Causal Overdetermination and Modal Compatibilism

Compatibilists respond to the problem of causal exclusion for nonreductive physicalism by rejecting the exclusionist's ban on overdetermination. By the compatibilist's lights there are two forms of overdetermination, one that's problematic and another that is entirely benign. Furthermore, multiple causation by "tightly related" causes requires only the benign form of overdetermination. Call this the tight relation strategy for avoiding problematic forms of overdetermination. To justify the tight relation strategy, modal compatibilists appeal to a widely accepted counterfactual test. The argument of this paper is that the counterfactual test fails to legitimize the tight relation strategy as it fails to adequately distinguish between problematic and benign overdetermination. Contrary to modal compatibilists, modal dependence does not suffice for benignity. I conclude by arguing that adequately addressing overdetermination worries requires a much heavier metaphysical burden than modal compatibilists have typically recognized.