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052185959X - The Principle of Sufficient Reason - A Reassessment - by Alexander R. Pruss
Frontmatter/Prelims

The Principle of Sufficient Reason

The Principle of Sufficient Reason (PSR) says that all contingent facts must have explanations. In this volume, the first on the topic in the English language in nearly half a century, Alexander Pruss examines the substantive philosophical issues raised by the PSR, which currently is considered primarily within the context of various cosmological arguments for the existence of God. Discussing several forms of the PSR and selected historical episodes from Parmenides, Aquinas, Leibniz, Hume, and Kant, Pruss defends the claim that every true contingent proposition must have an explanation against major objections, including Hume’s imaginability argument and Peter van Inwagen’s argument that the PSR entails modal fatalism. Pruss also provides a number of positive arguments for the PSR, based on considerations as different as the metaphysics of existence, counterfactuals and modality, negative explanations, and the everyday applicability of the PSR. Moreover, Pruss shows how the PSR would advance the discussion in a number of disparate fields, such as metaethics and the philosophy of mathematics.

Alexander R. Pruss is Assistant Professor of Philosophy at Georgetown University. He has published many papers on metaphysics, philosophy of religion, applied ethics, probability theory, and geometric symmetrization theory. With Richard M. Gale he is coeditor of The Existence of God.

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The Principle of Sufficient Reason

A Reassessment

ALEXANDER R. PRUSS
Georgetown University

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Pruss, Alexander R.
The principle of sufficient reason : a reassessment / Alexander R. Pruss.
p. cm. – (Cambridge studies in philosophy)
Includes bibliographical references and index.
ISBN 0-521-85959-X (hardback)
1. Sufficient reason. I. Title. II. Series.
BD591.P78 2006
111–dc22 2005015857

ISBN-13 978-0-521-85959-2 hardback
ISBN-10 0-521-85959-X hardback

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For my father and mother

Acknowledgments		page xiii
Part I The Principle of Sufficient Reason and the Causal Principle
1	Introduction	3
	1.1. The Significance of the PSR	3
	1.2. A Restriction to Contingent Truths	10
	1.3. Why Accept the PSR?	13
	1.4. What Are We Talking About?	16
2	Reflections on Some Historical Episodes	20
	2.1. Parmenides	20
	2.2. Thomas Aquinas	26
	2.3. Leibniz	28
	2.4. Hume	31
	2.5. Kant	37
3	The Causal Principle and the PSR	41
	3.1. Chains of Causes	41
	3.2. The ex Nihilo Nihil Principle, the PSR, and the CP	58
	3.3. Resisting the Extension to Necessary Truths	62
	3.4. Resisting the Restriction to Positive States of Affairs	64
	3.5. A Survey of Some Principles	66
Part II Objections to the PSR
4	A Modern Version of the Hume Objection	75
	4.1. Toy Models	75
	4.2. A Possibility Principle	76
	4.3. A Stronger Possibility Principle	77
	4.4. The Empty World	78
	4.5. Physicists Are Not Merely Logicians	79
5	The Anti-theological Argument That There Are No Necessary Beings	82
	5.1. Cosmological Arguments	82
	5.2. Necessary Beings and Absurdity	84
	5.3. Rescher’s Alternatives to Invoking the Existence of a Necessary Being	85
	5.4. Is the Notion of a Necessary Being Absurd?	90
	5.5. Philosophy of Mind Objections	93
	5.6. Lawmakers and Laws	95
6	Modal Fatalism	97
	6.1. Van Inwagen’s Argument	97
	6.2. The Existence of the Big Conjunctive Contingent Fact	99
	6.3. The Nature of Explanation	103
7	Free Will	126
	7.1. How to Explain Free Actions?	126
	7.2. Reasoned Choices	132
	7.3. Objections to Libertarianism	138
	7.4. Sufficient Reasons	142
	7.5. An Incredulous Stare	147
	7.6. Contrastive Explanations?	148
	7.7. The Modesty of This Account and Some Alternatives	155
	7.8. Conclusions	158
8	Quantum Mechanics	160
	8.1. The Problem of Indeterminism	160
	8.2. Rejecting Indeterminism	161
	8.3. Indeterminism and PSR	168
	8.4. Particles Coming into Existence ex Nihilo	169
9	Turning Leibniz against the PSR	171
	9.1. In Favor of (86)	171
	9.2. A Defense of the TPII	175
	9.3. Against (86)	177
	9.4. Against (87)	178
10	What Survives the Criticisms of the PSR?	184
Part III Justifications of the PSR
11	Self-Evidence	189
	11.1. A Definition of Self-Evidence	190
	11.2. The Objection from Smart People Who Disagree	190
	11.3. But Isn’t the PSR Easy to Understand?	191
	11.4. Two Ways Not to Understand	193
	11.5 More Detail	196
	11.6. Smart People Who Accept the PSR but Not as Self-Evident	198
	11.7. The Impasse	199
	11.8. Mathematical Analogies	200
	11.9. What Self-Evidence Could Be	205
	11.10. Paradoxes	207
12	Three Thomistic Arguments	209
	12.1. First Thomistic Argument: The Regress of Existence	209
	12.2. Second Thomistic Argument: The Interdependence of Existence and Essence	217
	12.3. Third Thomistic Argument: Substance-Accident Ontology	229
13	Modal Arguments	231
	13.1. The Strategy	231
	13.2. Sullivan’s Argument for the CP	232
	13.3. The Weak PSR	234
	13.4. Causality and Counterfactuals	239
	13.5. Conclusions	248
14	Is the Universe Reasonable?	249
15	Explanation of Negative States of Affairs	252
	15.1. The Argument	252
	15.2. The Defectiveness Objection	252
	15.3. The Nomic Necessity Objection	253
16	The Puzzle of the Everyday Applicability of the PSR	254
	16.1. The Argument	254
	16.2. An Abundance of Objections	255
	16.3. Laws of Nature	262
	16.4. Laws of Nature and the CP	267
17	Inference to the Best or Only Explanation	280
	17.1. Can Inference to Best or Only Explanation Be Rational without the PSR?	280
	17.2. Preference for Explanatory Theories	281
	17.3. The Sherlock Holmes Principle	283
	17.4. Alternatives to the PSR That “Do the Job”	285
18	Inductive Skepticism	295
19	The Nature of Possibility	299
	19.1. Alethic Modality	299
	19.2. A Formalist Account	301
	19.3. Lewis’s Theory	302
	19.4. Platonism: The Main Extant Realist Alternative to Lewis	312
	19.5. An Aristotelian Alternative	316
20	Conclusions	321
Bibliography		323
Index		331

Acknowledgments

I am grateful for encouragement, discussions, comments, and/or suggestions to Denis Bradley, Robert Brandom, Robert Clifton, William Lane Craig, Kevin Davey, Wayne Davis, William Dembski, James Dreier, Thomas Flint, Peter Forrest, Richard Gale, Jerome Gellman, Alfonso Gomez-Lobo, Michael Gorman, John Haldane, Jeremy Heis, Christian Jenner, Chauncey Maher, David Manley, Mark Murphy, Thane Naberhaus, J. Brian Pitts, Alvin Plantinga, Nicholas Rescher, Lionel Shapiro, Richard Sisca, Ernest Sosa, Thomas Sullivan, Joanna Tamburino, Peter van Inwagen, Linda Wetzel, and anonymous readers who went beyond the call of duty. I would also like to thank Mark Pitlyk for a thorough proofreading of the manuscript, and the National Endowment for the Humanities and Georgetown University for summer research support.

Portions of Chapter 13 are taken from my article “Ex Nihilo Nihil Fit: Arguments New and Old for the Principle of Sufficient Reason,” in: J. Campbell, M. O’Rourke, and H. Silverstein (eds.), Explanation and Causation: Topics in Contemporary Philosophy, Cambridge, MA: MIT Press (2006), copyright © 2006 MIT Press, with kind permission of the MIT Press. Chapter 19 is largely taken verbatim from my article “The Actual and the Possible,” in Richard M. Gale (ed.), Blackwell Guide to Metaphysics, Oxford: Blackwell (2002), pp. 317–333, copyright 2002 Blackwell Publishing, with kind permission of Blackwell Publishing. The extended footnote 6 of Chapter 16 is adapted from footnote 2 in my article “The Cardinality Objection to David Lewis’s Modal Realism,” Philosophical Studies 104 (2001), pp. 167–176, copyright 2001 Kluwer Academic Publishers, with kind permission of Springer Science and Business Media.

I would also like to thank Susan Thornton and Barry Koffler for patiently correcting many infelicities and unclarities in my original manuscript. Any remaining ones I take full responsibility for, of course.