What are the physical conditions required for agency? Recent work has rigorously shown that purely unitary, coherence-preserving quantum dynamics are insufficient to support deliberation, comparison of counterfactual actions, and reliable action selection. These results establish a genuine no-go theorem for agency in a strictly quantum-coherent regime. This paper provides a structural completion of that no-go result. Rather than challenging its correctness, the analysis identifies the underlying assumption on which it rests: that unitarity alone is sufficient as an admissibility criterion for decision endpoints. We show that this assumption is incomplete. Working within the Tier-0 closure framework, physical lawfulness is characterized by closure-stable fixed points selected by structural constraints rather than by unconstrained dynamical evolution. Within this framework, coherent quantum states may function as intermediate computational or representational states but are excluded as lawful endpoints for records, decisions, and control. Applying closure stability to quantum systems yields a classical decision subspace without introducing new dynamics, observer-dependent postulates, or interpretation-specific assumptions. The paper further shows that agency requires a closure-stable internal selection process capable of consistent expected-utility comparison. Imposing closure compatibility rigidly fixes the standard quadratic Born probability rule as the only weighting compatible with stability, representation-independence, and admissibility-preserving re-expression. Together, these results integrate agency into the same structural framework that accounts for quantum measurement and probability. The absence of agency in purely quantum-coherent models is shown to reflect an under-constrained admissibility regime rather than a fundamental limitation of quantum theory. Lawful agency emerges as a closure-stable property of coupled agent–world dynamics, fully consistent with standard quantum mechanics. This work clarifies the physical limits of purely quantum models of decision, sharpens existing no-go arguments, and provides a mathematically explicit foundation for agency grounded in structural admissibility rather than interpretation.
What are the physical conditions required for agency? Recent work has rigorously shown that purely unitary, coherence-preserving quantum dynamics are insufficient to support deliberation, comparison of counterfactual actions, and reliable action selection. These results establish a genuine no-go theorem for agency in a strictly quantum-coherent regime. This paper provides a structural completion of that no-go result. Rather than challenging its correctness, the analysis identifies the underlying assumption on which it rests: that unitarity alone is sufficient as an admissibility criterion for decision endpoints. We show that this assumption is incomplete. Working within the Tier-0 closure framework, physical lawfulness is characterized by closure-stable fixed points selected by structural constraints rather than by unconstrained dynamical evolution. Within this framework, coherent quantum states may function as intermediate computational or representational states but are excluded as lawful endpoints for records, decisions, and control. Applying closure stability to quantum systems yields a classical decision subspace without introducing new dynamics, observer-dependent postulates, or interpretation-specific assumptions. The paper further shows that agency requires a closure-stable internal selection process capable of consistent expected-utility comparison. Imposing closure compatibility rigidly fixes the standard quadratic Born probability rule as the only weighting compatible with stability, representation-independence, and admissibility-preserving re-expression. Together, these results integrate agency into the same structural framework that accounts for quantum measurement and probability. The absence of agency in purely quantum-coherent models is shown to reflect an under-constrained admissibility regime rather than a fundamental limitation of quantum theory. Lawful agency emerges as a closure-stable property of coupled agent–world dynamics, fully consistent with standard quantum mechanics. This work clarifies the physical limits of purely quantum models of decision, sharpens existing no-go arguments, and provides a mathematically explicit foundation for agency grounded in structural admissibility rather than interpretation.
What are the physical conditions required for agency?Recent work has rigorously shown that purely unitary, coherence-preserving quantum dynamics are insufficient to support deliberation, comparison of counterfactual actions, and reliable action selection. These results establish a genuine no-go theorem for agency in a strictly quantum-coherent regime.This paper provides a structural completion of that no-go result. Rather than challenging its correctness, the analysis identifies the underlying assumption on which it rests: that unitarity alone is sufficient as an admissibility criterion for decision endpoints. We show that this assumption is incomplete.Working within the Tier-0 closure framework, physical lawfulness is characterized by closure-stable fixed points selected by structural constraints rather than by unconstrained dynamical evolution. Within this framework, coherent quantum states may function as intermediate computational or representational states but are excluded as lawful endpoints for records, decisions, and control.Applying closure stability to quantum systems yields a classical decision subspace without introducing new dynamics, observer-dependent postulates, or interpretation-specific assumptions. The paper further shows that agency requires a closure-stable internal selection process capable of consistent expected-utility comparison. Imposing closure compatibility rigidly fixes the standard quadratic Born probability rule as the only weighting compatible with stability, representation-independence, and admissibility-preserving re-expression.Together, these results integrate agency into the same structural framework that accounts for quantum measurement and probability. The absence of agency in purely quantum-coherent models is shown to reflect an under-constrained admissibility regime rather than a fundamental limitation of quantum theory. Lawful agency emerges as a closure-stable property of coupled agent–world dynamics, fully consistent with standard quantum mechanics.This work clarifies the physical limits of purely quantum models of decision, sharpens existing no-go arguments, and provides a mathematically explicit foundation for agency grounded in structural admissibility rather than interpretation. https://doi.org/10.5281/zenodo.18028427
(This version has been superceeded, see v.3) Contemporary approaches to physical unification typically emphasize dynamical laws, interpretive frameworks, or information-theoretic reconstructions. Less attention is given to the structural constraints that determine which physical descriptions can remain coherent and stable under interaction, scale transition, and aggregation. This paper develops a constraint-first analysis of coherence, arguing that persistence and unification require restrictions on admissible physical continuations that are not reducible to dynamics alone. Within the framework referred to here as Quantum Coherence Theory (QCT), coherence is treated not as a fragile quantum resource but as a structural property governed by interaction geometry and constraint density. On this view, classical behavior emerges when accumulated constraints sufficiently narrow admissible evolution, while quantum behavior re-emerges when constraints are relaxed. The account does not introduce new dynamics, collapse mechanisms, or modifications of quantum formalism, but instead clarifies the conditions under which existing formalisms yield stable, unified descriptions. The resulting constraints distinguish QCT from observer-centric, intrinsic-collapse, and purely descriptive decoherence accounts, while remaining compatible with globally unitary dynamics. Formal analysis in later sections develops operational redundancy conditions, admissibility constraints on joint states, and rigidity-style arguments linking redundant record structure to the stability of classical descriptions. These results do not constitute a complete theory of unification, but they narrow the space of physically admissible descriptions and clarify the structural role of coherence in bridging quantum and classical regimes.
Foundational problems in physics—including quantum measurement, spacetime emergence, gravitational dynamics, nonlocality, the arrow of time, and the status of physical existence—are typically addressed in isolation, via model-dependent extensions or interpretive assumptions. This work proposes a different approach. We introduce a constraint-based framework, the Closure Admissibility Principle (CAP), which specifies minimal structural conditions any physical description must satisfy in order to be globally consistent. CAP is formulated in operational terms, using admissibility of states, recoverability under refinement, and stability of closed records, without assuming spacetime, dynamics, or ontology a priori. We show that enforcing these constraints induces a unifying closure structure on law-space, from which several persistent foundational puzzles are resolved as structural consequences rather than postulates. In particular, collapse is reclassified as record selection, spacetime and gravity emerge only in compressible regimes, General Relativity appears as an infrared universality class rather than a fundamental law, singularities correspond to failures of admissible description, and null (“nothing”) models are excluded as inadmissible fixed points. The framework is explicitly falsifiable via operational and weak-field tests, and its scope and limits are stated precisely. The results suggest that many foundational paradoxes arise not from incomplete dynamics, but from admitting globally incoherent physical descriptions.
This paper proposes a structural framework in which physical laws and quantum probability emerge from a common admissibility principle, rather than from the unification of dynamical equations.No new forces, fields, particles, or dynamical laws are introduced.Instead, a universal structural constraint governing which states are admissible as physically realizable is identified. Building on results established in Admissibility Frameworks I and II, the existence of a universal frame constant limiting allowable transitions is taken as a starting point.From this principle, an equation of existence is formulated, which does not describe time evolution but instead delineates the boundary between admissible and non-admissible states.Different physical interactions are shown to correspond to distinct structural interpretations of the same admissibility condition. Within this framework, quantum states are interpreted not as probability amplitudes but as admissibility distributions.Measurement is described as structural filtering at the admissibility boundary, rather than as a dynamical collapse process.Under minimal and physically natural assumptions—phase invariance, orthogonal additivity, and locality—the admissibility measure is shown to be uniquely quadratic, yielding the Born rule as a structural consequence rather than a postulate. The resulting theory reframes unification as the closure of existence conditions shared by all physical theories.Dynamics remain domain-specific, but admissibility is universal.In this sense, unification is achieved not by combining forces, but by identifying the single structural condition under which any physical state may exist. AI Usage Declaration: The core concepts and mathematical intuitions of this paper were conceived by the author (Byeong-Young Oh). The technical formalization of the mathematical framework and the English drafting process were performed in collaboration with Artificial Intelligence (AI) models. The author takes full responsibility for the contents and logical integrity of this work. This work is part of an ongoing independent research program. Official research index :https://jingyu-papa.github.io/publications/
Modern theoretical physics faces an abundance of mathematically consistent frameworks and a scarcity of decisive empirical constraints. This work proposes a principled response to that situation by identifying stability under intervention as a primary selection criterion for viable physical theories. Adopting an explicitly operational perspective, the paper formulates stability as the non-amplification of operational distinguishability under physical processes, a requirement motivated by the finite precision and reproducibility of experimental practice. When combined with compositional consistency, purification, and reversible symmetry, this principle strongly constrains admissible statistical frameworks. Within this setting, quantum theory emerges not as a fundamental ontology or a historically contingent choice, but as the uniquely stable non-classical fixed point compatible with reproducible physical control by finite agents embedded within the systems they study. The defining structural features of quantum mechanics, including convex state spaces, affine dynamics, state–effect duality, and a Born-type probability rule, arise as consequences rather than postulates. The framework further suggests that spacetime locality and geometry need not be assumed a priori, but can be understood as constraints on the propagation of distinguishability in composite systems. Potential deviations from quantum theory are predicted to manifest as failures of stability, such as breakdown of dilation, violation of distinguishability monotonicity, or loss of local tomography. This repository contains the final submission-ready manuscript together with its LaTeX source and bibliography, deposited on Zenodo prior to journal submission.This version (v1.1) incorporates clarifications on scope, logical dependencies between principles, worked examples within the Jordan-algebra classification, strengthened hedging of speculative material, and refined statements of falsifiability, in response to detailed referee feedback.
What are the physical requirements for agency? We investigate whether a purely quantum system (one evolving unitarily in a coherent regime without decoherence or collapse) can satisfy three minimal conditions for agency: an agent must be able to create a world-model, use it to evaluate the likely consequences of alternative actions, and reliably perform the action that maximizes expected utility. We show that the first two conditions conflict with the no-cloning theorem, which forbids copying unknown quantum states: world-model construction requires copying information from the environment, and deliberation requires copying the world-model to assess multiple actions. Approximate cloning strategies do not permit sufficient fidelity or generality for agency to be viable in purely quantum systems. The third agency condition also fails due to the linearity of quantum dynamics. These results imply four key consequences. First, agency requires significant classical resources, placing clear constraints on its physical basis. Second, they provide insight into how classical agents emerge within a quantum universe. Third, they show that quantum computers cannot straightforwardly simulate agential behavior without significant classical components. Finally, they challenge quantum theories of agency, free will, and consciousness.