The Reality and Measurement of the Wavefunction

TL;DR

This paper critically examines claims that the wavefunction has an ontological reality, arguing that such claims are not supported by measurement models and that the wavefunction remains an epistemological tool.

Contribution

The paper clarifies the distinction between the ontological significance of certain operators and the epistemological role of the wavefunction in quantum mechanics.

Findings

Measurement models do not establish the wavefunction's ontological status.

The argument for wavefunction measurement on a single system is insufficient.

Operators in quantum theory have ontological significance, unlike the wavefunction.

Abstract

Using a simple version of the model for the quantum measurement of a two level system, the contention of Aharonov, Anandan, and Vaidman that one must in certain circumstances give the wavefunction an ontological as well as an epistemological significance is examined. I decide that their argument that the wave function of a system can be measured on a single system fails to establish the key point and that what they demonstrate is the ontological significance of certain operators in the theory, with the wave function playing its usual epistemological role.