Synthetic Ethical Naturalism Michael Rubin University of Massachusetts Amherst, [email protected]
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University of Massachusetts Amherst ScholarWorks@UMass Amherst Open Access Dissertations 2-2009 Synthetic Ethical Naturalism Michael Rubin University of Massachusetts Amherst, [email protected] Follow this and additional works at: https://scholarworks.umass.edu/open_access_dissertations Part of the Ethics and Political Philosophy Commons Recommended Citation Rubin, Michael, "Synthetic Ethical Naturalism" (2009). Open Access Dissertations. 24. https://doi.org/10.7275/qhda-m972 https://scholarworks.umass.edu/open_access_dissertations/24 This Open Access Dissertation is brought to you for free and open access by ScholarWorks@UMass Amherst. It has been accepted for inclusion in Open Access Dissertations by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact [email protected]. SYNTHETIC ETHICAL NATURALISM A Dissertation Presented by MICHAEL RUBIN Submitted to the Graduate School of the University of Massachusetts Amherst in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY February 2009 Philosophy © Copyright by Michael Rubin 2009 All Rights Reserved SYNTHETIC ETHICAL NATURALISM A Dissertation Presented by MICHAEL RUBIN Approved as to style and content by: _____________________________________ Fred Feldman, Chair _____________________________________ Phillip Bricker, Member _____________________________________ Hilary Kornblith, Member _____________________________________ Christopher Potts, Member _______________________________________ Phillip Bricker, Department Head Philosophy DEDICATION To my family: Linda, Michelle and Neil Rubin ACKNOWLEDGEMENTS In writing this dissertation, I have incurred a number of debts, not all of which are financial. My greatest debt is to my dissertation director Fred Feldman. I am also grateful to Hilary Kornblith, Jason Raibley, Lynne Rudder Baker, Jake Bridge, Phil Bricker, Vere Chappell, Sam Cowling, Dan Doviak, Chris Heathwood, Kristen Hine, Justin Klocksiem, Uri Leibowitz, Helen Majewski, Kris McDaniel, Kirk Michaelian, Andrew Platt, Chris Potts, Alex Sarch, Kelly Trogdon, and Brandt Van der Gaast. Material from chapters one and two appear in “Sound Intuitions on Moral Twin Earth,” Philosophical Studies (2008) 139: 307-327. I thank Springer for permission to reprint that material here. Chapter five is published as “Is Goodness a Homeostatic Property Cluster?” (2008) Ethics 118: 496-528. I thank the University of Chicago Press for permission to reprint that material here. I am grateful to anonymous referees from both journals for helpful comments. v ABSTRACT SYNTHETIC ETHICAL NATURALISM FEBRUARY 2009 MICHAEL RUBIN, B.A., BOSTON UNIVERSITY M.A., NEW YORK UNIVERSITY Ph.D., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Fred Feldman This dissertation is a critique of synthetic ethical naturalism (SEN). SEN is a view in metaethics that comprises three key theses: first, there are moral properties and facts that are independent of the beliefs and attitudes of moral appraisers (moral realism); second, moral properties and facts are identical to (or constituted only by) natural properties and facts (ethical naturalism); and third, sentences used to assert identity or constitution relations between moral and natural properties are expressions of synthetic, a posteriori necessities. The last of these theses, which distinguishes SEN from other forms of ethical naturalism, is supported by a fourth: the semantic contents of the central moral predicates such as ‘morally right’ and ‘morally good’ are fixed in part by features external to the minds of speakers (moral semantic externalism). Chapter 1 introduces SEN and discusses the most common motivations for accepting it. The next three chapters discuss the influential “Moral Twin Earth” argument against moral semantic externalism. In Chapter 2, I defend this argument from the charge that the thought experiment upon which it depends is defective. In Chapters 3 and 4, I consider two attempts to amend SEN so as to render it immune to the Moral vi Twin Earth argument. I show that each of these proposed amendments amounts to an abandonment of SEN. Chapter Five explores Richard Boyd’s proposal that moral goodness is a “homeostatic property cluster.” If true, Boyd’s hypothesis could be used to support several metaphysical, epistemological, and semantic claims made on behalf of SEN. I advance three arguments against this account of moral goodness. In the sixth chapter, I argue that moral facts are not needed in the best a posteriori explanations of our moral beliefs and moral sensibility. Because of this, those who accept a metaphysical naturalism ought to deny the existence of such facts or else accept skepticism about moral knowledge. In Chapter 7, I consider a counterargument on behalf of SEN to the effect that moral facts are needed in order to explain the predictive success of our best moral theories. I show that this argument fails. vii TABLE OF CONTENTS Page ACKNOWLEDGEMENTS.................................................................................................v ABSTRACT....................................................................................................................... vi CHAPTER 1. MORAL REALISM, ETHICAL NATURALISM, AND THE NECESSARY A POSTERIORI .................................................................................................................1 1.1. Introduction.....................................................................................................1 1.2. Moral Realism.................................................................................................4 1.2.1. Moral Realism and Moral Constructivism....................................4 1.2.2. The presumptive case for moral realism.......................................6 1.3. Naturalism: Metaphysical and Ethical............................................................9 1.3.1. Ethical naturalism. ........................................................................9 1.3.2. Metaphysical naturalism. ............................................................11 1.4. Analytic Ethical Naturalism..........................................................................12 1.4.1. The general strategy of analytic ethical naturalism. ...................12 1.4.2. Semantic assumptions of analytic ethical naturalism. ................13 1.4.3. First-order normative ethics as conceptual analysis. ..................16 1.5. The Rejection of Realistic Analytic Ethical Naturalism...............................17 1.5.1. The rejection of analyticity. ........................................................17 1.5.2. Doubts about descriptivism.........................................................18 1.5.3. The open question argument.......................................................19 1.5.4. Chauvinistic conceptual relativism.............................................21 1.5.5. The argument from normativity..................................................23 1.5.6. Analyticity and stance-independence. ........................................25 1.6. Synthetic Ethical Naturalism. .......................................................................26 1.6.1. The necessary a posteriori..........................................................26 1.6.2. The semantic and metaphysical underpinnings of the necessary a posteriori..................................................................................28 1.6.3. Causal theories of reference........................................................30 1.6.4. The epistemological commitments of SEN. ...............................34 viii 1.7. How SEN answers the objections to AEN....................................................39 2. MORAL TWIN EARTH VERSUS EXTERNALIST MORAL SEMANTICS...........43 2.1. Introduction...................................................................................................43 2.2. Putnam’s Twin Earth. ...................................................................................44 2.3. Moral Twin Earth..........................................................................................47 2.4. The Attack on the Moral Twin Earth Thought Experiment..........................51 2.4.1. Introduction.................................................................................51 2.4.2. A preliminary objection. .............................................................52 2.4.3. First objection: competing theories of a kind. ............................55 2.4.4. First reply....................................................................................56 2.4.5. Second reply................................................................................57 2.5. Isolating Moral Properties.............................................................................60 2.5.1. Second objection.........................................................................60 2.5.2. Reply to (i). .................................................................................62 2.5.3. Reply to (ii).................................................................................63 2.5.4. Reply to (iii)................................................................................65 2.6. Functional and Non-Functional Kinds..........................................................68 2.6.1. Third objection............................................................................68 2.6.2. Reply...........................................................................................69