Klint Finley of Wired summarizes Peter Turchin’s cliodynamics:
What Turchin and his colleagues have found is a pattern of social instability. It applies to all agrarian states for which records are available, including Ancient Rome, Dynastic China, Medieval England, France, Russia, and, yes, the United States. Basically, the data shows 100 year waves of instability, and superimposed on each wave — which Turchin calls the “Secular Cycle” — there’s typically an additional 50-year cycle of widespread political violence. The 50-year cycles aren’t universal — they don’t appear in China, for instance. But they do appear in the United States.
The 100-year Secular Cycles, Turchin believes, are caused by longer-term demographic trends. They occur when a population grows beyond its capacity to be productive, resulting in falling wages, a disproportionately large number of young people in the population, and increased state spending deficits. But there’s a more important factor, one that better predicts instability than population growth. Turchin calls it “elite overproduction.” This refers to a growing class of elites who are competing for a limited number of elite positions, such as political appointments. These conflicts, Turchin says, can destabilize the state.
Many of these issues persist in industrial societies. Although population growth is no longer likely to result in mass starvation, it can push the supply of labor beyond demand, leading to increased unemployment.
Then you have the 50-year cycles of violence. Turchin describes these as the building up and then the release of pressure. Each time, social inequality creeps up over the decades, then reaches a breaking point. Reforms are made, but over time, those reforms are reversed, leading back to a state of increasing social inequality. The graph above shows how regular these spikes are — though there’s one missing in the early 19th century, which Turchin attributes to the relative prosperity that characterized the time.
He also notes that the severity of the spikes can vary depending on how governments respond to the problem. Turchin says that the United States was in a pre-revolutionary state in the 1910s, but there was a steep drop-off in violence after the 1920s because of the progressive era. The governing class made decisions to reign in corporations and allowed workers to air grievances. These policies reduced the pressure, he says, and prevented revolution. The United Kingdom was also able to avoid revolution through reforms in the 19th century, according to Turchin. But the most common way for these things to resolve themselves is through violence.
Turchin takes pains to emphasize that the cycles are not the result of iron-clad rules of history, but of feedback loops — just like in ecology. “In a predator-prey cycle, such as mice and weasels or hares and lynx, the reason why populations go through periodic booms and busts has nothing to do with any external clocks,” he writes. “As mice become abundant, weasels breed like crazy and multiply. Then they eat down most of the mice and starve to death themselves, at which point the few surviving mice begin breeding like crazy and the cycle repeats.”
(Hat tip to the perfidious Buckethead, of Veil War fame.)