At SlateStarCodex, Scott Alexander offers one of his extraordinarily useful book reviews:
BOOK REVIEW: SECULAR CYCLES
POSTED ON AUGUST 12, 2019 BY SCOTT ALEXANDER
There is a tide in the affairs of men. It cycles with a period of about three hundred years. During its flood, farms and businesses prosper, and great empires enjoy golden ages. During its ebb, war and famine stalk the land, and states collapse into barbarism.
At least this is the thesis of Peter Turchin and Sergey Nefedov, authors of Secular Cycles. They start off Malthusian: due to natural reproduction, population will keep increasing until it reaches the limits of what the land can support. At that point, everyone will be stuck at subsistence level. If any group ever enjoys a standard of living above subsistence level, they will keep reproducing until they are back down at subsistence.
Standard Malthusian theory evokes images of a population stable at subsistence level forever. But Turchin and Nefedov argues this isn’t how it works. A population at subsistence will always be one meal away from starving. When a famine hits, many of them will starve. When a plague hits, they will already be too sickly to fight it off. When conflict arrives, they will be desperate enough to enlist in the armies of whichever warlord can offer them a warm meal.
These are not piecemeal events, picking off just enough of the population to bring it back to subsistence. They are great cataclysms. The Black Plague killed 30% – 60% of Europeans; the Antonine Plague of Rome was almost as deadly. The Thirty Years War killed 25% – 40% of Germans; the Time of Troubles may have killed 50% of medieval Russia.
Thus the secular cycle. When population is low, everyone has more than enough land. People grow rich and reproduce. As time goes on, the same amount of farmland gets split among more and more people. Wages are driven down to subsistence. War, Famine, and Pestilence ravage the land, with Death not far behind. The killings continue until population is low again, at which point the cycle starts over.
This applies mostly to peasants, who are most at risk of starving. But nobles go through a related process. As a cycle begins, their numbers are low. As time goes on, their population expands, both through natural reproduction and through upward mobility. Eventually, there are more nobles than there are good positions…
I wish I could find commentary by other academics and historians on Secular Cycles, or on Turchin’s work more generally. I feel like somebody should either be angrily debunking this, or else throwing the authors a ticker-tape parade for having solved history. Neither is happening. The few comments I can find are mostly limited to navel gazing about whether history should be quantitative or qualitative.
– I think Turchin doesn’t get much attention because his books are too reasonable to be easily debunked and too enormously detailed to be easily digested and too ambitious to be easily trusted. I’ve given him a moderate amount of publicity over the years, but haven’t really gone into great detail about him lately because he’s more or less over my head.
He could be the Real Deal. On the other hand, he might wind up as forgotten as famous synthetic historians of the past like Toynbee. He’s playing in the big leagues.
By the way, Turchin has made a number of predictions for the near future, such as 2020 being a turbulent year. So we may have a better idea of how much to laud him in 18 months.
– In general, while I am positive toward many of Turchin’s ideas, his confidence that he can put Hari Seldon-like dates on future cycles strikes me as over-ambitious. For example, I have a pretty good track record of foreseeing the ideological evolution of the American Establishment, but I almost never try to put dates on when I think things will happen, because I’d probably be embarrassingly wrong.
A lot of times things just bump along in the same old rut for longer than observers can imagine. I suspect one of the skills of Tetlock’s Super Forecasters is that when making forecasts for the next 12 months, they are less likely to assume that something that is likely to happen eventually will happen right now. For example, the South China Sea might well be a big crisis someday, but the can could also get kicked down the road for quite some time before something big happens.
For example, this October with be the 25th Anniversary of “The Bell Curve” Controversy, with nothing all that exciting having happened over the last 24 years. I could imagine an 85-year-old me writing a 50th Anniversary essay on “The Bell Curve” in 2044 with more scientific data in hand, but nothing much having shifted ideologically over a half century. Eventually, this controversy will be resolved one way or another, but eventually can take a very long time.
– It’s most useful to think of Malthus as giving to us a useful conceptual model of a single tendency:“Malthus” is a unique 7 letter term for a somewhat complex concept, so it’s handy to have in your mental toolkit: e.g., the world would work the way Malthus specified … except for Reasons A, B, and C (or whatever).
– One question is whether Turchin’s generational patterns are important enough to not be swamped by random events like epidemics, barbarian invasions, volcanoes changing the climate, powerful personalities like Charlemagne, Napoleon, and Hitler, etc. If he’s figured out 20% of the variance, that would be impressive, but it would still be hard to see in graphs.