Pain is not a natural kind

Pain is central to our lives. Despite that, I argue, pain is not a natural kind. Chapter 1 identifies a kind as natural insofar as it is usefully referred to in the generalizations of the relevant science(s). Following Boyd, I take the best indicator of this to be causally interlinked clusters of properties, and I update Boyd's approach by relating it to recent work on mechanistic explanation. Chapter 2 employs clinical observations to argue that philosophical, unitary accounts of pain are inadequate. Pain is a multidimensional experience that paradigmatically includes sensation, perception, emotion, cognition, and motivational responses. This multidimensionality is included in the dominant scientific models of pain to which I turn in Chapter 3, but none identify a mechanism (neurobiological or otherwise) underlying the usual co-occurrence of pain's clustering properties. Chapter 4 argues that recent research attempting mechanism-based classifications of pain types allows us to conclude that each token pain is determined by an idiosyncratic convergence of the activity of multiple mechanisms. Neither pain nor any type of pain is a natural kind.;Once it is established that a folk kind is not natural, it is customary to become an eliminativist or a pluralist; I resist both options and offer an alternative. Chapter 5 characterizes pluralism as the position that the mechanical heterogeneity of a kind does not undermine its naturalness---either because there is homogeneity at another level, or because the heterogeneity is negligible relative to the target phenomenon. I argue against both options. In the final chapter, I argue that pains are very real despite their non-naturalness; eliminativism should be resisted. The idiosyncrasy argued to subvert scientific generalizations mentioning pain does not disrupt utile reference to pain in everyday life. Neither does idiosyncrasy entail non-existence. The dissertation as a whole may then be considered a case study of a robust and important folk-psychological kind that scientific inquiry reveals is not natural.