physical and mental causes, there cannot be any irreducible mental causes. In addition, Kim has argued that the nonreductive physicalist must give up completeness, and embrace the possibility of downward causation. This paper argues first that this extra argument relies on a principle of property individuation, which the nonreductive physicalist need not accept, and second that once we get clear on overdetermination, there is a way to reject the exclusion principle upon which the causal exclusion argument depends, but third that this should not lead to the belief that mental causation is easily accounted for in terms of counterfactual dependencies.

In a series of influential articles (Kim 1989b, 1992b, 1993a and 1998), Jaegwon Kim has developed a strong argument against nonreductive physicalism as a plausible solution to mental causation. The argument is commonly called the ’causal exclusion argument’, and it has become, over the years, one of the most serious threats to the nonreductivist point of view. In the first part of this paper I offer a careful reconstruction and detailed discussion of the exclusion argument. In the second part I show why some important objections to it actually fail.