An Unpublished Debate Brought to Light: Karl Popper's Enterprise against the Logic of Quantum Mechanics

TL;DR

This paper uncovers Karl Popper's extensive and largely unpublished critique of quantum logic, revealing a broader campaign that sparked private debates but was never formally addressed in scientific literature.

Contribution

It uncovers the full extent of Popper's unpublished criticisms against quantum logic and clarifies the historical debate surrounding his 1968 critique.

Findings

Popper's critique was part of a larger unpublished campaign.

The debate remained confined to private correspondence.

Popper's criticisms were based on misinterpretations and later abandoned.

Abstract

Karl Popper published, in 1968, a paper that allegedly found a flaw in a very influential article of Birkhoff and von Neumann, which pioneered the field of "quantum logic". Nevertheless, nobody rebutted Popper's criticism in print for several years. This has been called in the historiographical literature an "unsolved historical issue". Although Popper's proposal turned out to be merely based on misinterpretations and was eventually abandoned by the author himself, this paper aims at providing a resolution to such historical open issues. I show that (i) Popper's paper was just the tip of an iceberg of a much vaster campaign conducted by Popper against quantum logic (which encompassed several more unpublished papers that I retrieved); and (ii) that Popper's paper stimulated a heated debate that remained however confined within private correspondence.