Unobservable entities in QBism and phenomenology

TL;DR

This paper explores the philosophical foundations of QBism, linking it with phenomenology to clarify the nature of observable entities and their role in the interpretation of quantum mechanics.

Contribution

It proposes interpreting QBism's 'experiences' as 'perceived phenomena' from phenomenology, offering a new ontological perspective on observability in quantum theory.

Findings

Reconciles QBism's subjective experiences with phenomenological perceptions.

Clarifies the concept of observability for quantum entities.

Suggests an ontology where only observable entities are physically real.

Abstract

The interpretation of quantum theory known as QBism argues that many elements of the formalism have a subjective interpretation. At the same time, QBism claims to be a broadly realist program. This implies that reality in QBism must be somehow founded upon an agent's subjective experiences (measurement outcomes). To make this idea more precise, we propose to interpret QBism's "experiences" as synonymous with the concept of "perceived phenomena" in phenomenology. This suggests an approach to ontology in which objects can only be physically real if they are in principle observable. But what does "observable" mean? Are atoms, electromagnetic fields, quantum states, or probabilities observable? Here we discuss the different answers to this question given by QBists and phenomenologists, and attempt to reconcile them.