Rational Responses to Risks

Good decisions account for risks. For example, the risk of an accident while driving in the rain makes a reasonable driver decide to slow down. While risk is a large topic in theoretical disciplines such as economics and psychology, as well as in practical disciplines such as medicine and finance, philosophy has a unique contribution to make in developing a normative theory of risk that states what risk is, and to what extent our responses to it are rational. Weirich here develops a philosophical theory of the rationality of responses to risk. He first distinguishes two types of risk: first, a chance of a bad event, and second, an act's risk in relation to its possible outcomes. He argues that this distinction has normative significance in the sense that one's attitudes towards these types of risks - and how one acts on them - are governed by different general principles of rationality. Consequently, a comprehensive account of risk must not only characterize rational responses to risk but also explain why these responses are rational. Weirich explains how, for a rational ideal agent, the expected utilities of the acts available in a decision problem explain the agent's preferences among the acts. As a result, maximizing expected utility is just following preferences among the acts. His view takes an act's expected utility, not just as a feature of a representation of preferences among acts, but also as a factor in the explanation of preferences among acts. The book's precise formulation of general standards of rationality for attitudes and for acts, and its rigorous argumentation for these standards, make it philosophical; but while mainly of interest to philosophers, its broader arguments will contribute to the conceptual foundations of studies of risk in all disciplines that study it. "A philosophical account of risk, such as this book provides, states what risk is, which attitudes to it are rational, and which acts affecting risks are rational. Attention to the nature of risk reveals two types of risk, first, a chance of a bad event, and, second, an act's risk in the sense of the volatility of its possible outcomes. The distinction is normatively significant because different general principles of rationality govern attitudes to these two types of risk. Rationality strictly regulates attitudes to the chance of a bad event and is more permissive about attitudes to an act's risk. Principles of rationality governing attitudes to risk also justify evaluating an act according to its expected utility given that the act's risk, if any, belongs to every possible outcome of the act. For a rational ideal agent, the expected utilities of the acts available in a decision problem explain the agent's preferences among the acts. Maximizing expected utility is just following preferences among the acts. This view takes an act's expected utility, not just as a feature of a representation of preferences among acts, but also as a factor in the explanation of preferences among acts. It takes account of an agent's attitudes to an act's risk without weakening the standard of expected-utility maximization. The view extends to evaluations of combination of acts, either simultaneous or in a sequence. Applications cover hedging, return-risk evaluation, professional advice, and government regulation." -- Oxford Scholarship Online "A philosophical account of risk, such as this book provides, states what risk is, which attitudes to it are rational, and which acts affecting risks are rational. Attention to the nature of risk reveals two types of risk, first, a chance of a bad event, and, second, an act's risk in the sense of the volatility of its possible outcomes. The distinction is normatively significant because different general principles of rationality govern attitudes to these two types of risk. Rationality strictly regulates attitudes to the chance of a bad event and is more permissive about attitudes to an act's risk. Principles of rationality governing attitudes to risk also justify evaluating an act according to its expected utility given that the act's risk, if any, belongs to every possible outcome of the act. For a rational ideal agent, the expected utilities of the acts available in a decision problem explain the agent's preferences among the acts. Maximizing expected utility is just following preferences among the acts. This view takes an act's expected utility, not just as a feature of a representation of preferences among acts, but also as a factor in the explanation of preferences among acts. It takes account of an agent's attitudes to an act's risk without weakening the standard of expected-utility maximization. The view extends to evaluations of combination of acts, either simultaneous or in a sequence. Applications cover hedging, return-risk evaluation, professional advice, and government regulation"-- Provided by publisher Cover 1 Rational Responses to Risks 4 Copyright 5 Dedication 6 Contents 8 Preface 10 Acknowledgments 12 Introduction 14 I. RISKS AND ATTITUDES TO THEM 30 1. Types of Risk 32 2. Attitudes 54 3. Rational Attitudes toward Risks 77 II. ACTS AFFECTING RISKS 98 4. Evaluation of an Act 100 5. Rational Management of Risks 125 6. Combinations of Acts 149 III. ILLUSTRATIONS AND GENERALIZATIONS 172 7. Return-​Risk Evaluation of Investments 174 8. Advice about Decisions 191 9. Regulation of Risks 209 10. Rolling Back Idealizations 234 Conclusion 261 References 264 Index 274