Burden of Proof, Presumption and Argumentation The notion of burden of proof and its companion notion of presumption are central to argumentation studies. This book argues that we can learn a lot from how the courts have developed procedures over the years for allocating and reasoning with presumptions and burdens of proof, and from how artii cial intelligence has built precise formal and computational systems to represent this kind of reasoning. The book provides a model of reasoning with burden of proof and presumption based on analyses of many clearly explained legal and nonlegal examples. The model is shown to i t cases of everyday conversational argumentation as well as argumentation in legal cases. Burden of proof deter- mines (1) under what conditions an arguer is obliged to support a claim with an argument that backs it up and (2) how strong that argument needs to be to prove the claim in question. Douglas Walton holds the Assumption Chair in Argumentation Studies and is Distinguished Research Fellow of the Centre for Research in Reasoning, Argumentation and Rhetoric at the University of Windsor, Canada. His most recent book is M ethods of Argumentation (Cambridge University Press, 2013). Walton’s work has been used to prepare better legal arguments and to help develop artii cial intelligence. His books have been translated worldwide and he attracts students from many countries to study with him. A festschrift hon- oring his contributions, D ialectics, Dialogue and Argumentation: An Examination of Douglas Walton’s Theories of Reasoning and Argument , edited by C. Reed and C. W. Tindale (2010), shows how his theories are increasingly i nding applica- tions in computer science. Burden of Proof, Presumption and Argumentation DOUGLAS W ALTON University of Windsor, Canada 32 Avenue of the Americas, New York , NY 10013-2473, USA Cambridge University Press is part of the University of Cambridge. It furthers the University’s mission by disseminating knowledge in the pursuit of education, learning and research at the highest international levels of excellence. www.cambridge.org Information on this title: w ww.cambridge.org/9781107678828 © D ouglas Walton 2 014 This publication is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published 2 014 Printed in the United States of America A catalog record for this publication is available from the British Library. Library of Congress Cataloging in Publication data Walton, Douglas N., author. Burden of proof, presumption and argumentation / Douglas Walton, University of Windsor, Canada. pages cm Includes bibliographical references and index. ISBN 978-1-107-04662-7 (hardback) – ISBN 978-1-107-67882-8 (paperback) 1. Burden of proof. 2. Proof theory. I. Title. K2263.W348 2014 347′.06–dc23 2014014939 ISBN 978-1-107-04662-7 Hardback ISBN 9 78-1-107-67882-8 Paperback Cambridge University Press has no responsibility for the persistence or accuracy of URLs for external or third-party Internet Web sites referred to in this publication and does not guarantee that any content on such Web sites is, or will remain, accurate or appropriate. For Karen, with love. Contents Acknowledgments page x i 1 Introduction to Basic Concepts and Methods . . . . . . . . . . . . . 1 1. P roblems and Objections 2 2. A rguments from Ignorance 6 3. T hree Examples of Burden of Proof Problems 9 4. S urvey of Theories of Presumption and Burden of Proof in Argumentation 1 3 5. P resumption and Burden of Proof in Legal Argumentation 1 9 6. S hifting of Burden Proof and Critical Questioning 23 7. The Carneades Argumentation System 2 6 8. D ialogue Models of Argumentation 3 1 9. F ormal Dialogue Models for Legal Argumentation 38 10. A Formal Model of Burden of Proof in the Critical Discussion 4 2 2 Burdens of Proof in Legal Reasoning . . . . . . . . . . . . . . . . . . 4 9 1. T he Normal Default Rule 50 2. Burden of Persuasion and Evidential Burden 52 3. Standards of Proof 5 7 4. S tages of Dialogue and Legal Burden of Proof 61 5. O ther Legal Burdens of Proof 6 5 6. T he Link between Burden of Persuasion and Production 68 7. The Abstract Argumentation Model 70 8. T he Self-Defense Example 7 3 9. H ow Carneades Models the Self-Defense Case 7 7 10. Conclusions 83 3 Presumption in Legal Reasoning . . . . . . . . . . . . . . . . . . . . . . 85 1. T he Five Components of Argumentation in a Trial 8 6 2. P resumption in Law and Everyday Reasoning 8 9 vii viii Contents 3. R ules and Inferences 9 1 4. T he Logical Component 94 5. The Dialogical Component 9 7 6. T he Letter and the Dark Stairway 101 7. C ombining the Inferential and Dialogical Components 105 8. Application of the Dialogical Theory to Examples 109 9. Conclusions 114 10. Directions for Future Research 118 4 Shifting the Burden of Proof in Witness Testimony . . . . . . .1 22 1. W itness Testimony in the Carneades Argumentation System 123 2. T he Case of the S tate v. Classen 126 3. S cientii c Evidence on the Fallibility of Witness Testimony 128 4. T he State of Oregon v. Lawson 131 5. T he Change Made in Oregon Law 133 6. R econi guring the Argumentation Schemes 135 7. The Critical Questions Matching the Scheme 137 8. Admissibility, Bias and Burden of Proof 139 9. A dmissibility, Relevance and Examination 140 10. Conclusions 142 5 Burden of Proof in Dialogue Systems . . . . . . . . . . . . . . . . . .1 45 1. H amblin’s Why-Because System with Questions 146 2. A n Example Argument 1 49 3. B urden of Proof in Dialogue 1 50 4. S ituating Support Requests in Types of Dialogue 152 5. Specii cations for a Why-Because System with Questions 155 6. A nalysis of the Argumentation in the Example 158 7. S olution to the Problem of Evasion and Shifting of Burden of Proof 162 8. Speech Acts in Dialogue Systems 1 64 9. T he Dialogue Systems CB1 and CB1CK 167 10. Dialogue Systems with Argument and Explanation 173 6 Solving the Problems of Burden of Proof . . . . . . . . . . . . . . .1 76 1. P roblems To Be Solved 177 2. Meta-Arguments and Metadialogues in Logic and AI 178 3. Theoretical Problems of Metadialogues 181 4. A nalyzing the Los Gatos Example Using Carneades 183 5. A nalyzing the Los Gatos Example Using Abstract Argumentation 1 87 6. A rguments from Ignorance Revisited 1 90 7. T he Nonfallaciousness of Argument from Ignorance 196 8. When Should a Persuasion Dialogue Be Closed? 200 Contents ix 9. A Solution to These Problems 2 03 10. An Explanation-Based Approach to Modeling Standards of Proof 205 7 Burdens of Proof in Different Types of Dialogue . . . . . . . .2 11 1. S ome Examples 212 2. T he Formal Structure of Deliberation Dialogue 216 3. D eliberation versus Persuasion Over Action 218 4. A nalysis of the No-Fault Insurance Example 224 5. A nalysis of the Wigmore, FDA and Precautionary Principle Examples 229 6. T he Persuasion Interval in Deliberation 232 7. Conclusions on Burden of Proof in Deliberation 234 8. Burden of Proof in Inquiry and Discovery Dialogues 236 9. I nformation-Seeking Dialogue, Negotiation and Eristic Dialogue 240 10. The Contextual Nature of Burden of Proof 241 8 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 45 1. T he Allegation of Hasty Transference 246 2. Comparing Legal and Nonlegal Burden of Proof 249 3. Normative Models and Everyday Conversational Arguments 252 4. The Dialogue on Tipping 256 5. B urdens of Proof in the Dialogue on Tipping 263 6. B urdens of Proof in a Forensic Debate 269 7. The Connection between Burden of Proof and Presumption 273 8. Dialectical Rei nements of the Theory of Presumption 277 9. The Legal and the Everyday Notions of Presumption 279 10. Conclusions and Suggestions for Further Research 281 Bibliography 285 Index 297