Centre for Decision Research and Experimental Economics

CeDEx 2011-01: Common Reasoning in Games: A Lewisian Analysis of Common Knowledge of Rationality


The game-theoretic assumption of ‘common knowledge of rationality’ leads to paradoxes when rationality is represented in a Bayesian framework as cautious expected utility maximisation with independent beliefs (ICEU). We diagnose and resolve these paradoxes by presenting a new class of formal models of players’ reasoning, inspired by David Lewis’s account of common knowledge, in which the analogue of common knowledge is derivability in common reason. We show that such models can consistently incorporate any of a wide range of standards of decision-theoretic practical rationality. We investigate the implications arising when the standard of decision-theoretic rationality so assumed is ICEU.

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Now published in Economics and Philosophy


Robin P. Cubitt and Robert Sugden


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Posted on Saturday 1st January 2011

Centre for Decision Research and Experimental Economics

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