Group Membership
Chapter 11 is concerned with the nature of the membership relation relevant to sorting agents under the concept of a mob or organization and the nature of groups organized under such relations. First, it develops a taxonomy of different sorts of groups, distinguishing natural groups, institutions or organizations, and mobs and crowds. Second, it provides an account of membership in institutions, the key idea of which is that membership is a matter of having a determinable status role characterized by the nature of the relevant institution. Third, it takes up a counting puzzle connected with the reductive view of organizations. If an organization at a time is nothing but its members, then two clubs with the same members are the same, but this seems counterintuitive. Finally, it gives an analysis of membership specifically in mobs and crowds.