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.

Conceptual Foundations of Quantum Mechanics provides a detailed view of the conceptual foundations and problems of quantum physics, and a clear and comprehensive account of the fundamental physical implications of the quantum formalism. This book deals with nonseparability, hidden variable theories, measurement theories and several related problems. Mathematical arguments are presented with an emphasis on simple but adequately representative cases. The conclusion incorporates a description of a set of relationships and concepts that could compose a legitimate view of the world.

In this largely nontechnical book, eminent physicists and philosophers address the philosophical impact of recent advances in quantum physics. These are shown to shed new light on profound questions about realism, determinism, causality or locality. The participants contribute in the spirit of an open and honest discussion, reminiscent of the time when science and philosophy were inseparable. After the editors' introduction, the next chapter reveals the strangeness of quantum mechanics and the subsequent discussions examine our notion of reality. The spotlight is then turned to the topic of decoherence. Bohm's theory is critically examined in two chapters, and the relational interpretation of quantum mechanics is likewise described and discussed. The penultimate chapter presents a proposal for resolving the measurement problem, and finally the topic of loop quantum gravity is presented by one of its founding fathers, Carlo Rovelli. The original presentations and discussions on which this volume is based took place under the auspices of the French "Academie des Sciences Morales et Politiques". The book will appeal to everybody interested in knowing how our description of the world is impacted by the results of the most powerful and successful theory that physicists have ever built.

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.

"Conceptual Foundations of Quantum Mechanics" provides a detailed view of the conceptual foundations and problems of quantum physics, and a clear and comprehensive account of the fundamental physical implications of the quantum formalism. This book deals with nonseparability, hidden variable theories, measurement theories and several related problems. Mathematical arguments are presented with an emphasis on simple but adequately representative cases. The conclusion incorporates a description of a set of relationships and concepts that could compose a legitimate view of the world.

In this largely nontechnical book, eminent physicists and philosophers address the philosophical impact of recent advances in quantum physics. These are shown to shed new light on profound questions about realism, determinism, causality or locality. The participants contribute in the spirit of an open and honest discussion, reminiscent of the time when science and philosophy were inseparable. After the editors' introduction, the next chapter reveals the strangeness of quantum mechanics and the subsequent discussions examine our notion of reality. The spotlight is then turned to the topic of decoherence. Bohm's theory is critically examined in two chapters, and the relational interpretation of quantum mechanics is likewise described and discussed. The penultimate chapter presents a proposal for resolving the measurement problem, and finally the topic of loop quantum gravity is presented by one of its founding fathers, Carlo Rovelli. The original presentations and discussions on which this volume is based took place under the auspices of the French "Academie des Sciences Morales et Politiques". The book will appeal to everybody interested in knowing how our description of the world is impacted by the results of the most powerful and successful theory that physicists have ever built.

Among the great ironies of quantum mechanics is not only that its conceptual foundations seem strange even to the physicists who use it, but that philosophers have largely ignored it. Here, Bernard d'Espagnat argues that quantum physics--by casting doubts on once hallowed concepts such as space, material objects, and causality-demands serious reconsideration of most of traditional philosophy.

"On Physics and Philosophy" is an accessible, mathematics-free reflection on the philosophical meaning of the quantum revolution, by one of the world's leading authorities on the subject. D'Espagnat presents an objective account of the main guiding principles of contemporary physics-in particular, quantum mechanics-followed by a look at just what consequences these should imply for philosophical thinking.

The author begins by describing recent discoveries in quantum physics such as nonseparability, and explicating the significance of contemporary developments such as decoherence. Then he proceeds to set various philosophical theories of knowledge--such as materialism, realism, Kantism, and neo-Kantism--against the conceptual problems quantum theory raises. His overall conclusion is that while the physical implications of quantum theory suggest that scientific knowledge will never truly describe mind-independent reality, the notion of such an ultimate reality--one we can never access directly or rationally and which he calls "veiled reality"--remains conceptually necessary nonetheless.

Die Grundlage jeder Wissenschaft ist stets das auf ihrem Gebiet am wenigsten Erforschte. Was am ehesten anzweifelbar ist, sind nicht die verwickeltsten Anwendungen und Folgerungen, sondern die Gesamtheit der Elemente. Zu einem nicht ubersehbaren Teil besteht der wahre geistige Gehalt der Wissenschaften sogar gerade in der uberwindung dieses ursprunglichen Mangels. So ist es zum Beispiel zweifelliaft, ob die als rational be- zeichnete Mechanik jemals hatte geschaffen werden koennen, ware dafm unentbehrlich ge- wesen, dass man die Begriffe Masse und Kraft wirklich begreifen koenne. Auch die Theorie des Elektromagnetismus bietet ein sehr gutes Beispiel. Man staunt, wie diese Theorie im vergangenen Jahrhundert bei der vollkommenen Unkenntnis so vieler grundlegender, die Elektrizitat betreffender Tatsachen einen so bemerkenswerten Aufschwung nehmen konn- te. Die Quantenmechanik, die quantitative Grundlage der Physik der Gegenwart, macht von dieser Regel keine Ausnahme. Obwohl ihre Fruchtbarkeit ausser Zweifel steht, geben ihre Prinzipien doch Anlass zur Diskussion und werden oft nur schlecht verstanden.

"This book is a monument to d'Espagnat's excellent work and style; it is surely the most complete book to have been written on this subject and one likely to last a long time, at least until we come to fully understand the remaining mysteries in the field."--Roland Omnes, Professor Emeritus of Theoretical Physics, Universite de Paris-Sud

"Bernard d'Espagnat is an accomplished theoretical physicist and philosopher, whose two disciplines are interrelated in the present book. He conclusively argues that features of quantum mechanics--particularly the Uncertainty Principle, the nonlocality exhibited by entangled systems, and the measurement problem--revolutionize epistemology and metaphysics. His novel and lucid philosophy, called 'veiled realism, ' criticizes Kant's doctrine of synthetic a priori knowledge but shares the thesis that scientific knowledge provides empirical regularities while pointing to an underlying 'noumenal' reality whose structure is not revealed."--Abner Shimony, Professor Emeritus of Philosophy and Physics, Boston University

"With exceptional scientific, historical, and philosophical insights, d'Espagnat examines the implications of recent developments in quantum physics for philosophy and the implications of philosophical reflections for the understanding of fundamental physics. D'Espagnat's book not only challenges ingrained ways of thinking; it is indeed a visionary and critical reorientation for both physics and philosophy."--Tian Yu Cao, Boston University

"D'Espagnat has performed an intellectual feat by distilling the essential conceptual puzzles of quantum mechanics into a few core principles without relying on any mathematical formalism, and in a veryreadable style at that. At the same time, this book is not some trendy everyman's guide to the exotic features of quantum physics, with some philosophical commentary--but a work of mature scholarship."--Jeffrey Bub, University of Maryland, author of "Interpreting the Quantum World"

"Here, d'Espagnat discusses virtually all the central philosophical issues related to quantum mechanics and its interpretation. The book is nontechnical, presupposing no previous knowledge of science or philosophy. It is a pleasure to read."--Andrew Z. Wayne, University of Guelph, coeditor of "Ontological Aspects of Quantum Field Theory"

"This book takes the theme of d'Espagnat's influential "Veiled Reality" and develops it into a 'world view, ' as he calls it. This extensive treatment is rich in detailed arguments, deft rebuttal of rival viewpoints, and historical perspectives."--Arthur G. Zajonc, Amherst College, coauthor of "The Quantum Challenge"