Overdetermination, Counterfactuals, and Mental Causation
Authors: Won Chiwook 
Published: April 2014

The overdetermination problem has long been raised as a challenge to nonreductive physicalism. Nonreductive physicalists have, in various ways, tried to resolve the problem through appeal to counterfactuals. This essay does two things. First, it takes up the question whether counterfactuals can yield an appropriate notion of causal redundancy and argues for a negative answer. Second, it examines how this issue bears on the mental causation debate. In particular, it considers the argument that the overdetermination problem simply does not arise on a dependency conception of causation and shows why this idea, though initially appealing, does not address the real problem. As the essay shows, the idea derives its spurious plausibility from the fact that the dependency conception cannot even make sense of our pretheoretic idea of causal redundancy. The essay concludes by briefly discussing a possible picture of mental causation that suggests itself in light of these results.

The overdetermination problem has long been raised as a challenge to nonreductive physicalism. The problem is that a nonreductive physicalist view of mind seems to make every case of mental causation a case of overdetermination. Nonreductive physicalists have, in various ways, tried to resolve the problem through appeal to counterfactuals. In this essay, I take up the question whether counterfactuals can yield an appropriate notion of causal redundancy and examine how this issue bears on the mental causation debate. In particular, I'll be discussing whether, or to what extent, the overdetermination problem turns on particular conceptions of causation.

The essay falls into two parts. In the first half (sections 1–2), after briefly presenting the overdetermination problem in section 1, I address the question whether counterfactuals can capture the notion of overdetermination and argue in section 2 for a negative answer. First, I consider David Lewis's (1986) and Jonathan Schaffer's (2003) definitions of overdetermination, and possible revisions to them, and show that the conditions they specify are neither necessary nor sufficient for overdetermination. I then argue that counterfactual analyses of overdetermination face the same kinds of problems as counterfactual analyses of causation and show that the source of these problems is that counterfactual analyses of overdetermination—just as those of causation—cannot accommodate the intuitive idea that causation is an intrinsic relation between events.

The second half (sections 3–4) explores the implications of these observations for the mental causation problem. In section 3, I first argue that the attempt of Karen Bennett (2003, 2008) and similar attempts to resolve the overdetermination problem by invoking counterfactuals rest on a false premise, and then respond to the argument that the overdetermination problem simply does not arise on a dependency conception of causation (e.g., Burge 1993; Loewer 2002, 2007). I show why this idea, though initially appealing, does not address the real problem. As we will see, the idea derives its spurious plausibility from the fact that the dependency conception cannot make sense of our pretheoretic idea of causal redundancy. This means that the overdetermination problem cannot even be coherently stated on the dependency approach, revealing that counterfactual talk about causation is expressively impoverished. I conclude in section 4 by briefly discussing a possible picture of mental causation that suggests itself in light of these results.