Structural Resonance Theory: Duality Dynamics and the Structure of Emergence The Complexity Threshold Principle

Structural Resonance Theory establishes that resonance under constraint is the ontological primitive from which structure, experience, and identity emerge. This paper introduces a foundational extension: the Complexity Threshold Principle (CTP), which formalizes the generative dynamics of duality across all scales of organization. The argument proceeds in four stages. First, the original symmetry break --- the fracture of complete coherence into asymmetric structure --- is identified as the cosmological origin of all categorical dualities. Second, the stagnation condition is formalized: dualities cannot resolve at their center without extinguishing the experience they sustain. Third, the Complexity Threshold Principle is stated formally: what is structurally impossible at any given level of organization becomes accessible when sufficient prerequisite complexity, diversity, or constraint satisfaction has accumulated to cross a threshold into a new duality regime. Fourth, the principle is shown to unify previously distinct mechanisms within SRT --- mutation as necessary perturbation, the Finite Envelope Lemma, the Perfection Limit Theorem, and the major evolutionary transitions --- as scale-specific instantiations of a single generative law. The paper concludes that complexity does not increase by design. It increases because the structural alternative, stagnation at duality center, extinguishes experience. The universe complexifies because experience requires it.