SKEPTICISM IN PHILOSOPHY In this book, Henrik Lagerlund offers students, researchers, and advanced general readers the first complete history of what is perhaps the most famous of all phi- losophical problems: skepticism. As the first of its kind, the book traces the influence of philosophical skepticism from its roots in the Hellenistic schools of Pyrrhonism and the Middle Academy up to its impact inside and outside of phi- losophy today. Along the way, the book covers skepticism during the Latin, Arabic, and Greek Middle Ages and during the Renaissance before moving on to cover Descartes’ methodological skepticism and Pierre Bayle’s super-skepticism in the seventeenth century. In the eighteenth century, it deals with Humean skepticism and the anti-skepticism of Reid, Shepherd, and Kant, taking care to also include reflections on the connections between idealism and skepticism (including skep- ticism in German idealism after Kant). The book covers similar themes in a chapter on G.E. Moore and Ludwig Wittgenstein, and then ends its historical overview with a chapter on skepticism in contemporary philosophy. In the final chapter, Lagerlund captures some of skepticism’s impact outside of philosophy, highlighting its relation to issues like the replication crisis in science and knowl- edge resistance. Henrik Lagerlund is Professor of the History of Philosophy at Stockholm University, Sweden. He works primarily on medieval and Renaissance philoso- phy, and has written several articles and books. He is also the editor of The Rou- tledge Companion to Sixteenth Century Philosophy (2017) and The Encyclopedia of Medieval Philosophy, second edition (2020). PRAISE FOR THIS BOOK: “Henrik Lagerlund’s Skepticism in Philosophy: A Comprehensive, Historical Introduc- tion has the rare distinction of offering a rich and thorough historical overview of skeptical thought, while nonetheless remaining engaging and accessible through- out. This book will be particularly welcomed by those teaching in this field.” Duncan Pritchard, University of California, Irvine, and The University of Edinburgh “Henrik Lagerlund’s Skepticism in Philosophy: A Comprehensive, Historical Introduc- tionis precisely this:comprehensiveandhistorical,butmore thananything,[it’s]a philosophically rich engagement with skepticism. The book will engage and enlighten any philosopher thinking about skepticism and the history of epistemology.” Katja Maria Vogt, Columbia University SKEPTICISM IN PHILOSOPHY A Comprehensive, Historical Introduction Henrik Lagerlund Firstpublished2020 byRoutledge 52VanderbiltAvenue,NewYork,NY10017 andbyRoutledge 2ParkSquare,MiltonPark,Abingdon,OxonOX144RN RoutledgeisanimprintoftheTaylor&FrancisGroup,aninformabusiness ©2020Taylor&Francis TherightofHenrikLagerlundtobeidentifiedasauthorofthisworkhasbeen assertedbyhiminaccordancewithsections77and78oftheCopyright, DesignsandPatentsAct1988. Allrightsreserved.Nopartofthisbookmaybereprintedorreproducedor utilisedinanyformorbyanyelectronic,mechanical,orothermeans,now knownorhereafterinvented,includingphotocopyingandrecording,orinany informationstorageorretrievalsystem,withoutpermissioninwritingfromthe publishers. Trademarknotice:Productorcorporatenamesmaybetrademarksorregistered trademarks,andareusedonlyforidentificationandexplanationwithoutintent toinfringe. LibraryofCongressCataloging-in-PublicationData Acatalogrecordforthistitlehasbeenrequested ISBN:978-1-138-55554-9(hbk) ISBN:978-1-138-55556-3(pbk) ISBN:978-1-315-14962-2(ebk) TypesetinBembo byTaylor&FrancisBooks To Eliza CONTENTS Preface ix List of Abbreviations and References xi Introduction 1 1 Pyrrhonism and Sextus Empiricus 7 2 Academic Skepticism 25 3 Augustine and Early Medieval Skepticism 41 4 Al-Ghazâlî and Skepticism in Medieval Arabic and Greek Philosophy 62 5 God as a Deceiver: External World Skepticism in Later Medieval Times 78 6 Skepticism in the Sixteenth Century: Montaigne, Charron, and Sanches 101 7 Descartes’ Methodological Skepticism, Bayle’s Super- Skepticism, and Berkeley’s Anti-Skepticism 119 8 Hume’s Skepticism and Hume on Skepticism 144 9 The Anti-Skepticism of Thomas Reid, Lady Mary Shepherd, and Immanuel Kant as well as Skepticism in German Idealism 160 10 G.E. Moore and Ludwig Wittgenstein on Skepticism 187 viii Contents 11 Skepticism in Contemporary Philosophy 207 12 Non-Philosophical Skepticism 223 Index 235 PREFACE My interest in skepticism stems, foremost, from my interest in medieval and Renaissance philosophy, but also from my worry that something is lost by not takingintoaccountfourteenth-centurythinkingwhenwritingthehistoryoflater, particularly Renaissance and early modern, philosophy. Skepticism is a case in point.AsIhopewillbeclearfromthisbook,manyofthemostsignificantchanges toskepticismweremadeduringthattime,anditseemstomeessentialtokeepthat inmindwhenapproachingsixteenth-andseventeenth-centuryskepticism. Another longstanding infatuation with skepticism stems from my own initial encounter with philosophy through Descartes and the titillating thoughts that I amlockedbehindmyperceptionsorideas,andthatIdonotknowwhetherthere is an external world or not. I was defending my dissertation in medieval philo- sophythesameyearasTheMatrixpremiered,in1999.IwasflabbergastedbyThe Wachowskis’ take on the problem. I have been wanting to take the red pill ever since; although the philosopher in me keeps pointing out that it will not help. Naturally, it is not possible to write a book, any book, but certainly not this book,withouthelpalongtheway.IamgratefultotheDepartmentofPhilosophy atWesternUniversity,Canada,andmycolleaguesthere,whereIbegantodevelop thethoughtspresentedhere.IamalsogratefultotheDepartmentofPhilosophyat UCLAforallowingmetoteachthefirsthalfofthisbookduringmyyearasavis- iting professor there in 2016–2017. I am furthermore indebted to my present employertheDepartmentofPhilosophyatStockholmUniversityforallowingme torearrangemyteachingscheduletofitwithmywritingschedule.Theyalsogave metheopportunitytoteachthesecondhalfofthisbooklastyear. I would especially like to thank the following people: Benjamin Hill, Lorne Falkenstein,KarenNielsen,TomLennon,CalvinNormore,LilliAlanen,Deborah Brown, Katja Vogt, Åsa Wikforss, Hans Mathlein, Guido Alt, Sandra Lindblom,