Mental Causation: a Real Phenomenon in a Physicalistic World Without Epiphenomenalism Or Overdetermination

Grazer Philosophische Studien 65 (2002), 139–167.

MENTAL CAUSATION: A REAL PHENOMENON IN A PHYSICALISTIC WORLD WITHOUT EPIPHENOMENALISM OR OVERDETERMINATION

Albert NEWEN & Rimas ČUPLINSKAS University of Bonn

Summary The so-called problem of mental causation as discussed in the recent literature raises three central challenges for an adequate solution from a physicalist perspective: the threat of epiphenomenalism, the problem of externalism (or the difÞ culty in accounting for the causal efÞ cacy of extrinsic mental properties) and the problem of causal exclusion (or the threat of overdetermination). We wish to account for mental causation as a real phenomenon within a physicalistic framework without accepting epiphenomenalism or overdetermination. The key ideas of our proposal are an internal realism of causation combined with a relative notion of individuating events. We are arguing — contra Davidson — that there is no absolute notion of events (neither as types nor as tokens) but rather one which is relative to explanatory interests and our intuitions concerning a relevant spatial and temporal overlap. Furthermore, we are presupposing a metaphysics of internal realism: We can only characterize entities by means of concepts produced within our epistemological framework. Physical concepts and mental concepts crossclassify the world as it is. Relying on this framework we try to explain how mental causation can be adequately described: Although mental concepts are not reducible to physical concepts and mental event-tokens may be different from “underlying” physical event-tokens, mental events are real phenomena that are realized by physical phenomena in special context- conditions.

1. Three Challenges

The so-called problem of mental causation as discussed in the recent literature raises three central challenges for an adequate solution from a physicalist perspective: the threat of epiphenomenalism, the problem of externalism (or the difÞ culty in accounting for the causal efÞ cacy of extrinsic mental properties) and the problem of causal exclusion (or the threat of overdetermination). Mental causation thus constitutes the core of the traditional mind-body problem which can be summarized as a trilemma or an apparent inconsistency between the following three claims (Bieri 1993, 5):

(i) Mental phenomena are not physical phenomena. (ii) There is mental causation. (iii) The physical world is causally closed: For every physical event, there is a sufÞ cient physical cause.1

All three claims are supported by strong intuitions: (Ad i) Mental states and processes, e.g. our feelings, emotions and perceptions, seem to be essentially different from all physical states and processes. (Ad ii) From the perspective of folk psychology, our beliefs, desires and intentions have causal effects in the physical world, this being a necessary condition for human agency. Furthermore, feelings and emotions also cause bodily states, e.g. someone blushes because he is embarrassed for making a mess. (Ad iii) It is a key methodological principle of physics that the world is causally closed. Science has thus far been rather successful in relying on this principle, and the alternatives, such as an interactionist dualism, clearly raise more problems than they resolve.2 However, unless we accept overdeterminism, we cannot simply hold all three claims at once, and the history of attempts to solve the problem of mental causation can be seen as the history of rejecting or at least strongly modifying one of the three. One possibility would be to give up claim (ii) and to deny that there is mental causation. This would be equivalent to holding some version of epiphenomenalism, according to which mental phenomena are causally irrelevant. Another possibility is to give up claim (iii), which would imply rejecting a leading methodological principle of science. Since these alternatives would constitute a

1. This interpretation of the closure of the physical world is held e.g. by Chalmers 1996, 125. Since we would not exclude the possibility of physical events without any causes, we have to add the qualiÞ cation that the principle is only held for physical events which have causes. This possibility is not discussed in this paper. 2. There is a dispute concerning the question as to whether the principle of causal closure is really a methodological principle of modern science (see Papineau 2001). Although difÞ cult to deÞ ne, for the purposes of this paper we maintain the position that the principle of causal closure is an adequate claim when discussing the problem of mental causation.

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