Social Inertia: The Dynamic Mechanism by Which New Differentials Are Absorbed into Old Co-Nuclei in High-Compression Social Fields

Drawing on sedimentation field dynamics, this paper defines social inertia as a structural inevitability of high compression-strength (K_{F_S}) social fields — the systematic absorption of new inputs into existing Co-Nuclei — rather than a product of cultural or political choice. The central claim is that reform perception does not imply structural transformation: only inputs that cause K_{F_S} to decline or Co-Nucleus restructuring constitute genuine structural change, while any input below the replacement threshold is absorbed and may trigger an inertia rebound. The paper derives the dynamic equation for social inertia intensity, its self-reinforcing loop, three observable forms, and three theorems (Inertia Inevitability, Reform Absorption, Inertia Scale Law). All propositions are accompanied by breakdown conditions.