Margaret Patricia Gilbert

May social unity - the unity of a society or social group - be a matter of sharing values? Political philosophers disagree on this topic. Kymlicka answers: No. Devlin and Rawls answer: Yes. It is argued that given one common 'summative' account of sharing values a negative answer is correct. A positive answer is correct, however, given the plural subject account of sharing values. Given this account, those who share values are unified in a substantial way by their participation in a joint commitment. Some consequences of such sharing of values for the liberty of the people involved are noted.

Philosophers using game-theoretical models of human interactions have, I argue, often overestimated what sheer rationality can achieve. (References are made to David Gauthier, David Lewis, and others.) In particular I argue that in coordination problems rational agents will not necessarily reach a unique outcome that is most preferred by all, nor a unique 'coordination equilibrium' (Lewis), nor a unique Nash equilibrium. Nor are things helped by the addition of a successful precedent, or by common knowledge of generally accepted personal principles. Commitments like those generated by agreements may be necessary for rational expectations to arise. Social conventions, construed as group principles (following the analysis in my book On Social Facts), would suffice for this task.

Different accounts of what it is for something to have a social nature have been given. Sociality does not appear to be a category worthy of philosophical focus, given some of these accounts. If sociality is construed as plural subjecthood, it emerges as a category crucial for our understanding of the human condition. Plural subjects are constituted by a joint commitment of two or more persons to do something as a body. Such commitments generate rights and obligations of a special type, and underlie such phenomena as social conventions, agreements, shared action and social groups on one standard understanding of what these are.

Among other things, this paper considers what so-called collective guilt feelings amount to. If collective guilt feelings are sometimes appropriate, it must be the case that collectives can indeed be guilty. The paper begins with an account of what it is for a collective to intend to do something and to act in light of that intention. An account of collective guilt in terms of membership guilt feelings is found wanting. Finally, a "plural subject" account of collective guilt feelings is articulated, such that they involve a joint commitment to feel guilt as a body.

Collective action is interpreted as a matter of people doing something together, and it is assumed that this involves their having a collective intention to do that thing together. The account of collective intention for which the author has argued elsewhere is presented. In terms that are explained, the parties are jointly committed to intend as a body that such-and-such. Collective action problems in the sense of rational choice theory—problems such as the various forms of coordination problem and the prisoner’s dilemma—are then considered. An explanation is given of how, when such a problem is interpreted in terms of the parties’ inclinations, a suitable collective intention resolves the problem for agents who are rational in a broad sense other than the technical sense of game theory. Key Words: rationality • collective action • collective intention • joint commitment.

What is it for a group to believe something? A summative account assumes that for a group to believe that p most members of the group must believe that p. Accounts of this type are commonly proposed in interpretation of everyday ascriptions of beliefs to groups. I argue that a nonsummative account corresponds better to our unexamined understanding of such ascriptions. In particular I propose what I refer to as the joint acceptance model of group belief. I argue that group beliefs according to the joint acceptance model are important phenomena whose aetiology and development require investigation. There is an analogous phenomenon of social or group preference, which social choice theory tends to ignore.

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

This article will compare and contrast two very different accounts of convention: the game-theoretical account of Lewis in Convention, and the account initially proposed by Margaret Gilbert (the present author) in chapter six of On Social Facts, and further elaborated here. Gilbert’s account is not a variant of Lewis’s. It was arrived at in part as the result of a detailed critique of Lewis’s account in relation to a central everyday concept of a social convention. An account of convention need not be judged by that standard. Perhaps it reveals the nature of an important phenomenon. Looked at in that light, these very different accounts are not incompatible. Indeed, neither should be ignored if one is seeking to understand the way in which human beings arrive at some degree of social order.