How to spell out the epistemic conception of quantum states

TL;DR

This paper explores the epistemic view of quantum states, emphasizing how correct state assignments can be understood without assuming the existence of an objective quantum state, using Searle's constitutive rules.

Contribution

It proposes an account of quantum state assignment based on constitutive rules, addressing the challenge of understanding correct state assignment without positing a true quantum state.

Findings

Provides an interpretation of state assignment rules as constitutive rules.

Addresses the challenge of understanding correct state assignment epistemically.

Supports the epistemic conception as a solution to quantum measurement and non-locality issues.

Abstract

The paper investigates the epistemic conception of quantum states---the view that quantum states are not descriptions of quantum systems but rather reflect the assigning agents' epistemic relations to the systems. This idea, which can be found already in the works of Copenhagen adherents Heisenberg and Peierls, has received increasing attention in recent years because it promises an understanding of quantum theory in which neither the measurement problem nor a conflict between quantum non-locality and relativity theory arises. Here it is argued that the main challenge for proponents of this idea is to make sense of the notion of a state assignment being performed correctly without thereby acknowledging the notion of a true state of a quantum system---a state it is in. An account based on the epistemic conception of states is proposed that fulfills this requirement by interpreting the rules governing state assignment as constitutive rules in the sense of John Searle.