Why Do Some Civilisations Collapse? An Evolutionary Game Theory Model of Societal Decline

The collapse of civilisations is a recurring theme in human history. This paper formalises the concept of societal decline through the lens of evolutionary game theory (EGT) and replicator dynamics, illustrating how interactions among competing social groups, such as elites, commoners, and external forces, can produce feedback loops that lead to collapse. Historical case studies are quantitatively analysed to corroborate the theoretical framework. Graphics demonstrate how resource depletion, inequality, and institutional fragility create conditions conducive to collapse. Findings indicate that societies with adaptive institutions and sustainable cooperation tend to ensure their survival, while those that ignore harmful dynamics risk collapse.