Complexity scientist · Author · Founder of cliodynamics
Peter Turchin is a complexity scientist who works in the field of historical social science that he and his colleagues call: Cliodynamics

Research
Peter Turchin examines how large-scale societies form, remain cohesive, and enter periods of instability. The research draws on mathematical models and comparative historical data, including the Seshat Global History Databank.
What Complexity Science Tells Us about the Evolution of Complex Societies
Why do the 99.9% of humanity live in large-scale societies organized as states? During the Holocene (the last 10,000 years), human societies have been transformed utterly: from small groups of nomadic foragers to our current interconnected world of large-scale societies organized as states. Population numbers, agricultural productivity, technological…
View BookTheory and Society
This article engages with Mark Moffett’s proposed definition of society, which emphasizes shared group identification over social interaction, and argues for a different, problem-driven approach to definition in evolutionary social science. Rather than treating definitions as primary, I situate them within the broader research agenda aimed at explaining the Great Holocene Transformation—the dramatic expansion of human societies in scale and complexity over the past 10,000 years. My central analytical focus is on cooperation: the capacity of individuals to coordinate actions toward collective goals despite incentives to free-ride. Accordingly, society is defined here as a collective of individuals engaged in sustained cooperation, with interest group proposed as a more flexible and analytically useful term. Within this framework, polities represent a key subtype of interest groups, characterized by their role as independent political units whose persistence depends on maintaining cooperative cohesion, particularly among elites. Other commonly cited features of societies—such as group identification, territoriality, and intergenerational continuity—are treated as secondary mechanisms that support cooperation rather than defining properties. Ultimately, I argue that flexible, operational definitions are most valuable at intermediate stages of scientific inquiry, where they facilitate the construction and empirical testing of theoretical models.
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ReadRecent publications, books, essays, lectures, scholarly reviews, Substack posts, and media appearances.
Dans cet éditorial, Peggy Sastre mobilise les travaux de Peter Turchin pour analyser les violences à Paris : appauvrissement des classes populaires, concurrence entre élites et affaiblissement des capacités de l’État.
Entretien avec Peter Turchin à l’occasion de la parution du Déclin des empires. Il présente ses recherches sur la formation et le déclin des empires, ainsi que ses perspectives sur la Russie, la Chine, les États-Unis et les tensions politiques en Europe.
And New Chinese and French Translations
France’s PolitiSequence
Do States Age?
ENTRETIEN - Dans son best-seller aux États-Unis Le Chaos qui vient, désormais disponible en poche en France, le spécialiste de l’évolution des sociétés* apporte un éclairage saisissant sur la crise que traversent les pays occidentaux. Sa thèse : nous produisons trop d’aspirants au pouvoir et l’histoire montre que cela finit toujours mal.