We can all attest to the fact that our thoughts, beliefs, attitudes, and volitions make a difference to what happens, but substantiating this claim with an explanation of how our minds are entitled to this causal status has not proved easy to achieve. The ontological constraints of physicalism have made it difficult to disentangle minds from brains and establish an autonomous role for mental activity within a physical world. In this book I examine two influential accounts of the mind/body relation that are situated within the physicalist ontology: Donald Davidson’s non-reductive ‘anomalous monism’ and Jaegwon Kim’s reductive ‘conditional physical reduction’. The lesson is that mental causation, qua mental, is unlikely to be adequately explained within a physicalist ontological picture, regardless of whether that picture is a reductive or non-reductive one. This book offers beneficial access to two important recent figures in the philosophy of mind and the relationships that exist between their respective doctrines.