The pretersensual part of physical reality includes not only theories and conceptions, but also the objective reality itself, viz., being as defined not by man alone. As far as conceptions of the physical reality are concerned, they are subject to experimenting. Experimentation, however, serves to verify the metaphysical conceptions as well consider the theories of Parmenides (integrity and continuity) and Democritus (atomism, the reduction of a whole to its parts) as an example. This paper examines one of the latest examples of theories put to verification: the famous argument between Albert Einstein and Niels Bohr, each of whom shared different metaphysical conceptions. Experimental analysis of the metaphysical conceptions of physical reality has shown that future physical theories must be both local (Democritus' metaphysics) and inseparable (Parmenides' metaphysics).
The pretersensual part of physical reality includes not only theories and conceptions, but also the objective reality itself, viz., being as defined not by man alone. As far as conceptions of the physical reality are concerned, they are subject to experimenting. Experimentation, however, serves to verify the metaphysical conceptions as well consider the theories of Parmenides (integrity and continuity) and Democritus (atomism, the reduction of a whole to its parts) as an example. This paper examines one of the latest examples of theories put to verification: the famous argument between Albert Einstein and Niels Bohr, each of whom shared different metaphysical conceptions. Experimental analysis of the metaphysical conceptions of physical reality has shown that future physical theories must be both local (Democritus' metaphysics) and inseparable (Parmenides' metaphysics).
The pretersensual part of physical reality includes not only theories and conceptions, but also the objective reality itself, viz., being as defined not by man alone. As far as conceptions of the physical reality are concerned, they are subject to experimenting. Experimentation, however, serves to verify the metaphysical conceptions as well – consider the theories of Parmenides (integrity and continuity) and Democritus (atomism, the reduction of a whole to its parts) as an example. This paper examines one of the latest examples of theories put to verification: the famous argument between Albert Einstein and Niels Bohr, each of whom shared different metaphysical conceptions. Experimental analysis of the metaphysical conceptions of physical reality has shown that future physical theories must be both local (Democritus’ metaphysics) and inseparable (Parmenides’ metaphysics).
The objective of this article is to demonstrate how the historical debate between materialism and idealism, in the field of Philosophy, extends, in new clothes, to the field of Quantum Physics characterized by realism and anti-realism. For this, we opted for a debate, also historical, between the realism of Albert Einstein, for whom reality exists regardless of the existence of the knowing subject, and Niels Bohr, for whom we do not have access to the ultimate reality of the matter, unless conditioning it to the existence of an observer endowed with rationality, position adopted in the Interpretation of Complementarity (1927) – posture that was expanded in 1935 when Bohr assumed a “relationalist” conception, according to which the quantum state is defined by the relationship between the quantum object and the entire measuring device. This is an extremely important debate, as it further consolidates the results of nascent Quantum Mechanics, guaranteeing Bohr the leadership of the orthodoxy based on the interpretation of complementarity. Here, when dealing with Quantum Theory, we will not make any distinction between the terms Quantum Physics, Quantum Theory or Quantum Mechanics. The entire discussion will be held under the name “Quantum Theory”. Theory that tries to analyze and describe the behavior of physical systems of reduced dimensions, close to the sizes of molecules, atoms and subatomic particles. We hope that the reader will appreciate the genius of these two titans in this field of Physics when they magnificently formulate the arguments that support the object of their defenses.
The objective of this article is to demonstrate how the historical debate between materialism and idealism, in the field of Philosophy, extends, in new clothes, to the field of Quantum Physics characterized by realism and anti-realism. For this, we opted for a debate, also historical, between the realism of Albert Einstein, for whom reality exists regardless of the existence of the knowing subject, and Niels Bohr, for whom we do not have access to the ultimate reality of the matter, unless conditioning it to the existence of an observer endowed with rationality, position adopted in the Interpretation of Complementarity (1927) – posture that was expanded in 1935 when Bohr assumed a “relationalist” conception, according to which the quantum state is defined by the relationship between the quantum object and the entire measuring device. This is an extremely important debate, as it further consolidates the results of nascent Quantum Mechanics, guaranteeing Bohr the leadership of the orthodoxy based on the interpretation of complementarity. Here, when dealing with Quantum Theory, we will not make any distinction between the terms Quantum Physics, Quantum Theory or Quantum Mechanics. The entire discussion will be held under the name “Quantum Theory”. Theory that tries to analyze and describe the behavior of physical systems of reduced dimensions, close to the sizes of molecules, atoms and subatomic particles. We hope that the reader will appreciate the genius of these two titans in this field of Physics when they magnificently formulate the arguments that support the object of their defenses.
ASPECTS OF THE DEBATE The debate between Niels Bohr and Albert Einstein concerning the interpretation of quantum mechanics extended from the fifth Solvay Conference in 1927 until the end of Einstein's life. The most dramatic exchange occurred in 1935, when Einstein, in collaboration with B. Podolsky and N. Rosen, published a paper in Physical Review entitled “Can quantum-mechanical description of physical reality be considered complete?”, concluding with a negative answer, and Bohr replied in the same journal, with a paper of the same title but giving a positive answer. Their arguments were restated, in some respects with greater clarity, in the Library of Living Philosophers volume on Einstein in 1949. The disagreements between Bohr and Einstein concerned not only the physical question expressed in the common title of their papers, but also philosophical questions about physical reality and human knowledge. Much light was thrown upon the Bohr–Einstein debate by the theorem of J. S. Bell (1964) and the experiments which it inspired. Bell showed that any physical theory which applies to a pair of spatially separated systems (as considered in the thought experiment of Einstein, Podolsky, and Rosen) and satisfies a certain locality condition will, in certain circumstances, disagree statistically with quantum mechanics. Consequently, the supplementation of the quantum mechanical description envisaged by Einstein and his collaborators (usually referred to as a “hidden variables theory”) must either violate the locality condition or clash with quantum mechanical predictions.
The article discusses a new understanding of the reality in the 20th century. Since the key figure in these changes was the Danish physicist Niels Bohr, we refer to his early and later articles to analyze the use of the term “reality”. Through an analysis of the terms, it is shown that Bohr describes discoveries in earlier articles that are inconsistent with old concepts in physics, and it is these questions that will further lead him to a new understanding of reality. In the article we also indicate how many times and in what contexts the term “reality” is used. Further, we find that the term “reality” is more common in later articles than in his earlier works (Copenhagen’s interpretation of quantum theory had not yet been formulated at the time of writing the early works). Through the analyzing of usage of certain terms, we show how the emphasis in the early and late Bohr’s articles shifts. For many years, the Danish physicist has sought to clarify quantum theory. In some later articles, we note that the problems affect not only physical, but also other areas of knowledge. We also analyze the use of the term in later articles. This analysis shows how Niels Bohr’s discoveries in the nature of the objects of the micro-world lead him to questions about the nature of reality. How discoveries in the microcosm affect the new conception of reality is best traced in controversy with other physicists. As the most striking example, we took the article “Discussion with Einstein on epistemological problems in atomic physics”. In this article, Bohr describes the specific behavior of micro-objects, features of physical experiments and proves the idea that a fundamentally new (including ontological plan) understanding of physical processes is needed. An analysis of the terms shows that, from Bohr’s point of view, reality itself is as described by its quantum mechanics. We strive to show the evolution of Bohr’s views in the context of how they influenced the revision of all physics. We conclude that the discovery of stationary states in an atom is the first step to rethinking philosophical questions of a nature of reality.
The EPR controversy between Albert Einstein and Niels Bohr about the completeness of the quantum mechanics is one of the most essential contemporary debates in physics with respect to the issue of realism. Initially considered as a though-experiment, the EPR paradox was meant to evidence the inadequacy of quantum mechanics with respect to the traditional leading principle of physics such as locality, independence of the system elements of reality with respect to the observer or semantic reference of theories to elements of the reality in itself. Bell’s mathematical inquiry opened the possibility to empirically discriminate between the view of Bohr and Einstein through the so-called Bell’s inequalities. Based on these inequalities, the experimental test provided in particular by the work of Alain Aspect settled the debate in favor of Bohr and the completeness of quantum mechanics. The previously evident assumption that physical theories are describing the reality in it-self can thus be questioned. Several approaches have been proposed to face that challenge, such as the orthodox quantum physics formulation coupled with the interpretation of Bernard d’Espagnat , the non-local theory of De Broglie-Bohm or the quantum mechanics approach with extended probability of James B. Hartle . In this paper, we consider the idea according to which the field of experiments and measurements on quantum systems is a research context where several epistemic values traditionally leading the scientific activity are in conflict. Instead of conceiving the transition from classical to quantum physics along Thomas Kuhns’ theory of revolutionary paradigm change , characterized by a strong incommensurability between the old and the new approaches, we argue that this epistemological shift could be rationally understood as an incremental evolution of the epistemic values leading scientific activity. As the analysis in this paper aims to show, such a rational reconstruction shows a process of gradual change, where core epistemic values are maintained, while others are broadened to account for the new scientific approaches. The settling of the EPR controversy could be understood as the indication that the previously assumed epistemic values cannot be consistently held together in the quantum context. The values of logical consistency and empirical adequacy remained universally shared, but the controversy leads to question the other traditionally admitted principles, such as the locality, the requirement of semantic references to the reality in itself and the independence of experimental results with respect to the observer, all tightly connected with the realistic conceptions of the world. This first part of the paper characterizes the selected contemporary approaches in quantum context with respect to the modification of the epistemic principles they adopt to restore their consistency. While the de Broglie-Bohm theory explicitly follows the requirement of referring to the reality in itself at the expense of the locality principle, the approaches of d’Espagnat and of Hartle give priority to the values of theoretical framework simplicity and predictive power. In the case of d’Espagnat, the descriptive purpose of the scientific activity remains, but only in a weak objectivity perspective, restricted to the “empirical reality” in which the observer is involved. In the case of Hartle, the extended probability formulation of quantum mechanics is conceived as “an extension of familiar probability theory that incorporates negative probabilities”6, which relies on the Bayesian conception of “probabilities as instruction for betting” (negative probability is thus associated to the instruction “don’t bet”). In a second part, the paper uses this reconstruction of the various theories in order to address the epistemic status of the principles of descriptive power and of independence of the observed system with respect to the observer. In particular, our analysis aims to assess if a reference to the observer is part of the reality description or if such reference is avoidable. This is of prior interest in exploring the main characteristics of a realistic approach that would be applicable in the context of experiments and measurements on quantum systems. In that perspective, we argue that the direct holistic realism, developed by Hilary Putnam in The Threefold Cord , could be a promising intermediate option between a classical realism, which assumes that theoretical structures are describing the reality in it-self, and a more instrumentalist view, focusing mainly on the modeling of the empirical reality as a result of experimental operations while rejecting access to the reality in itself.