Nature Has No Elementary Particles and Makes No Measurements or Predictions: Quantum Measurement and Quantum Theory, from Bohr to Bell and from Bell to Bohr

Abstract

This article reconsiders the concept of physical reality in quantum theory and the concept of quantum measurement, following Bohr, whose analysis of quantum measurement led him to his concept of a (quantum) “phenomenon,” referring to “the observations obtained under the specified circumstances,” in the interaction between quantum objects and measuring instruments. This situation makes the terms “observation” and “measurement,” as conventionally understood, inapplicable. These terms are remnants of classical physics or still earlier history, from which classical physics inherited it. As defined here, a quantum measurement does not measure any preexisting property of the ultimate constitution of the reality responsible for quantum phenomena. An act of measurement establishes a quantum phenomenon by an interaction between the instrument and the quantum object or in the present view the ultimate constitution of the reality responsible for quantum phenomena and, at the time of measurement, also quantum objects. In the view advanced in this article, in contrast to that of Bohr, quantum objects, such as electrons or photons, are assumed to exist only at the time of measurement and not independently, a view that redefines the concept of quantum object as well. This redefinition becomes especially important in high-energy quantum regimes and quantum field theory and allows this article to define a new concept of quantum field. The article also considers, now following Bohr, the quantum measurement as the entanglement between quantum objects and measurement instruments. The argument of the article is grounded in the concept “reality without realism” (RWR), as underlying quantum measurement thus understood, and the view, the RWR view, of quantum theory defined by this concept. The RWR view places a stratum of physical reality thus designated, here the reality ultimately responsible for quantum phenomena, beyond representation or knowledge, or even conception, and defines the corresponding set of interpretations quantum mechanics or quantum field theory, such as the one assumed in this article, in which, again, not only quantum phenomena but also quantum objects are (idealizations) defined by measurement. As such, the article also offers a broadly conceived response to J. Bell’s argument “against ‘measurement’”.

“Yet Once More”: The Double-Slit Experiment and Quantum Discontinuity

“…Interminably discussed, it remains the dominant paradigmatic quantum experiment, even though it has acquired some competition during the last half-century, such as those of the Einstein–Podolsky–Rosen (EPR) type concerning quantum correlations. The latter experiments can, however, be shown to be in accord with RWR-type interpretations, specifically the one adopted here, which contains Dirac discontinuity, as considered by this author previously, although Dirac discontinuity, while assumed in these works, was not named as such [ 1 , 2 , 3 ]. This form of discontinuity is not necessarily found in other RWR-type interpretations, for example, that of N. Bohr, historically the first RWR-type interpretation, although it was intimated by assuming Heisenberg discontinuity by W. Heisenberg in his discovery of QM [ 4 ].…”

“…I shall now outline the concept of reality-without-realism (RWR) and the philosophical view, the RWR view, which grounds the corresponding interpretations, RWR-type interpretations, of quantum theory, such as that of Bohr in its ultimate version. This outline follows [ 1 , 2 , 3 ], which contain further details. This concept is grounded in more general concepts of reality and existence, which are assumed to be primitive concepts and are not given analytical definitions.…”

“…As noted from the outset, however, although high-energy quantum regimes and QFT, where the concept of a quantum field, again, becomes essential, offer strong reasons for adopting the concept of Dirac discontinuity and the designation itself [ 1 ] (pp. 273–306) and [ 2 ], there are more immediate reasons in low-energy (QM) quantum regimes for doing so, including certain key aspects of the double-slit and related experiments, as discussed below. One such reason is suggested, even if not strictly required, by the nature of quantum phenomena as such, regardless of an interpretation, although RWR-type interpretations of this nature make the idea of Dirac discontinuity more compelling.…”

“…In Bohr’s view, the ultimate constitution of the reality responsible for quantum phenomena (again, physically described by classical physics) was associated with quantum objects, which, on Kantian lines, is different from quantum phenomena because of the irreducible role of measuring instruments in their constitution, the role leading Bohr to Bohr discontinuity, coupled to Heisenberg discontinuity. The interpretation adopted in this article takes a more stratified view of the situation by adding Dirac discontinuity to Heisenberg and Bohr discontinuities and, via them, to RWR-type interpretations, following [ 1 , 2 , 3 ], although, while adopting the concept of Dirac discontinuity, these works did not use the term as such. This stratification is as follows.…”

“Most tantumising state of affairs”: Mathematical and non-mathematical in quantum-like understanding of thinking

“…The ultimate constitution of the reality responsible for quantum phenomena was associated with quantum objects. The interpretation adopted here takes a more stratified view, following ( Plotnitsky, 2021a ,c). The ultimate RWR reality responsible for quantum phenomena is an idealization assumed to exist independently of our interactions with it and thus of observation .…”