Coupling Tension Between Individual Fields and the Social Field: The Dynamic Contest Between Differential-Generative Pressure and Assimilation Pressure

Drawing on sedimentation field dynamics, this paper advances the relationship between the individual and society from descriptive accounts of socialization or agency to the level of dynamic equations. The central claim is that individual fields and the social field are engaged in a continuous contest under tension — the social field exerts assimilation pressure (AssimPress ∝ Cpl · K_{F_S} · FamOverlap) that tends to absorb individual fields, while individual fields resist absorption through differential-generative pressure (P_Δ). The paper derives the complete dynamic equation for coupling tension (CplTension = P_Δ − AssimPress), identifies three states (assimilation dominance, tension equilibrium, differentiation dominance), and establishes three theorems: (1) Tension Equilibrium Instability — trending increase in K_{F_S} systematically drifts the equilibrium point toward assimilation dominance; (2) Forced Assimilation Rejection — assimilation pressure exceeding the tolerance threshold triggers a rejection mechanism that reduces actual assimilation effect; (3) Innovation Concentrated in the Tension-Equilibrium Band — genuine structural social innovation systematically originates from individual fields in the equilibrium state that remain coupled while retaining differential-generative margin. A corollary establishes the Innovation Equilibrium Band Compression Effect: the tension-equilibrium band systematically narrows in mature social fields, providing a unified dynamic source for bureaucratization, ideological homogenization, and algorithmic domestication.