Stephen Johnson on Peter Turchin's theory:
"Turchin's model is based on structural-demographic theory, which seeks to understand the broad underlying forces that cause societies to become unstable. The theory has revealed that regular cycles of political instability have occurred not only in the U.S., but also in the Roman Empire, Egypt, China, and Russia.
To better understand the theory, try thinking about the causes of revolutions as being similar to the tectonic processes that cause earthquakes, as Turchin and economic historian Andrey Korotayev wrote in a 2020 paper:
"In both revolutions and earthquakes it is useful to distinguish 'pressures' (structural conditions, which build up slowly) from 'triggers' (sudden releasing events, which immediately precede a social or geological eruption). Specific triggers of political upheavals are difficult, perhaps even impossible to predict.
On the other hand, structural pressures build up slowly and more predictably, and are amenable to analysis and forecasting. Furthermore, many triggering events themselves are ultimately caused by pent-up social pressures that seek an outlet—in other words, by the structural factors." (https://bigthink.com/politics-current-affairs/2020-predictions?rebelltitem=3#rebelltitem3)