No-go for fully unitary quantum mechanics from Bell's Theorem; comment on "Physics and Metaphysics of Wigner's Friends: Even performed pre-measurements have no results''

Abstract

The purpose of this comment is to show that a reinterpretation of the results from the Letter: "Physics and Metaphysics of Wigner's Friends: Even performed pre-measurements have no results" allows for reaching the conclusion "pre-measurements have no resul" [arXiv:2003.07464] based only on postulates of quantum mechanics without additional assumptions on irreversibility. Additionally, with supplementary reasoning based on Bell's theorem, one can show that unitary decoherence cannot be solely responsible for the quantum-to-classical transition, and an additional irreversibility model is required for its full description. Consequently, the black hole information paradox has no physical basis.