Human cycles: history as science

August 7, 2012

(Credit: Missouri Historical Society/Wikimedia Commons)

Advocates of “cliodynamics” say that they can use scientific methods to illuminate the past. But historians are not so sure, Nature News reports.

To Peter Turchin, who studies population dynamics at the University of Connecticut in Storrs, the appearance of three peaks of political instability at roughly 50-year intervals starting with the U.S. Civil War is not a coincidence. For the past 15 years, Turchin has been taking the mathematical techniques that once allowed him to track predator-prey cycles in forest ecosystems, and applying them to human history.

He has analyzed historical records on economic activity, demographic trends and outbursts of violence in the United States, and has come to the conclusion that a new wave of internal strife is already on its way. The peak should occur in about 2020, he says, and will probably be at least as high as the one in around 1970. “I hope it won’t be as bad as 1870,” he adds.

Turchin’s approach — which he calls cliodynamics after Clio, the ancient Greek muse of history — is part of a groundswell of efforts to apply scientific methods to history by identifying and modelling the broad social forces that Turchin and his colleagues say shape all human societies.

Cliodynamics is viewed with deep scepticism by most academic historians, who tend to see history as a complex stew of chance, individual foibles and one-of-a-kind situations that no broad-brush ‘science of history’ will ever capture. “After a century of grand theory, from Marxism and social Darwinism to structuralism and postmodernism, most historians have abandoned the belief in general laws,” said Robert Darnton, a cultural historian at Harvard University in Cambridge, Massachusetts, in a column written in 1999.

Most think that phenomena such as political instability should be understood by constructing detailed narratives of what actually happened — always looking for patterns and regularities, but never forgetting that each outbreak emerged from a particular time and place. “We’re doing what can be done, as opposed to aspiring after what can’t,” says Daniel Szechi, who studies early-modern history at the University of Manchester, UK. “We’re just too ignorant” to identify meaningful cycles, he adds.

But Turchin and his allies contend that the time is ripe to revisit general laws, thanks to tools such as nonlinear mathematics, simulations that can model the interactions of thousands or millions of individuals at once, and informatics technologies for gathering and analysing huge databases of historical information. And for some academics, at least, cliodynamics can’t come a moment too soon. “Historians need to abandon the habit of thinking that it’s enough to informally point to a sample of cases and to claim that observations generalize,” says Joseph Bulbulia, who studies the evolution of religion at Victoria University of Wellington in New Zealand.

In their analysis of long-term social trends, advocates of cliodynamics focus on four main variables: population numbers, social structure, state strength and political instability. Each variable is measured in several ways. Social structure, for example, relies on factors such as health inequality — measured using proxies including quantitative data on life expectancies — and wealth inequality, measured by the ratio of the largest fortune to the median wage. Choosing appropriate proxies can be a challenge, because relevant data are often hard to find. No proxy is perfect, the researchers concede. But they try to minimize the problem by choosing at least two proxies for each variable.

Then, drawing on all the sources they can find — historical databases, newspaper archives, ethnographic studies — Turchin and his colleagues plot these proxies over time and look for trends, hoping to identify historical patterns and markers of future events. For example, it seems that indicators of corruption increase and political cooperation unravels when a period of instability or violence is imminent. Such analysis also allows the researchers to track the order in which the changes occur, so that they can tease out useful correlations that might lead to cause–effect explanations.

Global trends

Cliodynamics has another ally in Jack Goldstone, director of the Center for Global Policy at George Mason University and a member of the Political Instability Task Force, which is funded by the US Central Intelligence Agency to forecast events outside the United States. Goldstone has searched for cliodynamic patterns in past revolutions, and predicts that Egypt will face a few more years of struggle between radicals and moderates and 5–10 years of institution-building before it can regain stability. “It is possible but rare for revolutions to resolve rapidly,” he says. “Average time to build a new state is around a dozen years, and many take longer.”

If Turchin’s prediction of unrest in the United States around 2020 is correct, the next few years should see an increase in tightly knit US groups whose rituals have a threatening quality but promise great rewards.

Turchin can’t say who those groups might be, what cause they will be fighting for or what form the violence will take. Previous bouts of turbulence were not dominated by any one issue, he says. But he already sees the warning signs of social strife, including a surplus of graduates and increasing inequality. “Inequality is almost always a bad thing for societies,” he says.