Coherence as a System-Level Constraint: Limiting Function via Admissible Global Modes

Abstract This preprint proposes a conceptual framework in which biological and complex-system function is constrained not primarily by energy availability or information throughput, but by the number of dynamically admissible global coordination modes. We formalize coherence as a system-level order parameter defined over an admissible region of state space, shaped by geometric and coupling constraints rather than by component-level resource depletion. Although systems may retain many local degrees of freedom, effective global degrees of freedom are sharply reduced by closure requirements, yielding a small set of stable collective modes. Breakdown is proposed to occur when no admissible global configuration remains, rather than when energy or information are exhausted. This framing is consistent with regime shifts, nonlinearity, and phase-transition–like behavior observed across biological, neural, metabolic, and engineered systems. The work is presented as a falsifiable conceptual framework. No new empirical claims are asserted; instead, testable predictions and conditions for falsification are explicitly outlined.