Priority Monism, Dependence, and Fundamentality

Priority monism (PM) is roughly the view that the universe is the only fundamental object, that is, a concrete object that does not depend on any other concrete object. Schaffer, the main advocate of PM, claims that PM is compatible with dependence having two different directions: from parts to wholes for subcosmic wholes, and from whole to parts for the cosmic whole. Recently it has been argued that this position is untenable. Given plausible assumptions about dependence, PM entails that dependence has only one direction, it always goes from wholes to parts. One such plausible assumption is a principle of Isolation. I argue that, given all extant accounts of dependence on the market, PM entails No Isolation. The argument depends upon a particular feature of the dependence relation, namely, necessitation and its direction. In the light of this, I contend that the argument is important, insofar as it suggests that we should distinguish dependence from other cognate notions, e.g. grounding. Once this distinction is made, I suggest we should also distinguish between two different notions of fundamentality that might turn out to be not-coextensive.