The everyday concept of a social group is approached by examining the concept of going for a walk together, an example of doing something together, or "shared action". Two analyses requiring shared personal goals are rejected, since they fail to explain how people walking together have obligations and rights to appropriate behavior, and corresponding rights of rebuke. An alternative account is proposed: those who walk together must constitute the "plural subject" of a goal. The nature of plural subjecthood, the thesis (...) that social groups are plural subjects, and the relation of these ideas to Rousseau's and Hobbes 's, are briefly explored. (shrink)