Complexity scientist · Author · Founder of cliodynamics
Peter Turchin
Peter Turchin is a complexity scientist who works in the field of historical social science that he and his colleagues call: Cliodynamics
Research
Research on long-term social change
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.
Selected Work
Latest Work
The Great Holocene Transformation
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 BookWhat is society?
Theory 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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When ripples become tidal waves: Can we predict when the next global crisis will hit?
BBCArticle
ReadLatest Work
Recent publications, books, essays, lectures, scholarly reviews, Substack posts, and media appearances.
Eight Centuries of Wages in Britain II
Secular Cycles of Well-Being in the Industrial Period
Eight Centuries of Wages in Britain I
Secular Cycles of Well-Being in the Pre-Industrial Period
Human Unpredictability is Overrated
And History Is Not “One Damn Thing After Another”
Peter Turchin : «Surproduction d’élites, crise budgétaire… En France, les ingrédients pour une crise majeure sont réunis»
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.
CCS 26 Keynote : The Great Holocene Transformation
During the Holocene the scale and complexity of human societies increased dramatically. Generations of scholars have proposed different theories explaining this evolution, which range from functionalist explanations, focusing on the provision of public goods, to conflict theories, emphasizing the role of internal class struggle or external warfare.…
Social complexity promotes cooperation and functional integration in large-scale societies
How do large-scale human societies maintain functional integration? Over the last 12,000 years, polities grew over six orders of magnitude in population, far exceeding the scale at which the interpersonal mechanisms that promote cooperation in small-scale societies can operate. Here we test the hypothesis that cooperation and functional integration in large-scale societies is promoted by social (and, specifically, institutional) complexity. We model large-scale societies as territorial social networks subject to energetic, cognitive, and competitive constraints. We demonstrate that agricultural intensification generates increasing population density, raising the per capita rate of social interaction beyond what small-scale mechanisms can sustain and requiring institutional rules to substitute for interpersonal knowledge. The model predicts that territory and social complexity scale with polity population with exponents of 5/6 and 1/6. Tests against data describing hundreds of polities spanning the Holocene support these predictions, providing quantitative evidence that social complexity is a central integrative mechanism enabling large-scale human cooperation.