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9789400707139.Pdf Games, Norms and Reasons SYNTHESE LIBRARY STUDIES IN EPISTEMOLOGY, LOGIC, METHODOLOGY, AND PHILOSOPHY OF SCIENCE Editors-in-Chief: VINCENT F. HENDRICKS, University of Copenhagen, Denmark JOHN SYMONS, University of Texas at El Paso, U.S.A. Honorary Editor: JAAKKO HINTIKKA, Boston University, U.S.A. Editors: DIRK VAN DALEN, University of Utrecht, The Netherlands THEO A.F. KUIPERS, University of Groningen, The Netherlands TEDDY SEIDENFELD, Carnegie Mellon University, U.S.A. PATRICK SUPPES, Stanford University, California, U.S.A. JAN WOLEN´SKI, Jagiellonian University, Krako´w, Poland VOLUME 353 For further volumes: http://www.springer.com/series/6607 Games, Norms and Reasons Logic at the Crossroads Edited by Johan van Benthem ILLC, University of Amsterdam, The Netherlands and Stanford University, USA Amitabha Gupta Indian Institute of Technology Bombay, India and Eric Pacuit Tilburg University, Tilburg Institute for Logic and Philosophy of Science, The Netherlands 123 Editors Prof. Johan van Benthem Prof. Amitabha Gupta University of Amsterdam Adi Shankaracharya Marg Institute for Logic 503 Whispering Woods Language and Computation (ILLC) Powai Vihar, Bldg. 3 Science Park, P.O. Box 94242 700076 Powai, Mumbai 1090 GE Amsterdam India The Netherlands [email protected] [email protected] Asst. Prof. Eric Pacuit Tilburg University Tilburg Institute for Logic and Philosophy of Science Warandelaan 2 5037 AB Tilburg The Netherlands [email protected] ISBN 978-94-007-0713-9 e-ISBN 978-94-007-0714-6 Set ISBN 978-94-007-0920-1 DOI 10.1007/978-94-007-0714-6 Springer Dordrecht Heidelberg London New York Library of Congress Control Number: 2011923658 c Springer Science+Business Media B.V. 2011 No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Preface This book continues a series called “Logic at the Crossroads” of which the first vol- ume appeared in 2007.1 The series title reflects a view of our discipline as a vantage point for seeing new developments across academic fields, as well as a catalyst in making them happen. In particular, the editors feel that the deep insights from the classical phase of mathematical logic can form a harmonious mixture with a new, more ambitious research agenda of understanding and enhancing human reasoning and intelligent interaction in their full extent, whence our title “Games, Norms and Reasons”. This broad view of logic animated the Second Indian Conference on “Logic and its Relationship with other Disciplines” held at IIT Bombay, Mumbai 2007, the origin of most of the papers in this volume, while a few additional ones have been solicited by the editors to round out coverage. But the Mumbai conference also added a very concrete focus, by honouring one person who embodies the general trend described, namely Professor Rohit Jivanlal Parikh. Rohit stands at the cross- roads of many academic disciplines, and of two major human cultures, and why and how this is so, is admirably explained in the Congratulatory Citation that was read at a special event at IIT Bombay celebrating Rohit’s 70th birthday. This document has been reprinted here, after the following brief editorial description of contents. The papers in this volume do two things. First, they paint a lively portrait of modern logic as it is expanding today with many new themes and concerns. But at the same time, they include a gallery of friends and colleagues of Rohit’s who eagerly responded to our call for honouring him. The chapters to follow highlight major dimensions of his work and influence, in particular, his “Social Software” program for studying the procedural behaviour of interactive human agents with beliefs and preferences. Horacio Arlo´ Costa and Arthur Paul Pedersen start off with a key interest of Parikh’s, viz. bridging between realistic models of human behaviour and logic based 1 Logic at the Crossroads: An Interdisciplinary View, Amitabha Gupta, Rohit Parikh and Johan van Benthem, editors, Allied Publishers, New Delhi. Recently reissued by Springer Publishers under the new title Proof, Computation and Agency: Logic at the Crossroads. v vi Preface ones. They analyze Gigerenzer’s “Take the Best” algorithm for successful decisions by bounded-rational agents, and show how it can be understood and taken further using formal models of choice and preference. Sergei Artemov continues with an account of “justification logics”, which merge ideas from proof theory and prov- ability logic with epistemic logic to arrive at rich and more realistic accounts of evidence in human reasoning that link up with formal epistemology. Next, Akeel Bilgrami discusses a key aspect of what holds communication together, viz. mean- ingful discourse, and argues that linguistic meanings are not normative in any deep sense – while still fully acknowledging Wittgenstein’s insights about the norma- tivity of human intentions. Melvin Fitting follows up on his long-standing formal studies of logics of proofs, and gives a new proof of a “realization theorem” link- ing the epistemic logic S5 to its justification counterpart. Next, Sujata Ghosh and Fernando Velazquez-Quesada´ discuss current models of belief and belief change based on networks, and relate these to the more qualitative ones found in epistemic and doxastic logic, including an account of successive dynamic steps that change a current belief network. Patrick Girard analyzes another crucial dynamic social scenario, viz. merge of individual preferences into a group-based one over a set of outcomes. He shows how preference merging in structured groups receives a per- spicuous semantic and axiomatic formulation using the tools of modal and dynamic preference logic. Amy Greenwald, Amir Jafari and Casey Marks develop new links between the fields of game theory and computational learning theory, both crucial ingredients of intelligent interaction – based on a new notion of “no-Φ-regret”. Vin- cent Hendricks returns to Parikh’s interests in the fit between formal models and our natural ways of understanding knowledge and information. He gives an insight- ful discussion of the intuitive distinction between “first person” and “third person” perspectives, linking this to a wide range of issues from philosophy to economics. Dexter Kozen and Ganesh Ramanarayanan present another innovative social use of classical ideas from proof theory, developing a universal Horn equational logic with dynamic operations of “publish”, “cite” and “forget” which describe the ac- tual construction and maintenance of mathematical knowledge. Lawrence Moss re- turns to the use of natural language in human interaction, and shows how reasoning in natural language has interesting syllogistic subsystems allowing for negations that form a hitherto hardly explored level in between the classical Syllogistic and full-fledged first-order predicate logic. Jeff Paris and Alena Vencovska´ consider an- other major aspect of our natural reasoning, namely, its use of probabilistic features, whether quantitative, or qualitative with tags like “probably”. Linking up with De Finetti’s foundations of probability, they develop a sophisticated new version of Carnap’s inductive logic for monadic predicates which handles the right inference relations between agents’ degrees of belief. They also generalize this approach to binary and higher-order predicates, and develop its mathematical theory further, us- ing a new principle of “Spectrum Exchangeability”. Finally, R. Ramanujam and S.P. Suresh look at the central role of knowledge in reasoning about security pro- tocols. The semantics of conventional epistemic logics throws up challenges, since cryptographic primitives in communication lead to problems of unboundedness and Preface vii undecidability. The authors propose an alternative epistemic logic which is expres- sive enough while its protocol verification procedure is decidable. Taken together, these papers show how logic can extend its scope without any sacrifice in rigour or focus. Moreover, their quality, and their cast of authors, speaks for itself about Rohit Parikh’s intellectual breadth and influence. It has been a plea- sure to arrange this tribute, and beyond logistics, the editors have learned a lot in the process. We end with a citation which was read during the 2007 Mumbai conference. The present volume has taken some time to appear, due to circumstances beyond our control, but the editors feel that the sentiments expressed then are as fresh and appropriate as ever. Stanford Johan van Benthem Bombay Amitabha Gupta Tilburg Eric Pacuit Dedication On the occasion of his seventieth birthday, we, the participants and organizers of the “Second Indian Conference on Logic and its Relationship with Other Disciplines”, acclaim and honour Professor Rohit Jivanlal Parikh and celebrate his many extraor- dinary achievements and outstanding contributions in his pursuit of knowledge. Born on November 20, 1936, he was educated at Mumbai, and then at Harvard University, where he obtained degrees with highest honors in Physics (A.B.) and Mathematics (Ph.D.). Parikh’s romance with Logic began with a course by Quine. Later on he was
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