Quantum Probabilities Are Objective Degrees of Epistemic Justification

TL;DR

This paper proposes an interpretation of quantum mechanics where probabilities are objective epistemic justifications, aiming to reconcile QBism's subjective view with scientific objectivity.

Contribution

It introduces a novel interpretation that maintains QBism's virtues while incorporating objectivity into quantum probabilities as epistemic justifications.

Findings

Quantum probabilities can be understood as objective epistemic degrees.

The interpretation aligns subjective Bayesian probabilities with objective scientific standards.

It offers a way to integrate objectivity into QBist-inspired quantum theory.

Abstract

QBism is currently one of the most widely discussed 'subjective' interpretations of quantum mechanics. Its key move is to say that quantum probabilities are personalist Bayesian probabilities and that the quantum state represents subjective degrees of belief. Even probability-one predictions are considered subjective assignments expressing the agent's highest possible degree of certainty about what they will experience next. For most philosophers and physicists this means that QBism is simply too subjective. Even those who agree with QBism that the wave function should not be reified and that we should look for alternatives to standard Psi-ontic interpretations often argue that QBism must be abandoned because it detaches science from objectivity. The problem is that from the QBist perspective it is hard to see how objectivity could enter science. In this paper, I introduce and motivate an interpretation of quantum mechanics that takes QBism as a starting point, is consistent with all its virtues, but allows objectivity to enter from the get-go. This is the view that quantum probabilities should be understood as objective degrees of epistemic justification.