Essays on Overdetermination

Abstract

I present a thorough metaphysics of causal overdetermination, which yields new insights into mental causation, our world's counterfactual structure, and properties of moral responsibility. I investigate causal overdetermination in three related papers.In "Overdetermination Underdetermined," I show that overdetermination has been underspecified in the literature, leading to a conflation of several important questions: (i) what is overdetermination?, (ii) is overdetermination physically possible, and if so, how ubiquitous is it?, and (iii) is overdetermination a problem?I diagnose the source of confusion as the following definition implicitly used in the literature:(OD) Causes c1 and c2 overdetermine an effect e if c1 and c2 are (i) distinct, (ii) they occur, and (iii) they are each sufficient to cause e in the way that it occurs.I hold that this is not in fact a definition, but a schema with several open definienda: distinctness, occurrence, causation, and precision in the way that the effect occurs. Different satisfiers yield different notions of overdetermination. Answers to the central questions regarding overdetermination are sensitive to the kinds of overdetermination in play. Once we are clear on what overdetermination is and to which sorts we are ontologically committed, we can also be clear on what is at stake for each debate--and it typically is not acceptance or denial of causal overdetermination per se.In "Overdetermination and Counterfactual Sensitivity," I show that the counterfactual structure of the world is richer than previously thought. I introduce a novel class of events that are insensitive to the additive force of multiple causes. They do not covary counterfactually with the multiplicity or force of their causes. They are to be contrasted with sensitive effects, which counterfactually covary according to the number and sorts of causes they have.In "Moral Overdetermination", I examine causal overdetermination in the context of moral responsibility. I use cases of moral overdetermination to introduce puzzles about the relationship between causal responsibility and moral responsibility that deserve further exploration. Along the way, I consider the instrumental value of various reductive theories of causation as guides to moral assessment, and I unearth interesting consequences for moral luck and for collective responsibility.