[Paper Review] QBism, FAPP and the Quantum Omelette. (Or, Unscrambling Ontological Problems from Epistemological Solutions in QM)

Christian de Ronde|arXiv (Cornell University)|Aug 1, 2016

Quantum Mechanics and Applications36 references3 citations

TL;DR

This paper critiques the conflation of ontological and epistemological frameworks in quantum mechanics, arguing that 'FAPP' (For All Practical Purposes) justifications for decoherence evade core ontological questions about the quantum-to-classical transition. It defends QBism as a coherent epistemic framework that dissolves certain ontological puzzles by rejecting physical realism in favor of agent-centered probabilities, thereby offering a way to unscramble the 'quantum omelette' of mixed metaphysical and epistemic interpretations.

ABSTRACT

In this paper we discuss the so called "quantum omelette" created by Bohr and Heisenberg through the mix of (ontic) objective accounts and (epistemic) subjective ones within the analysis of Quantum Mechanics (QM). We will begin by addressing the difficult relation between ontology and epistemology within the history of both physics and philosophy. We will then argue that the present "quantum omelette" is being presently cooked in two opposite directions: the first scrambling ontological problems with epistemological solutions and the second scrambling epistemic approaches with ontological questions. A good example of the former is a new type of argumentation strategy attempting to justify the use of decoherence, namely, the "For All Practical Purposes" (shortly known as FAPP) type of justification. We will argue that 'FAPP-type solutions' remain, at best, epistemological answers which not only escape the ontological questions at stake -regarding the quantum to classical limit- but also turn the original problem completely meaningless. The latter omelette can be witnessed in relation to some criticisms raised against the epistemic Bayesian approach to QM (shortly known as QBism). We will argue that QBists have produced a consistent scheme that might allow us to begin to unscramble -at least part of- the "quantum omelette". In this respect, we will show why the epistemic QBist approach is safe from several (ontological) criticisms it has recently received (see [42, 47, 48]). We end our paper with a discussion about the importance of ontological approaches within foundations of QM.

Motivation & Objective

• To analyze the historical and philosophical roots of the persistent confusion between ontology and epistemology in quantum mechanics.
• To critique the 'FAPP' justification of decoherence as an epistemological evasion of genuine ontological problems regarding the quantum-to-classical transition.
• To defend QBism as a consistent epistemic framework that avoids ontological commitments while resolving foundational puzzles.
• To argue that ontological questions remain essential for foundational physics, even as epistemic interpretations like QBism offer meaningful alternatives.
• To advocate for clearer philosophical distinctions between ontological and epistemological levels in quantum theory to prevent conceptual confusion.

Proposed method

• Analyzes historical tensions between ontology and epistemology in Western philosophy and physics, tracing them to pre-Socratic thought and Plato’s metaphysics.
• Examines the 'quantum omelette' metaphor as a critique of mixed ontic-epistemic interpretations in early quantum foundations, particularly in Bohr and Heisenberg’s work.
• Evaluates FAPP-type arguments for decoherence as epistemological solutions that fail to address the underlying ontological problem of the quantum-to-classical transition.
• Applies QBism’s epistemic Bayesian framework to show how it avoids ontological commitments by treating quantum states as personal degrees of belief and measurement outcomes as agent-dependent.
• Engages with recent criticisms of QBism (e.g., [42, 47, 48]) to demonstrate their incompatibility with QBism’s internal consistency and philosophical foundations.
• Argues that QBism dissolves ontological problems by rejecting the need for a physical reality independent of agents, thus unscrambling part of the quantum omelette.

Experimental results

Research questions

• RQ1 How has the historical conflation of ontology and epistemology shaped foundational debates in quantum mechanics?
• RQ2 Why do FAPP-type justifications for decoherence fail to resolve the ontological problem of the quantum-to-classical transition?
• RQ3 In what way does QBism provide a coherent epistemic framework that avoids ontological commitments in quantum theory?
• RQ4 How can QBism be defended against recent ontological criticisms that misrepresent its core principles?
• RQ5 What is the role of ontological inquiry in the foundations of quantum mechanics, and why must it be distinguished from epistemological analysis?

Key findings

• FAPP justifications for decoherence are epistemological in nature and fail to resolve the core ontological problem of how the classical world emerges from quantum mechanics.
• The 'quantum omelette' metaphor effectively captures the conceptual confusion arising from mixing ontological and epistemological perspectives in quantum foundations.
• QBism provides a consistent epistemic framework that treats quantum mechanics as a tool for an agent’s personal beliefs and predictions, thereby dissolving certain ontological puzzles.
• QBism is robust against recent ontological criticisms because those criticisms misrepresent its foundational principles as if they made realist claims.
• The paper concludes that while epistemological approaches like QBism are valuable, ontological questions remain essential and must not be conflated with epistemic ones in foundational research.