Panpsychism is the view that every concrete and unified thing has some form of phenomenal consciousness or experience. It is an age-old doctrine, which, to the surprise of many, has recently taken on new life. In philosophy of mind, it has been put forth as a simple and radical solution to the mind–body problem (Chalmers 1996, 2003;Strawson 2006; Nagel 1979, 2012). In metaphysics and philosophy of science, it has been put forth as a solution to the problem of accounting for (...) the intrinsic nature of the physical itself (Strawson 2006, Seager 2006). In this thesis, I show that panpsychism can also be defended on the basis of an argument from our (arguable) acquaintance with the nature of causation in agency. This argument has made frequent appearances throughout the history of philosophy, with philosophers such as Leibniz, Schopenhauer and James, and I construct and defend an updated version of it. Furthermore, I offer a solution to the combination problem: how can complex (human and animal-type) consciousness result from simple (fundamental particle-type) consciousness? This is generally regarded as the most serious problem facing contemporary panpsychism. I propose that mental combination can be construed as kind causal process culminating in a fusion, and show how this avoids the main difficulties with accounting for mental combination. (shrink)