The Principle of Structural Non-Neutrality in Coherent Systems

This paper introduces and formalizes the Principle of Structural Non-Neutrality: In a coherent system, no part can be structurally neutral. Beginning from the quantum limits of measurement—where informative observation necessarily disturbs the observed system—we argue that this apparent "strangeness" of quantum mechanics is not an anomaly but a minimal requirement for any system in which the observer is physically embedded. Classical physics, by contrast, implicitly assumes an external observer who can extract information without interaction—a privilege that no physical theory can consistently grant. From this insight, we derive a sharp distinction between systems and models: A system is that which cannot be known without being changed A model is that which can be known without being changed This distinction yields our central principle: in a genuinely coherent system, every part must contribute to the global structure. Structural neutrality—the presence of a part that makes no difference to the system's state space—is logically incompatible with coherence. Key Contributions Formal definition of structural relevance using mutual information: R(p, S) = I(p; S \ {p}), with exact neutrality defined as R = 0 Proof by contradiction demonstrating that coherent systems (as defined) cannot contain structurally neutral elements Unification of existing frameworks: reliability theory's "component relevance," quantum non-separability, and Integrated Information Theory's irreducibility are shown to be instances of a single structural requirement Resolution of apparent counterexamples: redundant components, silent genes, weakly coupled systems, and gauge degrees of freedom are analyzed and shown to be compatible with the principle Connection to quantum interpretations: the principle constrains (without adjudicating among) many-worlds, decoherence-based, QBist, and relational interpretations Applications: epistemology (coherentist justification), reliability engineering, biological networks, and ecological systems Theoretical Framework The paper traces a conceptual path: Quantum measurement limits → Observer embeddedness → Systems vs. models distinction → Structural non-neutrality principle → Applications across domains The principle is offered not as a revolutionary discovery but as a unifying formulation that makes explicit what several frameworks already imply, while grounding this shared requirement in the impossibility of genuinely external observation. Keywords quantum measurement; observer problem; coherent systems; structural non-neutrality; systems theory; integrated information; reliability theory; quantum foundations; philosophy of physics; mutual information; non-separability; decoherence Academic Context This work bridges quantum foundations, general systems theory, and philosophy of science. It is relevant to researchers in: Foundations of quantum mechanics Philosophy of physics Complex systems theory Integrated Information Theory Reliability engineering Theoretical biology Epistemology (coherentism) Note: This paper underwent multiple rounds of peer review and revision, addressing concerns about scope, mathematical formalization, relation to existing literature, and applicability limits. The final version includes a graded measure of structural relevance, explicit comparison with IIT and reliability theory, treatment of apparent counterexamples, and open questions for future research.