Lectures on S tmcture and Significance of Science

Lectures on S tmcture and Significance of Science

H. Mohr Lectures on Structure and Significance of Science Springer-Verlag New York Heidelberg Berlin

1-1. Mohr Biologisches instihlt II der Uoiversitiil Schiim:lestrasse I 7800 F reiburg Federal Republic of Cermany With 22 figures Library of Congress Cataloging in Publication Data Mohr, Hans, 1930- Lectures Oll struchlte and significance of science. Bibliography: p. Includes index. I. ScienCt'"-Addresses. essays, lectures. 2. Science Philosophy-Addr(.'Sses, essays, lccrurcs. L T itle. QI 7LM687 501 76-51383 All rights reserv(..'<l. No part of this book may be translated or reproduced in any form without written permission from Springer-Verlag. 1977 by Springer-Vcrlag Solkover reprinl of the Hardcover 1 st edit ion 1977 98 7 654321 ISBN- 13: 978-3-642-45498-1 001: 10. 1007/978-3-642-45496-7 e- ISBN- 13: 978-3-642-45496-7

Acknowledgements The opportunity of writing this treatise was made possible by a Visiting Professorship granted to me by the University of Massachusetts during the fall term of 1975. The present text is based on a series of 15 lectures that I delivered at U Mass. I am grateful to the students, and to my colleagues and friends in the Departments of Botany and Philosophy at U Mass, for their cordial reception, continuous interest, and constructive criticism. It was the positive response of my class and the fascinating intellectual climate at Amherst that encouraged me to prepare the lectures for print. Two of my colleagues in Freiburg, the evolutionary biologist, Gunther Osche, and the biophysicist, Eberhard Schafer, have carefully read the first draft of the manuscript. Their criticisms and suggestions have been considered in the final version. My American secretary, Barbara Hoffmann, has checked the manuscript with respect to grammar and style. This book is dedicated to Erwin Bunning and to Walter Kossel. In 1953, Bunning's book Theoretische Grundfragen der Physiologie was an important determinant in my decision to become a biologist. My Ph.D. work with Erwin Bunning has been the decisive experience in my scientific life. The late Walter Kossel introduced me to physics. He was not only a great physicist but also a fascinating philosopher and an admirable personali ty. Freiburg i. Breisgau, March 1977 H. MOHR

Contents To the Reader IX 1st Lecture Prologue: Science and Responsibility 1 2nd Lecture The Motivation of Science 21 3rd Lecture The Scientific Approach (1): Terminology and Language 29 4th Lecture The Scientific Approach (2): Data, Hypotheses, and Theories 42 5th Lecture The Scientific Approach (3): Laws, Prediction, Explanation 56 6th Lecture The Principle of Causality 76 7th Lecture The Structure of Teleological Action 86 8th Lecture Physics and Biology: The Problem of Reduction 95 9th Lecture Physiology and Comparative Biology 107 10th Lecture Tradition and Progress in Science: The Notion of Paradigms 127

VlIl Contents 11 th Lecture The Ethics of Science 143 12th Lecture Science and Technology 155 13th Lecture The Crisis of Science 169 14th Lecture Science and Values 180 15th Lecture Epilogue: Epistemology and Evolution 196 References 208 Subject Index 221

To the Reader I am not a professional philosopher of science. Rather, I am a nahlial scientist with some interest in the nature of scientific thought and in the significance of science. In the following lectures, I will make use of my (limited) knowledge about the sociology of science and of my (equally limited) knowledge about philosophy and history of science. The main source, however, on which I depend is my own personal experience as a practicing scientist. I hope that the professional philosophers will forgive me if my treatise does not always respect the conventional division of labor between science and philosophy. I fully agree with David Hull who recently criticized some noted scientists who tried their hands at "philosophizing": "Just as scientists are entitled to established standards of competence for their undertakings, philosophers have a right to expect at least minimal competence in theirs (1)". On the other hand, however, I feel that it is legitimate to base a reflection about the "Structure and Significance of Science" primarily on the self-understanding of the practicing scientist. My deep-rooted respect for philosophy in toto and for epistemology in particular will hopefully prevent me from becoming chauvinistic in favor of the scientific world view. In the prologue (Science and Responsibility), the problems will be formulated in broad terms. In the following lectures, the chief issues will be treated in more detail. While there is a well-established tradition of scholarship in the treatment of the "Scientific Method," [For an excellent recent collection of texts on the philosophy of science see: KRUGER (2)] the responsibility of the scientist has only recently become a starting point in considering the phenomenon of science; an interesting recent experiment has been published by Michaelis and Harvey (3). The influential Anglo Saxon schools in the philosophy of science have generally equated philosophy with epistemology, treating ethics as not properly part of academic philosophy. Since I am not obliged to any epistemological school but look

x To the Reader at the problems from the point of view of a practicing scientist, I will not follow the tendency of excluding anything from consideration that might raise moral problems. Rather, I intend to emphasize this aspect. I will further take the liberty to look at some traditionally epistemological problems, such as empirism and rationalism, from the point of view of scientific knowledge. Another point is that most philosophers of science, in particular within the dominant positivist school, take the Comtean view of physics as the paradigmatic science and of biology as a relatively immature and secondary study. Even as a biologist who is proud of biology, I cannot ignore this tendency since there is some truth in it. While there is no principal difference between physics and biology, the general approach in both fields and the nature of physical and biological theories and laws obviously differ to a considerable extent. I will often refer to physics rather than to biology not only for the sake of simplicity, clarity, and brevity, but also for the reason that physics has a far wider scope than biology. Physics deals with the properties of all matter whereas biology is only concerned with living systems or with ecosystems in which living systems play the major part. All living systems are physical objects, but only a very small number of physical objects are considered to be living systems. In the following I will often use the term "responsibility." This term implies, and I want to emphasize this at the very beginning, that we are responsible for our acts. I indeed presume that moral responsibility is part of human nature, irrespective of the century-long discussion on determination, free will, and moral responsibility. Determination to a scientist conveys the general proposition that every event has a cause. Whether this general proposition is true is a difficult question to decide, but it is certainly assumed to be true by most scientists. Otherwise science, in particular prediction, explanation, and purposive action, would not be possible. On the other hand, however, we presume that we are responsible for our acts. It is implied as a matter of course that moral responsibility is an integral part of human nature. Indeed, we all believe that moral responsibility is real. Since moral responsibility implies free will and self-determination (in the sense that we can create de novo determinants for our conduct and thus break causal continuity), the very serious and difficult question arises whether moral responsibility (which implies free will) is compatible with our scientific knowledge, which plainly says that the concept of a breach in causal continuity is not acceptable. From the point of view of science the reality of free will cannot be conceded. On the other hand, as human beings, we depend on the belief that at least some of our actions (called "willed actions") are preceded by deliberation and choice and that our choice can be influenced by consideration of consequences. I will leave this question open at the moment. We will return to this problem when we

To the Reader Xl try to analyze the nature of the principle of causality (6th Lecture) and the structure of teleological action (7th Lecture). I suppose in the following treatise that the discoveries of science had a profound effect on man's philosophy, ethics, and spiritual beliefs. However, science still has a long way to go to reach its major goal. In the words of Sir George Porter (4) The highest wisdom has but one science, the science of the whole, the science explaining the Creation and man's place in it.