Against (unitary) interpretation (of quantum mechanics): removing the metaphysical load

TL;DR

This paper critiques the metaphysical assumptions in traditional interpretations of quantum mechanics, advocating for a focus on observable events and the rejection of unobservable entities, emphasizing the role of decoherence and classicality.

Contribution

It proposes an interpretation of quantum mechanics that emphasizes observable events and dismisses unobservable elements, challenging the metaphysical load of unitary interpretations.

Findings

Quantum theory should focus on observable events, not unobservable entities.

Decoherence explains classicality without ontological commitments.

Unitary quantum mechanics is a metaphysical interpretation, not empirically testable.

Abstract

In June 1925 Heisenberg arrived at Helgoland/Heligoland island to escape a fit of hay fever. He returned with a sketch of a strange theory of the micro-world, which we now call quantum mechanics. This essay attempts to present a look at this theory, which tries to return to the original insight of Heisenberg on what should be the essence of a theory of atomic realm: it must be a theory of the observable events, in which fundamentally unobservable quantities have no place. No ontological status is given to elements of the mathematical formulation of the theory. The theory is about our description of events in laboratories, probabilities of which are given by the Born rule. Following Bohr, these events involve macroscopic measuring apparatuses, and the accessible final events are classically describable. Information about the events is cloneable, as it is of a classical nature. The modern quantum theory of classicality is the decoherence theory. It treats "the pointer variable" of measuring apparatus as an open system interacting with an environment consisting of all other "zillions" of degrees of freedom of the device, and anything coupled to it. Because such environment is uncontrollable we have no possibility to reverse measurements. The quantum mechanical measurement theory based on decoherence theory is reproducing the predictions of Born rule. Notwithstanding, possibility of reversing measurements and of application of Born rule in situations other than these which lead to macroscopically observable events are features of a modification of quantum mechanics which is called by its adherents "unitary quantum mechanics". As its predictions, which go beyond quantum mechanics, are not testable - we claim that unitary quantum mechanics in an interpretation of quantum mechanics. As such it is metaphysics.