LOG ICAL P O S I T I V I S M Edited by A lfr e d sjufes A. J. AYER, M/o - The Free Press, New York Copyright © 1959 by The Free Press, a Corporation Printed in the United States of America All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, re­ cording, or by any information storage and retrieval system, without permission in writing from the Publisher. Collier-Macmillan Canada, Ltd., Toronto, Ontario Library of Congress Catalog Card Number: 58-6467 Second printing July 1966 Preface Logical Positivism is the second in a series of books which will make available to the general public some of the most interesting work of philosophers of very diverse viewpoints. Each volume will deal with one or, in some cases, with two, philosophical “schools” or “movements.” It is fortunate that philosophers are rarely united by the kind of common purpose which inspires political or religious “movements.” Nevertheless, it is frequently helpful to consider the work of different writers according to the similarities in their aim and content; and this is the policy which has been adopted in de­ signing the Library of Philosophical Movements. This volume presents, for the first time in English, many of the most influential papers by leading members of the Vienna Circle. These and other articles contain authoritative expositions of the doctrines most commonly associated with logical positivism. How­ ever, for reasons explained by Professor Ayer in his introduction, several pieces which cannot be regarded as expositions or defenses of logical positivism have also been included. The scope of the bibliography, too, is broader than the title of the book would sug­ gest. No volume dealing with other forms of analytic philosophy is contemplated in this series and it was therefore thought desirable to list the most important books and articles dealing with all types of analytic philosophy and not only with logical positivism. I wish to express my gratitude to all the translators who gen­ erously contributed their labor, to Marvin Zimmerman, James Bayley, Irving Saltzmann, and a number of my students for helping to com­ pile the bibliography, and to Leon Satinoff, Maxwell Grober, and José Huerta-Jourda for preparing the index. Special thanks are due to Professors Carnap and Hempel for supplying notes which indi­ cate their present position on the issues dealt with in their papers. Professor Carnap was also kind enough to assist in the translation of his own articles. Paul Edwards [v] Contents P reface v E ditor’s Introduction 3 Logical Atomism 7. Bertrand Russell “Logical Atomism” 31 , Philosophy Metaphysics and Meaning 2. Moritz Schlick “The T urning Point in Philosophy” 53 3. Rudolf Carnap “The Elimination of M etaphysics through Logical A nalysis of Language” 60 4. Moritz Schlick “Positivism and Realism” 82 5. Carl G. Hempel “The Empiricist Criterion of M eaning” 108 Logic and Mathematics 6. Rudolf Carnap “T he Old and the New Logic” 133 7. Hans Hahn “Logic, Mathematics and Knowledge of Nature” 147 [vii] [ viii] Contents Knowledge and Truth 8. Rudolf Carnap 165 “Psychology in Physical L anguage” 9. Otto Neurath 199 “P ro to c o l S e n ten c e s” 10. Moritz Schlick “T he Foundation of K now ledge” 209 11. A. J. Ayer 228 “Verification and E xperience” Ethics and Sociology 12. Moritz Schlick “What Is the Aim of E thics?” 247 13. C.L. Stevenson “The Emotive M eaning of E thical Terms” 264 14. Otto Neurath “Sociology and Physicalism” 282 Analytical Philosophy 15. Frank D. Ramsey “Philosophy” 321 16. Gilbert Ryle “Philosophical Arguments” 327 17. Friedrich Waismann “How I See Philosophy” 345 Bibliography of Logical Positivism 381 Index 447 L O G I C A L P O S I T I V I S M Editor s Introduction I. H istory op the Logical Positivist Movement The term “Logical Positivism” was coined some thirty years ago to characterize the standpoint of a group of philosophers, scientists and mathematicians who gave themselves the name of the Vienna Circle. Since that time its reference has been extended to cover other forms of analytical philosophy; so that disciples of Bertrand Russell, G. E. Moore or Ludwig Wittgenstein at Cambridge, or members of the contemporary Oxford movement of linguistic analysis may also find themselves described as logical positivists. This wider usage is especially favored by those who are hostile to the whole modern development of philosophy as an analytical rather than a speculative enquiry. They wish to tar all their adversaries with a single brush. This is irritating to the analysts themselves who are rather more sensitive to their differences; they would prefer that the appellation of “logical positivist” be reserved for those who share the special outlook of the Vienna Circle. In compiling this anthology, I have not been quite so strict. I have drawn mainly on the writings of the members of the Vienna Circle, or of those who stand closest to them, but I have also included several pieces which fall outside this range. They are all, in some sense, analytical but the scope of what I regard as analytical philosophy is wide. It allows for serious disagreement, not only over technical niceties, but on major points of doctrine, including the method and purpose of analysis itself. The Vienna Circle came into being in the early 1920’s when Moritz Schlick, around whom it centered, arrived from Kiel to be­ come professor of philosophy at the University of Vienna. On the philosophical side its leading members, besides Schlick himself, were Rudolf Carnap, Otto Neurath, Herbert Feigl, Friedrich Wais- mann, Edgar Zilsel and Victor Kraft; on the scientific and mathe­ matical side, Philipp Frank, Karl Menger, Kurt Godel and Hans Hahn. At the beginning, it was more of a club than an organized movement. Finding that they had a common interest in, and a [3] [ 4 ] Editor's Introduction similar approach to, a certain set of problems, its members met regularly to discuss them. These meetings continued throughout the life of the Circle but they came to be supplemented by other activi­ ties which transformed the club into something more nearly resem­ bling a political party. This process began in 1929 with the publi­ cation of a manifesto entitled “Wissenschaftliche Weltauffassung, Der Wiener Kreis”—The Vienna Circle; Its Scientific Outlook— which gave a brief account of the philosophical position of the group and a review of the problems in the philosophy of mathematics and of the physical and social sciences that they were chiefly concerned to solve. This pamphlet, which was written by Carnap, Neurath and Hahn, is also of interest as showing how the Circle situated itself in the history of philosophy. After claiming that they were developing a Viennese tradition which had flowered at the end of the nineteenth century in the work of such men as the physicists Emst Mach and Ludwig Boltzmann, and, in spite of his theological interests, the philosopher Franz Brentano, the authors set out a list of those who-i they regarded as their main precursors. As empiricists and positivists they named Hume, the philosophers of the enlightenment, Comte, Mill, Avenarius and Mach; as philosophers of science, Helm­ holtz, Riemann, Mach, Poincare, Enriques, Duhem, Boltzmann and Einstein; as pure and applied logicians, Leibniz, Peano, Frege, Schroder, Russell, Whitehead and Wittgenstein; as axiomatists, Pasch, Peano, Vailati, Pieri and Hilbert; and as moralists and sociologists of a positivistic temper, Epicurus, Hume, Bentham, Mill, Comte, Spencer, Feuerbach, Marx, Müller-Lyer, Popper-Lynkeus and the elder Carl Menger. This list is surprisingly comprehensive, but it must be remembered that in most cases it is only a question of a special aspect of the author’s works. Thus Leibniz is included for his logic, not for his metaphysics; Karl Marx is included neither for his logic nor his metaphysics but for his scientific approach to history. If we exclude contemporaries from the list, those who stand closest to the Vienna Circle in their general outlook are Hume and Mach. It is indeed remarkable how much of the doctrine that is now thought to be especially characteristic of logical positivism was already stated, or at least foreshadowed, by Hume. Among contemporaries, Einstein, Russell, and Wittgenstein are singled out by the authors of the pamphlet for their kinship to the Vienna Circle and the extent of their influence upon it. Wittgenstein, indeed, stood to the Vienna Circle in a special relation. Having been a pupil of Russell’s at Cambridge before the first world war he returned to Vienna and was there when his Logisch-Philosophische Editor's Introduction [ 5 ] Abhandlung was published in 1921. This famous book, which is better known as Tractatus Logico-Philosophicus, the title given to its English translation, had an enormous effect upon the positivist movement, both in Vienna and elsewhere. It would not be quite correct to say that the Vienna Circle drew its inspiration from it. Schlick himself, in his book on the theory of knowledge, Allgemeine Erkenntnislehre, of which the first edition appeared in 1918, had independently arrived at a similar conception of philosophy; and there is a hint of mysticism in the Tractatus which some members of the Circle, especially Neurath, found disquieting; but as a whole they ac­ cepted it, and it stood out as the most powerful and exciting, though not indeed the most lucid, exposition of their point of view. Wittgen­ stein did not officially adhere to the Circle but he maintained close personal relations at least with Schlick and Waismann whom he con­ tinued to influence even after his departure for Cambridge in 1929. In Cambridge, where he taught until 1947, four years before his death, he exercised an almost despotic sway over his pupils, and though he published nothing during these years except one short article his influence was strongly, if in most cases indirectly, felt by almost all the younger generation of British philosophers. He himself modified the rigors of his early positivism to an extent that can be measured by comparing the Tractatus with his posthumously pub­ lished Philosophical Investigations; and it is to his influence, com­ bined with that of Moore, that one may largely attribute the pre­ occupation of contemporary British philosophers with the everyday uses of language, and their tendency to deal with philosophical ques­ tions in an unsystematic, illustrative way, in contrast to the more rigorous would-be scientific method which was favored by the Vienna Circle. This is one reason why they are not happy to be described as Logical Positivists. But I shall have more to say about these alter­ native conceptions of analysis later on. It was in 1929 also that the Vienna Circle organized its first in­ ternational congress. It was held at Prague and was followed at inter­ vals throughout the thirties by further congresses at Königsberg, Copenhagen, Prague, Paris and Cambridge. These meetings furthered the ambition of the Circle to develop Logical Positivism as an inter­ national movement. It had formed an early alliance with the so-called Berlin school of which Hans Reichenbach, Richard von Mises, Kurt Greiling and at a later date Carl Hempel were the leading members. The congresses helped it to make contact also with Scandinavian philosophers such as Eino Kaila, Arne Naess, Ake Petzäll, Joergen Joergensen, and the Uppsala school of empiricists, with the Dutch