Born, de Broglie, Wigner, Bondi, Popper, and others of comparable stature here express their esteem for and his lifelong dedication to his science in a particularly appropriate way: by contributing to this book articles in which they operate at their deepest level of ongoing concern rather than by offering simple tributes or reminiscences. No better salute could be accorded to a man who, in his eighties, continues to operate at such a level himself.Some of the papers deal with the specific areas in which made important contributions to the theory of atomic structure in his younger days, such as the Lande g-factor so important to spectral analysis. Most of them, however, take up the larger issues of the nature of quantum reality and the consistency and completeness inherent in our descriptions of it.Lande was an early supporter of the Copenhagen of quantum phenomena, developed in the late 1920s by Bohr and Heisenberg. This depends on a fundamental duality in which the wave-like and particle-like aspects of matter and radiation are each regarded as necessary but partial views of reality, mutually complementing one another.In his later years, however, became increasingly dissatisfied with this interpretation and began to develop a unitary approach does not depend on this dualism. This was to lead to his demonstration that quantum theory, instead of being a set of enigmatic, though most successful, rules of calculation, can be understood as the logical consequence of a few almost self-evident postulates of symmetry and invariance. To Lande's own scientific conscience, the quantum riddle has found its solution. Even those who take a different point of view, including some of the contributors to this book, treat this solution with the respect its seriousness has earned.The contributors and their topics are as follows: Max Born: An Open Letter to Lande; Louis de Broglie: A New Interpretation Concerning the Coexistence of Waves and Particles; Hans-Jurgen Treder: The Einstein-Bohr Box Experiment; Eugene P. Wigner: Quantum-Mechanical Distribution Functions Revisited; Margenau and James L. Park: The Logic of Noncommutability of Quantum-Mechanical Operators--and Its Empirical Consequences; Alfred Kastler: How the Factor of an Atom Can Be Changed by Putting the Atom in a Radiofrequency Bath; David Bohm: Space-Time Geometry as an Abstraction from Spinor Ordering; Helmut Honl: A Contribution to the Thermodynamics of the Universe and to 3K Radiation; Dennis Caldwell and Henry Eyring: Quantum-Mechanical Rate Processes; O. Costa de Beauregard: Statistical Irreversibility and Quantized Wave Retardation; Fritz Bopp: The Internal Symmetries of Elementary Particles Resulting from the Geometric Structure of Lattice Space; Jean-Pierre Vigier: Hidden Parameter Theory; Karl R. Popper: Particle Annihilation and the Argument of Einstein, Podolsky, and Rosen; Walter M. Elsasser: Philosophical Dissonances in Quantum Mechanics; Leon Rosenfeld: Unphilosophical Considerations on Causality in Physics; Hermann Bondi: Logical Foundations in Physics; Andre Mercier: Forms of Determinism, Objectivity, and the Classification of Sciences; and Paul Bernays: Causality, Determinism, and Probability.
Born, de Broglie, Wigner, Bondi, Popper, and others of comparable stature here express their esteem for and his lifelong dedication to his science in a particularly appropriate way: by contributing to this book articles in which they operate at their deepest level of ongoing concern rather than by offering simple tributes or reminiscences. No better salute could be accorded to a man who, in his eighties, continues to operate at such a level himself.Some of the papers deal with the specific areas in which made important contributions to the theory of atomic structure in his younger days, such as the Lande g-factor so important to spectral analysis. Most of them, however, take up the larger issues of the nature of quantum reality and the consistency and completeness inherent in our descriptions of it.Lande was an early supporter of the Copenhagen of quantum phenomena, developed in the late 1920s by Bohr and Heisenberg. This depends on a fundamental duality in which the wave-like and particle-like aspects of matter and radiation are each regarded as necessary but partial views of reality, mutually complementing one another.In his later years, however, became increasingly dissatisfied with this interpretation and began to develop a unitary approach does not depend on this dualism. This was to lead to his demonstration that quantum theory, instead of being a set of enigmatic, though most successful, rules of calculation, can be understood as the logical consequence of a few almost self-evident postulates of symmetry and invariance. To Lande's own scientific conscience, the quantum riddle has found its solution. Even those who take a different point of view, including some of the contributors to this book, treat this solution with the respect its seriousness has earned.The contributors and their topics are as follows: Max Born: An Open Letter to Lande; Louis de Broglie: A New Interpretation Concerning the Coexistence of Waves and Particles; Hans-Jurgen Treder: The Einstein-Bohr Box Experiment; Eugene P. Wigner: Quantum-Mechanical Distribution Functions Revisited; Margenau and James L. Park: The Logic of Noncommutability of Quantum-Mechanical Operators--and Its Empirical Consequences; Alfred Kastler: How the Factor of an Atom Can Be Changed by Putting the Atom in a Radiofrequency Bath; David Bohm: Space-Time Geometry as an Abstraction from Spinor Ordering; Helmut Honl: A Contribution to the Thermodynamics of the Universe and to 3K Radiation; Dennis Caldwell and Henry Eyring: Quantum-Mechanical Rate Processes; O. Costa de Beauregard: Statistical Irreversibility and Quantized Wave Retardation; Fritz Bopp: The Internal Symmetries of Elementary Particles Resulting from the Geometric Structure of Lattice Space; Jean-Pierre Vigier: Hidden Parameter Theory; Karl R. Popper: Particle Annihilation and the Argument of Einstein, Podolsky, and Rosen; Walter M. Elsasser: Philosophical Dissonances in Quantum Mechanics; Leon Rosenfeld: Unphilosophical Considerations on Causality in Physics; Hermann Bondi: Logical Foundations in Physics; Andre Mercier: Forms of Determinism, Objectivity, and the Classification of Sciences; and Paul Bernays: Causality, Determinism, and Probability.
For many years the physical interpretation of quantum theory has been dominated by the “wave-particle duality” attitude of the “Copenhagen school.” This point of view is eloquently described in Bohr's collection of essays on the subject. Despite persistent concerns with apparent paradoxes and limitations to this interpretation (as exemplified by Schrodinger's cat, the paradox of Einstein, Podolsky and Rosen, among others), the Copenhagen view persists de facto in the daily life of the modern physicist. Traditional quantum theory has so successfully explained such a vast amount of data in atomic and molecular physics, solid state physics (and to a lesser extent, elementary particle physics) that little doubt can exist concerning its essential validity. As a consequence of the overwhelming practical success of the “Copenhagen interpretation, ” the latter has acquired the status of dogma. For many years, therefore, most physicists have found it expedient to relegate the puzzling aspects of the theory to philosophers, and mathematicians. Nevertheless, a persistent interest in this subject has produced a significant and fascinating literature, reviewed by Jammer. In recent years, concerns over the proper meaning to be ascribed to quantum theory have produced an increasingly deep and incisive series of investigations. These investigations fall generally into two categories: either (1) discussion of the philosophical content of the theory, or (2) analyses of the mathematical variants of the theory and their connection with differing interpretational schemes. Physicists tend to be detached from a commitment to philosophical issues, because of their realization of the transient character of the meanings attached to theories of the day. As a simple illustration of this we can mention the profound differences between nonrelativistic and relativistic quantum mechanics.
THE conceptual problems raised by the discovery of quantum effects have not been fully resolved after half a century. Part of the reason for this is undoubtedly to be found in the mutual ignorance which prevails between physicists and philosophers. In his book Heisenberg brings together a philosophically inclined temperament with an unrivalled knowledge of physics. The result is a book of very great interest, however much one might disagree with his conclusions. The collection of essays of which the other book is made up is intended to bring crucial conceptual problems in physics especially to the notice of philosophers. The design and intention of the collection is admirable for this is the proper way to overcome the departmentalization of interest that has left the deep conceptual problems still unresolved. Men like Heisenberg who combine philosophical temperament with scientic knowledge of great distinction are rare, and yet the difficulties can only be cleared up by the application of philosophical techniques of analysis to problems which are an intimate and difficult part of physics. A great deal of the interest of Heisenberg's book lies in the very comprehensive account he gives of the origin and growth of the Copenhagen school, and the way the new phenomena forced a largely unwelcome picture of nature upon Bohr and his friends. The most important chapter from a philosophical point of view is that in which Heisenberg defends this interpretation against the attacks to which it has been subjected. The essence of his argument for the interpretation can be summed up in two propositions. (i) The Copenhagen interpretation of physical theory, which depends upon the acceptance of the so-called Principle of Complementarity, is an inevitable and final interpretation. The reason for this is that there are only two possible general models for understanding given physical phenomena; a particle model or a wave model. These are exhaustive and exclusive because the former depends upon discontinuous and the latter upon continuous (using substance here in the traditional philosophical sense). If we find, as we do, that the two fundamental constituents of the universe, matter and radiation, each exhibit two classes of phenomena, one explainable only on a particle model and one on a wave model, then we are compelled to adopt a complementarity hypothesis and give up the idea of finding a single and uniform model for the understanding of phenomena. There are only two kinds of models; they are mutually exclusive; both are required; hence we either despair before an insoluble problem or adopt the Copenhagen interpretation. (2) Any serious criticism of this interpretation must offer an alternative
Quantum mechanics is a most intriguing theory, the empirical success of which is as great as its departure from the basic intuitions of previous theories. Its history has attracted much attention. In the 1960s, three leading contributors to this history, Thomas Kuhn, Paul Forman, and John Heilbron, put together the Archive for the History of Quantum Physics (AHQP), which contains manuscripts, correspondence, and interviews of early quantum physicists. In the same period, Martin Klein wrote clear and penetrating essays on Planck, Einstein, and early quantum theory; and Max Jammer published The Conceptual Development of Quantum Mechanics , still the best available synthesis. Since then, this subfield of the history of science has grown considerably, as demonstrated in accounts such as the five-volume compilation by Jagdish Mehra and Helmut Rechenberg; the philosophically sensitive studies by Edward MacKinnon, John Hendry, and Sandro Petruccioli; Bruce Wheaton’s work on the empirical roots of wave-particle dualism; my own book on the classical analogy in the history of quantum theory; and a number of biographies. These sources nicely complement one another. There have been, however, a couple of bitter controversies. Historians notoriously disagree about the nature of Planck’s quantum work around 1900. Whereas Klein sees in it a sharp departure from classical electrodynamics, Kuhn denies that Planck introduced any quantum discontinuity before Einstein. Here I take Kuhn’s side, although it follows from Allan Needell’s insightful dissertation that neither Klein nor Kuhn fully identified Planck’s goals.
Prologue A memorial conference for John Bell, open to the public, was held at Rutgers University around 20 years ago. I gave a short talk there on Bell's views about David Bohm's “hidden variables” formulation of quantum mechanics, a version of quantum mechanics often called the de Broglie–Bohm theory or Bohmian mechanics. This theory was in fact discovered by Louis de Broglie in 1927. In 1952, it was rediscovered and developed by Bohm, who was the first to appreciate its connection to the predictions of standard quantum mechanics. I did not publish the talk. I have decided that it would be appropriate to publish a very lightly edited version of it here, in this volume devoted to the work of Bell on the foundation of quantum mechanics. One reason for doing so is that the connection between Bell and Bohm continues to be somewhat underplayed, with the strength of his advocacy of Bohmian mechanics not properly appreciated. For example, about half of the papers in Bell's collected works on the foundations of quantum mechanics deal with Bohmian mechanics. But in his fine introduction to the revised edition of this great book [1], Alain Aspect mentions this theory in only a single sentence, and parenthetically at that. For several decades after Bell proved his nonlocality theorem, based in part on Bell's inequality, it was widely claimed that Bell had shown that hidden variables – and Bohmian mechanics in particular – were impossible, that they were incompatible with the predictions of quantum mechanics. For example, the great physicist Eugene Wigner, who, unlike most of his contemporaries, was profoundly concerned with the conceptual foundations of quantum mechanics and usually wrote on the subject with great clarity and insight, has written that This [hidden variables] is an interesting idea and even though few of us were ready to accept it, it must be admitted that the truly telling argument against it was produced as late as 1965, by J. S. Bell … This appears to give a convincing argument against the hidden variables theory.
By questioning the validity of some of our basic concepts, such as space, object, and causality, quantum physics contributes quite decisively to the dramatic changes now taking place in our world picture.This book is addressed not only to physicists at an early stage in their careers (the first or second year graduate student) but also to philosophers, as well as to all the senior physicists interested in the interpretation problem. Beginning with a chapter that could be described as ?philosophy for physicists,? it presents an in-depth analysis of present-day quantum mechanical concepts, an analysis of physicists and philosophers alike. Specifically, it first offers an extensive critical analysis of such topics as the Einstein, Podolsky, Rosen reality criterion, nonseparatability, the quantum measurement riddle, decoherence theory, consistent histories approaches and ontologically interpretable theories. All this then naturally leads to philosophical questions concerning, in particular, intersubjective agreement and the limit of realism. And a thorough examination of this whole material finally leads to the view that distinguishing between empirical reality and a veiled man-independent reality yields an acceptable answer to the perplexing question of how to interpret quantum physics. Veiled Reality offers nonspecialists, including students in physics, philosophy and the history of science, an accessible perspective on basic problems in the foundations of physics.
Preface. In defense of dogma: why there cannot be a relativistic quantum mechanics of (localizable) particles D.B. Malament. Just how radical is hyperplane dependence? G. Fleming. Is there superluminal causation in relativistic quantum field theory? M. Redei. EPR, relativity, and the GHZ experiment C. Pagonis, et al. Hidden quantum non-locality N.D. Mermin. Royer's measurements - the rise and fall of (yet another) signalling scheme I. Pitowsky. Tails of Schrodinger's cat D.Z. Albert, B. Loewer. Wavefunction collapse models with nonwhite noise P. Pearle. The emergence of classical properties from quantum mechanics L.E. Ballentine. Relativism S. Saunders. Wave and particle concepts in quantum field theory P. Teller. The conceptual relation between standard quantum mechanics and quantum field theory D. Robinson. What measurement problem? J.T. Cushing. Bovine metaphysics: remarks on the significance of the gravitational phase effect in quantum mechanics H.R. Brown. Exotic (quixotic?) applications of Bohm theory R. Weingard. Complementarity and the orthodox (Dirac-von Neumann) interpretation of quantum mechanics J. Bub. Logical reflections on the Kochen-Specker theorem J.L. Bell. Construction of quantum mechanics via commutative operations S. Kochen.