Abstract Orthodox decision theory presupposes that agency is invested in individuals. An opposing literature allows team agency to be invested in teams whose members use distinctive modes of team reasoning. This paper offers a new conceptual framework, inspired by David Lewis's analysis of common reasons for belief, within which team reasoning can be represented. It shows how individuals can independently endorse a principle of team reasoning which prescribes acting as a team member conditional on assurance that others have endorsed the (...) same principle. It argues that there can be such assurance even when no individual has an obligation to act on team reasoning. *This paper originated in a lecture that I gave at a Colloquium on Collective Intentions at Erasmus University Rotterdam. I thank participants, and particularly Govert den Hartogh, for comments. The analysis presented in this paper is an offshoot of a larger project, which uses David Lewis's work as the starting point for a reconstruction of the foundations of game theory. That project is joint work with Robin Cubitt. The specific idea of using this approach to analyse team reasoning grew out of a discussion with Michael Bratman. My work was supported by the Leverhulme Trust. (shrink)

For most of the problems that economists consider, the assumption that agents are self-interested works well enough, generating predictions that are broadly consistent with observation. In some significant cases, however, we find economic behavior that seems to be inconsistent with self-interest. In particular, we find that some public goods and some charitable ventures are financed by the independent voluntary contributions of many thousands of individuals. In Britain, for example, the lifeboat service is entirely financed by voluntary contributions. In all rich (...) countries, charitable appeals raise large amounts of money for famine relief in the Third World. The willingness of individuals to contribute to such projects is an economic fact that requires an explanation. (shrink)

Hurley here revives a classical idea about rationality in a modern framework, by developing analogies between the structure of personality and the structure of society in the context of contemporary work in philosophy of mind, ethics, decision theory and social choice theory. The book examines the rationality of decisions and actions, and illustrates the continuity of philosophy of mind on the one hand, and ethics and jurisprudence on the other. A major thesis of the book is that arguments drawn from (...) the philosophy of mind may be used to undermine widely-held subjectivist positions in ethics and politico-economic theory. The work is inspired by the philosophies of Wittgenstein and Davidson, but goes on to connect their arguments about interpretation with formal work in decision theory and social choice theory, and with the theory of adjudication. (shrink)

Some philosophers hold that trust grows fragile when people become too rational. They advocate a retreat from reason and a return to local, traditional values. Others hold that truly rational people are both trusting and trustworthy. Everything hinges on what we mean by 'reason' and 'rational'. If these are understood in an egocentric, instrumental fashion, then they are indeed incompatible with trust. With the help of game theory, Martin Hollis argues against that narrow definition and in favour of a richer, (...) deeper notion of reason founded on reciprocity and the pursuit of the common good. Within that framework he reconstructs the Enlightenment idea of citizens of the world, rationally encountering, and at the same time finding their identity in, their multiple commitments to communities both local and universal. (shrink)

A framing effect occurs when an agent's choices are not invariant under changes in the way a decision problem is presented, e.g. changes in the way options are described (violation of description invariance) or preferences are elicited (violation of procedure invariance). Here we identify those rationality violations that underlie framing effects. We attribute to the agent a sequential decision process in which a “target” proposition and several “background” propositions are considered. We suggest that the agent exhibits a framing effect if (...) and only if two conditions are met. First, different presentations of the decision problem lead the agent to consider the propositions in a different order (the empirical condition). Second, different such “decision paths” lead to different decisions on the target proposition (the logical condition). The second condition holds when the agent's initial dispositions on the propositions are “implicitly inconsistent,” which may be caused by violations of “deductive closure.” Our account is consistent with some observations made by psychologists and provides a unified framework for explaining violations of description and procedure invariance. (shrink)

This book offers original accounts of a number of central social phenomena, many of which have received little if any prior philosophical attention. These phenomena include social groups, group languages, acting together, collective belief, mutual recognition, and social convention. In the course of developing her analyses Gilbert discusses the work of Emile Durkheim, Georg Simmel, Max Weber, David Lewis, among others.

David Lewis is widely credited with the first formulation of common knowledge and the first rigorous analysis of convention. However, common knowledge and convention entered mainstream game theory only when they were formulated, later and independently, by other theorists. As a result, some of the most distinctive and valuable features of Lewis' game theory have been overlooked. We re-examine this theory by reconstructing key parts in a more formal way, extending it, and showing how it differs from more recent game (...) theory. In contrast to current theories of common knowledge, Lewis' theory is based on an explicit analysis of the modes of reasoning that are accessible to rational individuals and so can be used to analyse the genesis of common knowledge. Lewis' analysis of convention emphasises the role of inductive reasoning and of salience in the maintenance of conventions over time. Footnotes Earlier versions of this paper were presented at the 13th Amsterdam Colloquium at the University of Amsterdam, at a workshop on social norms at Wissenschaftskolleg zu Berlin, and at seminars at Tilburg University and the University of Bristol. We are grateful for comments from participants at those meetings, from two anonymous referees, and from Michael Bacharach, Nick Bardsley, Cristina Bicchieri, Luc Bovens, Simon Grant, David McCarthy, Shepley Orr, Brian Skyrms, Peter Vanderschraaf, Peter Wakker and Jörgen Weibull. Robert Sugden's work was supported by the Leverhulme Trust. (shrink)

Philosophers and economists write about collective action from distinct but related points of view. This paper aims to bridge these perspectives. Economists have been concerned with rationality in a strategic context. There, problems posed by “coordination games” seem to point to a form of rational action, “team thinking,” which is not individualistic. Philosophers’ analyses of collective intention, however, sometimes reduce collective action to a set of individually instrumental actions. They do not, therefore, capture the first person plural perspective characteristic of (...) team thinking. Other analyses, problematically, depict intentions ranging over others’ actions. I offer an analysis of collective intention which avoids these problems. A collective intention aims only at causing an individual action, but its propositional content stipulates its mirroring in other minds. (shrink)

Some philosophers hold that trust grows fragile when people become too rational. They advocate a retreat from reason and a return to local, traditional values. Others hold that truly rational people are both trusting and trustworthy. Everything hinges on what we mean by 'reason' and 'rational'. If these are understood in an egocentric, instrumental fashion, then they are indeed incompatible with trust. With the help of game theory, Martin Hollis argues against that narrow definition and in favour of a richer, (...) deeper notion of reason founded on reciprocity and the pursuit of the common good. Within that framework he reconstructs the Enlightenment idea of citizens of the world, rationally encountering, and at the same time finding their identity in, their multiple commitments to communities both local and universal. (shrink)

This is a revision of game theory which takes account of agents' own descriptions of their situations, and which allows people to reason as members of groups.