Twenty Years of Cliodynamics

Peter Turchin


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Almuzara is about to publish a Spanish translation of my book Historical Dynamics. When they asked for a foreword to the Spanish edition, I realized that it has already been 20 years since I wrote Historical Dynamics. So this foreword serves as a kind of retrospective. Here’s the English version.

Foreword to the Spanish Edition of Historical Dynamics

Historical Dynamics (HD) was my first major work in the new field of Cliodynamics. In fact, it was in the last chapter of HD that I proposed to call this new discipline after Clio (the muse of History) and dynamics (the science of change). I wrote the bulk of HD 20 years ago and this is a good time to look back at what happened since then. Thus, a request from the Spanish publisher of HD for a foreword to its upcoming translation fell on fertile soil.

As HD explains at considerable length, the overarching goal of Cliodynamics is to systematically test the many theories that thinkers of the past and social scientists of today have proposed to explain why things happened the way they did in history. Other goals flow from this key objective. Thus, we need mathematical models in order to derive predictions from theories to be compared to data. In the process of translating theories into explicit models, we often find that proposed verbal explanations are, actually, logically flawed (as is discussed in Chapter 2 of HD). Most importantly, we need lots of data to test these predictions. In the past two decades cliodynamics research addressed both of these goals. Let me say a few words about the second one, data.

Over the past 10 years I poured most of my energy into coordinating an international and interdisciplinary research consortium that has been constructing a huge compendium of knowledge about past societies. We named it Seshat: Global History Databank. Seshat is an Egyptian deity of writing (her name means “she who scribes”) and by implication of information and databases. Thus, Cliodynamics now has two heavenly advocates: Clio and Seshat.

Seshat was designed to answer Big Questions in history, such as what drives the evolution of technology, what propelled societies to become the large, centralized states we are familiar with in the modern world, and why did moralizing “world religions” spread. But aren’t we severely limited by the poor knowledge about past societies? In fact, this is a misconception—thanks to truly heroic efforts of historians and archaeologists, and aided by constantly developing new methodologies, the store of knowledge about the past has become truly enormous (and continues to grow at a seemingly accelerating pace). The trick is to translate that knowledge into data for analysis. And that’s what Seshat has done—it has brought “Big Data” to bear on Big Questions in History. Most recently (in 2021) we have completed a large analysis of Seshat data that tested all major classes of theories attempting to explain the evolution of large scale, complex societies during the past 10,000 years worldwide. We found that two classes of variables have a strong predictive effect on where and when social complexity has grown: agriculture and, especially, warfare. At the same time, other theories, including internal conflict (e.g., class struggle), functional theories (providing public goods and infrastructure), and religion (for example, the Big Gods theory) were not supported. What this means is that the theory of cultural group selection, developed in Chapters 3 and 4, has acquired a lot of additional support, because it postulated competition and warfare among states and empires as the most important driver of social evolution.

As a result of this and other “success stories” Cliodynamics has enjoyed an increasing degree of support in the scientific community, and in 2010, together with a group of like-minded colleagues, I launched an academic journal, Cliodynamics: The Journal of Quantitative History and Cultural Evolution. This support has been reflected in an increasing number of publications about this new discipline in the popular media.

Cliodynamics has also been making inroads into the historical community. My initial expectation was that most historians would be resistant to the interlopers from “hard sciences” into their home turf. And many historians have been critical of Cliodynamics, although the most negative reactions are not to what the practitioners of Cliodynamics do and write, but to an often sensationalist coverage in the popular press. Other historians, when they take the trouble to actually find out what cliodynamicists do and say, become less critical. And a significant and growing minority have become supporters. Thus, the majority of contributors to Seshat are historians (alongside with archaeologists, religion scholars, and other scholars of the past). The governing board of Seshat consists of three historians, an anthropologist, and a complexity scientist (the last one is, of course, me). This support is very important, because without active help from historians the Seshat Databank would be impossible. Overall, the degree of help that this and other cliodynamic initiatives enjoyed from historians has exceeded my greatest expectations when I started on this road.

As a last thought, I am also pleased by how well HD aged. It is true that many of the theories I discuss in HD have been further refined in the past two decades. New and more sophisticated mathematical models have been published by colleagues. And the greatest advances had to do with data and empirical tests of theories, as I related above. But HD remains the best general introduction to the goals and methods of Cliodynamics, and so far it has not been superseded by any other volume.

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Is there going to be a digital version of historical dynamics?

As far as I know there is only the expensive hard cover version available

Loren Petrich

I got that book online as a Kindle e-book. Cheaper than I expected. Interesting that it has an attempt to predict where nation-states would emerge, at “metaethnic frontiers”. I also like the mathematical modeling.

Dick Illyes

I am grateful for this body of work. With a level of self-understanding never before achieved by humans can harmony be found?

Recent polls show a huge Independent group that apparently went strongly for Biden and has now gone the other way. Andrew Yang and his attempt to create a new party would seem to come at the right time. His ideas of term limits, ranked choice voting, open primaries, and UBI have the support of a large part of the technological elite.

Ray Kurzweil with his observations that technology grows exponentially, which I think is correct, means that humans are entering a period never before experienced.

Martin Gurri recently wrote:
To some extent, this is a family drama: the last gasp of the Baby Boomers before their children snatch the world away from their palsied hands. It would be good to believe that a rising generation, at ease with new models and habits, simply by taking over could broker a fair peace between the public and the industrial elites. But this places too great a weight of expectation on the young.

We are living through the early stages of a colossal transformation: from the industrial age to something that doesn’t yet have a name. Many periods of history have been constrained by structural necessity. This isn’t one of them.

For younger elites, trust involves a sort of cosplay of historical conflicts. They put on elaborate rhetorical superhero costumes, and fight mock-epic battles with Nazis, fascists, “patriarchs,” slave-owners, George III, and the like. Because it’s only a game, no one gets seriously hurt – but nothing ever gets settled, either.

Juan Alfonso del Busto

That’s great news, Peter!
By the way, in the Spain version of the TV show PassWord “Cliodinámica” showed up once in the C.



Craig Brackbill

Another twenty years of data should continue to strengthen Cliodynamics. But I’m really not looking forward to living through those years.


I wonder if there’d be any synergy between your work and that of Bart Ehrman…

Tessaleno Devezas

Hi Peter

congratulations for the excellent piece on the 20th anniversary of HD, indeed a groundbreaking book that so far has not been superseded by any other volume published in complexity science.

Ross Hartshorn

So, for someone who has read your more recent work (e.g. Secular Cycles, War and Peace and War, Ages of Discord, Ultrasociety, Figuring Out The Past), does this book have anything not covered (in as much detail) in those later books? Or would it be primarily of historical (pun intended) interest?

Regardless, thanks for sharing the introduction with us.

Loren Petrich

Has anyone tried to expand on this work? Like analyze more regions. The most I’ve found is ancient Rome, medieval and early-modern England, France, and Russia, and Imperial China. The Byzantine Empire seems like a good subject for this research, and maybe also the medieval caliphates, the Ottoman Empire, medieval and early-modern Japan, Pharaonic Egypt, … I’m trying to think of polities that were relatively united, and that were not easily overpowered.

Most of the theory has been developed for preindustrial polities, and there is plenty of record on that. There is much less on industrialized ones, and the most work I’ve seen has been done on the United States. Anything on the United Kingdom or France? As an indication of what we have to work with, the US has only about 1.5 – 1.75 of a cycle since its independence, while preindustrial polities have had a lot more.


I was never a fan of Isaac Asimov but I have been watching the new Foundation series. Were you influenced at all by the idea of psychohistory? I was struck by some similarities.

Loren Petrich

No idea, but the premise of cliodynamics seems like another Isaac Asimov story: Nightfall. The people of some planet have suffered periodic destructions of their civilization, and some astronomers have discovered that the cause of it is soon to happen. So they warn everybody and try to get everybody ready.

Ross Hartshorn

thank you. I see a hint of quantum theory in the works. The more accurate the instrument, i.e. the more people are aware of the unfolding history, the less accurate is the measurement.

Vladimir Dinets

I wonder if recent events have made modeling easier. Vaccination rates ( in countries where vaccines are freely available) are such a perfect proxy for asabiya 🙂


Is this really the case ? I wondered about that but I don’t think it’s a clear correlation.

Does Israel have high asabiya? One would think so but their vaccination rate is still at only 66%.

Vladimir Dinets

Israel’s asabiya is not nearly as high as it used to be. 30 years ago I heard some Israelis say that the only thing keeping the country together was the external threat. And now that threat has largely evaporated.
Disclaimer: I haven’t been there since 1994.


That was just a random example, you also have countries like Switzerland with a low vaccination rate but then you have Spain which is basically fracturing with a very high rate.
I just dont think its that clear of a correlation

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