THE LAW OF CAUSALITY AND ITS LIMITS

THE LAW OF CAUSALITY AND ITS LIMITS

VIENNA CIRCLE COLLECTION lienk L. MULDER, University of Amsterdam, Amsterdam, The Netherlands ROBERT S. COHEN, Boston University, Boston, Mass., U.SA. BRIAN MCGUINNESS, University of Siena, Siena, Italy RUDOLF IlALLER, Charles Francis University, Graz, Austria Editorial Advisory Board ALBERT E. BLUMBERG, Rutgers University, New Brunswick, N.J., U.SA. ERWIN N. HIEBERT, Harvard University, Cambridge, Mass., U.SA JAAKKO HiNTIKKA, Boston University, Boston, Mass., U.S.A. A. J. Kox, University of Amsterdam, Amsterdam, The Netherlands GABRIEL NUCHELMANS, University of Leyden, Leyden, The Netherlands ANTH:ONY M. QUINTON, All Souls College, Oxford, England J. F. STAAL, University of California, Berkeley, Calif., U.SA. FRIEDRICH STADLER, Institute for Science and Art, Vienna, Austria VOLUME 22 VOLUME EDITOR: ROBERT S. COHEN

PHILIPP FRANK

PHILIPP FRANK THELAWOF CAUSALITY AND ITS LIMITS Edited by ROBERT s. COHEN Boston University Translated by MARIE NEURATH and ROBERT S. COHEN 1Ii.....,~ SPRINGER SCIENCE+BUSINESS MEDIA, B.V.

Library of Congress Cataloging-in-Publication data Frank, Philipp, 1884-1966. [Kausalgesetz und seine Grenzen. Englishl The law of causality and its limits / Philipp Frank; edited by Robert S. Cohen ; translation by Marie Neurath and Robert S. Cohen. p. cm. -- (Vienna Circle collection ; v. 22) Inc I udes index. ISBN 978-94-010-6323-4 ISBN 978-94-011-5516-8 (ebook) DOI 10.1007/978-94-011-5516-8 1. Causation. 2. Science--Phi losophy. I. Cohen, R. S. (Robert Sonne) 11. Title. 111. Series. BD543.F7313 1997 122--dc21 97-8414 ISBN 978-94-010-6323-4 Das Kausalgesetz und seine Grenzen (Springer-Verlag, Vienna, 1932) Printed on acid-free paper All Rights Reserved 1998 Springer Science+Business Media Dordrecht Originally published by Kluwer Academic Publishers in 1998 Softcover reprint of the hardcover 1 st edition 1998 No part of this publication may be reproduced or utilized in any form or by any means, electronic, mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner.

TABLE OF CONTENTS INTRODUCTION DAS KAUSALGESETZ UND SEINE GRENZEN 1 Analytical Table of Contents 3 Preface by Philipp Frank (Prague, 1931) 11 I. The dangers of meaningless for statements of great generality 17 II. The most incisive formulation of the law of causality: Laplace's demand for a world-formula 43 III. Currents of thought hostile to causality 64 IV. Causality, finalism and vitalism V. Physical lawfulness and causality VI. Causality and chance VII. Causality and quantum mechanics VIII. Causality, chance or plan in the development of the world? IX. Difficulties in the formulation of a general law of causality X. On the so-called 'true' world XI. On the validity of the law of causality Notes Bibliography of Philipp Frank INDEX OF NAMES ix 95 137 155 161 197 218 240 271 281 290 297 vii

ROBERTS. COHEN INTRODUCTION The Law of Causality and its Limits was the principal philosophical work of the physicist turned philosopher, Philipp Frank. Born in Vienna on March 20, 1884, Frank died in Cambridge, Massachusetts on July 21, 1966. He received his doctorate in 1907 at the University of Vienna in theoretical physics, having studied under Ludwig Boltzmann; his subsequent research in physics and mathematics was represented by more than 60 scientific papers. Moreover his great success as teacher and expositor was recognized throughout the scientific world with publication of his collaborative Die Differentialgleichungen der Mechanik und Physik, with Richard von Mises, in 1925-27. Frank was responsible for the second volume, on physics, and especially noted for his authoritative article on classical Hamiltonian mechanics and optics. Among his earliest papers were those, beginning in 1908, devoted to special relativity, which together with general relativity and physical cosmology occupied him throughout his life. Already in 1907, Frank published his seminal paper 'Kausalgesetz und Erfahrung' ('Experience and the Law of Causality'), much later collected with a splendid selection of his essays on philosophy of science, in English (1941c and 1949g, in our Bibliography). Joining the first 'Vienna Circle' in the first decade of the 20th century, with Hans Hahn, mathematician, and Otto Neurath, sociologist and economist, and deeply influenced by studies of Ernst Mach's critical conceptual histories of science and by the striking challenge of Poincare and Duhem, Frank continued his epistemological investigations. He set for himself "to bring about the closest possible rapprochement between philosophy and science", and above all "to avoid the traditional ambiguity and obscurity of philosophy". In 1912, upon Einstein's recommendation, Philipp Frank was appointed to the physics faculty at the (German language) University of Prague, as Einstein's successor, and in 1917 Frank was promoted to full Professor, and Director of the University'S Institute for Theoretical ix

x ROBERTS. COHEN Physics. He continued his wider research interests beyond pure physics, and participated through the years of fundamental development of logical empiricism in the Vienna seminars of Moritz Schlick and Rudolf Carnap. Through Frank's efforts, a special faculty post was arranged for Carnap at the University of Prague in 1931. Frank, with his wife, left Prague in 1938 on a lecture tour in America, never to return to Czechoslovakia. German forces occupied that land, and had already taken power in Austria. The Schlick/Carnap circle, named the Vienna Circle by genial Otto Neurath, had scattered to the West, and Frank found an ongoing modest half-time Lectureship in physics and mathematics at Harvard University. He inspired and led a new Institute of the Unity of Science, a transplant in America, so it seemed, of the first Institute which had been established by Neurath in the Netherlands and soon removed to England (Neurath died in Oxford in 1945). Frank met his American environment with curiosity and courage. One Harvard physicist wrote of Frank: His was a gentle, unassuming spirit combined with a luminous mind and gifts of simplicity and humor that endeared him to all. He understood the nature of truth and the criteria that must be used to separate truth from mythology. He was a humanist as well as a scientist and philosopher... he had the patience, the perception and the wit to make profound truths intelligible to a wide public. (B.C. Kemble) The treatise on causality was written and published (1931) during the mature years of the Vienna Circle, to form a volume in a series of books on logic and the philosophy of science, and inclusive of studies on values, and sociological matters. How useful the logical empiricist analysis would be in achieving a 'scientific philosophy' is demonstrated in this book; as the reader will see, Frank clarifies both the strengths and the limitations of the full range of concepts that have been linked to 'causal' explanation, most fascinating perhaps in his analysis of misuse of the causal, by what he calls metaphysical misinterpretations. Among the historically significant topics in this book we have: the Laplacean determinism of global causal laws of nature; loss of causal simplicity with the establishment of field concepts; cause and chance, in classical, statistical-mechanical, and quantum physics; conservation laws and causal laws; the seeming irreversibility of natural processes; extremal principles; vitalist explanations as also causal; miracles and theological explanation; lawfulness in the phenomena of life; causal hypotheses in historical studies and sociology; causality and the understanding of

INTRODUCTION xi Marxist dialectical expositions from the Soviet literature of the late 1920s; and the logical plus the psychological appreciation of the question of 'free will' as well as of the question of our knowledge of the real or (as Frank termed it) 'true' world. Of Philipp Frank's life work in the philosophy of science, we may say, with his younger colleague at the Vienna Circle, Herbert Feigl, that "it combines informal logical analysis of the sciences (and their formal mathematical structures) with a vivid awareness of the psychological and social-cultural factors operating in the selection of problems, and the acceptance or rejection of hypotheses, and which contribute to the shaping of styles of scientific theorizing". * Several brief remarks may focus Frank's evaluations of so much that had gone before, and still prevails in European culture. In his historical considerations of traditional philosophies, he concludes that they plainly preserve the residue of obsolete scientific theories, at their best; for the desire to know the 'true' world, he sees motives derived from an animistictheological base. But at a higher level, Frank examines the use of analogies, perhaps legitimate, perhaps not, in scientific explanations, as in his respectful account of Bergson's appeal to feeling and instinct for the understanding of "the ancestral history of organisms". Indeed, Frank says admiringly of Bergson's Creative Evolution (p. 84) that we "could believe we are reading a genuine psychological novel of development". And yet he is careful in criticizing, for we are not scientifically in command of the phenomena of "strivings and tendencies". Indeed from the materialistic Age of Englightenment, Frank selects for critique the blunt argument for teleology from Voltaire's Philosophical Dictionary: If a clock is not made in order to tell the time of the day, I will then admit that final causes are nothing but chimeras, and be content to go by the name of a final-causefinder - in plain language, a fool- to the end of my life. (86) * Frank takes pleasure time and again in words of others. From Nietzsche: The mystical explanations are considered to be deep; but they are not even superficial. (74) And Frank welcomed Nietzsche's sociological explanation of the traditional search for a 'true world', an explanation for 'the psychology

xii ROBERTS. COHEN of metaphysics', which includes a poignant recognition: Suffering inspires these conclusions [that there is a true world]: basically they are desires that such a world might exist; as well, a hatred is expressed by them against a world that causes suffering, by imagining another, more valuable world: the resentment of the metaphysician is here creative. (257) But while 'creative', yet ultimately destructive too and the logical empiricist agrees, and goes on to cite Nietsche further: It is of cardinal importance to do away with the true world (for) it is the great devaluation ofthe world that is us: it has so far been our most dangerous attack on life. * Frank's critique of Kant's epistemology was respectful but severe, but his discussion of the eminent neo-kantian philosophers of physics was more collegial while cautious. Foremost was Ernst Cassirer whose careful analysis in his treatment of fundamental classical physics (in Substance and Function) and of Einstein's relativity had drawn the interest of theoretical physicists and philosophers, including Einstein, Schlick and Reichenbach. The categorical a priori, revised to be hypothetical, or as Arthur Pap later noted, serving theoretical research as a 'functional' a priori, offered an adjustable bridge to the logical empiricists. However a metaphysical issue remained. Frank discussed the issue as analysed in one of the leading neo-kantian treatments of causality in modern physics, Hugo Bergmann's 1929 essay Der Kampf um das Kausalgesetz in der jungsten Physik [Translated as The Controversy Concerning the Law of Causality in Contemporary Physics in Boston Studies in the Philosophy of Science, vol. 2 pp. 395-462 (Dordrecht, 1974)]. Bergman (dropping the final m) soon emigrated to Palestine, and was to be a most distinguished philosopher at the Hebrew University of Jerusalem. We see how close he was to Philipp Frank, almost in parallel, for he was born in Prague in 1883, educated in physics, mathematics, and philosophy at the German University there, and a participant like Frank in Einstein's theoretical physics seminar during Einstein's time in Prague, 191O-12! But Frank points to Bergmann's desire for something more: "He (the neo-kantian) is not satisfied with what can be constructed scientifically and uncontestably, with the confrontation of a world of experiences and a world of symbols in which the world of science exists... he wants to operate science with the experiences themselves". (260) *

INTRODUCTION xiii This English translation of the 1931 book is based on a draft made by Marie Neurath some twenty years ago. Sadly, she did not live to finish the work. I am responsible for the final text with its errors, its awkwardness, and its other faults. We were pleased to be able to include here a full Bibliography of the published works of Philipp Frank. I note that the German original was reprinted, with a new introduction by Anne Jacob Kox, in the series Wiener Kreis - Schriften zum Logischen Empirismus (Suhrkamp, Frankfurt-a-M., 1988). Further, a Festschrift for Professor Frank was published in 1965, with ten greetings and reminiscences from his students and colleagues (Boston Studies in the Philosophy of Science, vol. 2). September 1997 Robert S. Cohen

SCHRIFTEN ZUR WISSENSCHAFTLICHEN WELTAUFFASSUNG PHILIPP FRANK o. II. PROFESSOR AN DER UNIVERSITAT PRAG HERAUSGEGEBEN VON UND BAND 6 MORITZ SCHLICK o. II. PROFESSOR AN DER UNIVERSITAT WI EN DA.S KAUSALGESETZ UND SEINE GRENZEN VON PHILIPP FRANK PROFESSOR AN DER DEUTSCHEN UNIVERSITAT IN PRAG MIT 4 ABBILDUNGEN WIEN. VERLAG VON JULIUS SPRINGER 1932

ANALYTICAL TABLE OF CONTENTS PREFACE BY PHILIPP FRANK (PRAGUE, 1931) 11 I. THE DANGERS OF MEANINGLESSNESS FOR STATEMENTS OF GREAT GENERALITY 17 1. 'Science' as an instrument, and its manipulation 17 2. Formulas are not statements about the real world 19 3. Only tautologies or statements about the real world are true or false 20 4. An individual general statement is neither true nor false 20 5. There is no philosophy aside from the special sciences 22 6. Meaningless inquiries 23 7. The so-called philosophical neutrality of science 25 8. The fight against philosophy in Soviet Russia 27 9. General statements slip into the tautological 28 10. How can statements about the real world be recognised? 29 11. The statement 'A straight line never returns to itself' 31 12. The law of inertia as tautology 32 13. The law of inertia as a statement about the real world 33 14. 'The predetermination of the future' as the meaning of the law of causality 34 15. The statement 'everything is predetermined' as tautological, and as a statement about the real world 35 16. The 'existence of a world formula' as the meaning of the law of causality 36 17. Conventionalism and its significance 37 18. Hugo Dingler's conception of science 38 19. Difficulties in recognising pure tautologies 41 3

4 ANALYTICAL TABLE OF CONTENTS II. THE MOST INCISIVE FORMULATION OF THE LAW OF CAUSALITY: LAPLACE'S DEMAND FOR A WORLD FORMULA 1. The content of Laplace's demand 43 2. The role of superhuman intelligence in Laplace's formulation 45 3. What does Laplace's demand say about the real world? 45 4. What does the 'position' of a mass-point mean? 46 5. Laplace's hypothesis and Newtonian mechanics 47 6. The meaning of Laplace's demand for a human intelligence 49 7. Astronomy as ideal case 50 8. Bodies of finite dimensions never fit into Laplace's scheme 51 9. Introduction of continuous media instead of mass-points 52 10. The mechanics of continua is not causal in Laplace's sense 53 11. The mechanics of continua necessarily leads to the statistical conception 54 12. Laplace's demand and the theory of electricity 55 13. Causality and the ether 56 14. Introduction of more general laws of motion than the Newtonian 57 15. State predetermination during a finite time 58 16. By the introduction of the field in place of bodies, the law of causality loses its simplicity 58 17. Field physics and occult qualities 59 18. The scientific meaning of field physics 60 19. The law of causality offield physics is much more indeterminate than Laplace's 60 20. How can the law of causality in field physics be made more precise? 62 III. CURRENTS OF THOUGHT HOSTILE TO CAUSALITY 1. The sources of anti-causal currents of thought 64 2. The first 'relaxation' of the law of causality in physics 66 3. The conception of nature in energetics 67 4. The attempt to rescue mechanical causality with statistical ideas 69 5. The statistical conception implies parting from Laplace's causality 70

ANALYTICAL TABLE OF CONTENTS 5 6. Maxwell's demon 71 7. Physicists speak against the general validity of mechanical causality 72 8. Anti-causal conception in quantum mechanics 74 9. Causality and the belief in miracles 75 10. The 'rupture' of the laws of nature 76 11. A historical remark 78 12. 'Gaps' in the laws of nature 78 13. 'Gaps' in consequence of the difference between mathematical points and observable places in space 80 14. On the use of gaps in the laws of mechanics 81 15. For a miracle, the interference in the gaps must be according to a plan 82 16. Teleological considerations instead of causal conceptions 83 17. The direction of progress in the history of the natural sciences 84 18. The character of lawfulness is the same in physics and biology 85 19. Thorough and superficial understanding of natural events 86 20. 'Understanding' [verstehende] science in contrast to merely 'classifying' sciences 87 21. Nature works with the greatest possible economy 90 22. The scientific meaning of the principle ofleast action 91 23. Strivings and tendencies as components of biological theories 92 24. Psychology of higher beings as the basis of biology 94 IV. CAUSALITY, FINALISM AND VITALISM 1. The age of the enlightenment and final causes 95 2. Are 'causality' and 'finalism' characteristics of the real world? 96 3. Explanations through 'aiming at a purpose' are always superficial 97 4. The mere assumption of the 'existence of a plan' is meaningless 98 5. The 'determination of the present by the future' in mechanics 100 6. Furthermore the 'present' state is in fact the state at several points of time 101 7. In the case ofliving organisms too, the mere claim of 'aiming at a purpose' is meaningless 102 8. Only the purposes of a living being are meaningful 103 9. In the study of history too, the introduction of purposes at which nobody aims is something very superficial 104

6 ANALYTICAL TABLE OF CONTENTS 10. The 'autonomy' of the phenomena of life is often accepted without scrutiny 105 11. A proof of the autonomy of the phenomena of life, by Hans Driesch 106 12. Misgivings about the proof 107 13. Driesch wants to prove the incompatibility of the processes of life with Newton's mechanics 109 14. An attempt to formulate the proposition of vitalism as description of an observable factual condition 110 15. Another proof by Driesch from analysis of human actions 112 16. Misgivings about the proof 113 17. Positive formulations of vitalism lead to spiritualism 115 18. In a strict sense, vitalism is not a scientific theory 116 19. Attempts to formulate vitalism 'positivistically' 117 20. Dialectical materialism and vitalism 120 21. The fight against the 'mechanists' in Soviet Russia 122 22. Which statements about real processes does dialectical materialism contain? 124 23. Biologists as opponents of vitalism and teleology 125 24. What do the tenets of 'holism' [Ganzheits philosophie] mean? 127 25. Vitalism in biology and finalist conceptions in physics 129 26. Finalism and the quantum theory 131 V. PHYSICAL LAWFULNESS AND CAUSALITY 1. Processes without change of energy are supposed not to need any mechanical cause 137 2. The role of the law of the conservation of energy must not be exaggerated 138 3. Is there a special form of energy for processes oflife? 140 4. What constitutes the special role of the law of the conservation of energy? 141 5. Are cause and effect interchangeable? 142 6. The causal form of physical laws 145 7. An example: the perturbations of planetary orbits 146 8. 'Free' and 'forced' motions in mechanics 147 9. 'Free' and 'forced' human actions 148 10. The question of the 'freedom' of human actions has nothing to do with the question of determinism 150

ANALYTICAL TABLE OF CONTENTS 7 11. For the world as a whole the word 'free' loses its meaning 151 12. The division of human actions into 'free' and 'forced' has a scientific character and does not form a bridge to metaphysics 152 VI. CAUSALITY AND CHANCE 1. An event can be called 'accidental' only with reference to a definitive causal law 155 2. 'An event is accidental' states something negative 156 3. The game of chance and the positive concept of accident [chance] 157 4. Each series of physical experiments is the result of a game of chance 159 5. The hypothesis of determinism 160 VII. CAUSALITY AND QUANTUM MECHANICS 1. Determinism and Laplace's conception of the world 161 2. Determinism demands exact numerical values for the state variables 162 3. Determinism and the atomistic conception 163 4. Determinism was never totally carried through 164 5. Bohr's atomic theory and determinism 165 6. The proposition: What is true in -the small, is also true in the large 167 7. Determinism for events on the smallest scale 168 8. Rupture between mechanics in the large and in the small 170 9. An arbitrarily precise measurement of all state variables is impossible in principle 171 10. Heisenberg's uncertainty relations 173 11. The impossibility to predict the result of an individual experiment from its conditions 175 12. From classical mechanics to the new 'wave' mechanics 176 13. Wave optics and uncertainty relations 178 14. Matter waves and the uncertainty relations 180 15. There can be no target practice with arbitrarily small mass particles 183 16. The statements of wave mechanics 185 17. Wave mechanics and the Laplacean spirit 186

8 ANALYTICAL TABLE OF CONTENTS 18. Future prediction in wave mechanics 187 19. Using wave mechanics to overthrow the causal-mechanistic world conception 189 20. Wave mechanics brings no 'irrational' element into the conception of nature 191 21. Wave mechanics and the 'gaps' in mechanistic causality 193 22. Wave mechanics and 'freedom of the will' 194 VIII. CAUSALITY, CHANCE OR PLAN IN THE DEVELOPMENT OF THE WORLD? 1. Lawfulness of different state variables means something different 197 2. A characteristic of sociological and historical laws 198 3. The role of causality and chance in the materialist conception of history 199 4. An example: changes of state in a gas 201 5. The different probabilities of individual states 204 6. The probability of different density distributions in a gas 206 7. The 'irreversibility' of natural processes 207 8. Entropy and probability of state 208 9. The 'improbability' of regular figures 210 10. The origin of organisms by 'chance' is supposed to be 'infinitely improbable' 211 11. The age of the Enlightenment and the question of the origin of the Iliad by chance 212 12. The 'probability' of an origin of organisms by chance is not at all defined 214 13. If chance is rejected it does not follow that a plan exists 215 IX. DIFFICULTIES IN THE FORMULATION OF A GENERAL LAW OF CAUSALITY 1. Preliminary survey of some difficulties 218 2. Formulations with the help of the return of identical states 220 3. Partial circular processes 221 4. 'Return of a state' can mean very different things 223 5. The character of causal prediction of the future differs according to the conception of 'return' 224

ANALYTICAL TABLE OF CONTENTS 9 6. Application to individual and social psychology 225 7. Prediction on the basis of return of a state and on the basis of laws 227 8. The law of causality as the claim that laws exist 228 9. The law of causality easily becomes a tautology 229 10. How can the law of causality be preserved as a statement about the real world? 230 11. Poincare, Kant and Lenin 230 12. The coordination of numerically defined magnitudes of state to observations creates difficulties 232 13. The usual rules of coordination fail in the case of micro-events 234 14. The statement 'A is always followed by B' becomes a statement about reality only with indication of the rules of coordination 235 15. The difficulties discussed are not superfluous sophistries 236 16. The statement that the 'true' state variables obey the law of causality is not a statement about the real world 237 17. In spite of all these difficulties we apply the law of causality in life successfully 238 x. ON THE SO-CALLED 'TRUE' WORLD 1. 'Real' and 'apparent' 240 2. What do 'real' and 'apparent' mean in physics? 241 3. 'True' and 'apparent' mass, 'true' and 'apparent' force 242 4. 'True', 'real' world in physics 243 5. The meaning of a 'true' world beyond experience 244 6. Attempts to define the 'true' world with the help of experience 245 7. The 'true' world as a limit toward which the scientific theories strive 247 8. A convergence of physical theories towards a limit cannot be detected 248 9. The physical theories and the 'true' world 250 10. The new quantum mechanics and the 'true' world 251 11. The founders of quantum mechanics and the 'true' world 253 12. 'Philosophy' wants to say something about the 'true' world 254 13. Ernst Mach as opponent of the concept 'true world' 256 14. The struggle of Lenin and his philosophical disciples against 'Machism' 257

10 ANALYTICAL TABLE OF CONTENTS 15. There is nothing sceptical in the refusal to speak of a 'true' world 259 16. 'Ignorabimus' is meaningless 260 17. The so-called limits of science 261 18. Accepting limits of science means accepting extra-scientific knowledge 262 19. Traditional 'school' philosophy preserves the residues of obsolete scientific theories 263 20. 'Philosophy' as defender of popular prejudice 265 21. 'Philosophy' in the struggle against the progress of science 266 22. The significance of neo-kantianism for a scientific worldconception 268 XI. ON THE VALIDITY OF THE LAW OF CAUSALITY 1. In practical life we never rely on the general law of causality but on our knowledge of special correlations 271 2. The causal connection of experiences is not the only correct one, but it is the only one that has great practical significance 273 3. Also the 'general' law of conservation of energy is not used in real physics 274 4. Also the 'conservation' of energy is not meaningful for any processes whatever 276 5. However the law of conservation of energy is closer to a statement about the real world than the law of causality 278 6. The causal relationships between experiences are, in principle, not different in kind according to the new and the old physics; only the coordination to the tool: 'science', in the relationship between symbols, has been modified 279

PHILIPP FRANK PREFACE I. When one comes to expressions like space, time, causality and the like in scientific writings, one can often read that here the competence of physics, even of natural science, came to an end and that problems in which such expressions occur could only be solved on a 'higher', the 'philosophical' plane. The ascent to that higher plane consists mainly in discarding the fetters of the strict scientific thinking to which one is subjected in the 'special sciences', and starting a kind of deliberation with results that one could call, recalling a well-known saying, 'opium for science'. This book aims to treat all questions put in it without this opium that is often called 'philosophy', by misuse of an honourable name. Nowhere will we attempt to make unsettled questions appear as if they were settled, by the use of dazzling turns of phrase; moreover, nowhere will we attempt to avoid questions concerning the borders of the area commonly called 'science', by shifting to another plane. Much more, our object is to treat all problems that appear during the operation of science with the same striving toward real solutions to which one is accustomed within the fields called often with benign condescension the 'special sciences'. I am not of the conviction that there are questions of principle about which one has to quarrel forever; rather I believe that only those statements can be considered to be scientific which can be made clear and evident to any person practiced in thinking. Already as a student I was firmly convinced that all progress in knowledge of the world can be reached only by a scientific pathway, never by leaving this way and climbing to a higher plane. At that time, then, in a university seminar, a professor of philosophy told us that after years of mental effort he had solved the problem of causality and summarised his solution in the statement "causality is the necessary relation between cause and effect", I could not fully suppress my 11

12 PHILIPP FRANK convulsive laughter, was reprimanded, and was from then on resolved to find out what could be said about this problem scientifically. Under the influence of Hilbert's Foundations of Geometry we then often regarded axiomatics as a true scientific substitute for the old philosophy. I tried to develop the axiomatics of physics, especially mechanics, in which the law of causality should appear as one of the most important axioms. However, when I proceeded to carry it out, I soon noticed to my great astonishment that precisely this axiom is almost insignificant and hardly restricts the course of actual events. At that time I had the insight that much fewer statements about the real observable world are hidden in the general law of causality than is commonly believed. This was in my essays of 1907 and 1908: 'The law of causality and experience' and 'Mechanism or vitalism?'; but the way in which I formulated it, I must consider one-sided todayl. The most recent developments in physics have encouraged me to return to the problems that I treated so many years ago. On the one hand it was the conception of statistical laws and their relation to dynamic laws which has been developed in several publications of Richard von Mises; on the other hand the new formulation of the law of causality in quantum mechanics as expounded by Max Born, Werner Heisenberg, P.A.M. Dirac and others. But what more than anything else made me once again follow the thread that I had abandoned nearly twenty-five years ago was the misuse that is often made today of the new conceptions of causality, with the purpose of exploiting it precisely to favour the most backward and unscientific currents. II. The usual philosophical teaching at our universities is mostly little suited for furthering a consistent thinking through to the conclusion of a scientific problem but rather favours breaking it off at a certain point and continuing it on a so-called higher plane. Within the various streams of traditional scholastic philosophy, it is perhaps only Neo Kantianism, especially in the form that Ernst Cassirer has given it, that stimulates consistent scientific thinking, but it wants to hold on to the ways of expression of idealistic philosophy, and therefore cannot achieve clarity. This tendency has to be evaluated as a phenomenon of disintegration within traditional philosophy, and in this sense it has a progressive character.

THE LAW OF CAUSALITY AND ITS LIMITS 13 In Germany it was above all Ernst Mach, and in England Bertrand Russell, who in principle rejected this jump onto a higher plane and wanted to think scientific problems through scientifically to the end. Beginning with these two scholars, more and more movements towards consistent scientific thinking may be noticed. In the most recent past these currents have fortified each other by a certain measure of collaborative work that perhaps for the first time became apparent to a wider public at the two congresses for the epistemology of the exact sciences in Prague, 1929, and in Konigsberg, 1930 2. In the most decisive way, the demand for a purely scientific conception of the world is advocated by the Vienna Circle, among whose representatives only Moritz Schlick and Rudolf Camap may be mentioned here. Its aim was recently formulated by Otto Neurath as a 'unified science' in opposition to the split that is favoured by our established philosophy, into philosophy and the special sciences, into mental science and natural science [Geisteswissenschaft and Naturwissenschaft]. In France the 'Union rationaliste' pursues similar aims (to the Vienna Circle). Among its representatives we may mention only Paul Langevin and Marcel Boll who struggle especially against misusing modem science as a prop for unscientific endeavours. Whatever one thinks about the radicalism of the Vienna Circle, one effect can already be established today: many of those who have lectured on the doctrines of traditional school philosophy as an evident matter of course now begin to sense that these are problematic, and to defend them. If, for example, we examine the presentation of the usual philosophy of nature in the well-known book by Bavink in which the present state of the special sciences is described very clearly and adequately, the following must attract attention: the conception of the metaphysical 'school philosophy' was formerly deeply interwoven with a presentation in which it seemed to belong to scientifically established propositions like the Pythagorean theorem or Newton's law of gravitation. This 'philosophically neutral' standpoint which consisted in a merely implicit use of traditional conceptions, now however is completely abandoned in Bavink's latest edition, and the metaphysical point of view is stressed expressly in opposition to the Vienna Circle. Max Planck has called the opposing views of which we speak the positivist and the metaphysical conceptions of science. He characterises them perfectly correctly in this way: according to the metaphy-

14 PHILIPP FRANK sical conception, the aim of science is the discovery of an existing 'true' world, while according to the positivist, however, it is the construction of a system of statements with the help of which we can find our way in the world of our experiences. Planck finds fault with the latter conception: the passion and readiness for sacrifice with which men like Galileo have fought for their convictions could not be understood if the matter had been merely purposeful, useful, constructions and not the discovery of truth. However these passions and this fighting spirit are facts that are as empirical as those of physics. In a system of unified science, both kinds of experience may find places side by side. Planck may be right insofar as perhaps the establishment of theories by the positivist wing has often been made all too often in empty space, without connections with the total activity of mankind, and most acutely this becomes apparent perhaps in Hugo Dingler's formulation that the creation of a theory is an act of 'free will'. The events around Galileo make it clear that the passionate conflicts connected with a physical theory have nothing to do with its suitability to represent natural processes but much more with their relationships to the political and social events of the time. Therefore there is no need to amplify the positivist conception of science by a metaphysical concept of truth but only by a more comprehensive study of the connections that exist between the activity of the invention of theories and the other normal human activities. III. Since I am not of the conviction that a philosophy working above and beyond science can achieve anything for knowledge of the world that resembles the achievements of science, there is little by way of confrontation with such philosohical theories in this book, even though they may be ingenious, sagacious or sublime. The only significance of such theories for the real world is the encouragement and support that can by drawn from them for extrascientific activities. Therefore relatively extensive treatment is given here to such philosophical systems as have given strong impulses to real actions in our time, even though these systems may be less cleverly constructed than others. Thus in this book frequent mention is made of statements of

THE LAW OF CAUSALITY AND ITS LIMITS 15 'holism', the holistic philosophy which forms the philosophical basis of those political movements that are usually called right-wing, e.g., of Italian fascism and German national socialism. On the other side, dialectical materialism, the philosophical basis of all Marxist groups, has been considered extensively. In this, I kept mainly to the formulations of Russian Marxists because the connection between theory and political practice is closest in their case. I have almost completely left aside polemical debates with views that resemble mine, so that the main features emerge clearly, and contours are not blurred. However I have occasionally mentioned titles and authors of writings that seem to me to be useful in connection with the basic questions of the development toward a scientific world conception. I have not arranged the book strictly systematically but so that individual sections may be more or less understood separately. The problem is attacked from new sides time and again, only with care taken that the main goal, toward which everything converges, always becomes clear. Nowhere will the answer to complex questions be found summarised in a short, effective statement, for I cannot agree with the belief that there are sorcerers' formulas that are hidden somewhere and need only be detected. If we examine such merely verbal formulas more closely, we mostly find concealed in them that opium of science mentioned earlier. Though human life may be so full of suffering that only the application of drugs brings ease and relief, scientific activity must in this respect be clearly separated from others. That intoxication and narcosis could be advantageous in science does not seem at all convincing to me; instead of superficial comfort through fine words, there is no other way here but going steadily onward with a more and more refined creation of the great instrument we call science. I have occasionally discussed some of the problems that are treated in this book with friends and colleagues and have utilised some suggestions from these conversations; on questions of physics, lowe special thanks to A. Einstein, R.v. Mises and E. Schrodinger, in those of biology to J. Gicklhorn and Fr. Knoll, in those of sociology to o. Neurath. In proof reading I had the devoted support of O. Altrichter and Marianne Lederer, who deserve grateful acknowledgment. Prague, November 1931 Philipp Frank