Quantum Agency in the Emergent Multiverse
Integrating Wallace’s Quantum Decision Theory with the Thermodynamics of Agency
Introduction
David Wallace’s The Emergent Multiverse (EM) positions the Many-Worlds Interpretation (MWI) of quantum mechanics as a coherent and emergent ontology where quantum branches objectively split through decoherence. At its core, Wallace's approach frames decision-making as intrinsically quantum, providing a naturalistic foundation for rational choice.
In parallel, the Three Thermodynamic Laws of Agency ground agency in physical principles:
Control Work: Exercising intentional control requires physical work proportional to kybits exerted, analogous to energy conservation.
Agency Decay: Without external energy input, agency inevitably diminishes, analogous to entropy increase.
Agency Limits: Perfect frictionless control is physically impossible, analogous to the unattainability of absolute zero.
This article explores how Wallace's quantum ontology and decision theory integrate coherently with these thermodynamic principles.
Agency and Quantum Branching
Wallace argues quantum branching emerges naturally from decoherence, making separate worlds objectively distinct. In this branching landscape, choices represent distinct quantum outcomes. Each decision-point shapes the quantum measure of subsequent branches.
This directly aligns with Agency Law 1 (Control Work), asserting that intentional outcomes demand physical effort. In quantum terms, choosing branches equates to exerting control, physically realized by influencing quantum states and their probabilities—thus performing "quantum work."
Quantum Decision Theory and Predictive Control
Wallace’s Quantum Decision Theory formalizes rational choice as maximizing quantum-measure-weighted expected utility. Rational agents align subjective probabilities with the objective quantum measure (Deutsch-Wallace theorem), inherently minimizing predictive error.
This corresponds to the underlying logic of Agency Law 1, whereby kybits measure intentional control effort: rational agents naturally minimize predictive error by steering toward high-measure quantum branches. Effective quantum agency involves not arbitrary but predictive work, optimizing future states toward desired outcomes.
Decoherence, Entropy, and Agency Decay
Decoherence, central in Wallace's emergent multiverse, irreversibly increases entropy, making quantum outcomes effectively classical. This thermodynamic irreversibility underpins the emergence of distinct branches and clarifies why agency faces inherent physical constraints.
This perfectly resonates with Agency Law 2 (Agency Decay). In closed systems lacking external energy input, agency deteriorates due to increasing entropy. The emergent multiverse emphasizes precisely this entropic inevitability—without replenishment or energy gradients to exploit, quantum agency cannot sustain intentional control indefinitely.
Limits of Quantum Control
Wallace’s interpretation implicitly acknowledges practical limitations on quantum decision-making: infinite precision or frictionless quantum manipulations are impossible. Each quantum choice inherently involves uncertainty, decoherence, and thermodynamic losses.
This directly matches Agency Law 3 (Agency Limits), stating perfect frictionless control is unattainable. Quantum mechanics forbids perfectly isolated, frictionless control because decoherence and quantum uncertainties are intrinsic. Thus, Wallace's ontology naturally aligns with thermodynamic constraints on perfect control.
Synthesis: Quantum-Thermodynamic Landscape of Agency
Wallace's emergent quantum ontology provides the physical context within which agency operates. Quantum Decision Theory explicates how rational agents select optimal branches. Meanwhile, the Three Thermodynamic Laws specify the physical conditions and constraints under which quantum agency manifests:
Rational agency (Law 1) exploits quantum control work.
Agency inevitably decays without energy input (Law 2).
Perfect frictionless control remains unreachable (Law 3).
The emergent multiverse thus becomes a quantum-thermodynamic landscape through which agents navigate, shaping their trajectories by optimizing predictive outcomes while constrained by fundamental physical laws.
Conclusion
Integrating Wallace’s Emergent Multiverse with the Three Thermodynamic Laws of Agency provides a robust and coherent framework for understanding quantum agency. Decisions become physical quantum events constrained by thermodynamics, bridging ontology, decision theory, and fundamental physics in a unified explanatory framework.
References
Wallace, David. (2012). The Emergent Multiverse: Quantum Theory according to the Everett Interpretation. Oxford University Press.