Open realism, B. d'Espagnat quantum mechanics and objectivity - an analysis of some paradoxes, A. Peres non-locality and wave-packet reduction in optical experiments - physical and philosophical issues in the Bohr-Einstein debate, A. Shimony actualization perception and reality - an epistemological approach based on psychological analysis - a draft, K. Rainio do we need an introvert physics?, E. Huhmar quantum theory of measurement - a review, P. Lahti the archetypal hypothesis of Wolfgang Pauli and C.G. Junge - origins, development and implications, C.R. Card Wolfgang Pauli between quantum reality and the royal path of dreams, C.P. Enz Einstein, Bohr, Pauli and the principle of individuation, H. van Erkelens the role of the Copenhagen interpretation today - quantum mechanics and realism, remarks on physics and the psyche, K.V. Laurikainen the Cartesian cut, the Heisenberg cut, dressed objects, and detached observers, H. Primas mind, matter, and Pauli, H. Stapp a possible explanation for the quantum structure, D. Aerts the observer in the age of man - from Laplace's demon to Wigner's friend, F. Borg universal gravitational interaction and the (non)-measurability of physical field quantities, on a new type of uncertainty relations in quantum general relativity, H-H. v. Borzeskowski non-detachability of language and the Pauli-Bohr dialogue, L. Lofgren quantum mechanics as a continuous theory of discrete processes, P. Sibelius.
Open realism, B. d'Espagnat quantum mechanics and objectivity - an analysis of some paradoxes, A. Peres non-locality and wave-packet reduction in optical experiments - physical and philosophical issues in the Bohr-Einstein debate, A. Shimony actualization perception and reality - an epistemological approach based on psychological analysis - a draft, K. Rainio do we need an introvert physics?, E. Huhmar quantum theory of measurement - a review, P. Lahti the archetypal hypothesis of Wolfgang Pauli and C.G. Junge - origins, development and implications, C.R. Card Wolfgang Pauli between quantum reality and the royal path of dreams, C.P. Enz Einstein, Bohr, Pauli and the principle of individuation, H. van Erkelens the role of the Copenhagen interpretation today - quantum mechanics and realism, remarks on physics and the psyche, K.V. Laurikainen the Cartesian cut, the Heisenberg cut, dressed objects, and detached observers, H. Primas mind, matter, and Pauli, H. Stapp a possible explanation for the quantum structure, D. Aerts the observer in the age of man - from Laplace's demon to Wigner's friend, F. Borg universal gravitational interaction and the (non)-measurability of physical field quantities, on a new type of uncertainty relations in quantum general relativity, H-H. v. Borzeskowski non-detachability of language and the Pauli-Bohr dialogue, L. Lofgren quantum mechanics as a continuous theory of discrete processes, P. Sibelius.
Editorial. Part I: Epistemology and Philosophy of Language. A Realism, Idealism, and General Terms E. Bencivenga. From Normal Machine to Social Colony: Toward a Complex Dynamical Philosophy of Science W.E. Herfel, C.A. Hooker. Observation and Reliable Detection P. Humphreys. Conceptual Idealism and Stove's Gem A. Musgrave. Holism in Artificial Intelligence C. Penco. Part II: Philosophy of Probability. Model Selection for Causal Theories B. Desjardins. Nonstandard Analysis and a Classification of Probability Spaces S. Fajardo. Some Remarks on Objective Chance (F.P. Ramsey, K.R. Popper and N.R. Campbell) M.C. Galavotti. Misapprehensions about Significance Tests and Bayesianism M.G. Sandrini. Part III: Philosophy and Foundations of Physics. The Quantum Probabilistic Approach to the Foundations of Quantum Theory: Urns and Chameleons L. Accardi. The Creation-discovery-view: Towards a Possible Explanation of Quantum Reality D. Aerts, B. Coecke. Virtual Reality: Consequences of No-Go Theorems for the Modal Interpretation of Quantum Mechanics G. Bacciagaluppi, P. Vermaas. Is Chaos Indeterministic? R.C. Bishop, F.M. Kronz. Wormholes and Timelike Curves: Is There Room for the Grandfather Paradox? G. Boniolo. John von Neumann met Kurt Godel: Undecidable Statements in Quantum Mechanics T. Breuer. Set-theoretical Models for Quantum Systems N.C. da Costa, D. Krause. Non-Ideal Measurements and Physical Possibility in Quantum Mechanics M. Del Seta, M. Suarez. Time, Relativity, and the Spatiality of Mental Events M. Dorato. Bell-type Inequalities and Orthomodular Lattices A. Dvurecenskij. An Informal Presentation of Semantic Realism and Its Solution of Quantum Paradoxes C. Garola.Individualistic versus Statistical Interpretation of Quantum Mechanics P. Mittelstaedt. The Locality Scandal of Quantum Mechanics F.A. Muller. Uncertainty and Dependence in Classical and Quantum Logic -- the Role of Triangular Norms. Quantum Logics and Quantum Measurements M. Navara, P. Ptak. Quantum Logics and Quantum Measurements S. Pulmannova. Attempt at the Logical Explanation of the Wave-particle duality J. Pykacz. Part IV: History of Science. The Bohr-Einstein Photon Box Debate D. Dieks. Kantianism and Physics from the 19th to the 20th Century. Part V: Science and Music. Epimoric Ratios and Greek Musical Theory F. Bellissima. Music and Science G. Toraldo di Francia.
Quantum mechanics is usually defined in terms of some loosely connected axioms and rules. Such a foundation is far from the beauty of, e.g., the `principles' underlying classical mechanics. Motivated, in addition, by notorious interpretation problems, there have been numerous attempts to modify or `complete' quantum mechanics. A first attempt was based on so-called hidden variables; its proponents essentially tried to expel the non-classical nature of quantum mechanics. More recent proposals intend to complete quantum mechanics not within mechanics proper but on a `higher (synthetic) level'; by means of a combination with gravitation theory (R Penrose), with quantum information theory (C M Caves, C A Fuchs) or with psychology and brain science (H P Stapp). I think it is fair to say that in each case the combination is with a subject that, per se , suffers from a very limited understanding that is even more severe than that of quantum mechanics. This was acceptable, though, if it could convincingly be argued that scientific progress desperately needs to join forces. Quantum mechanics of a closed system was a beautiful and well understood theory with its respective state being presented as a point on a deterministic trajectory in Liouville space---not unlike the motion of a classical N -particle system in its 6N -dimensional phase-space. Unfortunately, we need an inside and an outside view, we need an external reference frame, we need an observer. This unavoidable partition is the origin of most of the troubles we have with quantum mechanics. A pragmatic solution is introduced in the form of so-called measurement postulates: one of the various incompatible properties of the system under consideration is supposed to be realized (i.e. to become a fact, to be defined without fundamental dispersion) based on `instantaneous' projections within some externally selected measurement basis. As a result, the theory becomes essentially statistical rather than deterministic; furthermore there is an asymmetry between the observed and the observing. This is the point where consciousness may come in. Complemented by an introduction and several appendices, Henry Stapp's book consists essentially of three parts: theory, implications, and new developments. The theory part gives a very readable account of the Copenhagen interpretation, some aspects of a psychophysical theory, and, eventually, hints towards a quantum foundation of the brain--mind connection. The next part, `implications', summarizes some previous attempts to bridge the gap between the working rules of quantum mechanics and their possible consequences for our understanding of this world (Pauli, Everett, Bohm, Heisenberg). The last section, `new developments', dwells on some ideas about the conscious brain and its possible foundation on quantum mechanics. The book is an interesting and, in part, fascinating contribution to a field that continues to be a companion to `practical' quantum mechanics since its very beginning. It is doubtful whether such types of `quantum ontologies' will ever become (empirically) testable; right now one can hardly expect more than to be offered some consistent `grand picture', which the reader may find more or less acceptable or even rewarding. Many practicing quantum physicists, though, will remain unimpressed. The shift from synthetic ontology to analytic ontology is the foundation of the present work. This means that fundamental wholes are being partitioned into their ontologically subordinate components by means of `events'. The actual event, in turn, is an abrupt change in the Heisenberg state describing the quantum universe. The new state then defines the tendencies associated with the next actual event. To avoid infinite regression in terms of going from one state of tendencies to the next, consciousness is there to give these events a special `feel', to provide a status of `intrinsic actuality'. The brain of an alert human observer is similar in an important way to a quantum detection device: it can amplify small signals to large macroscopic effects. On the other hand, actual events are not postulated to occur exclusively in brains. They are more generally associated with the formation of records. Records are necessarily part of the total state of the universe: it is obvious that the state of the universe cannot undergo a Schrödinger dynamics and at the same time record its own history. `The full universe consists therefore of an exceedingly thin veneer of relatively sluggish, directly observable properties resting on a vast ocean or rapidly fluctuating unobservable ones.' The present ideas also bear on how the world should be seen to develop. While conventional cosmology encounters problems as to how to define the intial conditions, which would enter the governing equations of motion, here `the boundary conditions are set not at some initial time, but gradually by a sequence of acts that imposes a sequence of constraints. After any sequence of acts there remains a collection of possible worlds, some of which will be eliminated by the next act.' Connected with those acts is `meaning': there has always been some speculation about the special significance of local properties in our understanding of the world. One could argue that correlations (even the quantum correlations found, e.g., in the EPR-experiments) were as real as anything else. But also Stapp stresses the special role of locality: the `local observable properties, or properties similar to them are the natural, and perhaps exclusive, carriers of meaning in the quantum universe. From this point of view the quantum universe tends to create meaning.' This sounds like an absolute concept: meaning not with respect to something else, but defined intrinsically---not easy to digest. The role of consciousness in the developing quantum universe requires more attention. `The causal irrelevance of our thoughts within classical physics constitutes a serious deficiency of that theory, construed as a description of reality.' This is taken to be entirely different within quantum mechanics. `The core idea of quantum mechanics is to describe our activities as knowledge-seeking and knowledge-using agents.' `21st century science does not reduce human beings to mechanical automata. Rather it elevates human beings to agents whose free choices can, according to the known laws, actually influence their behaviour.' An example with respect to perception is discussed: `Why, when we look at a triangle, do we experience three lines joined at three points and not some pattern of neuron firings?' The brain `does not convert an actual whole triangle into some jumbled set of particle motions; rather it converts a concatenation of separate external events into the actualization of some single integrated pattern of neural activity that is congruent to the perceived whole triangle.' How convincing is this proposal? It is hard to tell. I think Henry Stapp did a good job, but there are tight limitations to any such endeavour. Quantum mechanics is often strange indeed, but it also gives rise to our classical world around us. For the emergence of classicality jumps and measurement projections (the basic phenomena connected with those fundamental events of choice) are not needed. Therefore, I doubt whether the explanation of the evolution of our world really allows (or requires) that much free choice. On the other hand, most scientist will agree that empirical science was not possible without free will: we could not ask independent questions if this asking was part of a deterministic trajectory. The fact that the result of a quantum measurement is indeterminate (within given probabilities) does certainly not explain free will. How about the type of measurment? The experimentalist will have to assume that he can select the pertinent observable within some limits. But given a certain design the so-called pointer basis (producing stable measurement results) is no longer a matter of free choice. `The main theme of classical physics is that we live in a clocklike universe.' Today it is often assumed that the universe was a big (quantum-) computer or a cellular automaton. Many would be all too happy to leave that rather restrictive picture behind. But where to go? Stapp suggests giving consciousness a prominent role: `The most profound alteration of the fundamental principles was to bring consciousness of human beings into the basic structure of the physical theory.' How far we are able to go in this direction will depend on the amount of concrete research results becoming available to support this view.
Quantum Measurements.- Quantum mechanics of macroscopic systems and measurement processes.- The haunted measurement in quantum theory.- A quantum-statistical model of quantum measurement.- Potential and real states in quantum mechanics.- Wave function collapse in the ensemble interpretation.- Nonlinear models for quantum-mechanical measurements.- Meaning and measurability of nonlocal quantum states.- New Developments of Quantum Theory.- The mathematical expression of the uncertainty principle.- Quantization of Hamiltonian theories based on a probability operator.- Classical to quantum: A generalized phase transition.- Quantum description of microscopic and microscopic systems: Old problems and recent investigations.- Towards a process formalism in quantum physics.- A generalized Schroedinger formalism from a Hamiltonian flow in a higher dimensional space.- How the nonlinear phenomena impose the reinterpretation of quantum mechanics.- On the equivalence between the superposition principle and a global gauge invariance.- Meanings of Quantum Theory.- The 2-photon elementary quantum phenomenon and spacetime structure.- Causality as indentified with conditional probability and the quantal nonseparability.- Realism versus positivism: An attempt at reconcilement in the Einstein-Bohr debate.- Four-dimensional realism and waves carrying physical data codedly as keys to understandable models.- Testing interpretations of quantum mechanics.- On the relation between the recent new statistical prediction of quantum mechanics by Albert, Aharonov, and D'Amato, the EPR reasoning, and Bell's Inequality.- Beyond quantum theory: A realist psycho-biological interpretation of physical reality.- Locality, causality, quantum events, and all that.- The Einstein-Bohr debate: I. The background.- Contingency and lawfulness: Conditions for encounter.- Epr Paradox: Critical Examinations.- Towards a realist theory of measurement.- The tacit postulate on single events and the comparison of classical and quantum spin correlation experiments.- Weak realism for pairs of correlated systems.- Comments on EPR, locality and reality.- The EPR and the proposal of action at a distance.- The discription of separated systems and quantum mechanics and a possible explanation for the probabilities of quantum mehanics.- Against dualism: An observation concerning non-locality.- Bell's theorem: A note on locality.- EPR paradox considered as a criticism of the statevector reduction in the quantum mechanical description of correlated separated systems.- EPR and the strange nature of the quantum state or why I can live with EPR.- Why the EPR paradox has been resolved in favor of Einstein.- Probability and the way out of the great quantum muddle.- Where lies the mistake in the clauser and Home proof of Bell's theorem?.
The difficulties of the old quantum theory were largely dispelled by the development of quantum mechanics in the 1920s. First Heisenberg (1925) developed the rather abstract matrix mechanics and soon after Schro¨dinger (1926; see also Eckart, 1926) developed the physically more appealing wave mechanics. Subsequently he showed them to be mathematically equivalent. The physicists were greatly relieved; now they had once again a mathematical formalism that enabled the results of experiments to be calculated. It was possible to move forward. It is certainly a very elegant and indeed beautiful formalism, and does enable the results of many physical measurements to be calculated with great accuracy. It is used daily by atomic and nuclear physicists; there is no other way to make calculations. From the earliest days there has been intense debate about the interpretation of quantum mechanics, and it shows no signs of being settled; if anything it is becoming more intense over the years. As Penrose has remarked, no one understands quantum mechanics. Feynman (1967; see also Sykes, 1994) also admitted that ‘nobody understands quantum mechanics’, and Einstein once remarked: ‘I have thought a hundred times as much about the quantum problems as I have about general relativity theory’ (Pais, 1994, p. 57). It should therefore be evident that the most that can be done here is to try to show where the real difficulties lie, and how the failure to recognize that quantum mechanics is an essentially statistical theory has led to a series of confusing quantum paradoxes. It is just these paradoxes that have often been used to support theological speculations. It is useful to ask what ‘understanding quantum mechanics’ actually means. Certainly it means being able to calculate the results of many measurements. The same applies to Newton’s theory of gravitation, which we understand in the sense that we can use it as a basis of calculation, although we do not really understand the gravitational force itself. Very often, especially in modern physics, the mathematical formalism does not give us the sort of intuitive physical feeling for what is going on that we often obtain from classical mechanics. Perhaps we can never achieve more than this for quantum mechanics. In classical mechanics we can assume that a property that is measured objectively exists prior to the interaction of the measuring apparatus with the observed system. Quantum mechanics, however, ‘is incompatible with the proposition that measurement discovers some unknown but pre-existing property’ (Peres, 1997, p. 14). There is an important distinction between mysteries and absurdities. We may be forced to live with mysteries, but there is no reason why we should put up with absurdities such as the wave-particle duality, tunnelling through potential barriers, acausal events and the collapse of the wave function. These are the quantum paradoxes that will be discussed later on. They arise within the Copenhagen interpretation of quantum mechanics and are solved by other interpretations. These alternative interpretations enable us to make conjectures about what is going on, even though we cannot understand it in detail. This is acceptable and a stimulus to further research. It is certainly difficult enough to understand quantum mechanics, but there is no need to try to visualize logical absurdities in the effort to do so. Quantum mechanics is a mathematical formalism that makes it possible to calculate the results of some experiments. Anything more than this, such as questions about the interpretation of what is measured and whether it tells us what is actually going on in the system being studied, belongs to philosophy. Thus we are concerned here with what is essentially a philosophical debate; if it were just a matter of physics the debate would have been settled long ago. One of the difficulties is that it invokes the results of experiments and uses the language of quantum mechanics. Inevitably this language uses philosophical terms and then it is easy to give the impression that the philosophical propositions are in some way entailed by the physical results. These in turn can influence theological thinking. In order to be quite clear which arguments are justified and which are not, it is essential to separate the three levels of discourse: physical, philosophical and theological. Our task is to relate these together, and this immediately raises the traditional problems of the philosophy of science, including the relation of experiment to theory, and of theory to explanation. We begin by discussing experiments, distinguishing between those that are real and those that are imaginary.
The Copenhagen Interpretation of quantum mechanics has become the standard way of explaining the physical philosophical meaning of the mathematics of microscopic behavior. It developed from the thought of people who attended the Institute for Theoretical Physics of the University of Copenhagen during the 40 years that Niels Bohr directed it, from 1920 to 1962. Bohr took a large part in developing the Copenhagen Interpretation, he didn't escape all controversy over it (although the quote above is a bit of an exaggeration). Bohr did die before the experimental theoretical developments that have transposed the debate over the appropriateness adequacy of the Copenhagen Interpretation into a new key, he may well have been lucky to have escaped when he did. There is no authoritative codification of CI [the Copenhagen Interpretation], write T Gornitz C. E von Weizsacker of the Max Planck Institute in Starnberg, West Germany in' their formal presentation to the recent Loyola Conference on Mathematical Interpretational Problems in Relativistic Quantum Theory, and under the conditions of its origin there probably could not be one.... All prominent authors of the time who wrote on these questions, like Bohr, [Werner] Heisenberg, [Wolfgang] Pauli, J[ohn] v[on] Neumann on one side, [Albert] Einstein [Erwin] Schrodinger on the other, fell, so we feel, into some stammering when they tried to express their own positions. Nevertheless there is what might be called a Copenhagen attitude. It concentrates on observable phenomena, makes statistics probability central to its understanding, considers quantum mechanics primarily a theory of knowledge or information becomes a kind of physica negativa (analogous to a theologia negativa) in trying not to say too much about things that can't be seen or felt. For example, it doesn't much care whether the orbits of electrons in atoms are real or not and, in fact, tends to regard them as unreal. It appears in most textbooks as the standard way of looking at things.