The Journal of Philosophy

Does the global supervenience of one class on another entail reductionism, in the sense that any property in the former class is definable from properties in the latter class? This question appears to be at the same time formally tractable and philosophically significant. It seems formally tractable because the concepts involved are susceptible to rigorous definition. It is philosophically significant because in a number of debates about inter-level relationships, there are prima facie plausible positions that presuppose that there is no such entailment: standard versions of non-reductive physicalism and of normative non-naturalism accept global supervenience while rejecting reductionism. I identify a gap in an influential argument for the entailment, due to Frank Jackson and Robert Stalnaker, and draw on the model theory of infinitary languages to argue that some globally supervening properties are not reducible.

Groups are ubiquitous in our lives. But while some of them are highly structured and appear to support a shared intentionality and even a shared agency, others are much less cohesive and do not seem to demand much of their individual members. Queues, for example, seem to be, at a given time, nothing over and above some individuals as they exemplify a certain spatial arrangement. Indeed, the main aim of this paper is to develop the more general thought that at a given time, a group is nothing over and above some individual members as they exemplify a certain complex condition. The general conception of groups that emerges is able to accommodate a variety of constraints on a reasonable answer to the question of what are groups.