MECHANICAL EPISTEMOLOGY AND MIXED MATHEMATICS: Descartes’s Problems and Hobbes’s Unity by Marcus P. Adams B.A., Lee University, 2003 M.Div., Ashland Theological Seminary, 2006 M.A., Western Michigan University, 2008 Submitted to the Graduate Faculty of The Kenneth P. Dietrich School of Arts and Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy University of Pittsburgh 2014 UMI Number: 3583999 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMI 3583999 Published by ProQuest LLC (2014). Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, MI 48106 - 1346 UNIVERSITY OF PITTSBURGH THE KENNETH P. DIETRICH SCHOOL OF ARTS AND SCIENCES This dissertation was presented by Marcus P. Adams It was defended on April 8, 2014 and approved by Stephen Engstrom, Professor of Philosophy, University of Pittsburgh Daniel Garber, Stuart Professor of Philosophy, Princeton University Douglas Jesseph, Professor of Philosophy, University of South Florida Paolo Palmieri, Associate Professor History & Philosophy of Science, University of Pittsburgh Nicholas Rescher, Distinguished University Professor of Philosophy, University of Pittsburgh Dissertation Advisor: Peter Machamer, Professor of History & Philosophy of Science, University of Pittsburgh ii Copyright © by Marcus P. Adams 2014 iii MECHANICAL EPISTEMOLOGY AND MIXED MATHEMATICS: Descartes’s Problems and Hobbes’s Unity Marcus P. Adams, Ph.D. University of Pittsburgh, 2014 My dissertation answers what appears to be a simple question: How is Hobbes’s politics related to his physics and metaphysics? However, answering this question has proved more difficult for scholars than it appears at first glance, and there has there has been no consensus in the literature over the past fifty years. Two well-represented extremes dominate the literature: the first view claims that Hobbes’s politics is deduced from his physics and ultimately his metaphysics; and the second view claims that the politics arose independently of Hobbes’s other work. My dissertation argues that Hobbes does in fact provide a unified systematic philosophy, and I contrast this unity with problems in Descartes's epistemology and optics. To make this argument, I carve a middle way between the two extremes in the literature by situating Hobbes within mechanical philosophy and 17th century mathematics. I use three concepts to clarify Hobbes’s project: mechanical explanation, maker’s knowledge, and mixed mathematical science. First, I show that for Hobbes a mechanical explanation involves tracing the motions of bodies at various levels of complexity, from simple points in geometry to human bodies in the state of nature and to commonwealth bodies. This view provides Hobbes with resources for a naturalized epistemology, which I show is the point at issue in Hobbes’s Objections to Descartes's Meditations. Second, Hobbes says that we have “maker's knowledge” in geometry and politics. I show that “maker’s knowledge” is Hobbes's iv empiricist answer to (1) how we have causal knowledge in politics and mathematics by constructing and (2) how mathematics is applicable to the world. Finally, I show that the mixed mathematical sciences, e.g., optics, were Hobbes's inspiration for a unified philosophical system. I argue that the physics in De corpore, the optics in De homine, and the politics in Leviathan are treated by Hobbes as mixed mathematical sciences, which provides a new way to see Hobbes as a consistent and non-reductive naturalist. Viewed in this light, the Leviathan turns out to have more methodological similarities to optics than to geometry. v TABLE OF CONTENTS PREFACE .................................................................................................................................... XI 1.0 INTRODUCTION ........................................................................................................ 1 1.1 HOBBES AND THE UNITY OF THE SCIENCES ......................................... 1 1.2 UNIFIED VERSUS DISJOINT SCIENCES ..................................................... 4 2.0 THE WAX AND THE MECHANICAL MIND: REEXAMINING HOBBES’S OBJECTIONS TO DESCARTES’S MEDITATIONS ............................................................... 9 2.1 INTRODUCTION ............................................................................................... 9 2.2 THE WAX IN THE SECOND MEDITATION AND HOBBES’S OBJECTION ....................................................................................................................... 12 2.2.1 “Tak[ing] off the clothes, as it were”: Descartes’s Method and the Wax. 12 2.2.2 Hobbes’s Objection: Conceiving versus Perceiving and Reasoning as the “Linking of Names” ................................................................................................... 15 2.3 A MECHANICAL EPISTEMOLOGY FOR MECHANICAL MINDS ...... 17 2.3.1 Hobbes’s Philosophical Psychology: Stages 1 and 2 of the Mechanism ... 17 2.3.2 From the Mechanical Mind to Mechanical Epistemology: Stages 3 and 5 of the Mechanism ....................................................................................................... 22 2.3.2.1 Conceptions and Language ................................................................ 22 2.3.2.2 The Activity of Philosophizing ........................................................... 26 vi 2.3.2.3 Questioning an Epistemology of Simplest Conceptions ................... 30 2.4 REVISITING HOBBES’S FOURTH OBJECTION TO THE MEDITATIONS .................................................................................................................. 34 2.5 CONCLUSION .................................................................................................. 37 3.0 MECHANICAL EPISTEMOLOGY, MAKER’S KNOWLEDGE, AND SCIENTIA .................................................................................................................................... 38 3.1 INTRODUCTION ............................................................................................. 38 3.2 CAUSAL KNOWLEDGE IN A WORLD OF UNDERDETERMINED APPEARANCES ................................................................................................................ 41 3.3 GEOMETRIC CONSTRUCTION AND CAUSAL KNOWLEDGE ........... 45 3.3.1 Knowledge of Particular Causes in Geometry ............................................ 48 3.3.2 Knowledge of Universal Causes in Geometry through Definition ............ 52 3.4 FIRST PHILOSOPHY AS COMPUTATION AND CONSTRUCTION ..... 64 3.5 CONCLUSION: BUT IS CAUSAL KNOWLEDGE REALLY AVAILABLE IN NATURAL PHILOSOPHY? ....................................................................................... 73 4.0 HOBBES, ARISTOTLE, AND MIXED MATHEMATICS .................................. 76 4.1 INTRODUCTION ............................................................................................. 76 4.2 GEOMETRY AND HOBBESIAN OPTICS ................................................... 79 4.2.1 A Case study from Hobbes’s Optics in De homine 2 .................................. 79 4.2.2 Hobbes’s Geometry in De corpore Part III ................................................. 83 4.2.3 De homine Case Study Revisited .................................................................. 88 4.2.4 Hobbes’s Optics and the Deductivist Account ............................................ 92 4.3 ARISTOTLE AND HOBBES ON MIXED MATHEMATICS ..................... 94 vii 4.3.1 Aristotle on Mixed Mathematics .................................................................. 95 4.3.2 Hobbes and the Aristotelian Mixed Mathematics Tradition ..................... 97 4.4 CONCLUSION ................................................................................................ 101 5.0 HOBBES, BOYLE, AND NATURAL PHILOSOPHY AS “TRUE PHYSICS” 105 5.1 INTRODUCTION ........................................................................................... 105 5.2 DE CORPORE PART IV AS MIXED-MATHEMATICAL “TRUE PHYSICS” ......................................................................................................................... 108 5.2.1 The Explanation of Sensation in De corpore 25.1-2 .................................. 108 5.2.2 The Explanation of Swelling of the Parts of the Body when Warm in De corpore 27.3 ............................................................................................................... 115 5.2.3 De corpore Part IV Reconsidered ............................................................... 124 5.3 MIXED MATHEMATICS AND LEVIATHAN AND THE AIRPUMP ...... 125 5.4 CONCLUSION ................................................................................................ 132 6.0 HUMAN SCIENCE AND POLITICS .................................................................... 134 6.1 INTRODUCTION ........................................................................................... 134 6.2 HUMANS CONSIDERED AS NATURAL BODIES ................................... 136 6.2.1 Leviathan Part I versus Hobbes’s Other Works ....................................... 137 6.2.2 A Complete Account of the Passions.......................................................... 139 6.2.2.1 Elements of Law ................................................................................. 139 6.2.2.2 Complete Account of the Passions: De homine and Leviathan ..... 141 6.2.3 Making an “Inference from the Passions” to the State of Nature........... 145 6.2.3.1 Driving Passions and Humans outside of Society .......................... 148 6.2.3.2 How the Driving Passions are Related to One Another ................ 153 viii 6.2.4 Reason and Persons ..................................................................................... 156 6.3 HUMANS AS CITIZENS ............................................................................... 160 6.3.1 Final Causes in the Commonwealth and Not in Geometry ..................... 161 6.3.2 The Maker(s) of the Commonwealth versus The Maker in Geometry .. 164 6.3.2.1 Maker’s Knowledge for Those Who enter the Covenant? ............ 164 6.3.2.2 The Sovereign as Maker and Politics as Mixed Mathematics ...... 171 BIBLIOGRAPHY ..................................................................................................................... 179 ix