Online research in philosophy

A well-known ``overdetermination''argument aims to show that the possibility of mental causes of physical events in a causally closed physical world and the possibility of causally relevant mental properties are both problematic. In the first part of this paper, I extend an identity reply that has been given to the first problem to a property-instance account of causal relata. In the second, I argue that mental types are composed of physical types and, as a consequence, both mental and physical types may be causally relevant with respect to the same physical effect, contrary to the overdetermination argument. In further sections, I argue that mental types have causal powers, consider some objections and reject an alternative version of part-whole physicalism. Throughout I assume that causal relata are tropes and property types are classes of tropes.

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.

This paper argues that the non-reductive monist need not be concerned about the ‘problem’ of mental causation; one can accept both the irreducibility of mental properties to physical properties and the causal closure of the physical. More precisely, it is argued that instances of mental properties can be causally efficacious, and that there is no special barrier to seeing mental properties whose instances are causally efficacious as being causally relevant to the effects they help to bring about. It is then shown that the causal relevance of mental properties is consistent with there being no downward causation, so the dilemma of ‘epiphenomenalism or reduction’ can be avoided. Non-reductive monism lives on as a viable position in the philosophy of mind.

Stephen Yablo has recently argued for a novel solution to the mental causation problem: the mental is related to the physical as determinables are related to determinates; determinables are not causal rivals with their determinates; so the mental and the physical are not causal rivals. Despite its attractions the suggestion seems hard to accept. In this paper I develop the idea that mental properties and physical properties are not causal rivals. Start with property dualism, supervenience, multiple realizability, and the claim that no more than one supervenience base for a mental property can be had by a single instance of the mental property. Then a probabilistic account of causation will be unable to certify either mental properties or physical properties as causal factors for effect types. I suggest that this shows that we should not count mental properties as causal rivals with physical properties.

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 following framework of theses, roughly hewn, shapes contemporary discussion of the problem of mental causation: (1) Non-Identity of the Mental and the Physical Mental properties and states cannot be identified with specific physical properties and states. (2) Causal Closure (Completeness) of the Physical 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 There is at most one complete and wholly independent explanation for any given event or sequence of events.

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..

Abstract: The paper begins with the assumption that psychological event tokens are identical to or constituted from physical events. It then articulates a familiar apparent problem concerning the causal role of psychological properties. If they do not reduce to physical properties, then either they must be epiphenomenal or any effects they cause must also be caused by physical properties, and hence be overdetermined. It then argues that both epiphenomenalism and over-determinationism are prima facie perfectly reasonable and relatively unproblematic views. The paper proceeds to argue against Kim's ( Kim, 2000, 2005 ) attempt to articulate a plausible version of reductionism. It is then argued that psychological properties, along with paradigmatically causally efficacious macro-properties, such as toughness, are causally inefficacious in respect of their possessor's typical effects, because they are insufficiently distinct from those effects. It is finally suggested that the distinction between epiphenomenalism and overdeterminationism may be more terminological than real.

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: every physical event has a complete physical cause, a cause that is sufficient for the event’s occurrence. This apparently leaves us with a limited number of options concerning psychological causation, none of which appear hugely attractive. Either: (a) the psychological is epiphenomenal and can have no causal impact on the physical, or (b) the psychological is identical with the physical, or (c) thoughts and actions are all over-determined, each one having two distinct sufficient causes. Option (b) subdivides into two further options. Either (b1) the psychological reduces to the physical and every psychological property is identical with some physical property, or (b2) token psychological events are identical with or constituted from token physical events but psychological properties are not identical with physical properties. (b1) is widely held to be inconsistent with the multiple realisation of the psychological by the physical. And (b2) appears to bring us back to the original problematic, with the properties as the locus of tension. If one event causes another it does so in virtue some of its properties and not others. If I throw a stone at a window and the window breaks, it is because the stone was hard and heavy that it broke the window and not, say, because it was grey and millions of years old. The properties in virtue of which an event has a particular effect are typically called the ‘causally efficacious properties of the cause with respect to the effect.’ Suppose, then that token neural event causes an action. We can ask ‘Does it do so in virtue of its physical properties or its psychological properties?’ and we are back to choosing between options (a) and (c) or returning to (b1)..