The Theory of Co-Evolution, Version 2.1, is an integration of Versions 1.0/1.1 (the evolutionary framework) and Version 2.0 (empirical anchors). Version 1.0 proposed the "productivity-organization-distribution" triadic coupling as the core framework for understanding the evolution of human society. Version 2.0 introduced the 4.5% empirical anchor, moving discussions of social evolution toward a quantifiable dimension. Version 2.1 fuses these two, preserving the integrity of the evolutionary framework from 1.0/1.1 while incorporating the empirical support from 2.0, resulting in a comprehensive version that possesses both theoretical depth and practical guidance. **Core Proposition**: > The evolution of human society is a process of dynamic balancing between stability and complexity, mediated by the "productivity-organization-distribution" triadic coupling. The 4.5% "Third Space" is the quantitative baseline of this balance. Below this, society becomes rigidified; above this (entering the 10-40% range), society enters a transitional phase. The direction of transition depends on whether the thresholds of "self-preservation mechanism" and "gravitational strength" have been reached.
fuwenju (Thu,) studied this question.