Bernheim's paper explores rationalizable strategic behavior in games, proposing a concept of "rationalizability" as an alternative to Nash equilibrium. Rationalizable strategies are those that can be justified by an internally consistent system of beliefs, rather than being optimal in a post-hoc sense. The paper argues that rationalizable strategies cannot be discarded based on rationality alone, and that all rationally justifiable strategies are part of the rationalizable set. It examines the properties of rationalizable strategies, considers refinements, and analyzes their relationship to Nash strategies. The paper also discusses the topological properties of rationalizable strategies, noting that multiplicity is a significant issue. Refinements of the rationalizability criterion are proposed, which are viewed as "plausibility" requirements. The paper concludes that rationalizability provides a more general framework for strategic choice than Nash equilibrium, and that it is robust to various behavioral assumptions. The analysis shows that rationalizable strategies can be unique and finite under certain conditions, and that they are closely related to Nash strategies in many cases. The paper also discusses the implications of rationalizability for economic theory and the importance of considering psychological factors in strategic decision-making.Bernheim's paper explores rationalizable strategic behavior in games, proposing a concept of "rationalizability" as an alternative to Nash equilibrium. Rationalizable strategies are those that can be justified by an internally consistent system of beliefs, rather than being optimal in a post-hoc sense. The paper argues that rationalizable strategies cannot be discarded based on rationality alone, and that all rationally justifiable strategies are part of the rationalizable set. It examines the properties of rationalizable strategies, considers refinements, and analyzes their relationship to Nash strategies. The paper also discusses the topological properties of rationalizable strategies, noting that multiplicity is a significant issue. Refinements of the rationalizability criterion are proposed, which are viewed as "plausibility" requirements. The paper concludes that rationalizability provides a more general framework for strategic choice than Nash equilibrium, and that it is robust to various behavioral assumptions. The analysis shows that rationalizable strategies can be unique and finite under certain conditions, and that they are closely related to Nash strategies in many cases. The paper also discusses the implications of rationalizability for economic theory and the importance of considering psychological factors in strategic decision-making.