I suggest a contextual realist interpretation of Carlo Rovelli’s relational quantum mechanics. The principal point is a correct understanding of the concept of reality and taking into account the categorical distinction between the ideal and the real. Within my interpretation, consciousness of the observer does not play any metaphysical role. The proposed approach can also be understood as a return to the Copenhagen interpretation of quantum mechanics, corrected within the framework of contextual realism. The contextual realism allows one to get rid of the metaphysical problems encountered by various interpretations of quantum mechanics, including the relational one. A wave function neither literally reflects an “exterior reality”, nor is it merely a predictive mathematical tool. In particular, an entangled wave function can be viewed as the formal cause of quantum correlations whose reality is contextual. The reduction of a wave function is not a real physical process. And there are no autonomous quantum events which would be different from the facts of their representation. The quantum measurement problem results from a confusion between the categories of the ideal and the real. It is dissolved logically. The quantum theory plays the role of a Wittgensteinian rule (norm), “measuring” physical reality within a language game of its application.
I suggest a contextual realist interpretation of Carlo Rovelli’s relational quantum mechanics. The principal point is a correct understanding of the concept of reality and taking into account the categorical distinction between the ideal and the real. Within my interpretation, consciousness of the observer does not play any metaphysical role. The proposed approach can also be understood as a return to the Copenhagen interpretation of quantum mechanics, corrected within the framework of contextual realism. The contextual realism allows one to get rid of the metaphysical problems encountered by various interpretations of quantum mechanics, including the relational one. A wave function neither literally reflects an “exterior reality”, nor is it merely a predictive mathematical tool. In particular, an entangled wave function can be viewed as the formal cause of quantum correlations whose reality is contextual. The reduction of a wave function is not a real physical process. And there are no autonomous quantum events which would be different from the facts of their representation. The quantum measurement problem results from a confusion between the categories of the ideal and the real. It is dissolved logically. The quantum theory plays the role of a Wittgensteinian rule (norm), “measuring” physical reality within a language game of its application.
A realist interpretation of quantum mechanics is proposed - Contextual Quantum Realism (CQR) - according to which there exists a categorical distinction between the ideal (theory, observation instrument) and the real (quantum physical systems, properties), and, consequently, quantum ontology is context-sensitive. CQR is compared with QBism and Relational Quantum Mechanics (RQM), both of which also claim to offer realist interpretations. However, both approaches conflate the ideal and the real, thereby introducing an anti-realist dimension. RQM is an objectivist (physicalist) interpretation that naturalizes epistemic concepts, whereas QBism is subjectivist (phenomenological). RQM and QBism share a common presupposition of (post-)Modern philosophy - namely, the reduction of reality to objectivity - which CQR explicitly rejects.
For Kant causality is an a priori category of the understanding, a necessary condition for the possibility of any experience. Later Wittgenstein’s philosophy rejects transcendentalism. We can only speak of causes and effects if in some basic situations, or ‘language games’, we already treat some things as causes of what happens. Since the notion of cause becomes meaningful only within a language game, it is not unambiguous. Quantum causal language games presuppose the use of quantum theory. We treat the latter as Wittgenstein’s grammar of a quantum form of life’, or rule (norm), anchored in its applications — quantum phenomena as language games. Quantum correlations are often interpreted as a manifestation of the nonlocality of quantum mechanics. This is a view of quantum phenomena from the perspective of classical physics. Our contextual point of view rejects the nonlocality of quantum theory in the sense of instantaneous causal influence at a distance. But it does not admit its locality in the sense of classical causality either. We introduce the notion of quantum causality which allows us to treat quantum correlations as local, but context-dependent. Their formal cause is an entangled wave function. Any particular quantum correlation, identifiable in a context of its observation as a result of the wave function reduction, post factum can be treated as a classical causal correlation. From the point of view of the proposed contextual quantum realism, epistemology is secondary, and ontology is sensitive to context. Quantum correlations exist (are real) before application of the theory, independently of their identification (description, measurement), but have no identity, which appears only as a result of application of the theory and their identification in the context. In other words, they are real, but not pre-determined, not autonomous.
In the well known Copenhagen interpretation of Quantum mechanics, advocated by N. Bohr, the physical objects and the experimental results can be described only in a macroscopic language, leaving any possible microscopic description as unspeakable. This point of view has been deepened by C. Rovelli in the relational interpretation of Quantum mechanics. Most of the alternative interpretations, which try a detailed microscopic description of physical phenomena and of their evolution, have in common the explicit introduction of the wave function as the basic element of the theory. These interpretations require the notion of quantum state as the fundamental concept of the theory, which is the typical unspeakable physical element according to the Copenhagen interpretation. The two basic physical entities are intimately bound together by the integrity of the wave function. These interpretations are usually indicated as realistic. It is well known that the use of the wave function and its time evolution in the description of the physical processes leads unavoidably to some difficulties or so-called paradoxes. The measurement problem is at the center of these difficulties, mainly because it requires the introduction of the reduction process of the wave function, which is not included explicitly within the mathematical formalism of Quantum Mechanics. In this paper we build up and propose a model which goes beyond the standard formalism and which is able to solve the measurement problem and all the other difficulties which, in a way or in another, are related to it.
Non-relativistic classical physics can be considered from a contextual perspective. At fi rst glance, the difference between classical physics (including special relativity) and quantum physics lies in the fact that the latter is indeterministic – that is, in general, the context of a quantum event cannot be controlled. However, within the framework of our contextual realism, we interpret physical theories – including classical ones – as grammars of corresponding scientifi c practices: rules of Wittgensteinian language games, that is, Wittgensteinian rules/norms (W-rule). Any theory, as a W-rule, is essentially probabilistic, since a W-rule allows for new (non-predetermined) uses. Th erefore, classical mechanics, like quantum mechanics, must be given an essentially probabilistic interpretation, and the problem of measurement – that is, the gap between the W-rule and its application – exists in classical mechanics as well.
The present study is concerned with the problem of realism in quantum mechanics. Contrary to the prevailing view that quantum mechanics forces us to abandon the concept of realism and reality, the author attempts to substantiate another standpoint. Quantum objects indeed exist in a different way from classical bodies. Before the act of measurement begins, one cannot attribute any specific properties to the quantum object observed, as they only occur in the course observation. The concept of observation, however, should not be interpreted as the inclusion of subjective traits in the description of nature. Observation records processes in space and time and establishes the fact of transition from the potential to the reality. The potential is described by a wave function, which in its meaning does not fall in the habitual space and time, whereas the actual is described in terms of a reduction of the wave function, i.e. the transition from a range of possible states to the single one, the observed. Whatever has been observed, in contrast, already belongs to ordinary space and time and can be detected. What follows is that, in quantum mechanics, it is the notion of reality which needs to be reconsidered, not the realism as such rejected. A reconsideration of this sort is conducted here within the framework of a double-modus picture of reality including both potential and actual being, where the quantum level of existence is distinguished from the observed modi of being as described by means of classical concepts. Such a scheme can be described in terms of Aristotelian metaphysics (the fact first pointed out by Heisenberg). The act of transition from potential to actual can be accounted for both in the language of Aristotle’s metaphysics and the language of modern science. In traditional metaphysics it is called the 'principle of individuation', while in modern science it is known as the extended Mach principle. It is argued that the development of these ideas leads to the rejection of Cartesian paradigm in which the existence of a material object always means an existence in space and time.