A DEFENCE OF METAPHYSICAL ETHICAL NATURALISM RYO CHONABAYASHI This thesis is submitted to Cardiff University in fulfilment of the requirements for the degree of DOCTOR OF PHILOSOPHY February 2012 Philosophy 1 DEDICATION I dedicate this work to Daisaku Ikeda who has been giving me uncountable encouragement. If there had not been his great inspirations, I would not have found a great joy in doing philosophy, and could not have completed a doctoral work in philosophy. I also dedicate this work to my father, Naohiko, my mother Akiko, my sister, Mai, my brother, Shun and my sister in law Sae, and another brother Yu Chonabayashi. Without their unceasing support, I could not finish this work. Finally, I dedicate this work to my wife, Hisayo Chonabayashi. I hope this dissertation will be the first work from my side for our shared determination that we seek and promote a philosophy which enables us to manifest our full potential. ACKNOWLEDGEMENT I deeply thank my thesis supervisor, Nick Shackel for his constant encouragement and constructive comments on my writings. Without his support, this dissertation would be a much poorer work than it is. I also thank the people in the Philosophy Section of Cardiff University. Cardiff was such a great place to discuss philosophy with very talented teachers and friends. I especially thank Robin Attfield, Richard Gray, Jules Holroyd, Chris Norris, Clear Rees, Alessandra Tanesini, and Jon Webber who gave me various helpful suggestions about my dissertation. I also thank many talented postgraduate students there with whom I had invaluable opportunities to discuss philosophy and various things about life. Special thanks to Alison Venables and Rhian Rattray who supported my life in the Cardiff Philosophy Section in various ways. 2 These people very kindly gave me permission to read their published or unpublished work: Brian Leiter, Alex Miller, Christian Miller, Michael Rubin, Neil Sinclair, and Torbjörn Tännsjö. I wholeheartedly thank their kindness. I gave my papers on various occasions, and received many helpful comments which contributed to the completion of this dissertation. I thank all the audiences on those occasions. Especially I thank Charles Pigden and Christine Swanton who gave me helpful comments on my papers. This research is partly funded by So-Yu-Kai Research Scholarship which is provided by Soka University in Japan. I am grateful to the grant committee for supporting my research at Cardiff. Finally, I would like to express my gratitude to Yutaka Ishigami. He is the first person who taught me philosophy and I thank his constant encouragement since then. 3 Abstract This dissertation is a defence of metaphysical ethical naturalism according to which there is a moral reality which is part of the natural world. The implication of this view is that moral properties, such as moral goodness, justice, compassion and so forth are part of the natural world, and inquiries concerning these moral entities are conducted in similar empirical ways of reasoning to that in which scientific inquiries are conducted. I defend metaphysical ethical naturalism by a variety of explanationist argument in the tradition of Cornell realism. I examine preceding proposals for this argument, and focus on one version of it, which I call „the abductive argument for moral realism‟. Although there was a suggestion about the abductive argument, the argument has not been discussed enough in the literature. This dissertation is a defence and discussion about the abductive argument which has not been properly examined. The defence of the argument requires the examination of how first-order ethical theory can be developed in the similar empirical ways scientific theories are developed. This will be an attempt to show the analogy between scientific inquiries and ethical inquiries. Describing the analogy between science and ethics, I will argue that the analogy can be best explained in terms of the approximate truth of normative theory which implies the existence of mind-independent natural moral properties. 4 CONTENTS Page Introduction 9 1. Metaphysical Ethical Naturalism 15 1.1 Moral Realism 16 1.1.1 The Mind Independence of Moral Properties 16 1.1.2 The Epistemic Objectivity of Moral Judgements 18 1.1.3 Moral Realism and Moral Fallibilism 19 1.1.4 Moral Entities can be Platonic Ante Rem Universals 20 1.1.5 Moral Realism needs Moral Cognitivism 22 1.2 Ethical Naturalism 23 1.2.1 Moral Properties and Other Natural Properties 23 1.2.2 Non-Reductive Naturalism and Reductive Naturalism 26 1.2.3 Non-Reductive Naturalism and Non-Naturalism 28 1.3 Methodological Naturalism in Ethics 29 1.4 Other Naturalisms in Ethics 32 1.4.1 Foot 32 1.4.2 Jackson 34 2. The Explanationist Argument for Metaphysical Ethical Naturalism 38 2.1 Recent Work for Naturalism 38 2.1.1 Railton's Reductive Naturalism 39 2.1.2 Brink's Defence of Naturalism 40 2.2 The Basic Explanationist Argument for Naturalism 41 2.3 The Expalantionist Thesis 42 2.3.1 Phenomena We Experience 43 2.3.2 Explanation 47 2.3.3 The Best Explanation 51 2.3.4 Inference to the Best Explanation and Realism 53 2.3.5 The Explanationist Thesis and Naturalism 55 2.4 Two Ways to Defend the Second Premise 57 2.4.1 The Singular Argument and the Abductive Argument 58 2.4.2 The Absence of the Discussion on the Abductive Argument 60 2.5 Singular Moral Explanationist Argument 62 2.6 Objections Against the Singular Argument 64 2.6.1 The Epiphenomenalist Objection 64 2.6.2 The Alternative Explanation Objection 64 2.6.3 The Semantic Objection 65 2.6.4 Moral Pessimistic Induction 65 2.6.5 The Normativity Objection 66 3. The Boydian Abductive Argument for Moral Realism 69 3.1 Boyd's Suggestion in 'How to be a Moral Realist' 70 5 3.2 Boyd's Argument for Scientific Realism 70 3.2.1 Scientific Realist Theses 71 3.2.2 Approximate Truth 71 3.2.3 Empirical Reliability 74 3.2.4 Theoretical Presuppositions 75 3.2.5 Realist Explanation 78 3.2.6 Philosophical Package 80 3.3 Analogous Argument for Moral Realism 84 3.3.1 Abductive Argument for Moral Realism 85 3.3.2 The Approximate Truth of First-Order Ethical Theory 86 3.3.3 The Empirical Reliability of First-Order Ethical Theory 91 3.3.4 Theoretical Presuppositions of First Order Ethical Theory 93 3.3.5 Moral Realist Explanation 95 3.3.6 Moral Realist Philosophical Package 99 3.4 The Abductive Argument and the General Objections against Naturalism 102 3.5 Some Defects of Boyd's Suggestion 107 4. Prospect for the Defence of the Abductive Argument 113 4.1 The Summary of the Previous Three Chapters 113 4.2 The Abductive Argument as a Placeholder Argument 115 4.3 On the Empirical Reliability of Normative Theory 116 4.4 On the Different Methods of Ethics 121 4.5 On the Moral Realist Philosophical Package 122 5. In Defending the Abductive Argument (Part 1) -a case of consequentialism- 126 5.1 Consequentialism 126 5.1.1 Theory of Right Acts 127 5.1.2 Theory of Wellbeing 128 5.2 The Empirical Reliability of Consequentialism 131 5.2.1 Prediction about People's Wellbeing 132 5.2.2 Subjective Measures of Happiness 132 5.2.3 Objective Measures of Happiness 134 5.3 The Theoretical Presuppositions of Consequentialism 137 5.3.1 Carol's Society 137 5.3.2 Revising Consequentialism 139 5.3.3 Theoretical Presuppositions 143 5.4 The Moral Realist Explanation of Consequentialism 145 5.4.1 Constructivist Explanation 146 5.4.2 No-Miracle Argument for Consequentialism 146 6. In Defending the Abductive Argument (Part 2) -a case of virtue ethics- 150 6.1 Virtue Ethics 150 6.1.1 Theory of the Moral Virtues 152 6.1.2 Theory of Human Goodness 155 6.1.3 Theory of Right Acts 157 6 6.2 The Empirical Reliability of Virtue Ethics 158 6.2.1 Prediction about Human Goodness 158 6.2.2 Prediction about the Possession of the Moral Virtues 160 6.3 The Theoretical Suppositions of Virtue Ethics 163 6.3.1 Vicky's Society 163 6.3.2 Revising Virtue Ethics 164 6.3.3 Theoretical Presuppositions 166 6.4 The Moral Realist Explanation of Virtue Ethics 168 6.4.1 Constructivist Explanation 168 6.4.2 No-Miracle Argument for Virtue Ethics 169 7. In Defending the Abductive Argument (Part 3) -a case of deontology?- 172 7.1 Naturalism and Deontology 172 7.1.1 The Accommodation Problem 173 7.1.2 The Methodological Problem 175 7.1.3 Prospect for Naturalistic Deontology 178 7.2 Kamm-Style Deontological Theory 180 7.2.1 Case-Based Initial Judgements 180 7.2.2 Assessing Principles 182 7.2.3 How a Principle is Discovered 182 7.2.4 Killing and Letting Die 184 7.3 The Empirical Reliability of Deontology 184 7.3.1 Cases People have Never Thought About 185 7.3.2 Prediction about Our Brains 187 7.4 The Theoretical Presuppositions of Deontology 192 7.4.1 Danielle's Society 193 7.4.2 Revising Deontology 194 7.4.3 Theoretical Presuppositions 196 7.5 The Realist Explanation of Deontology? 198 7.5.1 Constructivist Explanation 198 7.5.2 No-Miracle Argument for Deontology 198 7.5.3 Difficulty of Defending the Mind-Independence Thesis 200 8. Two Kinds of Objection against the Abductive Argument 205 8.1 Summary of Chapters V, VI and VII 205 8.2 Empirical Objections and Philosophical Objections 207 9. The Abductive Argument and Empirical Research on Moral Judgements 210 9.1 Social Psychology Undermining the Abductive Argument 210 9.2 Haidt on the Social Intuitionist Model 211 9.2.1 The Rationalist and the Social Intuitionist Models 212 9.2.2 Some Empirical Findings for the Social Intuitionist Model 213 9.3 What Might the Social Intuitionist Model Imply? 216 9.4 Lawyers Defend her Case on Reason 217 7 9.5 Lay People and Expert Moral Theorists 221 9.6 How Normative Ethicists Build Up Their Theories 223 9.6.1 Hooker's Consequentialism 224 9.6.2 Theoretical Presuppositions of Hooker's Theory 227 10.