Philosophers and social scientists have recently turned to game theory and agent-based models to better understand social contract formation. The stag hunt game is an idealization of social contract formation. Using the stag hunt game, we attempt to determine what, if any, barrier diversity is to the formation of an efficient social contract. We uncover a deep connection between tolerance, diversity, and the social contract. We investigate a simple model in which individuals possess salient traits and behave cooperatively when the (...) difference between their trait and the trait of their counterpart is less than their ‘tolerance level’. If traits are fixed and correspond to permanent or semipermanent features of the individual, such as religion or race, social contract formation is a remote possibility. If traits are malleable, social contract formation is possible but comes at the steep cost of diversity and tolerance, that is, individuals are unwilling to cooperate with those much different from themselves. Yet homogeneity and intolerance are not a long-term feature of the population. Over time mutations allow for increasingly tolerant agents to prosper, thereby ushering in trait diversity. In the end, all reap the benefits of cooperation. (shrink)

Harsanyi defends utilitarianism by means of an axiomatic proof and by what he calls the 'equiprobability model'. Both justifications of utilitarianism aim to show that utilitarian ethics can be derived from Bayesian rationality and some weak moral constraints on the reasoning of rational agents. I argue that, from the perspective of Bayesian agents, one of these constraints, the impersonality constraint, is not weak at all if its meaning is made precise, and that generally, it even contradicts individual rational agency. Without (...) the impersonality constraint, Harsanyi's two justifications of utilitarianism on the grounds of Bayesian rationality fail. As an alternative, I develop a contractarian framework that is compatible with individual rational agency and Harsanyi's central assumptions, and that allows the derivation of moral conclusions on the grounds of Bayesian rationality. The developed framework offers a novel justification of contractarian ethics and may best be described as a combined version of Harsanyi's equiprobability model and Rawls's original position. (shrink)

Peter Vanderschraaf’s Strategic Justice is a powerful elaboration and defense of what he calls ‘justice as mutual advantage’. Vanderschraaf opens Strategic Justice by observing that ‘Plato set a template for all future philosophers by raising two interrelated questions: (1) What precisely is justice? (2) Why should one be just?’. He answers that (1) justice consists of conventions which (2) are followed because each sees that doing so is in her interest. These answers depend upon two conditions which Vanderschraaf calls Baseline (...) Consistency and Negative Mutual Expectations. I contend that the plausibility of the first condition depends upon principles which are prior to Vanderchraaf’s conventions of justice and that the second condition does not account for the interest Vanderschraaf must think we take in those principles. I therefore worry that Vanderschraaf does what he accuses other theorists of justice as mutual advantage of doing: going outside the bounds of justice as mutual advantage. To lay the groundwork for his conditions, Vanderschraaf analyzes the circumstances of justice. I argue that, his claims to the contrary notwithstanding, he does not take the circumstances to be the kind of conditions Hume takes them to be, but that he has good reason to do so. (shrink)

I reply to commentaries by Justin Bruner, Robert Sugden and Gerald Gaus. My response to Bruner focuses on conventions of bargaining problems and arguments for characterizing the just conventions of these problems as monotone path solutions. My response to Sugden focuses on how the laws of humanity present in Hume’s discussion of vulnerable individuals might be incorporated into my own proposed account of justice as mutual advantage. My response to Gaus focuses on whether or not my account of justice as (...) mutual advantage can incorporate deep differences in values across subgroups of a larger society. (shrink)

This book provides a systematic defense of moral contractarianism as a distinct approach to the social contract. It elucidates, in comparison to moral conventionalism and moral contractualism, the distinct features of moral contractarianism, its scope, and conceptual and practical challenges that concern the relationship between morality and self-interest, the problems of assurance and compliance, rule-following, counterfactualism, and the nexus between morals and politics. It argues that, if appropriately conceived, moral contractarianism is conceptually coherent, empirically sound, and practically relevant, and has (...) much to offer to contemporary moral philosophy. (shrink)

The author defends the ancient claim that justice is at bottom a body of social conventions. Recent analytical and empirical concepts and results from the social sciences together with insights and arguments of past masters of moral and political philosophy are integrated into a new game-theoretic conventionalist analysis of justice.

:Robert Nozick allegedly introduced his liberal theory of private ownership as an objection to theories of end-state justice. Nevertheless, we show that, in a stylized framework for the allocation of goods in joint ventures, both approaches can be seen as complementary. More precisely, in such a context, self-ownership followed by voluntary transfer can lead to end-state fairness. Furthermore, under a certain solidarity condition, the only way to achieve end-state fairness, following Nozick’s procedure, is to endorse an egalitarian rule for the (...) initial assignment of rights. (shrink)

Though the revised edition of A Theory of Justice, published in 1999, is the definitive statement of Rawls's view, so much of the extensive literature on Rawls's theory refers to the first edition. This reissue makes the first edition once again available for scholars and serious students of Rawls's work.

In this pithy and highly readable book, Brian Skyrms, a recognised authority on game and decision theory, investigates traditional problems of the social contract in terms of evolutionary dynamics. Game theory is skilfully employed to offer new interpretations of a wide variety of social phenomena, including justice, mutual aid, commitment, convention and meaning. The author eschews any grand, unified theory. Rather, he presents the reader with tools drawn from evolutionary game theory for the purpose of analysing and coming to understand (...) the social contract. The book is not technical and requires no special background knowledge. As such, it could be enjoyed by students and professionals in a wide range of disciplines: political science, philosophy, decision theory, economics and biology. (shrink)

To evaluate the overall good/welfare of any action, policy or institutional choice we need some way of comparing the benefits and losses to those affected: we need to make interpersonal comparisons of the good/welfare. Yet sceptics have worried either: that such comparisons are impossible as they involve an impossible introspection across individuals, getting ‘into their minds’; that they are indeterminate as individual-level information is compatible with a range of welfare numbers; or that they are metaphysically mysterious as they assume the (...) existence either of a social mind or of absolute levels of welfare when no such things exist. This article argues that such scepticism can potentially be addressed if we view the problem of interpersonal comparisons as fundamentally an epistemic problem – that is, as a problem of forming justified beliefs about the overall good based on evidence of the individual good. (shrink)

_ Convention_ was immediately recognized as a major contribution to the subject and its significance has remained undiminished since its first publication in 1969. Lewis analyzes social conventions as regularities in the resolution of recurring coordination problems-situations characterized by interdependent decision processes in which common interests are at stake. Conventions are contrasted with other kinds of regularity, and conventions governing systems of communication are given special attention.

In a recent article, McClennen (2012) defends an alternative bargaining theory in response to his criticisms of the standard Nash bargaining solution as a principle of distributive justice in the context of the social contract. McClennen rejects the orthodox concept of expected individual utility maximizing behavior that underlies the Nash bargaining model in favor of what he calls full rationality, and McClennen’s full cooperation bargaining theory demands that agents select the most egalitarian strictly Pareto-optimal distributional outcome that is strictly Pareto-superior (...) to the state of nature. I argue that McClennen’s full cooperators are best described as reasonable agents whose rationality is constrained by moral considerations and that McClennen’s bargaining theory is moralized in this regard. If, by contrast, the orthodox concept of rationality is assumed and plausible assumptions are made about human nature and social cooperation, then a modified version of the standard Nash bargaining solution, which I call the stabilized Nash bargaining solution (Moehler 2010), is justified. From the perspective of rational agents, the stabilized Nash bargaining solution can accommodate McClennen’s criticisms of the standard Nash bargaining solution in the context of the social contract and, for such agents, it can serve as a principle of distributive justice in deeply morally pluralistic societies. (shrink)

It is argued that the Nash bargaining solution cannot serve as a principle of distributive justice because (i) it cannot secure stable cooperation in repeated interactions and (ii) it cannot capture our moral intuitions concerning distributive questions. In this article, I propose a solution to the first problem by amending the Nash bargaining solution so that it can maintain stable cooperation among rational bargainers. I call the resulting principle the stabilized Nash bargaining solution. The principle defends justice in the form (...) 'each according to her basic needs and above this level according to her relative bargaining power'. In response to the second problem, I argue that the stabilized Nash bargaining solution can serve as a principle of distributive justice in certain situations where moral reasoning is reduced to instrumental reasoning. In particular, I argue that rational individuals would choose the stabilized Nash bargaining solution in Rawls' original position. (shrink)

A treatise of human nature, book 3: Of morale; preceded by selections from book 2: Of the passions.--An enquiry concerning the principles of morals.--Essays, moral and political; selections.

v. 1. Editorial introduction -- v. 2. The English and Latin texts (i) -- v. 3. The English and Latin texts (ii).

Winner of the 1975 National Book Award, this brilliant and widely acclaimed book is a powerful philosophical challenge to the most widely held political and social positions of our age--liberal, socialist, and conservative.

Is morality rational? In this book Gauthier argues that moral principles are principles of rational choice. He proposes a principle whereby choice is made on an agreed basis of cooperation, rather than according to what would give an individual the greatest expectation of value. He shows that such a principle not only ensures mutual benefit and fairness, thus satisfying the standards of morality, but also that each person may actually expect greater utility by adhering to morality, even though the choice (...) did not have that end primarily in view. In resolving what may appear to be a paradox, the author establishes morals on the firm foundation of reason. Gauthier's argument includes an account of value, linking it to preference and utility; a discussion of the curcumstances in which morality is unnecessary; and an application of morals by agreement to relations between peoples at different levels of development and different generations. Finally, he reflects on the assumptions about individuality and community made by his account of rationality and morality. (shrink)

Thomas Hobbes took a new look at the ways in which society should function, and he ended up formulating the concept of political science. His crowning achievement, Leviathan, remains among the greatest works in the history of ideas. Written during a moment in English history when the political and social structures as well as methods of science were in flux and open to interpretation, Leviathan played an essential role in the development of the modern world. This edition of Hobbes' landmark (...) work is based on the original text. It incorporates the author's own corrections and retains the period spelling and punctuation, offering both flavorful authenticity and the utmost clarity of expression. (shrink)

I propose a dynamical analysis of interaction in anarchy, and argue that this kind of dynamical analysis is a more promising route to predicting the outcome of anarchy than the more traditional a priori analyses of anarchy in the literature. I criticize previous a priori analyses of anarchy on the grounds that these analyses assume that the individuals in anarchy share a unique set of preferences over the possible outcomes of war, peace, exploiting others and suffering exploitation. Following Hobbes' classic (...) analysis of anarchy, I maintain that typically in anarchy some moderate individuals will most desire mutual cooperation while other dominators will most desire to exploit others' cooperation. I argue that once one allows for different types of individuals in anarchy, any a priori analysis of anarchy requires unrealistic assumptions regarding the agents' common knowledge of their situation. However, this move also suggests a dynamical analysis of anarchy, one that assumes no common knowledge. In the Variable Anticipation threshold model developed here, individuals modify their behavior as they learn from repeated interactions. I present specific instances of this model where the individuals in anarchy converge to different equilibria corresponding to either peace or war, depending on the initial conditions. I show that individuals are liable to converge to Hobbes' war of all against all even if only a small percentage of are dominators. The presence of only a few “nasty” individuals gradually drives all, including those inclined to be “nicer”, to imitate the “nasty” conduct of these few. This dynamic analysis suggests that the Hobbesian war in anarchy is indeed inevitable in most realistic circumstances. You have the same propension, that I have, in favor of what is contiguous above what is remote. You are, therefore, naturally carry'd to commit acts of injustice as well as I. Your example both pushes me forward in this way by imitation, and also affords me a new reason for any breach of equity, by showing me, that I shou'd be the cully of my integrity, if I alone shou'd impose on myself a severe restraint amidst the licentiousness of others. (David Hume, A Treatise of Human Nature) (Published Online July 11 2006) Footnotes1 Thanks to Luc Bovens, Sharon Lloyd, Brian Skyrms, Susanne Sreedhar and an anonymous referee for many helpful comments of early versions of this essay. (shrink)

This is a paperback edition of a major contribution to the field, first published in hard covers in 1977. The book outlines a general theory of rational behaviour consisting of individual decision theory, ethics, and game theory as its main branches. Decision theory deals with a rational pursuit of individual utility; ethics with a rational pursuit of the common interests of society; and game theory with an interaction of two or more rational individuals, each pursuing his own interests in a (...) rational manner. (shrink)

Very diverse societies pose real problems for Rawlsian models of public reason. This is for two reasons: first, public reason is unable accommodate diverse perspectives in determining a regulative ideal. Second, regulative ideals are unable to respond to social change. While models based on public reason focus on the justification of principles, this book suggests that we need to orient our normative theories more toward discovery and experimentation. The book develops a unique approach to social contract theory that focuses on (...) diverse perspectives. It offers a new moral stance that author Ryan Muldoon calls, "The View From Everywhere," which allows for substantive, fundamental moral disagreement. This stance is used to develop a bargaining model in which agents can cooperate despite seeing different perspectives. Rather than arguing for an ideal contract or particular principles of justice, Muldoon outlines a procedure for iterated revisions to the rules of a social contract. It expands Mill's conception of experiments in living to help form a foundational principle for social contract theory. By embracing this kind of experimentation, we move away from a conception of justice as an end state, and toward a conception of justice as a trajectory. (shrink)

Most moral and political theories require us to make interpersonal comparisons of welfare. This poses a challenge to the popular view that welfare consists in the satisfaction of preferences or des...

A Treatise of Human Nature, David Hume's comprehensive attempt to base philosophy on a new, observationally grounded study of human nature, is one of the most important texts in Western philosophy. It is also the focal point of current attempts to understand 18th-century western philosophy. The Treatise addresses many of the most fundamental philosophical issues: causation, existence, freedom and necessity, and morality. The volume also includes Humes own abstract of the Treatise, a substantial introduction, extensive annotations, a glossary, a comprehensive (...) index, and suggestions for further reading. (shrink)

Binmore argues that game theory provides a systematic tool for investigating ethical matters.

Employing the techniques of modern economic analysis, Professor Buchanan reveals the conceptual basis of an individual's social rights by examining the ...

In this article, I argue that if one closely follows Hobbes' line of reasoning in Leviathan, in particular his distinction between the second and the third law of nature, and the logic of his contractarian theory, then Hobbes' state of nature is best translated into the language of game theory by an assurance game, and not by a one-shot or iterated prisoner's dilemma game, nor by an assurance dilemma game. Further, I support Hobbes' conclusion that the sovereign must always punish (...) the Foole, and even exclude her from the cooperative framework or take her life, if she defects once society is established, which is best expressed in the language of game theory by a grim strategy. That is, compared to existing game-theoretic interpretations of Hobbes, I argue that the sovereign plays a grim strategy with the citizens once society is established, and not the individuals with one another in the state of nature. (shrink)

Natural Justice is a bold attempt to lay the foundations for a genuine science of morals using the theory of games. Since human morality is no less a product of evolution than any other human characteristic, the book takes the view that we need to explore its origins in the food-sharing social contracts of our prehuman ancestors. It is argued that the deep structure of our current fairness norms continues to reflect the logic of these primeval social contracts, but the (...) particular fairness norm a society operates is largely a product of cultural evolution. In pursuing this point, the book proposes a naturalistic reinterpretation of John Rawls' original position that reconciles his egalitarian theory of justice with John Harsanyi's utilitarian theory by identifying the environment appropriate to each. (shrink)

It is widely held that Bayesian decision theory is the final word on how a rational person should make decisions. However, Leonard Savage--the inventor of Bayesian decision theory--argued that it would be ridiculous to use his theory outside the kind of small world in which it is always possible to "look before you leap." If taken seriously, this view makes Bayesian decision theory inappropriate for the large worlds of scientific discovery and macroeconomic enterprise. When is it correct to use Bayesian (...) decision theory--and when does it need to be modified? Using a minimum of mathematics, Rational Decisions clearly explains the foundations of Bayesian decision theory and shows why Savage restricted the theory's application to small worlds. The book is a wide-ranging exploration of standard theories of choice and belief under risk and uncertainty. Ken Binmore discusses the various philosophical attitudes related to the nature of probability and offers resolutions to paradoxes believed to hinder further progress. In arguing that the Bayesian approach to knowledge is inadequate in a large world, Binmore proposes an extension to Bayesian decision theory--allowing the idea of a mixed strategy in game theory to be expanded to a larger set of what Binmore refers to as "muddled" strategies. Written by one of the world's leading game theorists, Rational Decisions is the touchstone for anyone needing a concise, accessible, and expert view on Bayesian decision making. (shrink)

Brian Skyrms, author of the successful Evolution of the Social Contract has written a sequel. The book is a study of ideas of cooperation and collective action. The point of departure is a prototypical story found in Rousseau's A Discourse on Inequality. Rousseau contrasts the pay-off of hunting hare where the risk of non-cooperation is small but the reward is equally small, against the pay-off of hunting the stag where maximum cooperation is required but where the reward is so much (...) greater. Thus, rational agents are pulled in one direction by considerations of risk and in another by considerations of mutual benefit. Written with Skyrms's characteristic clarity and verve, this intriguing book will be eagerly sought out by students and professionals in philosophy, political science, economics, sociology and evolutionary biology. (shrink)

Brian Skyrms applies adaptive dynamics (of cultural evolution and individual learning) to social theory, investigating altruism, spite, fairness, trust, division of labor, and signaling. Correlation is seen to be fundamental. Spontaneous emergence of social structure and of signaling systems are examined in the context of learning dynamics.

Peter Vanderschraaf’s Strategic Justice provides a defense of the egalitarian bargaining solution. Vanderschraaf’s discussion of the egalitarian solution invokes three arguments typically given to support the Nash bargaining solution. Overall, we reinforce Vanderschraaf’s criticism of arguments in favor of the Nash solution and point to potential weaknesses in Vanderschraaf’s positive case for the egalitarian solution.

This book develops a novel multilevel social contract theory that, in contrast to existing theories in the liberal tradition, does not merely assume a restricted form of reasonable moral pluralism, but is tailored to the conditions of deeply morally pluralistic societies which may be populated by liberal moral agents, nonliberal moral agents, and, according to the traditional understanding of morality, nonmoral agents alike. The book draws on the history of the social contract tradition, especially the work of Hobbes, Hume, Kant, (...) Rawls, and Gauthier, as well as on the work of some of the critics of this tradition, such as Sen and Gaus. The two-level contractarian theory holds that morality in its best contractarian version for the conditions of deeply morally pluralistic societies entails Humean, Hobbesian, and Kantian moral properties. The theory defines the minimal behavioral restrictions that are necessary to ensure, compared to violent conflict resolution, mutually beneficial peaceful long-term cooperation in deeply morally pluralistic societies. The theory minimizes the problem of compliance for morally diverse societies by maximally respecting the interests of all members of society. Despite its ideal nature, the theory is, in principle, applicable to the real world and, for the conditions described, most promising for securing mutually beneficial peaceful long-term cooperation in a world in which a fully just society, due to moral diversity, is unattainable. If Rawls’ intention was to carry the traditional social contract argument to a higher level of abstraction, then the two-level contractarian theory brings it back down to earth. (shrink)

Public reason theories are characterized by three conditions: constructivism, representation, and stability. Constructivism holds that justification does not rely on any antecedent moral or political values outside of the procedure of agreement. Representation holds that the reasons for the choice in the model must be rationally explicable to real agents outside the model. Stability holds that the principles chosen in the procedure should be stable upon reflection, especially in the face of diversity in a pluralistic society. Choice procedures that involve (...) at least two-stages with different information, as Rawls’s theory does, will be path-dependent and not meet the condition of representation since it will not be globally coherent. Attempts to solve this problem without eliminating the segmentation of choice in the procedure will run afoul of constructivism or stability. This problem is instructive because it highlights how public reason theories must evolve in the face of increased concerns about diversity. (shrink)

If some external enforcement agency compels us to honor deals reached in the original position, then Harsanyi has shown that the outcome will be utilitarian. Under the same hypotheses, Rawls claims that the outcome will be egalitarian. This chapter confirms that Harsanyi is correct. It goes on to use the concept of an empathy equilibrium to predict the standard of interpersonal comparison needed to operate a utilitarian norm that will evolve in the medium run.

This paper builds upon, but substantially revises, John Harsanyi's concept of ‘extended preferences’. An individual ‘history’ is a possible life that some person (a subject) might lead. Harsanyi supposes that a given spectator, formulating her ethical preferences, can rank histories by empathetic projection: putting herself ‘in the shoes’ of various subjects. Harsanyi then suggests that interpersonal comparisons be derived from the utility function representing spectators’ (supposedly common) ranking of history lotteries. Unfortunately, Harsanyi's proposal has various flaws, including some that have (...) hitherto escaped scholarly attention. In particular, it ignores the limits of personal identity. If the subject has welfare-relevant attributes that the spectator cannot acquire without changing who she is, full empathetic identification of the latter with the former becomes impossible. This paper proposes instead to usesympathyas the attitude on a spectator's part that allows us to make sense of her extended preferences. Sympathy – an attitude of care and concern – is a psychological state quite different from empathy. We should also allow for hetereogeneity in spectators’ extended preferences. Interpersonal comparisons emerge from a plurality of sympathetic spectators, not (as per Harsanyi) from a common empathetic ranking. (shrink)