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Great Divergence

Gregory Clark

British-American economic historian (b. 1957), professor at UC Davis. Trained at Cambridge and Harvard. One of the most provocative voices in modern economic history — a serious quantitative scholar who has built a substantial body of carefully-archived English long-run data, and who has used that data to advance a series of headline theses that the rest of the field has mostly rejected while continuing to use his data.

Intellectual program

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Clark’s signature claim, developed most fully in A Farewell to Alms (2007), is that the Industrial Revolution was caused by — or at least decisively prefigured by — centuries of differential reproduction by England’s propertied middle class. Working from English probate records 1250–1800, Clark documents that wealthier testators had on average roughly twice the surviving offspring of poorer testators, sustained over ~25 generations. Because primogeniture and economic-class downward mobility prevented this surplus from staying at the top, the descendants of the medieval rich diffused steadily downward through the social structure, carrying with them — Clark argues — heritable behavioral traits (patience, literacy, low violence, work intensity) that selected for market-compatible economic behavior. By 1800, England was populated by a downwardly-diffused descendant population of its propertied medieval classes, and the IR was the payoff.

The thesis is at once population-genetic in spirit (Clark explicitly entertains heritability of behavioral traits) and culturally-evolutionary in its weaker form (transmission could be cultural rather than genetic and the math still works for a substantial trait shift). Clark’s later work in The Son Also Rises (2014) used surname-based evidence to argue that “underlying social status” is far more heritable across generations than conventional mobility metrics suggest — slow regressing to the mean over 5–10+ generations rather than the 2–3 generations that mobility surveys imply. This is presented as the mechanism-compatible empirical foundation for the Farewell claim about pre-industrial selection.

Reception and contestation

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Clark’s empirical reconstructions of English long-run wages (the “Clark wage series” 1209–1869), interest rates, and demographic differentials are widely used and broadly trusted, even by those who reject his causal claims. His causal thesis has met sustained, near-universal scholarly resistance. The principal critiques:

  • The selection math is too small. Standard population-genetic calculations suggest 25 generations of even strong wealth-correlated fertility differentials produce trait shifts on the order of 0.2–0.4 standard deviations on heritable polygenic traits — substantial but well short of what would be needed to cause an IR on its own.
  • What’s being selected for? “Bourgeois traits” are constructs. Patience is partly heritable; “industriousness” is culturally coded; “market orientation” is a behavioral cluster of uncertain heritability. The selection claim is hard to make precise enough to test.
  • Cultural transmission works without genetics. The same downward-diffusion mechanism operates under pure cultural transmission of norms and skills, which is much less controversial. Critics argue Clark is really running a cultural-reproduction model dressed in population-genetic language.
  • The cross-civilizational story is thin. Tokugawa Japan, Song China, and the Dutch Republic all had propertied elites and stable reproduction; none produced an IR. The theory is tested essentially on England.
  • Adjacency to discredited racialist theory. The thesis sits uncomfortably close to older claims about European biological superiority that have been rightly rejected. Clark himself has worked to distance the framework from those associations, but the proximity remains a reception problem.

In later work Clark has somewhat softened the explicitly biological framing, shifting toward a “status heritability” formulation that some readers interpret as a retreat toward Bourdieuan cultural reproduction in population-genetic dress. His current standing in the field is curious: respected as a serious data-builder, treated as a productive provocateur, but with his headline thesis adopted by essentially no one outside his immediate orbit and Cochran-Harpending.

Associated positions

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Key works

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  • “The Long March of History: Farm Wages, Population, and Economic Growth, England 1209–1869” (Economic History Review, 2007).
  • A Farewell to Alms: A Brief Economic History of the World (2007).
  • The Son Also Rises: Surnames and the History of Social Mobility (2014).
  • “Microbes and Markets: Was the Black Death an Economic Revolution?” (Journal of Demographic Economics, 2016).