Why does the wavefunction 'collapse' in relational approaches to quantum mechanics?

TL;DR

The paper explains wavefunction collapse in relational quantum mechanics as a discontinuity during system-reference interactions, suggesting quantum mechanics is incomplete for describing all physical facts.

Contribution

It provides a straightforward interpretation of quantum events in relational quantum mechanics, emphasizing the necessity of acknowledging the theory's incompleteness.

Findings

Collapse occurs during system-reference interactions due to description discontinuity.

Quantum mechanics likely incomplete for a full account of physical facts.

Addresses recent concerns about quantum events in relational approaches.

Abstract

I argue that there is a straightforward way to understand the occurrence of wavefunction collapses or 'quantum events' in relational approaches to quantum mechanics: we necessarily encounter a discontinuity in our description when a system interacts with the reference relative to which we are describing it, since the reference system cannot be described relative to itself. This makes it clear how recent concerns around quantum events in relational quantum mechanics should be resolved. However, the solution requires accepting that quantum mechanics is not a complete description of all physical facts, and moreover I argue that this is most likely inevitable if we want to be able to give a precise description of quantum events.