Online research in philosophy

The exclusion problem is held to show that mental and physical events are identical by claiming that the denial of this identity is incompatible with the causal completeness of physics and the occurrence of mental causation. The problem relies for its motivation on the claim that overdetermination of physical effects by mental and physical causes is objectionable for a variety of reasons. In this paper, I consider four different definitions of ?overdetermination? and argue that, on each, overdetermination in all cases of mental causation either does not occur or is unobjectionable, even when mental and physical events are non-identical. I therefore conclude that the exclusion problem cannot be used as a reason to accept that mental and physical events are identical unless some other definition of ?overdetermination? is provided.

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.

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..

Please allow me to recapitulate some territory that will be familiar to most readers. Here is how the problem of mental causation has typically been set up since shortly after the onset of non-reductive physicalism. It is now widely assumed that the realm of the physical is causally closed. This means that the probability of any event’s occurring is fully determined by physical causes, and physical causes alone. There is no space in the physical causal nexus for any non-physical event to exert any influence.

Recent discussions of mental causation have focused on three principles: (1) Mental properties are (sometimes) causally relevant to physical effects; (2) mental properties are not physical properties; (3) every physical event has in its causal history only physical events and physical properties. Since these principles seem to be inconsistent, solutions have focused on rejecting one or more of them. But I argue that, in spite of appearances, (1)–(3) are not inconsistent. The reason is that 'properties' is used in different senses in the principles. In (1) and (3), 'properties' should be read as 'tropes' (properties here are particulars), while in (2) 'properties' should read as 'types' (properties here are universals or classes). Although mental types are distinct from physical types, every mental trope is a physical trope. This allows mental properties to be causally relevant to physical effects without violating the closed character of the physical world.

The anti-reductionist who wants to preserve the causal efficacy of mental phenomena faces several problems in regard to mental causation, i.e. mental events which cause other events, arising from her desire to accept the ontological primacy of the physical and at the same time save the special character of the mental. Psychology tries to persuade us of the former, appealing thereby to the results of experiments carried out in neurology; the latter is, however, deeply rooted in our everyday actions and beliefs and despite the constant opposition of science still very much alive. Difficulties, however, arise from a combination of two claims that are widely accepted in philosophy of mind, namely, physical monism and mental realism, the acceptance of which leads us to the greatest problem of mental causation: the problem of causal exclusion. Since physical causes alone are always sufficient for physical effects mental properties are excluded from causal explanations of our behaviour, which makes them “epiphenomenal”. The article introduces Van Gulick’s solution to the exclusion problem which tries to prove that physical properties, in contrast to mental properties, do not have as much of a privileged status with respect to event causation as usually ascribed. Therefore, it makes no sense to say that physical properties are causally relevant whereas mental properties are not. This is followed by my objection to his argument for levelling mental and physical properties with respect to causation of events. I try to show that Van Gulick’s argument rests on a premise that no serious physicalist can accept.

to counterintuitive results. Suppose a mental event, m1, causes another mental event, m2. Unless the mental and the physical are completely independent, there will be a physical event in your brain or your body or the physical world as a whole that underlies this event. The mental event occurs at least partly in virtue of the physical event’s occurring. And the same goes for m2 [2] and p2. Let’s not worry about what exactly “underlying” or “in virtue of” means here. Here’s the picture. m1 -----> m2 | | p1 -----> p2 The horizontal arrows represent causation, and the vertical lines represent underlying, whatever that may be. There’s some reason to think that the only way m1 can bring about m2 is by bringing about p2. You can’t convince someone of something through mental telepathy. You need to interact with the physical world, perhaps by saying something and so making some noise, or by pointing and getting them to turn their head and see. What goes for the case of two people goes for the case of one person as well. Superstition aside, there is no purely mental energy that floats free of the merely physical workings of the brain. If m1 brings about m2 by bringing about p2, then m1 brings about p2. This is downward causation. But wait. Doesn’t p1 bring about p2? Isn’t that what the bottom arrow represents? Maybe m1 and p1 work together to bring about p2. There are little holes in the physical causal structure that need to be filled by mental events. You don’t need a sweeping metaphysical thesis about the causal closure of the physical to find this implausible. Maybe p2 is overdetermined.

The paper argues that mental causation can be explained from the sufficiency of counterfactual dependence for causation together with relatively weak assumptions about the metaphysics of mind. If a physical event counterfactually depends on an earlier physical event, it also counterfactually depends on, and hence is caused by, a mental event that correlates with (or supervenes on) this earlier physical event, provided that this correlation (or supervenience) is sufficiently modally robust. This account of mental causation is consistent with the overdetermination of physical events by mental events and other physical events, but does not entail it.

Argument for Epiphenomenalism [I]: (A) Mental event-tokens are identical with physical event-tokens. (B) The causal powers of a physical event are determined only by its physical properties; and (C) mental properties are not reducible to physical properties.

The objective probability of every physical event is fixed by prior physical events and laws alone. (This thesis is sometimes expressed in terms of explanation: In tracing the causal history of any physical event, one need not advert to any non-physical events or laws. To the extent that there is any explanation available for a physical event, there is a complete explanation available couched entirely in physical vocabulary. We prefer the probability formulation, as it should be acceptable to any physicalist, though some reject the explanation formulation.) (3) Causal Exclusion.