“Ought Implies Can” as a Principle of the Moral Faculty By: Miklós Kürthy A thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy The University of Sheffield Faculty of Arts and Humanities Department of Philosophy January 2019 2 Abstract This thesis is a contribution to moral psychology, the systematic study of the cognitive processes underlying moral judgment. It has two main aims. First, it attempts to show that the so-called Linguistic Analogy (LA) is the most productive framework for the study of moral cognition. As its name suggests, LA has it that moral psychology can be fruitfully modelled on linguistics, in particular on the Chomskyan project of detailing the architecture of the Language Faculty (FL)—a domain-specific cognitive system dedicated to language. This means, amongst other things, that the fundamental task of moral psychology is to discover and detail the representations, principles, and computational operations of the Moral Faculty (FM)—a domain-specific cognitive system that underpins the human capacity for moral judgment. Second, the thesis argues that the “Ought Implies Can” principle (OIC)—according to which if an agent ought to perform an action, then she can perform that action—is one of the central principles of FM, and proposes a novel account of how OIC is implemented in FM. To achieve this second aim, the thesis presents novel empirical evidence on intuitive moral judgments of ordinary people and argues that the best explanation of these data is to consider OIC as a processing constraint on the operations of FM. 3 Acknowledgements Above all, I owe an enormous debt of gratitude to my amazing supervisors, Luca Barlassina and Stephen Laurence. I am lucky enough to have been Luca’s very first PhD student. In the past 4 years or so, we would repeatedly have 3-4 hour discussions on some of the topics discussed in the thesis (as well as many others). Given Luca’s wide-ranging knowledge and creativity, these discussions have always been the most intellectually inspiring moments of my years as a doctoral student. I only hope that the thesis reflects these discussions. When Luca and I meandered too far off the path, Steve was always there to nudge us back. His advice has always been extremely sensible and pragmatic. I must also thank both Luca and Steve for being available whenever needed, and, most importantly, for their patience. I am very grateful to the Department of Philosophy for letting me be part of this excellent department and for generously funding my PhD. In particular, I am much indebted to Jenny Saul for her support with various administrative issues. I want to thank Paulo Sousa and Holly-Lawford Smith for the collaboration, without which Chapter 3 would not have seen the light of day. Paulo invited me to Belfast no less than three times. During my visits, we had some extremely intellectually rewarding discussions, from which much of my thesis has benefitted. When I first arrived in Sheffield, Holly was one of the first friend/colleague who made me feel welcome. Our friendship has led to two collaborative papers and many interesting discussions. I also have to thank some of my friends who in one way or another have contributed fruitfully to my work. They are (in no particular order): Dávid Metzger, who is responsible for some of the most exciting bits in the thesis: the figures in the first two chapters. I can’t wait to return the favour Fecókam. Alex Duval, who has contributed to my thesis by lending me a laptop on which I ended up typing up the final two chapters, and more importantly by discussing some of the ideas in the thesis, and many others besides. I owe my greatest gratitude to José Avalos Díaz for drinking all my coffee and spoiling everything in Game of Thrones—and of course for being the best flatmate ever. Ryo Yokoe provided me with another laptop as well as endless conversations about topics of various degrees of seriousness. I thank Francesco Antilici for the peanuts, the gym tips, and all the heated arguments about conceptual content. I’m also grateful to Beth Flood for giving me inspiration for the examples in Chapter 1, Section 6. The Postgraduate student community of the Philosophy Department has also been a most welcome influence on my PhD years. In particular, I should mention (in random order) Lewis, Anton, Damiano, Emma, James, Barend, Phil, Gonzalo, Neri, Tony, Armin and Ahmad. Other Sheffield friends have also 4 shaped my experience in many unforgettable ways: Josie, Christina, Elle, Ingrid, Alexandra, John, Luisa. Thanks for all the memories. Many thanks also to my Budapest friends for always being there for me during my all too infrequent visits: Soma & Kata, Dávid & Anna, Koffer & Andi, Ancsa & Zsombor, Kata és a Kubasch család. Last, but by no means least, a massive thanks to my lovely family in Budapest: Mama, Apa, András, Ádám, Kristóf és Pau, Balázs és család. I miss you all! 5 Table of Contents Acknowledgements 4 List of figures 10 List of abbreviations 11 Introduction 12 Chapter 1: The Linguistic Analogy as a Framework for the Study of Moral Cognition 13 Chapter 2: The Linguistic Analogy—Comparisons, Objections and Replies 13 Chapter 3: The “Ought Implies Can” Principle and Descriptive Adequacy 14 Chapter 4: OIC Meets Cognitive Science—Hypotheses, Old and New 14 Chapter 1: The Linguistic Analogy as a Framework for the Study of Moral Cognition 15 Overview 15 1. The multiplicity of questions about morality 16 2. Two approaches to the Linguistic Analogy 18 3. The character of the explanandum 19 3.1. Mentalism 20 3.1.1. From behaviourism to cognitive science 20 3.1.2. E vs. I 21 3.2. Productivity in moral cognition: The Argument for Moral Grammar 23 3.2.1. The Argument for Mental (Linguistic) Grammar 23 3.2.2. The Argument for Moral Grammar 24 Issues with the Argument for Moral Grammar 27 A friendly amendment 28 3.3. Competence vs. performance 30 3.3.1. Language 30 3.3.2. Moral cognition 31 3.4. Production and perception 33 4. The nature of explanation 35 4.1. Computationalism and the search for moral principles 35 5. What is a principle? 37 6. Empirical standards of evaluation 47 6 Chapter 2: The Linguistic Analogy—Comparisons, Objections and Replies 54 Overview 54 1. The dual-process theory: Background and motivations 54 1.1. The bare bones 54 1.2. A tale of two systems: The DP framework 57 1.3. Evolution and the dual-process theory: A small detour 59 1.4. The efficiency-flexibility trade-off 63 2. The dual-process theory: An appraisal of the evidence 65 2.1. The flagship examples 65 2.2. Difficulties with the flagship examples 67 3. The appraisal problem: Descriptive adequacy 70 3.1. The problem 70 3.2. A second response to the appraisal problem 72 3.2.1. The bifurcation of the “personal” dimension 72 3.2.2. Modular myopia 73 3.3. Evaluation 75 3.3.1. Greene’s dual-process theory 75 3.3.2. The DP framework 76 4. LA: Objections and replies 77 4.1. Language vs. moral cognition 78 4.2. “Internal” vs. “external” principles 79 4.3. Is the Argument for Moral Grammar any good? 82 4.4. Do we need principles at all? 88 4.5. Is moral judgment a natural kind? 92 Chapter 3: The “Ought Implies Can” Principle and Descriptive Adequacy 95 Overview 95 1. Moral Philosophy, Moral Cognition, and Empirical Research 95 2. “Ought Implies Can” as a candidate principle of I-morality 97 2.1. Shape 98 2.2. Testing 99 3. First challenge: Buckwalter and Turri (2015) 100 4. Response to Buckwalter and Turri’s challenge 102 4.1. Potential problems with Buckwalter and Turri’s design 102 4.2. Initial evidence for the relevance of the problems identified: Two studies 103 7 4.2.1. Study 1 103 4.2.1.1. Method 104 Participants 104 Design, Materials and Procedure 104 4.2.1.2. Results 105 4.2.1.3. Discussion 106 4.2.2. Study 2 107 4.2.2.1. Method 107 Participants 107 Design, Materials and Procedure 108 4.2.2.2. Results 109 4.2.2.3. Discussion 109 4.3. The case against Buckwalter and Turri: Overview of new studies 110 4.4. Study 3: Promise 111 4.4.1. Method 112 Participants 112 Design, Materials and Procedure 112 4.4.2. Results 113 4.4.3. Discussion 113 4.5. Study 4: Playground safety worker 115 4.5.1. Method 115 Participants 115 Design, Materials and Procedure 115 4.5.2 Results 117 4.5.3 Discussion 117 4.6. Study 5: Lifeguard 120 4.6.1. Method 120 Participants 120 Design, Materials and Procedure 120 4.6.2. Results 121 4.6.3. Discussion 121 4.7. Study 6: Drowning child 122 4.7.1. Method 123 Participants 123 8 Design, Materials and Procedure 123 4.7.2. Results 124 4.7.3. Discussion 124 4.8. Summary of results 126 5. Second challenge: Chituc et al. (2016) 128 6. Conclusion 131 Chapter 4: OIC Meets Cognitive Science—Hypotheses, Old and New 133 Overview 133 1. Three rationales for OIC 133 2. The Semantic Hypothesis (SH) 136 2.1. Against SH 137 3. The Pragmatic Hypothesis (PH) 138 3.1. Against PH 140 4. OIC and FM 141 4.1. Problems with extant accounts of OIC 142 4.2. New hypotheses 145 4.2.1. OIC as a processing principle (descriptive adequacy) 145 4.2.2.