Reasoning about equilibria in normal form games involves the study of players’ incentives to deviate unilaterally from any profile. In the case of large anonymous games, the pattern of reasoning is different. Payoffs are determined by strategy distributions rather than strategy profiles. In such a game each player would strategise based on expectations of what fraction of the population makes some choice, rather than respond to individual choices by other players. A player may not even know how many players there (...) are in the game. Logicising such strategisation involves many challenges as the set of players is potentially unbounded. This suggests a logic of quantification over player variables and modalities for player deviation, but such a logic is easily seen to be undecidable. Instead, we propose a propositional modal logic using player types as names and implicit quantification over players. With modalities for player deviation and transitive closure, the logic can be used to specify game equilibrium and interesting patterns of reasoning in large games. We show that the logic is decidable and present a complete axiomatisation of the valid formulas. (shrink)

We study term modal logics, where modalities can be indexed by variables that can be quantified over. We suggest that these logics are appropriate for reasoning about systems of unboundedly many reasoners and define a notion of bisimulation which preserves propositional fragment of term modal logics. Also we show that the propositional fragment is already undecidable but that its monodic fragment is decidable, and expressive enough to include interesting assertions.

Preface of Festschrift on the occasion of Professor Rohit Parikh's 60th birthday.

In large anonymous games, payoffs are determined by strategy distributions rather than strategy profiles. If half the players choose a strategy a, all of them get a certain payoff, whereas if only one-third of the players choose that strategy, the players choosing may get a different payoff. Strategizing in such a game by a player involves reasoning about not who does what but what fraction of the population makes the same choice as that player.We present a simple modal logic to (...) reason about such strategization in large games. Since actual numbers are irrelevant, a player need not even know how many others are in the game, thus leading to the consideration of games with unboundedly many players. The logic we consider is the propositional modal fragment of a first order modal logic. We show that it has a bounded agent property, giving us a decision procedure for satisfiability. We also present a complete axiomatization of the valid formulas. The logic admits a natural model checking algorithm and bisimulation characterization. The logic with quantification over players is more appropriate, but is undecidable. (shrink)

We suggest that developing automata theoretic foundations is relevant for knowledge theory, so that we study not only what is known by agents, but also the mechanisms by which such knowledge is arrived at. We define a class of epistemic automata, in which agents’ local states are annotated with abstract knowledge assertions about others. These are finite state agents who communicate synchronously with each other and information exchange is ‘perfect’. We show that the class of recognizable languages has good closure (...) properties, leading to a Kleene-type theorem using what we call regular knowledge expressions. These automata model distributed causal knowledge in the following way: each agent in the system has a partial knowledge of the temporal evolution of the system, and every time agents synchronize, they update each other’s knowledge, resulting in a more up-to-date view of the system state. Hence we show that these automata can be used to solve the satisfiability problem for a natural epistemic temporal logic for local properties. Finally, we characterize the class of languages recognized by epistemic automata as the regular consistent languages studied in concurrency theory. (shrink)

When we reason about strategic games, implicitly we need to reason about arbitrary strategy profiles and how players can improve from each profile. This structure is exponential in the number of players. Hence it is natural to look for subclasses of succinct games for which we can reason directly by interpreting formulas on the (succinct) game description rather than on the associated improvement structure. Priority separable games are one of such subclasses: payoffs are specified for pairwise interactions, and from these, (...) payoffs are computed for strategy profiles. We show that equilibria in such games can be described in Monadic Least Fixed Point Logic (MLFP). We then extend the description to games over arbitrarily many players, but using the monadic least fixed point extension of existential second order logic. (shrink)

We study repeated normal form games where the number of players is large. We argue that it is interesting to look at such games as being divided into subgames, each of which we call a neighbourhood. The structure of such a game is given by a graph G whose nodes are players and edges denote visibility. The neighbourhoods are maximal cliques in G. The game proceeds in rounds where in each round the players of every clique X of G play (...) a strategic form game among each other. A player at a node v strategises based on what she can observe, i.e., the strategies and the outcomes in the previous round of the players at vertices adjacent to v. Based on this, the player may switch strategies in the same neighbourhood, or migrate to another neighbourhood.We are interested in addressing questions regarding the eventual stability of such games. We incrementally impose constraints on the ‘types’ of the players. First, we look at players who are unconstrained in their strategising abilities, in that, players who may use unbounded memory. We then consider the case of memoryless players. We show that in both these cases the eventual stability of the game can be characterised in terms of potentials. We then introduce a simple modal logic in which the types of the players can be specified. We show that when the players play according to these specified types, it can be effectively decided whether the game stabilises. Finally, we look at the important heuristic of imitation. Simple imitative strategies can be specified in the logic introduced by us. We show that in a population of optimisers and imitators, we can decide how ‘worse-off’ the imitators are by playing imitative strategies rather than optimal ones. (shrink)

The Asian Logic Conference (ALC) is a major international event in mathematical logic. It features the latest scientific developments in the fields of mathematical logic and its applications, logic in computer science, and philosophical logic. The ALC series also aims to promote mathematical logic in the Asia-Pacific region and to bring logicians together both from within Asia and elsewhere for an exchange of information and ideas. This combined proceedings volume represents works presented or arising from the 14th and 15th ALCs.

We investigate the semantics of messages, and argue that the meaning ofa message is naturally and usefully given in terms of how it affects theknowledge of the agents involved in the communication. We note thatthis semantics depends on the protocol used by the agents, and thus not only the message itself, but also the protocol appears as a parameter in the meaning. Understanding this dependence allows us to give formal explanations of a wide variety of notions including language dependence, implicature, (...) and the amount of information in a message. (shrink)

This book discusses major milestones in Rohit Jivanlal Parikh’s scholarly work. Highlighting the transition in Parikh’s interest from formal languages to natural languages, and how he approached Wittgenstein’s philosophy of language, it traces the academic trajectory of a brilliant scholar whose work opened up various new avenues in research. This volume is part of Springer’s book series Outstanding Contributions to Logic, and honours Rohit Parikh and his works in many ways. Parikh is a leader in the realm of ideas, offering (...) concepts and definitions that enrich the field and lead to new research directions. Parikh has contributed to a variety of areas in logic, computer science and game theory. In mathematical logic his contributions have been in recursive function theory, proof theory and non-standard analysis; in computer science, in the areas of modal, temporal and dynamic logics of programs and semantics of programs, as well as logics of knowledge; in artificial intelligence in the area of belief revision; and in game theory in the formal analysis of social procedures, with a strong undercurrent of philosophy running through all his work.This is not a collection of articles limited to one theme, or even directly connected to specific works by Parikh, but instead all papers are inspired and influenced by Parikh in some way, adding structures to and enriching “Parikh-land”. The book presents a brochure-like overview of Parikh-land before providing an “introductory video” on the sights and sounds that you experience when reading the book. (shrink)

Reason and Value collects 15 new papers by leading contemporary philosophers on themes from the work of Joseph Raz. Raz has made major contributions in a wide range of areas, including jurisprudence, political philosophy, and the theory of practical reason; but all of his work displays a deep engagement with central themes in moral philosophy. The subtlety and power of Raz's reflections on ethical topics make his writings a fertile source for anyone working in this area. Especially significant are his (...) explorations of the connections between practical reason and the theory of value, which constitute a sustained and penetrating treatment of a set of issues at the very center of moral philosophy as it is practiced today. The contributors to the volume acknowledge the importance of Raz's contributions by engaging critically with his positions and offering independent perspectives on the topics that he has addressed. The volume aims both to honour Raz's accomplishments in the area of ethical theorizing, and to contribute to an enhanced appreciation of the significance of his work for the subject. (shrink)

Despite All Critique (2014) -- World Politics and Western Reason (1980) -- The Doubled Outsides of the Modern International (2005) -- The Subject of Security (1995) -- The Protection of Nature and the Nature of Protection (2005) -- Social Movements/World Politics (1994) -- Europe is Not Where It is Supposed to Be (2000) -- They Seek it Here, They Seek it There : Looking for Politics in Clayoquot Sound (2003) -- Violence, Modernity, Silence : From Weber to International Relations (1993) (...) -- Hobbes, Origins, Limits (2011) -- War, Terror, Judgement (2002) -- International, Imperial, Exceptional (2005) -- Which Democracy for Which Demos? (2013) -- The Political Theory of Boundaries and the Boundaries of Political Theory : Interview With Raia Prokhovnik (2012). (shrink)

This book focuses upon the perennial question of the existence and nature of an obligation to obey the law. Leading writers have, at one time or another, emphasized considerations such as gratitude, 'divine ordering, ' prudence, contract, autonomy, and utility in seeking to justify, or to deny any justification for, some sort of obligation to obey the positive law. The book provides relevant selections from a sampling of the historical approaches to legal obligation taken by writers such as Plato, Augustine, (...) Aquinas, Hobbes, Locke, Hume, Rousseau, Thoreau, Bentham, Marx and Engels, and Martin Luther King, Jr. These classical discussions are augmented by critical questions and commentary, by independent discussions of the question of legal obligation by a wide range of contemporary writers, and by relevant judicial cases discussing matters such as conscientious objection and civil disobedience. (shrink)

The concept of yinyang lies at the heart of Chinese thought and culture. The relationship between these two opposing, yet mutually dependent, forces is symbolized in the familiar black and white symbol that has become an icon in popular culture across the world. The real significance of yinyang is, however, more complex and subtle. This brilliant and comprehensive analysis by one of the leading authorities in the field captures the richness and multiplicity of the meanings and applications of yinyang, including (...) its visual presentations. Through a vast range of historical and textual sources, the book examines the scope and role of yinyang, the philosophical significance of its various layers of meanings and its relation to numerous schools and traditions within Chinese philosophy. By putting yinyang on a secure and clear philosophical footing, the book roots the concept in the original Chinese idiom, distancing it from Western assumptions, frameworks and terms, yet also seeking to connect its analysis to shared cross-cultural philosophical concerns. (shrink)

Information can be public among a group. Whether or not information is public matters, for example, for accounts of interdependent rational choice, of communication, and of joint intention. A standard analysis of public information identifies it with (some variant of) common belief. The latter notion is stipulatively defined as an infinite conjunction: for p to be commonly believed is for it to believed by all members of a group, for all members to believe that all members believe it, and so (...) forth. This analysis is often presupposed without much argument in philosophy. Theoretical entrenchment or intuitions about cases might give some traction on the question, but give little insight about why the identification holds, if it does. The strategy of this paper is to characterize a practical-normative role for information being public, and show that the only things that play that role are (variants of) common belief as stipulatively characterized. In more detail: a functional role for “taking a proposition for granted” in non-isolated decision making is characterized. I then present some minimal conditions under which such an attitude is correctly held. The key assumption links this attitude to beliefs about what is public. From minimal a priori principles, we can argue that a proposition being public among a group entails common commitment to believe among that group. Later sections explore partial converses to this result, the factivity of publicity and publicity from the perspective of outsiders to the group, and objections to the aprioricity of the result deriving from a posteriori existential presuppositions. (shrink)

Recent Work on Intrinsic Value brings together for the first time many of the most important and influential writings on the topic of intrinsic value to have appeared in the last half-century. During this period, inquiry into the nature of intrinsic value has intensified to such an extent that at the moment it is one of the hottest topics in the field of theoretical ethics. The contributions to this volume have been selected in such a way that all of the (...) fundamental questions concerning the nature of intrinsic value are treated in depth and from a variety of viewpoints. These questions include how to understand the concept of intrinsic value, what sorts of things can have intrinsic value, and how to compute intrinsic value. The editors have added an introduction that ties these questions together and places the contributions in context, and they have also provided an extensive bibliography. The result is a comprehensive, balanced, and detailed picture of current thinking about intrinsic value, one that provides an indispensable backdrop against which future writings on the topic may be assessed. (shrink)

BLWith new text and full apparatus criticus The Eudemian Ethics was one of two ethical treatises which Aristotle wrote on the subject of ethica or `matters to do with character'. Although the two works cover much the same ground, the Nicomachean Ethics is better known; the poor manuscript tradition of the Eudemian Ethics has made correct translation and interpretation of the text extremely difficult. The subject of the work is the choice of a certain means of conduct, made by a (...) `man of practical wisdom', between two extremes of behaviour: asceticism and yielding to uncontrolled impulses. Aristotle also stresses the notion of moral intention and the importance of virtue of character. This new Oxford Classical Text of the Eudemian Ethics is the result of many years of work. After Sir David Ross's death, his original text was substantially reworked and revised by his friend and colleague R. R. Walzer, who was aided in the revision by his former pupil Mrs Jean Mingay, who continued his work after his death in 1974. Mrs Mingay was fortunate in being able to make use of previously unpublished contributions from D. J. Allan after his death in the late seventies, and more recently has been helped in her work by the suggestions of Professor D. A. Russell, David Robinson, and Christopher Rowe. (shrink)

"Williams's masterful translation satisfies (at last!) a long-standing need. There are lots of good translations of Augustine's great work, but until now we have been forced to choose between those that strive to replicate in English something of the majesty and beauty of Augustine's Latin style and those that opt instead to convey the careful precision of his philosophical terminology and argumentation. Finally, Williams has succeeded in capturing both sides of Augustine's mind in a richly evocative, impeccably reliable, elegantly readable (...) presentation of one of the most impressive achievements in Western thought--Augustine's Confessions." --Scott MacDonald, Professor of Philosophy and Norma K. Regan Professor in Christian Studies, Cornell University. (shrink)

Elliot R. Wolfson intervenes in the debate over Martin Heidegger and Nazism from a unique perspective, as a scholar of Jewish mysticism and philosophy who has been profoundly influenced by Heidegger's work. He reveals crucial aspects of Heidegger's thinking that betray an affinity with dimensions of Jewish thought.

This volume gathers together for the first time are all the key texts in a crucial debate in modern philosophy, centered on Leibniz's famous 1695 essay, the "New System of the Nature of Substances and their Communication," in which he introduced his strikingly original theory of metaphysics. His "system" became increasingly famous and drew him into discussion and development of these ideas, both in public and in private, with a variety of thinkers, most notably the great French philosopher Pierre Bayle. (...) Woolhouse's and Francks's new English edition gives the only full representation of this debate, and will therefore be essential reading for anyone who wishes to gain a proper understanding of Leibniz's philosophy and its intelletual context. All the texts are newly translated and extensively annotated; many appear in English for the first time. (shrink)

The young Hegel was entranced by the notion of intellectual intuition, and this notion continues to entrance many of Hegel’ commentators. I argue that Kant provided three distinct conceptions of an intuitive intellect, that none of these involve aconceptual intuitionism, and that they differ markedly from Fichte’s and Schelling’s conceptions of intellectual intuition. I further argue that by 1804 Hegel recognized that appealing to an aconceptual model, or to Schelling’s model, or to his own early model of intellectual intuition generates (...) inevitable and insoluble problems of question-begging. By incorporating several important points from Kant’s Transcendental Ideal into his reinterpretation of Kant’s Transcendental Deduction and Refutation of Idealism, Hegel’s mature discursive and conceptual account of ‘absolute knowing’ performs some of the functions Kant assigned to the intuitive intellect, though without invoking any such intuitive intellect. I discuss several of these functions. (shrink)

The authors of this paper earlier argued that concrete objects, such as things or persons, may have final value, which is not reducible to the value of states of affairs that concern the object in question. Our arguments have been challenged. This paper is an attempt to respond to some of these challenges, viz. those that concern the reducibility issue. The discussion presupposes a Brentano-inspired account of value in terms of fitting responses to value bearers. Attention is given to a (...) yet another type of reduction proposal, according to which the ultimate bearers of final value are abstract particulars rather than abstract states or facts. While the proposal is attractive, it confronts serious difficulties. To recognise tropes as potential bearers of final value, along with other objects, is one thing; but to reduce the final value of concrete objects to the final value of tropes is another matter. (shrink)

The View from Here is a study of our must fundamental attitudes toward the past. The book explores the dynamics of affirmation and regret, tracing the connections of each to our ongoing attachments. The focus is on situations in which our attachments commit us to affirming events or decisions that we know to have been unfortunate or regrettable.