Jessica M. Wilson

The physicalist thesis that all entities are nothing over and above physical entities is often interpreted as appealing to a supervenience-based account of "nothing over and aboveness”, where, schematically, the A-entities are nothing over and above the B-entities if the A-entities supervene on the B-entities. The main approaches to filling in this schema correspond to different ways of characterizing the modal strength, the supervenience base, or the supervenience connection at issue. I consider each approach in turn, and argue that the resulting formulation of physicalism is compatible with physicalism’s best traditional rival: a naturalist emergentism. Others have argued that supervenience-based formulations of physicalism fail. My aim here, besides addressing the full spectrum of supervenience-based approaches, is to show how certain philosophical and scientific theses concerning naturalism, properties, and laws give us new reasons to think that supervenience-based formulations of physicalism are untenable.

Arguably no concept is more fundamental to science than that of causality, for investigations into cases of existence, persistence, and change in the natural world are largely investigations into the causes of these phenomena. Yet the metaphysics and epistemology of causality remain unclear. For example, the ontological categories of the causal relata have been taken to be objects (Hume 1739), events (Davidson 1967), properties (Armstrong 1978), processes (Salmon 1984), variables (Hitchcock 1993), and facts (Mellor 1995). (For convenience, causes and effects will usually be understood as events in what follows.) Complicating matters, causal relations may be singular (Socrates’s drinking hemlock caused Socrates’s death) or general (Drinking hemlock causes death); hence the relata might be tokens (e.g., instances of properties) or types (e.g., types of events) of the category in question. Other questions up for grabs are: Are singular causes metaphysically and/or epistemologically prior to general causes or vice versa (or neither)? What grounds the intuitive asymmetry of the causal relation? Are macro-causal relations reducible to micro-causal relations? And perhaps most importantly: Are causal facts (e.g., the holding of causal relations) reducible to non-causal facts (e.g., the holding of certain spatiotemporal relations)?

Why believe Hume's Dictum, according to which there are, roughly speaking, no necessary connections between wholly distinct entities? Schaffer suggests that HD, at least as applied to causal or nomological connections, is motivated as required by the best account of of counterfactuals---namely, a similarity-based possible worlds account, where the operative notion of similarity requires 'miracles'---more specifically, worlds where entities of the same type that actually exist enter into different laws. The main cited motivations for such an account of similarity are first, that some salient contexts presuppose CF asymmetry, and second, that accounts of CFs failing to presuppose CF asymmetry are epistemologically problematic, such that under conditions of determinism, the variations in initial micro-conditions needed to implement a given counterfactual antecedent would result in so many changes to macro-states that evaluation of CFs would be rendered practically impossible. Against the first reason, I argue that no non-artificial contexts presuppose CF asymmetry; against the second, I observe that such micro-variation is compatible, in principle, with significant similarity as regards macroscopic states of affairs---enough, in particular, to allow CFs to be appropriately evaluated

Physicalism is the thesis that all entities are nothing over and above physical entities. Here I investigate into whether and how physicalism might be formulated so as to substantively contrast with its best traditional rivals---including and especially emergentism. Formulating physicalism requires making sense of both the physical/non-physical distinction and the nothing/something over and above distinction. It has been argued that no distinction between the physical and the non-physical exists, that can serve as the basis for a sub stantive physicalism. But such arguments miss the mark, for participants to the physicalism debates do not disagree about the boundary of the physical, which, while roughly drawn is clear enough for debate to proceed. Rather, participants disagree on whether there are any entities over and above those entities they agree are physical. Hence the viability of physicalism primarily depends on the over and above distinction. ;I argue that existing accounts of over and aboveness are inadequate, for the key class of cases where two properties are instanced in a single subject, and one property is supposed to necessitate the other, with at least nomological necessity. I go on to provide an adequate account of over and aboveness, by reference to the notion of a fundamental force . We can formulate physicalism and emergentism using Force-relative Over and Aboveness: according to physicalism, all causal powers bestowed by all properties are grounded only in fundamental physical forces; according to emergentism, some causal powers are grounded in a new fundamental force, different from any physical force. ;Understanding over and aboveness as involving fundamental forces is not new. But arguments against forces have lately been accepted; hence the notable absence of forces from contemporary philosophizing. I distinguish two uses of 'force', and show that these arguments do not tell against fundamental forces. I then give positive arguments for admitting fundamental forces, stemming from the reasonable hypothesis that fundamental forces are collections of interacting fields. Forces, so understood, are ontologically defensible; and thus can serve as the needed basis for formulating physicalism and emergentism