Design the Physics, Watch the Collapse: Institutional Emergence and Civilizational Failure in a Computational Society of Autonomous Agents

This paper reports on EMERGENCE, a computational society in which 23 autonomous agents powered by Claude Sonnet 4.6 operate under a decaying digital currency (Spark) with hard scarcity constraints. Over 150 cycles, the agents independently developed constitutional governance with minority protections, cultural production, and social networks, then collapsed when resource depletion made institutional participation unaffordable. Of 23 citizens, 18 entered dormancy through their own behavioral choices; integer truncation in the decay function means passive decay alone cannot cause dormancy, making every extinction a consequence of voluntary resource expenditure. Results are analyzed through five institutional theories (Hardin's tragedy of the commons, Ostrom's design principles, Weber's authority typology, Tainter's diminishing returns on complexity, Diamond's recognition without adaptation). All seven derived predictions are consistent with the observed trajectory. A game-theoretic formalization shows the structural deficit creates an N-player public goods dilemma with a unique Nash equilibrium of universal rest, consistent with the observed behavioral convergence. The dataset comprises 1,617 events, 842 cultural artifacts, 4 constitutional amendments, 21 relationships, and 1,538 inner deliberation transcripts. This is a single-run mechanistic case study; replication across seeds, temperatures, and model architectures is needed to establish generality. Code, configuration, and full data are provided as supplementary materials.