The Informational Observer in Relational Quantum Mechanics

TL;DR

This paper addresses how the concept of the observer in Relational Quantum Mechanics can be clarified by distinguishing physical interaction from informational coherence, thereby supporting empirical confirmation in complex measurement scenarios.

Contribution

It introduces a new account of the observer in RQM that separates physical interaction from informational coherence, enhancing empirical testability.

Findings

Distinction between physical interaction and informational coherence supports observer persistence.

Enhanced framework for empirical confirmation in Wigner's friend scenarios.

Clarifies the role of information in maintaining observer consistency.

Abstract

Relational Quantum Mechanics (RQM) treats quantum states as observer-dependent facts rather than absolute properties. While this relational stance is conceptually attractive, it raises concerns about empirical confirmation, particularly in multi-observer scenarios. Existing responses within RQM focus on securing agreement between observers by strengthening the status, stability, or accessibility of recorded outcomes. However, they leave open a more basic question: what grounds the persistence of an observer across time? Scientific observation presupposes stable records and the capacity to relate outcomes across successive measurements. We argue that the minimal definition of the observer in RQM as a merely interacting physical system is insufficient to support this requirement. We propose a complementary account of the observer that distinguishes physical interaction from informational coherence, and show how this distinction supports empirical confirmation in Wigner's friend-type scenarios.