Why does one theory "succeed" while another, possibly clearer interpretation, fails? By exploring two observationally equivalent yet conceptually incompatible views of quantum mechanics, James T. Cushing shows how historical contingency can be crucial to determining a theory's construction and its position among competing views. Since the late 1920s, the theory formulated by Niels Bohr and his colleagues at Copenhagen has been the dominant interpretation of quantum mechanics. Yet an alternative interpretation, rooted in the work of Louis de Broglie in the (...) early 1920s and reformulated and extended by David Bohm in the 1950s, equally well explains the observational data. Through a detailed historical and sociological study of the physicists who developed different theories of quantum mechanics, the debates within and between opposing camps, and the receptions given to each theory, Cushing shows that despite the preeminence of the Copenhagen view, the Bohm interpretation cannot be ignored. Cushing contends that the Copenhagen interpretation became widely accepted not because it is a better explanation of subatomic phenomena than is Bohm's, but because it happened to appear first. Focusing on the philosophical, social, and cultural forces that shaped one of the most important developments in modern physics, this provocative book examines the role that timing can play in the establishment of theory and explanation. (shrink)

Presents German physicist Werner Heisenberg's 1958 text in which he discusses the philosophical implications and social consequences of quantum mechanics and other physical theories.

Discussions of the interpretation of quantum theory are at present obstructed by (1) the increasing axiomania in physics and philosophy which replaces fundamental problems by problems of formulation within a certain preconceived calculus, and (2) the decreasing (since 1927) philosophical interest and sophistication both of professional physicists and of professional philosophers which results in the replacement of subtle positions by crude ones and of dialectical arguments by dogmatic ones. More especially, such discussions are obstructed by the ignorance of both opponents, (...) and also defenders of the Copenhagen point of view, as regards the arguments which once were used in its defence. The publication of Bunge's Quantum Theory and Reality and especially of Popper's contribution to it are taken as an occasion for the restatement of Bohr's position and for the refutation of some quite popular, but surprisingly naive and uninformed objections against it. Bohr's position is distinguished both from the position of Heisenberg and from the vulgarized versions which have become part of the so-called "Copenhagen Interpretation" and whose inarticulateness has been a boon for all those critics who prefer easy victories to a rational debate. Einstein's main counterargument is discussed, and Bohr's refutation restated. The philosophical background and earlier forms of Bohr's views are stated also. Considering that these views are more detailed, better adapted to the facts of the microdomain than any existing alternative it follows that fundamental discussion must first return to them. Their uniqueness is not asserted, however. Here the author still maintains that a hundred shabby flowers are preferable to a single blossom, however exquisite. But a hundred shabby flowers plus an exquisite blossom are more desirable still. (shrink)

In this dissertation I am pursuing three questions: first, what was the meaning of the use and rejection of mystical and paranormal terminology in the interpretations of quantum physics by Einstein, Schrodinger, Bohr, Pauli and Jordan, second what was the attitude of these physicists towards mysticism or mystical philosophy and, finally, what was their attitude towards paranormal phenomena like extrasensory perception and psychokinesis? I argue that Einstein and Schrodinger employed mystical and paranormal terminology in a derogatory, ironical, and polemical fashion (...) to pinpoint what they understood from their perspective to be the most devastating objections against Bohr's interpretation of quantum physics. Bohr, Pauli and, to a lesser extent, Jordan rejected mystical and paranormal interpretations as misunderstandings, or even misrepresentations, of their complementarity interpretation of quantum physics. Second, Schrodinger, Bohr and Pauli supported some kind of mysticism, whereas Einstein rejected a mystical interpretation of his "Spinozistic" realism; Jordan was indifferent towards mysticism. Third, as far as paranormal phenomena were concerned Einstein, Bohr and Pauli were skeptical; Schrodinger vehemently objected to paranormal phenomena as an outflow of an animistic, magical attitude, whereas Jordan was concerned with the depth-psychological and epistemological basis of these phenomena which he believed had been verified by Rhine and Bender. It is my conclusion that the thought of these physicists provides no basis for any claims that quantum physics somehow supports mystical philosophy or parapsychology for that matter. Instead, to the extent that expressions apparently suggesting such a base are found in their works, these arose as rhetorical devices in the mutual criticisms of Einstein and Bohr, or else in connection with the individual epistemological and metaphysical views of these quantum physicists rather than from the character of the physics they helped create. (shrink)

Die Relativitatstheorien (RT) Einsteins gehoren zu den meistdiskutierten Theorien der Physik des zwanzigsten Jahrhunderts. Nach der Formulie­ rung der sog. 'speziellen Relativitatstheorie' (SRT) im Jahr 1905 nah­ men zunachst nur einige Spezialisten von ihr Kenntnis, bis mit ungefiihr fiinf Jahren Verspatung dann auch zunehmend Nicht-Physiker sich mit ihr zu beschaftigen begannen, angeregt durch populiirwissenschaftliche, all­ gemeinverstiindliche 'Einfiihrungen' von Kollegen Einsteins wie z. B. Paul Langevin in Frankreich oder Max von Laue in Deutschland. Diese Pha­ senverschiebung zwischen fachwissenschaftlichem Ausbau der Theorie (...) und offentlicher Notiznahme wiederholte sich bei Einsteins 'allgemeiner Theorie der Relativitat und Gravitation' (ART). Zwischen 1913 und 1915 in ihren wesentlichen Ziigen ausformuliert, wurde sie erst nach einer spektakuliiren experimentellen Bestatigung im Jahr 1919 einem breiterem Publikum be­ kannt. In meiner Arbeit werde ich den Facettenreichtum der Ausdeutungen, die beide RT erfuhren, zunachst zu referieren und durch repriisentative Zi­ tate aus der Literatur der Zeit zu belegen haben. Der Umfang dieser Arbeit geht wesentlich auf das Konto dieser ausgewahlten Belege - davon verspre­ che ich mir, dafi nicht nur bislang unveroffentlichte Dokumente, sondern auch entlegene Texte hier in ihren zentralen Passagen leicht zuganglich ge­ macht werden. Fernerhin werde ich aber auch zu analysieren haben, warum derartig vielfaltige, einander mitunter diametral entgegengesetzte Interpre­ tationen einer wissenschaftlichen Theorie vorgelegt wurden. (shrink)

The contributions of few contemporary scientists have been as far reaching in their effects as those of Nobel Laureate Werner Heisenberg.

The nrst of the people to be thanked for their help during the composition of this work is Professor I.M. Bochenski, under whom I had the good fortune to study for an extended period of time. Without his help, it is doubtful that this work would have been writt"l1 at all. Among the other professors who helped along the way, I would like to cite in particular Professors A.F. Utz, M.D. Philippe and N. Luyten of the University of Fribourg. Many (...) friends were present at the birth of the ideas contained in this book. By naming K.G. Ballestrem, T.l. Blakeley and M.F. Gagern, I do not want to slight any of the rest. It was A. Spiekermann in Hollinghofen who saw to it that other preoccupations did not rob me of all the time needed for the study of the subject-matter and to the composition of this treatise. Of particular help in getting sources from the libraries of the world were Miss Lifschitz of the Institute of East-European Studies and Mr. Uldry of the Cantonal Library in Fribourg, Switzerland. Finally, my patient typist, Mrs. Frey in Munster, deserves special mention for her beautiful work. (shrink)

Murdoch describes the historical background of the physics from which Bohr's ideas grew; he traces the origins of his idea of complementarity and discusses its meaning and significance. Special emphasis is placed on the contrasting views of Einstein, and the great debate between Bohr and Einstein is thoroughly examined. Bohr's philosophy is revealed as being much more subtle, and more interesting than is generally acknowledged.

Of all the developments in twentieth century physics, none has given rise to more heated debates than the changes in our understanding of science precipitated by the quantum revolution''. In this revolution, Niels Bohr's dramatically non-classical theory of the atom proved to be the springboard from which the new atomic physics drew it's momentum. Furthermore, Bohr's contribution was crucial not only because his interpretation of quantum mechanics became the most widely accepted view but also because in his role as educator (...) and spokesman for atomic physics Bohr was very much the patron spirit of the entire quantum revolution. The conceptual framework which he proposed to provide a new viewpoint for understanding the quantum theoretical description of atomic systems became for most of this century the dominant outlook of countless productive experimental and theoretical physicists. He called this new framework complementarity''. (shrink)

What is commonly known as the Copenhagen interpretation of quantum mechanics, regarded as representing a unitary Copenhagen point of view, differs significantly from Bohr's complementarity interpretation, which does not employ wave packet collapse in its account of measurement and does not accord the subjective observer any privileged role in measurement. It is argued that the Copenhagen interpretation is an invention of the mid‐1950s, for which Heisenberg is chiefly responsible, various other physicists and philosophers, including Bohm, Feyerabend, Hanson, and Popper, having (...) further promoted the invention in the service of their own philosophical agendas. (shrink)

Within the past decade there has grown an acute and highly articulate group of critics of the orthodox interpretation of quantum theory,--the so-called "Copenhagen Interpretation." The writings of people like Bopp, Janossy, and particularly Bohm and Feyerabend, must be taken very seriously indeed. The future of some important discussions in the philosophy and the logic of science rests with these individuals. But they have, in their own writings, occasionally matched the inelegancies of Bohr and Heisenberg with as many inelegancies of (...) their own. The present paper is meant to present a quintet of considerations which may possibly lead to a reassessment of the issues between Bohr, Heisenberg, and their critics, especially Bohm and Feyerabend. (shrink)

“Bohr was primarily a philosopher, not a physicist, but he understood that natural philosophy... carries weight only if its every detail can be subjected to the... test of experiment”. As a result his approach differed from that of the school-philosophers whom he regarded with a somewhat “sceptical attitude, to say the least” and whose lack of interest in “the important viewpoint which had emerged during the development of atomic physics” he noticed with regret. But it also differed, and to a (...) considerable degree, from the spirit of what Professor T. S. Kuhn has called a “normal science.” Looking at Bohr's method of research we see that technical problems, however remote, are always related to a philosophical point of view; they are never treated as “tiny puzzles” whose solution is valuable in itself, even if one has not the faintest idea what it means, and where it leads: “For me” Bohr writes to Sommerfeld in 1922 “[the quantum theory] is not a matter for petty didactic details, but a serious attempt to reach... an inner coherence.” Emphasis is put on matters of principle and minor discrepancies, or “puzzles” in the sense of Kuhn, instead of being deemphasized, and assimilated to the older paradigm, are turned into fundamental difficulties by looking at them from a new direction, and by testing their background “in its furthest consequences by exaggeration”. A noteworthy example of Bohr's “non-normal” and rather metaphysical approach to physics is his scepticism in the face of the success of his own atomic model. (shrink)

Heisenberg, in constructing quantum mechanics, explicitly followed certain principles exemplified, as he believed, in Einstein's construction of the special theory of relativity which for him was the paradigm for radical theoretic change in physics. These were the principles of scientific realism, stability of background knowledge, E-observability, contextual re-interpretation, pragmatic continuity, model continuity, simplicity. Fifty years later, in retrospect, Heisenberg added the following two: a principle of non-proliferation of competing theories - scientific revolutions are not a legitimate goal of physics - (...) and a principle of tenacity - existing theories are to be conserved as far as possible. The conservative as well as the revolutionary potential of these principles is then discussed. A more penetrating philosophical criticism of these principles is postponed. (shrink)

It is widely believed that the development of the general theory of relativity coincided with a shift in Einstein’s philosophy of science from a kind of Machian positivism to a form of scientific realism. This article criticizes that view, arguing that a kind of realism was present from the start but that Einstein was skeptical all along about some of the bolder metaphysical and epistemological claims made on behalf of what we now would call scientific realism. If we read Einstein’s (...) philosophy of science in its proper late nineteenth-and early twentieth-century philosophical context, we find that a kind of Duhemian under determinationist holism and conventionalism was more important to Einstein than either positivism or realism. And, reading his philosophy of science in its proper scientific. (shrink)

Since the Niels Bohr centenary of 1985 there has been an astonishing international surge of scholarly analyses of Bohr's philosophy. Now for the first time in Niels Bohr and Contemporary Philosophy Jan Faye and Henry Folse have brought together sixteen of today's leading authors who have helped mould this new round of discussions on Bohr's philosophy. In fifteen entirely new, previously unpublished essays we discover a surprising variety of the different facets of Bohr as the natural philosopher whose `framework of (...) complementarity' shaped the final phase of the quantum revolution and influenced two generations of the century's leading physicists. There is much on which the authors included here agree; but there are also polar disagreements, which assure us that the philosophical questions revolving around Bohr's `new viewpoint' will continue to be a subject of scholarly interest and discussion for years to come. This collection will interest all serious students of history and philosophy of science, and foundations of physics. (shrink)

In the first comprehensive biography of Erwin Schrödinger--a brilliant and charming Austrian, a great scientist, and a man with a passionate interest in people and ideas--the author draws upon recollections of Schrödinger's friends, family and colleagues, and on contemporary records, letters and diaries. Schrödinger led a very intense life, both in his research and in the personal realm. This book portrays his life against the backdrop of Europe at a time of change and unrest. His best known scientific work was (...) the discovery of wave mechanics, for which he was awarded the Nobel Prize in 1933. In Dublin, he wrote his most famous and influential book What is Life?, which attracted some of the brightest minds of his generation into molecular biology. This highly readable biography of a fascinating and complex man will appeal to anyone interested in the history of our times, and in the life and thought of one of the great men of twentieth-century science. (shrink)

Copenhagen interpretation of quantum mechanics deals with these problems is reviewed. A new interpretation of the formalism of quantum mechanics, the transactional interpretation, is presented. The basic element of this interpretation is the transaction describing a quantum event as an exchange of advanced and retarded waves, as implied by the work of Wheeler and Feynman, Dirac, and others. The transactional interpretation is explicitly nonlocal and thereby consistent with recent tests of the Bell inequality, yet is relativistically invariant and fully causal. (...) A detailed comparison of the transactional and Copenhagen interpretations is made in the context of well-known quantum-mechanical Gedankenexperimenre and "paradoxes." The transactional interpretation permits quantum-mechanical wave functions to be interpreted as real waves physically present in space rather than as "mathematical representations of knowledge" as in the Copenhagen interpretation. The transactional interpretation is shown to provide insight into the complex character of the quantum-mechanical state vector and the mechanism associated with its "collapse." It also leads in a natural way to justification of the Heisenberg uncertainty principle and the Born probability law (P = ii iij*), basic elements of the Copenhagen interpretation. (shrink)

Popper conceived an experiment whose analysis led to a result that he deemed absurd. Popper wrote that his reasoning was based on the Copenhagen interpretation and therefore invalidated it. Many authors who have examined Popper's analysis have found in it various technical flaws which are briefly summarized here. However, the aim of the present article is not technical. My concern is to redress logical flaws in Popper's argument: the terminology he uses is ambiguous, his analysis involves counterfactual hypotheses, and it (...) violates Bohr's complementarity principle. Therefore, the absurdity of Popper's result only confirms Bohr's approach. (shrink)

In this paper, I argue that Heisenberg's mature philosophy of quantum mechanics must be understood in the context of his epistemological project to reinterpret and redefine Kant's notion of the a priori. After discussions with Weizsäcker and Hermann in Leipzig in the 1930s, Heisenberg attempted to ground his interpretation of quantum mechanics on what might be termed a 'practical' transformation of Kantian philosophy. Taking as his starting point, Bohr's doctrine of the indispensability of classical concepts, Heisenberg argued that concepts such (...) as space, time and causality can be regarded as 'practically a priori', in so far as they remain the conditions for the possibility of experience and even of 'objective reality', though they are not universal and necessary in a strictly Kantian sense. We cannot avoid using classical concepts in the description of experiments in quantum theory, despite the fact that there are limits to their applicability. Such concepts are, for Heisenberg, historically contingent, yet indispensable in our time, because we have no other language through which we can describe and conceive of the interaction between 'object' and 'measuring device'. (shrink)

My contribution will focus on only one question, which I would like to state in the simplest possible way. This question will be: why do we find Bohr obscure? Or, alternatively, why is there so much — and ever renewed — complaint in the literature over Bohr ‘being unintelligible’?

The bulk of the present book has not been published previously though Chapters II and IV are based in part on two earlier papers of mine: "The Influence of Harald H!1lffding's Philosophy on Niels Bohr's Interpretation of Quantum Mechanics", which appeared in Danish Yearbook of Philosophy, 1979, and "The Bohr-H!1lffding Relationship Reconsidered", published in Studies in History and Philosophy of Science, 1988. These two papers comple ment each other, and in order to give the whole issue a more extended treatment (...) I have sought, in the present volume by drawing on relevant historical material, to substantiate the claim that H!1lffding was Bohr's mentor. Besides containing a detailed account of Bohr's philosophy, the book, at the same time, serves the purpose of making H!1lffding' s ideas and historical significance better known to a non-Danish readership. During my work on this book I have consulted the Royal Danish Library; the National Archive of Denmark and the Niels Bohr Archive, Copenhagen, in search of relevant material. I am grateful for permission to use and quote material from these sources. Likewise, I am indebted to colleagues and friends for commenting upon the manuscript: I am especially grateful to Professor Henry Folse for our many discussions during my visit to New Orleans in November-December 1988 and again here in Elsinore in July 1990. (shrink)

An attempt is made to give a coherent account of the logical essence of the Copenhagen interpretation of quantum theory. The central point is that quantum theory is fundamentally pragmatic, but nonetheless complete. The principal difficulty in understanding quantum theory lies in the fact that its completeness is incompatible with external existence of the space—time continuum of classical physics.

The Austrian physicist Wolfgang Pauli (1900-1958) was often called the conscience of physics. He was famous for his sharp and critical mind which made him a central figure among the founders of quantum physics. He also was an outstanding philosopher, especially interested in finding a new conception of reality and of causality. A careful study of the original sources of the past culminated in his study of Kepler and of medieval symbolism, a concept that played a central role in his (...) discussion with Carl Jung on what they called the psycho-physical problem. Pauli considered the sharp distinctions between knowledge and faith and between spirit and matter as dangerous. He thought they should complement each other in our comprehension of reality. Professor Laurikainen here for the first time describes Pauli's ideas in detail. His book is based on the large and as yet unpublished correspondence between Pauli and M. Fierz. Its careful analysis adds depth and clarity to the few publications by Pauli on philosophical problems and explains why Pauli grasped the meaning of atomic theory more deeply than even Niels Bohr himself. The book should interest both philosophers and physicists and should encourage further studies on Pauli the humanist and his contribution to our understanding of reality. (shrink)