The recent literature on mental causation has not been kind to nonreductive, materialist functionalism (‘functionalism’, hereafter, except where that term is otherwise qualified). The exclusion problem2 has done much of the damage, but the epiphenomenalist threat has taken other forms. Functionalism also faces what I will call the ‘problem of metaphysically necessary effects’ (Block, 1990, pp. 157-60, Antony and Levine, 1997, pp. 91-92, Pereboom, 2002, p. 515, Millikan, 1999, p. 47, Jackson, 1998, pp. 660-61). Functionalist mental properties are individuated partly (...) by their relation to the very effects those properties’ instantiations are thought to cause. Consequently, functionalist causal generalizations would seem to have the following problematical structure: The state of being, among other things, a cause of e (under such-andsuch conditions) causes e (under those conditions).3 The connection asserted lacks the contingency one would expect of a causal generalization. Mental states of the kind in question are, by metaphysical necessity, causes of e; any state that does not cause e is thereby a different kind of state. Yet, a mental state’s being the sort of state it is must play some causal role if functionalism is to account for mental causation.4 In what follows, I first articulate more fully the problem of metaphysically necessary effects. I then criticize three functionalist attempts to solve the problem directly. Given the failure of functionalist efforts to meet the problem head-on, I consider less direct strategies: these involve formulating functionalism or its causal claims in such a way that they appear not to generate the problem of metaphysically necessary effects. I argue against these indirect solutions, in each case concluding either that the problem still arises or that avoiding it requires the adoption of an unorthodox form of functionalism (itself a surprising result). In the final.. (shrink)

Given their physical realization, what causal work is left for functional properties to do? Humean solutions to the exclusion problem (e.g. overdetermination and difference-making) typically appeal to counterfactual and/or nomic relations between functional property-instances and behavioural effects, tacitly assuming that such relations suffice for causal work. Clarification of the notion of causal work, I argue, shows not only that such solutions don't work, but also reveals a novel solution to the exclusion problem based on the relations between dispositional properties at (...) different levels of mechanism, which involves three central claims: (i) the causal work of properties consists in grounding dispositions, (ii) functional properties are dispositions, and (iii) the dispositions of mechanisms are grounded in the dispositions of their components. Treating functional mental properties as dispositions of components in psychological mechanisms, I argue that such properties do the causal work of grounding agent-level dispositions. These dispositions, while ultimately grounded in the physical realizers of mental properties, are indirectly so grounded, through a hierarchy of grounding relations that extends upwards, of necessity, through the mental domain. (shrink)