THE LOGIC OF GERSONIDES

Transcription

1 THE LOGIC OF GERSONIDES

2 The New Synthese Historical Library Texts and Studies in the History of Philosophy VOLUME 40 Series Editor: NORMAN KRETZMANN, Cornell University Associate Editors: DANIEL ELLIOT GARBER, University of Chicago SlMO KNUUTTILA, University of Helsinki RICHARD SORABJI, University of London Editorial Consultants: JAN A. AERTSEN, Free University, Amsterdam ROGER ARIEW, Virginia Polytechnic Institute E. JENNIFER ASHWORTH, University of Waterloo MICHAEL AYERS, Wadham College, Oxford GAIL FINE, Cornell University R. J. HANKINSON, University of Texas JAAKKO HINTIKKA, Boston University, Finnish Academy PAUL HOFFMAN, Massachusetts Institute of Technology DAVID KONSTAN, Brown University RICHARD H. KRAUT, University of Illinois, Chicago ALAIN DE LIBERA, Ecole Pratique des Hautes Etudes, Sorbonne DAVID FATE NORTON, McGill University LUCA OBERTELLO, Universita degli Studi di Genova ELEONORE STUMP, Virginia Polytechnic Institute ALLEN WOOD, Cornell University The titles published in this series are listed at the end of this volume.

3 ERRATA Ch. Manekin: The Logic of Gersonides ISBN Although the efforts of all involved, some errors have slipped in during the production process. p. 53 This page begins at line 33 with the titel 'The Book of the Correct Syllogism'. The first 32 lines of commentary belong on p p : please read dici de omni et nullo for did de omne et nullo p. 247 This page is to be omitted. p : please read AablEbcllEac for AablEbcllAac p : please read OablAcbllOac for OablAcbllEac p : please read 'Averoes' Epitome of the Organon' for Maimonides Logical Terms 1. p : The volume of G. Dahan (ed.) is entitled Gersonides en son temps and will be published with Peeters in Louvain, Belgium. p : The volume of G. Dahan (ed.) is entitled Gersonides en son temps and will be published with Peeters in Louvain, Belgium.

4 THELOGICOF GERSONIDES A Translation of Sefer ha-h eqqesh ha-yashar (The Book ofthe Correct Syllogism) of Rabbi Levi ben Gershom with Introduction, Commentary, and Ana1ytical Glossary by CHARLES H. MANEKIN University of Maryland. Maryland. U.S.A... SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.

5 Library of Congress Cataloging-in-Publication Data Levi ben Gershom, [He~esh ha-yashar. Engllshl The logic of Gersonldes : a translatlon of Sefer ha-heqqesh ha -yashar (The Book of the correct syllogism) of Rabbi Levi ben Gershom I wlth lntroductlon, commentary, and analytlcal glossary [byl Charles H. Manekln. p. cm. -- (The New synthese hlstorlcal llbrary ; v. 401 Translatlon of. Sefer ha-he~esh ha-yashar. Inc 1 udes 1 ndex. ISBN ISBN (ebook) DOI / Sylloglsm--Early works ta Philosophy, Jewlsh. 3. Phllosophy, Medleval. 1. Manekln, Charles Harry, II. Tltle. III. Ser les. B759.L43H dc ISBN Printed on acid-free paper AlI Rights Reserved 1992 Springer Science+Business Media Dordrecht Origina11y published by Kluwer Academic Publishers in 1992 Softcover reprint of the hardcover 1 st edition 1992 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner.

6 PREFACE In the great libraries of Europe and the United States, hidden in fading manuscripts on forgotten shelves, lie the works of medieval Hebrew logic. From the end of the twelfth century through the Renaissance, Jews wrote and translated commentaries and original compositions in Aristotelian logic. One can say without exaggeration that wherever Jews studied philosophy - Spain, France, Northern Africa, Germany, Palestine - they began their studies with logic. Yet with few exceptions, the manuscripts that were catalogued in the last century have failed to arouse the interest of modem scholars. While the history of logic is now an established sub-discipline of the history of philosophy, the history of Hebrew logic is only in its infancy. The present work contains a translation and commentary of what is arguably the greatest work of Hebrew logic, the Sefer ha-heqqesh ha-yashar (The Book of the Correct Syllogism) of Levi ben Gershom (Gersonides; ). Gersonides is well known today as a philosopher, astronomer, mathematician, and biblical exegete. But in the Middle Ages he was also famous for his prowess as a logician. The Correct Syllogism is his attempt to construct a theory of the syllogism that is free of what he considers to be the 'mistakes' of Aristotle, as interpreted by the Moslem commentator A verroes. It is an absorbing, challenging work, first written by Gersonides when he was merely thirty-one years old, then significantly revised by him. The translation presented here is of the revised version. I first came upon the Correct Syllogism in 1978 when, as a graduate student, I became interested in the history of logic and in the philosophy of Gersonides. After reading a microfilm of the Parma manuscript I decided that there was enough material for a doctoral dissertation. Yet I subsequently discovered that parts of the work had been analyzed in a doctoral dissertation written at the Hebrew University, Jerusalem, in When I traveled to Israel in 1979 I met its author, Dr. Shalom Rosenberg, who very generously 'bequeathed' the work to me, and even invited me to Jerusalem to study it with him, which I did. For his help and encouragement in many areas I am truly grateful. The present work grew out of my doctoral dissertation for Columbia University (1984). In my thesis I presented a partial Hebrew edition and translation of less than half of the Correct Syllogism. Since then I have prepared a critical edition based on all the known extant manuscripts. The translation here is based on that edition.

7 vi THE LOGIC OF GERSON IDES Over the last ten years my work on Gersonides' logic has been supported by a variety of foundations and institutions, which it is my pleasant task to acknowledge. The National Foundation of Jewish Culture, the Memorial Foundation of Jewish Culture, the Lady Davis Foundation, and the Center of Israel and Jewish Studies at Columbia University awarded me grants and fellowships when I was a doctoral candidate. The Warburg Foundation and the Lady Davis Foundation awarded me postdoctoral fellowships at the Hebrew University. I was fortunate to receive a substantial translation grant from the National Endowment of the Humanities and two research grants from the Graduate Research Board of the University of Maryland. Finally, the Meyerhoff Center for Jewish Studies at the University of Maryland underwrote some of the publication costs. Of the many teachers and colleagues who have helped me I would like to single out the following: Shalom Rosenberg (Jerusalem), a pioneer in the study of medieval Hebrew logic as well as a teacher and collaborator; Charles Parsons (Cambridge, Mass.), the second reader for my doctoral thesis, who was particularly helpful on questions of modem logic; Josef Stem (Chicago), who made many suggestions for improvement, and Gad Freudenthal (Paris), who read the Introduction very carefully and offered detailed and penetrating comments. I am also grateful to Michael Blaustein (Annapolis), who checked my transliterations from the Arabic, and to Rachel Manekin (College Park), who checked my transliterations from the Hebrew. Special thanks go to my colleagues in the Hebrew section of my department, Adele Berlin and Alan Mintz, and to my department chairperson, J. Thomas Rimer, for their encouragement and support. Above all, I would like to thank Arthur Hyman (New York), who has been my teacher and guide from the first day I entered graduate school until the present. For all that he has taught me, and for his embodying the 'scholar and gentleman', I am truly grateful. The Rabbis teach that 'silence is a hedge for wisdom', yet I cannot refrain from expressing gratitude to my parents and children for their constant love and support. To my wife Rachel, who has taught me things far more important than are dealt with here, I humbly dedicate this book. C.H.M.

8 TABLE OF CONTENTS INTRODUCTION 1 Logic and philosophy among the Jews in medieval Provence Gersonides' life and writings Gersonides' logical writings The Commentary on Logic The Commentary on the Logical Questions The Book of the Correct Syllogism Gersonides' logic: innovation within the bounds of tradition. (i) The interpretation of syllogistic (ii) The defense of the fourth figure (iii) The quantification of the predicate (iv) Inferences with relational terms and prepositions (v) The interpretation of modality The sources of the logical writings and their subsequent influence The edition of the Correct Syllogism Summary of major revisions Minor revisions (i) Condensement and abridgement (ii) Expansion and precision (iii) Accuracy and correction Group I (C, V, and n. Group II (P and L). The translation Editorial additions and formalization THE BOOK OF THE CORRECT SYLLOGISM INTRODUCTION 53 TREATISE ONE ON THE SIMPLE SENTENCE AND WHAT FOLLOWS FROM IT CHAPTER ONE On the Types of Sentences 54 Consequences involving simple sentences. The division of sentences. The types of sentences employed in syllogisms. The definition of a sentence and the types of modalities The possible The essentially possible The temporal assertoric. Objections to the Aristotelian-Averroist understanding of the assertoric. The rhetorical assertoric. The non-contingent Two types of the possible: exclusive and non-exclusive Two types of the necessary: essential and incidental Two types of the assertoric. The proper interpretation of modal sentences CHAPTER TWO On Retracted Sentences 63 Subject-retracted sentences. Predicate-retracted sentences

9 Vlll THE LOGIC OF GERSONIDES CHAPTER THREE On the Relative Extensions of Modally Qualified Terms 65 The relative extensions of simply modally qualified terms. The relations between retracted terms' An objection to the relation between possible and necessary terms CHAPTER FOUR On Consequences by Virtue of the Part and the Whole 67 Consequences in which a certain thing is affirmed of the particular by virtue of its being affirmed ofthe universal Conditions concerning such consequences Consequences in which a certain thing is negated of the particular by virtue of its being negated of the universal Consequences in which a certain thing is affirmed or negated of the universal by virtue of its being affirmed or negated of the particular Consequences in which a certain thing is affirmed or negated of one term by virtue of its being affirmed or negated of an equal term. Consequences in which the universal and particular are predicated of a certain thing CHAPTER FIVE On Consequences by Virtue of Subaltemation and Obversion 75 Subaltemation: Aablllab, EabllOab. Superaitemation: lab\\aab, Oab\\Eab. Simple sentences to predicate-retracted sentences: (i) Aabll Ea...,b, lablloa...,b. Simple sentences to predicate-retracted sentences: (ii) EabIIAa...,b, Oabllla...,b. Predicate-retracted sentences to simple sentences: (i) Aa...,bll Eab,la...,bIIOab Predicate-retracted sentences to simple sentences: (ii) Ea...,bIIOab, Oa...,blllab. Subject-retracted sentences to unqualifiedly retracted sentences and vice-versa Simple sentences to subject-retracted sentences and vice-versa Simple sentences to subject-retracted and to unqualifiedly retracted sentences when both terms exist: Eabllhab, EabIlO...,a...,b. Subject-retracted sentences to simple sentences and to predicate-retracted sentences when both terms exist: E...,ablllab, E...,abIIOa...,b CHAPTER SIX On Consequences by Virtue of the Placement and Removal of Relational Particles and Prepositions 80 Placement of particles in universal affirmative simple sentences: Aab//AelbR. Placement of particles in particular affirmative simple sentences: lablllelbr. Removal of particles in universal and particular affirmative simple sentences: AelbR\\Aab, lel~\vab. Placement of particles in universal negative simple sentences: Eab\\EelbR,; predicateretracted sentences. Removal of particles in universal negative simple sentences: Eel br II Eab. Placement and removal of particles in particular negative simple sentences:

10 CONTENTS IX Oab\\OifbR, OifbR/JOab; predicate-retracted sentences Placement and removal of particles in universal affirmative subject-retracted sentences: A..,ab\\A..,ifbR, A..,ifbR\\ A..,ab. Placement and removal of particles in particular negative subject -retracted sentences: O..,ab\\O..,ifbR, O..,ifbR\\O..,ab; unqualifiedly retracted sentences Placement and removal of particles in universal subject-retracted negatives: E"'abIIE..,ifbR, E..,ifbR\\E..,ab; unqualifiedly-retracted sentences Conditions for the use of these consequences CHAPTER SEVEN On Consequences by Virtue of the Placement and Removal of Modes 86 Placement and removal of the particular mode for the universal mode in simple terms. Placement and removal of the universal mode for the particular mode in simple terms. Placement and removal of modes in retracted terms Conditions for the use of these consequences CHAPTER EIGHT On Consequences by Virtue of the Conversion of Sentences 88 Conversion of simple sentences: (i) Aabl I lba,/abl Ilba. Conversion of simple sentences: (ii) EabllEba, Oab\\; predicate-retracted sentences Conversion of predicate-retracted and simple sentences to subject-retracted and unqualifiedly retracted sentences. Conversion of predicate-retracted sentences to subject-retracted sentences: (i) Aa..,blll..,ba. Conversion of predicate-retracted sentences to subject-retracted sentences: (ii) la..,bllf..,ba. Conversion of predicate-retracted sentences to subject-retracted sentences: (iii) Ea..,bIIE..,ba. Conversion of predicate-retracted sentences to subjectretracted sentences: (iv) Oab\\; unqualifiedly retracted and simple sentences. Conversion of subject-retracted sentences to predicate-retracted sentences Conversion of subject-retracted sentences to predicate-retracted sentences: (i) A..,abillb..,a, l..,abillb..,a. Conversion of subject-retracted sentences to predicate-retracted sentences: (ii) E..,abll Eb..,a, O"'ab\\; unqualifiedly retracted and simple sentences Non-conversion of subject-retracted sentences to subject-retracted sentences: (i) A..,ab\\x..,ba, l"'ab\\x..,ba. Non-conversion of subject-retracted sentences to subject-retracted sentences: (ii) E..,ab\\x..,ba, O..,ab\\x..,ba. Non-conversion of subject-retracted sentences to unqualifiedly retracted sentences. Non-conversion of unqualifiedly retracted sentences to subject-retracted or unqualifiedly retracted sentences

11 x THE LOGIC OF GERSONIDES CHAPTER NINE On the Modality of Consequences by Virtue of the Conversion of Sentences 95 Conversions in which the mode or particle remains with the term it previously modified Conversions in which the particle or the mode is transferred to the term it did not previously modify. Conversion of modal sentences: the classification of modal sentences (i) Subject necessary, predicate necessary (ii) Subject possible, predicate possible (iii) Subject possible, predicate necessary (iv) Subject necessary, predicate possible Conversion of necessary simple sentences Conversion of necessary predicateretracted sentences Conversion of necessary subject-retracted sentences Conversion of possible simple sentences Conversion of possible predicate-retracted sentences Conversion of possible subject-retracted sentences Criticisms of Aristotle Conversion of assertoric simple and predicate-retracted sentences Conversion of assertoric subjectretracted sentences CHAPTER TEN On the Extension of Terms in Sentences 114 The denotation of the subject and the predicate The quantification of the subject and the predicate TREATISE TWO ON THE EXPLANATION WHEN THERE WILL BE A <VALID> SYLLOGISM FROM THE PREMISES AND WHEN THERE WILL NOT, AND WHAT WILL BE THE MODE <OF THE CONCLUSION> IN SIMPLE SYLLOGISMS, I MEAN, POSSESSING ONE MODE, AND THOSE MIXED WITH SEVERAL MODES CHAPTER ONE On the Conditions of the Syllogism 117 The definition of the syllogism and syllogistic consequences Syllogistic conditions: (i) one term repeated; two terms distinct The division of syllogisms into figures and moods Syllogistic conditions: (ii) the repeated term must be taken univocally in both premises and (iii) in its entirety in at least one premise' (iv) At least one premise must be universal, and (v) at least one premise affirmative. Conditional Syllogisms' Syllogisms with a particular negative premise in which all of the middle term is taken Syllogistic conditions: (vi) unequivocality of terms in premises and conclusion. Syllogistic conditions: (vii) at least one universal premise

12 CONTENTS xi CHAPTER TWO On the Relationship between the Premises and the Conclusion of the Syllogism 129 The conclusion is in one of the premises potentially. The priority of the figures CHAPTER THREE On the First Figure 132 Conditions of the first figure. Moods of the first figure CHAPTER FOUR On the Second Figure 136 Conditions of the second figure. Moods of the second figure CHAPTER FIVE On the Third Figure 139 Conditions of the third figure Moods of the third figure CHAPTER SIX On the Fourth Figure 142 Conditions of the fourth figure Moods of the fourth figure The necessity of positing a fourth figure. Contra Averroes' rejection of the fourth figure CHAPTER SEVEN On Sorites 148 A syllogism possesses no more nor less than two premises CHAPTER EIGHT On the Conditions of Syllogisms with Modes, Particles, and Retracted Terms 149 Conditions of syllogisms with retracted terms or particles Conditions of syllogisms with mode The reduction of the middle term in syllogisms with retracted terms The reduction of the middle term in syllogisms with particles The reduction of the middle term in syllogisms with modes and temporal linkage CHAPTER NINE On Syllogisms with Necessary Premises 155 The first figure. The second figure. The third figure. The fourth figure CHAPTER TEN On Syllogisms with Assertoric Premises 162 The first figure. The second figure. The third figure. The fourth figure

13 xii THE LOGIC OF GERSONIDES CHAPTER ELEVEN On Syllogisms with Possible Premises 165 The first figure The second figure The third figure The fourth figure The critique of the Aristotelian position A defense of Aristotle Reply to this defense CHAPTER TWELVE On Syllogisms Mixed from Necessary and Assertoric Premises 174 The first figure. The second figure. The third figure. The fourth figure CHAPTER THIRTEEN On Syllogisms Mixed from-necessary and Possible Premises 183 The first figure. The second figure. The third figure. The fourth figure CHAPTER FOURTEEN On Syllogisms Mixed from Assertoric and Possible Premises 186 The first figure. The second figure. The third figure. The fourth figure COMMENTARY 189 EXCURSUS Aristotle's Modal Syllogistic and Averroes' Theory of Modalized Terms 300 WORKS CITED IN COMMENTARY AND EXCURSUS 310 HEBREW-ENGLISH GLOSSARY 313 ENGLISH-HEBREW GLOSSARY 315 SELECTED BIBLIOGRAPHY 324 INDEX 331