HENRY E. KYBURG, JR. & ISAAC LEVI

HENRY E. KYBURG, JR. & ISAAC LEVI

PROFILES AN INTERNATIONAL SERIES ON CONTEMPORAR Y PHILOSOPHERS AND LOGICIANS EDITORS RADU J. BOGDAN, Tulane University ILKKA NIINIL UOTO, University of Helsinki EDITORIAL BOARD D. F</>LLESDAL, University of Oslo S. KORNER, University of Bristol 1. 1. C. SMART, Australian National University w. STEGMULLER, Universitiit Munchen P. SUPPES, Stanford University K. SZANIA WSKI, University of Warsaw 1. VUILLEMIN, College de France VOLUME 3

HENRY E. KYBURG, JR. & ISAAC LEVI Edited by RADU J. BOGDAN Tulane University D. REIDEL PUBLISHING COMPANY DORDRECHT : HOLLAND/ BOSTON : U.S.A. LONDON: ENGLAND

Library of Congress Cataloging in Publication Data Main entry under title: Henry E. Kyburg, Jr. & Isaac Levi. (Profiles; v. 3) Bibliography: p. Includes index. \. Kyburg, Henry Ely, 1928-. 2. Levi, Isaac, 1930- I. Bogdan, Radu J. II. Title. III. Series: Profiles (Dordrecht, Holland); v. 3) B945.K94H46 191 81-15417 ISBN -13: 978-90-277-1309-4 e-isbn -13 :978-94-009-7718-1 DOl: 10.1007/978-94-009-7718-1 Published by D. Reidel Publishing Company, P.O. Box 17, 3300 AA Dordrecht, Holland. Sold and distributed in the U.S.A. and Canada by Kluwer Boston Inc., 190 Old Derby Street, Hingham, MA 02043, U.S.A. In all other countries, sold and distributed by Kluwer Academic Publishers Group, P.O. Box 322, AH Dordrecht, Holland. D. Reidel Publishing Company is a member of the Kluwer Group. All Rights Reserved Copyright 1982 by D. Reidel Publishing Company, Dordrecht, Holland Softcover reprint of the hardcover 1st edition 1982 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 informational storage and retrieval system, without written permission from the copyright owner

T ABLE OF CONTENTS EDITORIAL INTRODUCTION PREFACE VII xi I Part One 3 HENR Y E. K YBURG, JR. - Self-Profile 5 1. Introduction 5 2. A Glance Over the Shoulder 6 3. Probability II 4. Theory and Inference 28 5. Metaphysics and Ontology 40 6. Language and Logic 44 7. Value Theory 47 8. Social and Political Philosophy 50 9. Summary 52 Part Two 55 STEPHEN SPIELMAN-Kyburg's System of Probability 57 WILLIAM L. HARPER - Kyburg on Direct Inference HENRY E. KYBURG, JR. - Reply 97 129 v

CONTENTS Part Three BIBLIOGRAPHY OF HENRY E. KYBURG, JR. 163 165 II Part One 179 ISAAC LEVI - Self-Profile 181 1. Beginnings 181 2. Early Themes 185 3. Cognitive States 191 4. Revision of Knowledge 194 5. Credal Probability and Decision Making 202 6. Conditionalization and Revision of Probabilities 205 7. Inductive Logic 207 8. Statistical Probability and Direct Inference 210 9. Evidential Support 213 10. Unfinished Business 214 Part Two 217 WILLIAM K. GOOSENS - Levi's Theory of Acceptance 219 TEDDY SEIDENFELD - Levi on the Dogma of Randomization in Experiments 263 ISAAC LEVI'- Replies 293 Part Three 307 BIBLIOGRAPHY OF ISAAC LEVI 309 INDEX OF NAMES 319 INDEX OF SUBJECTS 321 vi

EDITORIAL INTRODUCTION The aim of this series is to inform both professional philosophers and a larger readership (of social and natural scientists, methodologists, mathematicians, students, teachers, publishers, etc.) about what is going on, who's who, and who does what in contemporary philosophy and logic. PROFILES is designed to present the research activity and the results of already outstanding personalities and schools and of newly emerging ones in the various fields of philosophy and logic. There are many Festschrift volumes dedicated to various philosophers. There is the celebrated Library of Living Philosophers edited by P. A. Schilpp whose format influenced the present enterprise. Still they can only cover very little of the contemporary philosophical scene. Faced with a tremendous expansion of philosophical information and with an almost frightening division oflabor and increasing specialization we need systematic and regular ways of keeping track of what happens in the profession. PROFILES is intended to perform such a function. Each volume is devoted to one or several philosophers whose views and results 'are presented and discussed. The profiled philosopher(s} will summarize and review his (their) own work in the main fields of significant contribution. This work will be discussed and evaluated by invited contributors. Relevant historical and/or biographical data, an up-to-date bibliography with short abstracts of the most important works and, whenever possible, references to significant reviews and discussions will also be included. Since rigorous argumentation and a rational approach to philosophical problems are among the most worthwhile trends in contemporary philosophical thought, PRO F I L E s will give priority to surveys of the work of vii

INTRODUCTION authors and schools of thought that meet these standards. However, this preference allows for a broad spectrum of philosophical and methodological viewpoints. As a vehicle of information about, and systematization of, contemporary philosophical and logical knowledge, PROFILES will strive to report on any major contribution to that body of knowledge, be it personal or collective. PROFILES will also report on research and new projects that, although still esoteric and even tentative, may be expected to become seminal and influential in some field of philosophical or logical studies. The sooner the information about such new ventures is disseminated and systematized, the greater will be its impact on undergraduate and graduate students, researchers, teachers on all levels, editors, publishers, university and foundation managers, etc. The editors will welcome information on personal and collective research in progress, Ph.D. theses, surveys and monographs dealing with individual philosophers and schools of thought working in contemporary philosophy and logic. We expect to publish one or two volumes yearly. RADU J. BOGDAN Tulane University ILKKA NIINILUOTO University of Helsinki viii

Left: Henry E. Kyburg, Jr.; right: Isaac Levi. (Photograph by Bart Crouwers.)

PREFACE Over the last two decades Henry Kyburg and Isaac Levi have been engaged in a sustained and systematic inquiry into the foundations of probability, inductive inference and scientific method. These are the major areas of their research that the present volume attempts to review and discuss. Yet it should be apparent from what follows that both philosophers have pursued other research lines as well, and that they are likely to do so in the future. Besides documenting their individual approaches and results, the volume also illuminates the ongoing, constructive dialogue between Kyburg and Levi. The volume has two similar divisions. The Self Profiles tell us the story of the two philosophers' intellectual evolution, of their philosophical interests and of the views they have developed in pursuing them. The papers by S. Spielman and W. K.. Goosens are comprehensive critical surveys of the main body of Kyburg's and Levi's work, respectively. While taking up other aspects and completing this overview, the papers by W. Harper and T. Seidenfeld also explore new areas of application and support for Kyburg's and Levi's theories and suggest ways of meeting a number of difficulties. After the profilees' replies to these papers the two divisions end with Kyburg's and Levi's complete and self-annotated bibliographies, supplemented by a representative sample of reviews and discussions of their work in the recent literature. Kyburg's and Levi's references in their Self Profile and Replies to their own works can be found in these final bibliographies. My thanks go to all the contributors for their cooperation and assistance and to Catalina for so many things. New Orleans, Mardi Gras 1981 RADU J. BOGDAN xi