Some observations are presented on the well-known article by Vladimir Fock, "Quantum Physics and Philosophical Problems," published in 1971. In this article, which crowns and summarizes for Western readers a long and complicated reflection on the foundations of quantum mechanics (QM), Fock illustrates his "minimal" interpretation of this theory. By minimal we mean that it only uses concepts related to the operational aspects of the measurement procedures, avoiding any mention to definite quantum onthologies (Bell's beables). It is argued that, by taking into account the time reversal invariance of the microscopic processes and introducing the notion of irreversibility in an appropriate manner, Fock's description becomes an anticipation of the "transaction" notion introduced by Cramer a decade later.
Some observations are presented on the well-known article by Vladimir Fock, "Quantum Physics and Philosophical Problems," published in 1971. In this article, which crowns and summarizes for Western readers a long and complicated reflection on the foundations of quantum mechanics (QM), Fock illustrates his "minimal" interpretation of this theory. By minimal we mean that it only uses concepts related to the operational aspects of the measurement procedures, avoiding any mention to definite quantum onthologies (Bell's beables). It is argued that, by taking into account the time reversal invariance of the microscopic processes and introducing the notion of irreversibility in an appropriate manner, Fock's description becomes an anticipation of the "transaction" notion introduced by Cramer a decade later.
Some observations are presented starting with the well-known article by Vladimir Fock “Quantum Physics and Philosophical Problems”, published in 1971. In this article, which summarizes for Western readers a long and complicated reflection of the foundations of quantum mechanics (QM), Fock illustrates his “minimal” interpretation of this theory. By minimal, we mean that it only uses concepts related to the operational aspects of the measurement procedures, avoiding any mention of definite quantum ontologies (Bell’s beables). It is argued that, by taking into account the time reversal invariance of the microscopic processes and introducing the notion of irreversibility in an appropriate manner, Fock’s description becomes an anticipation of the “transaction” notion introduced by Cramer a decade later. So, the concept of “collapse” does retain the features of a QM “freak” postulate to become a new way to look at the elementary quantum processes.
‘A Philosopher Looks at Quantum Mechanics’ (Putnam [1965]) explained why the interpretation of quantum mechanics is a philosophical problem in detail, but with only the necessary minimum of technicalities, in the hope of making the difficulties intelligible to as wide an audience as possible. When I wrote it, I had not seen Bell ([1964]), nor (of course) had I seen Ghirardi et al. ([1986]). And I did not discuss the ‘Many Worlds’ interpretation. For all these reasons, I have decided to make a similar attempt forty years later, taking account of additional interpretations and of our knowledge concerning non-locality. (The Quantum Logical interpretation proposed in Putnam [1968] is not considered in the present paper, however, because Putnam [1994b] concluded that it was unworkable.) Rather than advocate a particular interpretation, this paper classifies the possible kinds of interpretation, subject only to the constraints of a very broadly construed scientific realism. Section 7 does, however, argue that two sorts of interpretation—ones according to which a ‘collapse’ is brought about by the measurement (e.g. the traditional ‘Copenhagen’ interpretation), and the Many Worlds interpretation or interpretations—should be ruled out. The concluding section suggests some possible morals of a cosmological character. 1. Background 2. Scientific realism is the premise of my discussion 3. What ‘quantum mechanics’ says—and some problems 4. Other interpretations of quantum mechanics 5. The problem of Einstein's bed 6. Classification of the possible kinds of interpretation 7. Which interpretations I think we can rule out 8. The ‘moral’ of this discussion
We present a historical-epistemological analysis of the foundations of quantum mechanics, highlighting the relationships between quantum mechanics and scientific realism, as well as the influence of the neo-positivist philosophy of the first decades of the 20th century. The great significance of the measurement process in the context of quantum mechanics is underlined as an essential element in providing a coherent description of reality, moving from micro to macrocosm, as well as the role that the measurement apparatus and the consciousness of the observer assume during the act of measurement, the related ontological problems, the question of the objectification of the wave function, and that of the definition of discernibility. We consider also an overview of the most important alternative proposals to the standard interpretation of quantum mechanics (Copenhagen interpretation), with particular reference to hidden variable theories and other alternatives to standard quantum mechanics philosophical approach, that are modifying the vision of reality, such as the Everett’s many-worlds theory, the QBism and unified holistic approaches, such as the Primordial Dynamic Space.
INTRODUCTION In 1965 Hilary Putnam published the standard work on the interpretation of quantum mechanics, a piece that all philosophers of quantum mechanics of the time had to come to terms with. He laid out one-by-one in a clear non-technical way each of the available approaches to the problem and explained, again non-technically but very exactly, what is wrong with them. In his own final words Putnam took ‘the modest but essential step of becoming clear on the nature and magnitude of the difficulties’ (1965, 158). In the almost forty years since there have been a variety of advances, technical developments and new points of view. But none of these is uncontroversial. In fact each suffers from some one or another of the very difficulties that Putnam summarised. Many of the newer approaches explain why the problem is not a problem after all; a few bury the problems in technical detail; and some make heroic assumptions, often metaphysical, that cause the problems to disappear. My conclusion surveying the contemporary literature is the same as Putnam's in 1965: ‘no satisfactory interpretation of quantum mechanics exists today’ (1965, 157). The time scale is amazing. Putnam's important piece was written forty years after the first formulations and successes of quantum mechanics. I am writing forty years later, and about a theory that has transformed our technology and our way of thinking about the world. Why does this theory still have ‘no satisfactory interpretation’?
When investigating various interpretations of quantum mechanics one notices that each interpretation contains an element which escapes a complete and full description. This element is always associated with the stochasticity of the individual event in the quantum measurement process. It appears that the implications of this limit to any description of the world has not been sufficiently appreciated with notable exceptions of, for example, Heisenberg, Pauli and Wheeler. If we assume that a deeper foundation of quantum mechanics is possible, the question arises which features such a philosophical foundation might have. It is suggested that the objective randomness of the individual quantum event is a necessity of a description of the world in view of the significant influence the observer in quantum mechanics has. It is also suggested that the austerity of the Copenhagen interpretation should serve as a guiding principle in a search for deeper understanding. In recent years, a significant increase of interest in the foundations of quantum mechanics can be observed. This increase is certainly related to the immense progress made during the last two decades in experiments with individual quantum systems. This technological progress has made it possible to really perform more and more of the famous gedanken experiments which were so important in the early days of the theory. Not only did these experiments confirm the theory in every detail, they also opened up avenues for new experimental directions which might even lead some day to new technology. While such applications are certainly still far away, areas like quantum cryptography[1], quantum computation[2] and interaction-free measurement[3], just to name a few examples, certainly deserve the attention they receive. All this activity has also drawn more attention to the problems of understanding and interpreting quantum mechanics. It seems that there, a definitive consensus has not yet been reached. As witnesses quote authorities like Feynman as saying[4]: I think can safely say that nobody today understands quantum mechanics, whereby he apparently included himself, or like Roger Penrose[5], who describes his opinion remarking that while the theory agrees incredibly well with experiment and while it is of profound mathematical beauty, it makes absolutely no sense. Why did even physicists who have contributed so significantly to quantum theory Feynman was even rewarded the Nobel Prize for one of its mathematical formulations choose such emphatic and strong formulations? Why is it that the average physicist hears very little about such problems during his/her education? Why is the comprehension of the theory very often focused on formalism while questions that probe for deeper meaning are usually not tackled? To take a closer look at the situation, let us turn to a brief analysis of the interpretation of quantum mechanics. We note that there are at least two levels of interpreting a formalism, a physical theory. The first, basic, level supplies the rules that determine which element of the formalism corresponds to which measurable quantity or to which observable fact in a concrete experimental situation. Theses rules are a large, mostly not explicated but only implicit, set of instructions. These instructions concern the manner of working with the statements of the theory in order to obtain predictions for future experiments or events, and they concern the instructions on how to proceed in experiment in order to demonstrate or test a theoretical
The role played by irreversible processes, at the microscopic scale, in several examples of quantum measurements is studied within a "minimally realist" interpretation of the quantum formalism introduced in a recent publication. The analysis extends and confirms the basic results of the earlier work: separation of the collapse and amplification phases of the measurement, and decoherence and collapse happening already as a consequence of irreversible microscopic processes at the level of the "probe" itself (typically an atom in the examples considered). Additionally, the proposed interpretation of the formalism is shown to be consistent with previous interpretations, and a case for true irreversibility in physics is argued in some detail.