Since Leibniz's time, Cartesian mental causation has been criticized for violating the conservation of energy and momentum. Many dualist responses clearly fail. But conservation laws have important neglected features generally undermining the objection. Conservation is _local_, holding first not for the universe, but for everywhere separately. The energy in any volume changes only due to what flows through the boundaries. Constant total energy holds if the global summing-up of local conservation laws converges; it probably doesn't in reality. Energy conservation holds (...) if there is symmetry, the sameness of the laws over time. Thus, if there are time-places where symmetries fail due to nonphysical influence, conservation laws fail there and then, while holding elsewhere, such as refrigerators and stars. Noether's converse first theorem shows that conservation laws imply symmetries. Thus conservation trivially nearly entails the causal closure of the physical. But expecting conservation to hold in the brain simply assumes the falsehood of Cartesianism. Hence Leibniz's objection begs the question. Empirical neuroscience is another matter. So is Einstein's General Relativity: far from providing a loophole, General Relativity makes mental causation _harder_. (shrink)

John Locke discusses the notions of identity and diversity in Book 2, Chapter 27 of An Essay Concerning Human Understanding. At the beginning of this much-discussed chapter, Locke posits the place-time-kind principle. According to this principle, no two things of the same kind can be in the same place at the same time . Just what Locke means by this is unclear, however. So too is whether this principle causes problems for Locke, and whether these problems can be resolved. This (...) is significant because the place-time-kind principle is foundational to Locke's discussion of identity. Moreover, the place-time-kind principle stands at the center of a number of lively and long-standing debates in Locke scholarship. These include the debates over the ontological status of Lockean persons, and whether Locke is a relative identity theorist, to name just two. In this paper, I offer a survey of how Locke's place-time-kind principle has been interpreted in the secondary literature. The aim of this taxonomy is to clarify where the differences between competing interpretations lie, and additionally show just how challenging it is to determine which reading is best. (shrink)