THE JIANGNAN GENOTYPE: Institutional Darwinism, the Replicator-Interactor Distinction, and Why Endurance and Density Are K- and r-Selected Strategies for the Same Disruption

Geoffrey Hodgson and Thorbjørn Knudsen’s Generalized Darwinism (Darwin’s Conjecture, 2010) argues that variation, inheritance, and selection are domain-independent necessary and sufficient conditions for evolutionary explanation — applicable literally, not by analogy, wherever a population of entities varies, some mechanism transmits traits between generations with reasonable fidelity, and that variation causes differential persistence. This paper applies that claim to the Longevity Asymmetry Corpus’s Entropy-Resistant Institution Index (Huynh 2026, “Endurance or Density”), using David Hull’s (1988) replicator/interactor distinction — the unit that passes on structure with reasonable fidelity (replicator) versus the unit that interacts with the environment as a cohesive whole and whose fate makes replication differential (interactor) — to reanalyze the Jiangnan Regeneration Problem that paper’s Section VIII identifies. The paper argues four claims. First, Jiangnan is a literal replicator-interactor system, not a metaphor: a template of river-line defense doctrine, rice-paddy fiscal administration, and elite-absorption protocol persisted dormant for the entire 318-year span of unified Tang rule (589–907, during which no southern refuge regime existed at all) and re-expressed in three separate, non-continuous interactors — Eastern Jin–Southern Dynasties, Southern Tang, Southern Song — each time northern collapse recreated the triggering environmental condition. Second, this distinguishes homology from convergence with a precision the ERI paper’s own N = 3 circularity problem needed and did not yet have: Jiankang, Southern Tang, and Southern Song share common descent from one replicator, so their attribute agreement is not independent evidence. Japan’s Imperial House and the Holy See share no common ancestry with each other or with Jiangnan, yet independently evolved similar attribute profiles — decoupled legitimating authority, non-biological succession, universalist claims transcending territory — textbook convergent evolution, which in evolutionary biology is stronger evidence for adaptive significance than homology, precisely because independent origin rules out shared history as the explanation. Third, Formula A and Formula B from the ERI index are not two arbitrary weightings of one construct. They measure K-selected and r-selected fitness respectively (MacArthur and Wilson 1967) — two genuinely distinct, sometimes competing strategies in real ecological theory, not unique to institutions. Japan and the Holy See are K-strategists: one long-lived, heavily invested interactor, optimized for individual endurance. Jiangnan is an r-strategist at the regional level: rapid interactor turnover via extinction and recolonization (Levins 1969), persisting at the population level — the refuge function itself — even as every individual interactor eventually goes extinct. This explains, rather than merely redescribes, why the ERI paper’s ranking flip occurs: K-fitness and r-fitness are different quantities in nature, not an artifact of index construction. Fourth, applying Levins’s metapopulation persistence condition — persistence requires recolonization rate to exceed local extinction rate — to the density gap the ERI paper’s Section X.C already establishes (λ_bz ≈ 50 disruption-class events per century, against a historical maximum δ of 1.36) shows that neither historically realized strategy is obviously sufficient for F2-era disruption density. Jiangnan’s own recolonization rate — three episodes across 1,059 years, ≈ 0.28 per century — is itself roughly 180 times below what would be required to match