The Normativity of Rationality Ralph Wedgwood Contents Preface Introduction Chapter 1: Is Rationality Normative? Chapter 2: The Beginnings of an Answer Chapter 3: Rationally Ought Implies Can Chapter 4: The Pitfalls of Reasons Chapter 5: Objective and Subjective Ought Chapter 6: Rationality as a Virtue Chapter 7: Internalism Re-explained Chapter 8: Why Does Rationality Matter? Chapter 9: The Aim of Rationality: Correctness Conclusion: Looking Ahead
2 Preface Here are three fundamental truths about rationality. 1. Rationality is a normative concept: whenever a belief or a choice is rational, it is rationally permissible, in a sense of permissible that is closely akin to those that are central to ethics. 2. Rationality is an internal matter: whether a belief or choice is rational depends solely on what is going on inside the thinker s mind. 3. Rationality serves an external goal namely, believing the truth, and making good decisions that one will actually put into effect. I have been convinced of these three truths ever since the summer of 1988, around the end of my first year of studying philosophy at King s College London, when Christopher Peacocke tutored me in Epistemology and Metaphysics, and I wrote my Master s thesis under the supervision of Mark Sainsbury on scepticism and rational belief. I became convinced of the first and third truth from reading Alvin Goldman (1986), and convinced of the second truth from reading John Pollock (1986). Of course, Goldman rejects the second truth, while Pollock rejected the first and third. In this way, the view that I became convinced of at that time was a kind of middle way between the positions of those two distinguished epistemologists. Later, when I studied ethics and practical reason as a doctoral student at Cornell, I conceived the ambition of integrating my earlier interests in rational belief with my later interests in rational choice, and giving a unified theory of rationality, encompassing both rational belief and rational choice, in which these three truths play a fundamental role. Over the years, however, I slowly changed my mind about how exactly to reconcile these three truths with each other. During my years of teaching at MIT (1995 2002) and then at Oxford (2002 11), I grew increasingly interested in and sympathetic to the approaches to rationality that are characteristic of formal epistemology and rational choice theory, especially through studying the work of John Broome (1991a) and James M. Joyce (1998 and 1999). As a result, I finally came to endorse the thoroughly probabilistic conception of the relationship between rationality and its external goal that will be outlined in Chapters 5 and 9 of this book. It has taken me far longer than I initially expected to complete this work. After first conceiving the ambition of giving a unified theory of rationality, I started working out the
3 ideas in a series of articles over the next seventeen years (Wedgwood 1990, 1998, 1999, 2002a, 2002b, 2002c, 2002d, 2003, 2006a, and 2006b). But most of my work during that period was devoted to the broadly metaethical investigations that culminated in The Nature of Normativity (Wedgwood 2007a). So it was not until after 2007 that I turned in earnest to this long-postponed project on rationality. I started working on this project during a period of leave that I had from Oxford in 2008, which I spent visiting the Hebrew University of Jerusalem. Then in 2009, I successfully applied for a one-year Research Fellowship from the Leverhulme Trust, which gave me a whole year s leave from Oxford during 2009-10. My plan was to complete the work on rationality over the course of that year. I spent the last two months of that year visiting the Philosophy Program at the Research School of Social Sciences at the Australian National University. At that time, my idea was to present the whole work in a single big book, in twelve chapters. Over the course of 2009-10, I did indeed succeed in writing about six of those twelve chapters. Around the end of my time in Australia, however, I became convinced that there were some fundamental problems with the theory that I was defending. (Some of these problems emerged when I discussed parts of my draft with Declan Smithies, who was also visiting the ANU at the time; others emerged when Toby Handfield asked me some probing questions when I presented some of the work as a talk at Monash University.) So I realized that I had to abandon the book manuscript that I had produced so far, and start over from the beginning. Even though I had no more periods of leave from Oxford after the end of September 2010, I believe that I found the solution to some of these fundamental problems in the first half of 2011. Then at the beginning of 2012, I left Oxford and moved to the University of Southern California (USC). Moving and settling into California took a great deal of time, but by the end of 2012, I came to feel satisfied that I had solved the principal remaining problems. By then, however, the investigation of rationality that I was planning had grown to even greater proportions. So I decided that I would have to split this investigation up into three separate volumes. The result is the trilogy of which this book is the first instalment. Except for the Preface, Introduction, and Conclusion, every chapter of this book has been presented as at least part of a talk somewhere. Specifically, talks based on Chapters 1 and 2 were presented in 2010 at the University of Vienna and the University of Uppsala, in 2013 at the University of Tromsø, and in 2014 at the annual Philosophy Conference in Bled, Slovenia. Versions of Chapter 3 were presented in 2011 at the University of Reading, and in 2012 at a conference on Epistemic Agency in Oaxaca, Mexico (where I benefited from incisive comments by David Sosa and Aaron Zimmerman). Versions of Chapter 4 were presented in 2013 at a conference on Reasons at the University of St Andrews, in 2014 at New York
4 University, and in 2015 at the Massachusetts Institute of Technology (where I benefited from comments by Daniel Munoz). Versions of Chapter 5 were presented in 2012 at the University of California, Berkeley, in 2013 at the University of Edinburgh, and in 2014 at the University of Birmingham. Versions of Chapter 6 were presented in 2013 at a conference in honour of Gail Fine and Terence Irwin at Cornell University, and the Analytic Philosophy conference at the University of Texas at Austin, and in 2014 at the University of Nebraska. Versions of Chapter 7 were presented in 2010 at the University of Otago, in 2013 at a workshop on Narrow Content at the Centre for the Study of Mind in Nature at the University of Oslo, in 2014 at the University of Stockholm, and in 2015 at Rutgers University. Versions of Chapters 8 and 9 were presented in 2012 at the University of California, Riverside, at Stanford, at the Centre for Mathematical Philosophy in Munich, at the University of California, Santa Barbara, in 2013 at the University of Oxford, and in 2015 at the Université de Montréal. I am grateful to all those audiences for all their helpful comments. The final revisions to the book were carried out in 2016. At that point, I benefited greatly from the comments of two anonymous readers for Oxford University Press, from a workshop on the book manuscript at the Université de Montréal (and especially from my three commentators in Montreal, Sergio Tenenbaum, Kate Nolfi, and Bruno Guindon), and from the members of two audiences in Berlin, at the Free University and at the Humboldt University, who discussed Chapter 4 and Chapters 8 9 of the book manuscript respectively. As I explain below, earlier versions of Chapters 3 7 have already been either published or at least accepted for publication elsewhere. In three cases, I owe a special debt to philosophers who gave me written comments on these earlier versions. David Sosa and Aaron Zimmerman commented on an earlier version of Chapter 3; Ram Neta commented on an earlier version of Chapter 4; and Nate Charlow, Matthew Chrisman, Alex Silk, and Malte Willer all commented on earlier versions of Chapter 5. I am especially grateful for the help that I have received from all these perceptive commentators. I have also benefited over the years from many helpful comments from colleagues and students at Oxford, at USC, and elsewhere. I am particularly grateful to the doctoral students whom I have supervised and examined over this period; these students have helped me to understand the topics much better than I would otherwise have done. Of these doctoral students, the ones who have worked on topics that are immediately relevant to this book include: Julian Fink, Jane Friedman, Yair Levy, William MacAskill, and Amia Srinivasan (at Oxford); Rima Basu, Michael Hatcher, Shyam Nair, and Julia Staffel (at USC); Ittay Nissan-Rosen (at the LSE); and Alex Worsnip (at Yale).
5 I am also grateful to the Leverhulme Trust, who gave me a Research Fellowship during 2009-2010, when some of the work that went into this book was carried out; to the Hebrew University of Jerusalem and the Australian National University for Visiting Fellowships in 2008 and 2010 respectively; and to my current employer, USC, for partial teaching relief in 2012-2014, and for a period of sabbatical leave in the Spring Semester of 2015. An earlier version of Chapter 3 was published as Rational Ought Implies Can in Philosophical Issues (2013); a version of Chapter 4 was published as The Pitfalls of Reasons in Philosophical Issues (2016); and a version of Chapter 6 was published as Rationality as a Virtue in Analytic Philosophy (2014): these chapters appear here by permission of Wiley- Blackwell. A version of Chapter 5 was published as Objective and Subjective Ought in Matthew Chrisman and Nate Charlow, ed., Deontic Modality (Oxford University Press, 2016); a version of Chapter 7 was published as Internalism Re-explained in Julien Dutant, ed., The New Evil Demon Problem (Oxford University Press, 2017): these chapters appear here by permission of Oxford University Press. This book is dedicated to my mother, and to the memory of my father.