Extended Phenotype Legal Theory: Equilibrium Refinements and Cultural-Legal Index 3.0

This paper develops micro-foundations for legal systems as extended phenotypes using evolutionary game theory and Evolutionarily Stable Strategies (ESS). I introduce the Cultural-Legal Index 3.0 (CLI 3.0), a refined measure of transmission capacity calibrated via grid-search and validated through multi-AI inter-rater reliability (ICC(2,1) = 0.9335, n=30 US constitutional provisions) and out-of-sample testing across 193 jurisdictions (accuracy = 87.4%). CLI 3.0 distinguishes ESS provisions (mean = 0.812, n=25) from collapsed provisions (mean = 0.521, n=5); t(28) = 6.73, p < 0.001. I derive equilibrium refinements for four regime types: (1) risk-dominant ESS (CLI* = 0.71), (2) trembling-hand perfect equilibria (CLI >= 0.68, epsilon > 0.40), (3) subgame-perfect equilibria (CLI >= 0.50), and (4) correlated equilibria (0.40 0.25; cross-national evidence from 47 jurisdictions shows vague emergency language increases constitutional mutation odds 17.6-fold (p < 0.001). Case studies, US Prohibition (CLI = 0.303, 4.2 SD below mean), Argentina labor law (CLI = 0.89, 23 failed reform attempts), Singapore's PAP regime, and Iran's Islamic Republic (CLI = 0.57, sacralized subgame perfection), demonstrate predictive power. Independent convergence with Khurshid's (2006, 2025) TgmenkS framework, derived from the same Dawkins-Dennett evolutionary foundations but applied to political systems rather than legal institutions, provides reciprocal validation: CLI 3.0 quantifies Khurshid's MSSP/MRSP distinction (Method of Suppressing vs. Regulating the Struggle for Power), while TgmenkS supplies the political micro-foundations that explain why certain CLI configurations emerge. Seven contributions: (1) formal definitions of legal memes, strategies, and extended phenotypes; (2) adaptation of ESS framework to law; (3) development and validation of CLI 3.0; (4) empirical discrimination of ESS provisions; (5) capacity-gap hypothesis for institutional design; (6) phenotype-engineering design principles; (7) conceptual integration with evolutionary political theory via TgmenkS convergence.