Harmonic Physics: Structural Admissibility as a Pre‑Dynamical Framework

Across multiple physical domains—ranging from classical mechanics and electromagnetism to gravitation, thermodynamics, and astrophysical structure—recurring patterns appear that constrain which behaviors can exist, persist, or recur, independent of the specific forces or dynamics acting within them. This work presents Harmonic Physics as a minimal classification framework that makes these constraints explicit. Rather than introducing new forces, mechanisms, or particles, Harmonic Physics specifies the structural conditions of admissibility under which existing physical theories operate. Classical, quantum, and relativistic descriptions remain fully valid within their respective regimes; Harmonic Physics acts upstream, identifying the structural geometry that determines when such descriptions are meaningful, stable, or recoverable.