The Problem of Contextuality and the Impossibility of Experimental Metaphysics Thereof

TL;DR

This paper argues that due to the nature of existing models and definitions, experimental tests cannot definitively determine the metaphysical existence of contextuality in quantum mechanics.

Contribution

It demonstrates that under common definitions, no experiment can conclusively prove or disprove quantum contextuality, highlighting the philosophical limitations of such tests.

Findings

A specific MKC-model shown to be non-contextual and consistent with quantum predictions

No experimental test can definitively establish the metaphysical existence of contextuality

Operational definitions of non-contextuality depend on theoretical frameworks

Abstract

Recently a new impulse has been given to the experimental investigation of contextuality. In this paper we show that for a widely used definition of contextuality there can be no decisive experiment on the existence of contextuality. To this end, we give a clear presentation of the hidden variable models due to Meyer, Kent and Clifton (MKC), which would supposedly nullify the Kochen-Specker Theorem. Although we disagree with this last statement, the models play a significant role in the discussion on the meaning of contextuality. In fact, we introduce a specific MKC-model of which we show that it is non-contextual and completely in agreement with quantum mechanical predictions. We also investigate the possibility of other definitions of non-contextuality --with an emphasis on operational definitions-- and argue that any useful definition relies on the specification of a theoretical framework. It is therefore concluded that no experimental test can yield any conclusions about contextuality on a metaphysical level.