Constraint Geometry and Coherence Budgets: A Framework for Diagnosing Scaling Limits in Complex Systems

Complex systems routinely exhibit degradation as scale increases. In computing platforms, networked infrastructures, biological systems, and organizations, performance collapse or loss of controllability often emerges despite improvements in local components. Such failures are typically attributed to noise, implementation limitations, or insufficient engineering refinement. However, similar scaling pathologies appear across domains with fundamentally different substrates, suggesting a deeper structural cause. We introduce the Constraint-based Epistemology of Scaling (CES), a framework modeling scalability in terms of constraint accumulation and available control capacity. System degradation emerges when constraint burden grows faster than control capacity, exhausting a system's coherence budget and producing structured residual behavior that cannot be eliminated through local improvements alone. In this regime, system evolution becomes governed by constraint geometry rather than controllable dynamics. CES provides a domain-agnostic diagnostic lens for scalability limits and reframes many apparent engineering failures as manifestations of universal structural constraints. The framework clarifies why scalable architectures depend more on constraint management and modularity than on improvements in component precision or performance.