Abstract: In this paper I argue for a view of groups, things like teams, committees, clubs and courts. I begin by examining features all groups seem to share. I formulate a list of six features of groups that serve as criteria any adequate theory of groups must capture. Next, I examine four of the most prominent views of groups currently on offer – that groups are non-singular pluralities, fusions, aggregates and sets. I argue that each fails to capture one or more of the criteria. Last, I develop a view of groups as realizations of structures. The view has two components. First, groups are entities with structure. Second, since groups are concreta, they exist only when a group structure is realized. A structure is realized when each of its functionally defined nodes or places are occupied. I show how such a view captures the six criteria for groups, which no other view of groups adequately does, while offering a substantive answer to the question, ‘What are groups?’
Comment: The paper is ideal as an introduction to the ontology of groups and a good example for social metaphysics in general. It includes an easy to follow discussion of difference features of groups and accounts that aim to capture these features. The paper is especially well suited as part of an introductory metaphysics courses, but can also work as an introductory text in a course on social metaphysics.