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Turchin, Peter, et al. "War, space, and the evolution of Old World complex societies." Proceedings of the National Academy of Sciences 110.41 (2013): 16384-16389.

Turchin, Peter, et al. “War, space, and the evolution of Old World complex societies.” Proceedings of the National Academy of Sciences 110.41 (2013): 16384-16389.

Last week I had the pleasure of meeting Peter Turchin* and Peter Richerson, among others. Many things were discussed, but one the conversation brought me back to the results of Peter Turchin’s paper from last year, War, space, and the evolution of Old World complex societies. If you haven’t checked out the paper the figure to the right shows the major result: a model with only a few simple parameters was incredibly good at fitting the genuine growth and evolution of complex societies over 3,000 years. More quantitatively about two thirds of the variation spatially in ‘imperial density’ can be accounted for by the spread and emergence of military technology and the ruggedness of the landscape. Of course there are many objections you could make, and when Peter Turchin presented the map to the audience many people brought up areas where the model didn’t seem to be predicting very well. But, the very obvious take-home is that somehow a model with only a few parameters ended up doing a reasonable job predicting the distribution of the rise of empire in agricultural societies, and that’s something. You can have all the verbal models you want, but all that leads to in most cases is more argument, as you don’t have transparent access to the internal logic of someone else’s mind.

A second broader issue that Turchin has promoted is the idea of inter-group competition driving the rise of ultrasociality. In other words, cooperative societies stocked with highly social and altruistic individuals simply eliminated earlier forms of social organization which relied more on individual self interest. He is keen to not allow the argument to reduce down to ‘group selection,’ but rather to focus on the abstraction of multi-level selection more generally. Conflict and warfare are obviously key drivers of this culturally Darwinian process. But I wonder where that leaves us at the end of history? Perhaps without an external threat imposing cohesion and inducing norms to regulate and punish selfish strategies anomie will reign?

* At least in person

• Category: History • Tags: Cliodynamics 
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Citation: Turchin, Peter, et al. “War, space, and the evolution of Old World complex societies.” Proceedings of the National Academy of Sciences (2013): 201308825.

A few weeks ago, Peter Turchin, who runs the excellent Social Evolution Forum, published a paper in PNAS, War, space, and the evolution of Old World complex societies. It is open access, so you can read it yourself. And Turchin himself has responded to questions at length. You might also check out my reviews of two of his books, as well as my interview with him. From all that it should be clear that broadly speaking I am enthusiastic about Turchin’s project, Cliodynamics. Historical details matter, but Turchin’s aim is to establish a broad brush framework of the coarse dynamics which shape the scaffold for specific aspects of historical process. Without this background all we have are cluttered details.

The big top line finding is that 2/3 of the variation in the emergence of large scale states between 1500 BCE and 1500 CE can be explained by a model with 12 parameters, of which only 4 have large effects. The largest proportion of the variation is explained by the diffusion of military technology from the steppe in to the civilized world. As Turchin notes the beauty of this result is that a rather coarse data set and simple formal model has strong generality. The questions being explored have to do with the overall dynamics of civilizational rise, and fall, rather than specific historical events. But anyone with a cursory knowledge of world history sees the intuitive plausibility of the result. Much of history before the modern era has consisted of an almost dialectical synthesis between the steppe periphery and the agricultural lands beyond the limes of civilization. More generally high mobility populations which maintain martial competence due to at least some nomadic element to their lifestyle, in contrast to high density sedentary stratified societies dependent upon grain agriculture, have always loomed on the margins, only to become central players in subsequent epochs. It is not an if, but when.

Turchin’s model suggests that agriculture is necessary, but not sufficient, for civilization as we understand it. In particular, the complex institutions which allow for circles of trust, organization, and control, and allow for scalability in political units, can only be understood by conflict and competition driven by the friction between societies. Agriculture likely immediately gave rise to warlike tribal confederations. But Turchin’s results suggest that inter-group competition forged by pressures from highly organized and effective mobile military societies from the steppe added an extra impulse, which brought together proto-statelets (obviously the horse was a major catalyst here, as it increased the effectiveness of mobile nomads in relation to the farmers). In antiquity some societies had even formalized this tension in a nearly mythological sense; consider the dichotomy between “Iran and Turan” in ancient Persia.

Cliodynamics offers the hope of a robust interpretative framework for historical analysis. There is already a fair amount of comparative work, but it is too verbal and ad hoc to defend itself against sophisticated deconstructions and critiques. And when exploring particular issues in regional history it is often important to understand whether they are sui generis, or an inevitable part of the broader tapestry (e.g., the Chinese pattern of steppe influenced polities being central in dynastic development does not seem so peculiar or exceptional in this framework).

• Category: History, Science • Tags: Cliodynamics 
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I was alerted to Samuel’s Arbesman’s new paper, The Life-Spans of Empires, by the fact that he pointed to his research on his weblog. Interestingly I’m not the only one who was interested, as after I pointed to it on my link round up a few people asked if they could get a copy of the paper (yes, I almost always send papers if I have access). Luckily it’s a nicely elegant piece of work, basically quantifying what we’ve already probably known qualitatively. There isn’t that great of a value-add to quantification as such, but with a mathematical understanding of a topic one can engage in an algebra of mental manipulations so as to construct models with which one can project other facts. Quantitative information is often an excellent way to generate “free information” from theoretical models. The figure above is the primary result of the paper. Basically Arbesman took a data set which was laying around which measured the lengths of various empires (N = 41), and showed that the rise and fall of these political entities tends to follow an exponential distribution: e−λt . This is an incredibly elegant summation of what we know qualitatively: some empires last a long time, but most do not.

Interestingly the mean length of an empire is 220 years. That’s basically what you’d probably expect from intuition, especially if you knew Chinese history. To the left is a density plot I generated with the data provided in the paper. You can see that the mode and mean are a bit different because of the skewness. One of the interesting points about the exponential distribution is that it implies that the the duration of an empire at any given moment can’t tell you the probability that it’s going to collapse in the near future. The distribution is “memoryless.” In other words, the likelihood of doom striking isn’t greater as time passes. This seems somewhat counterintuitive. After all doesn’t the cohesion and elan of the a ruling caste of a given empire wane as the society slowly lose its vital force? Hasn’t the author read Spengler! Arbesman admits that there are more complex equations which can describe the distribution more precisely, but the exponential formula has only one parameter, so it’s quite parsimonious. But even if we have a first approximation we don’t have a total description.

Like evolutionary process as a whole I’m not convinced that the nature of the current data set is sufficient to deny the shifting background parameters which are operative over time. As I’ve noted before, there are two counteracting tendencies over time in human history when it comes to social & political entities:

– A greater rate of cultural change over time

– A greater cohesion and integrative power of social and political systems (more rapid bounce-backs from collapse, and greater civilizational continuity)

One thing I wanted to do is check to see what the correlation between age of the polity and its duration was. My intuition was that older polities will have greater recorded duration. Obviously there’s just more time for them, but some societies, such as Egypt, were very stable for longer periods of time in far antiquity. When I ran the correlate it was pretty weak, -0.23. Below is a chart which shows the scatter plot and the r-squared (correlation squared):

Here’s the original data:

Empire Adulthood Duration
Western Turk (C. Asia) 582 0.7
Avar (Europe) 580 2
T’u Chueh Turk (C. Asia) 550 0.9
Visigoth (Europe) 470 2.4
White Hun (Indo-Iran) 460 1
Toba (China) 440 1.3
Yuen-Yuen (C. Asia) 400 0.3
Byzantine (Europe) 395 3.5
Hun (Europe) 380 0.8
Gupta (India) 370 0.9
Liu-Sung (China) 330 2.1
Ptolemaic (Africa) 323 2.9
Bactria (Indo-Iran) 200 0.6
Kushan (Indo-Iran) 75 2
Rome (Europe) 0 4
Saka (Indo-Iran) -50 1.2
Parthia (Iran) -60 7
Ch’in (China) -90 2.9
Andhra (India) -170 3.7
Hsiung Nu Hun (C. Asia) -190 1
Maghada-Maurya (India) -300 0.9
Achaemenid (Iran) -540 3.2
Lydia (Anatolia) -610 0.6
New Babylon (Mesopotamia) -610 0.7
New Assyrian (Mesopotamia) -700 0.8
Late Period (Egypt) -715 1.9
Phrygia (Anatolia) -760 0.6
Urartu (Mesopotamia) -810 0.9
Babylon (Mesopotamia) -1000 2.5
Middle Assyrian (Mesopotamia) -1090 0.5
Hittite (Anatolia) -1320 1.3
Hsia-Shang (China) -1350 4
New Empire (Egypt) -1500 5
Mitanni (Mesopotamia) -1500 1.4
Elam (Mesopotamia) -1600 10
Hykso (Syria) -1650 0.8
Babylon—Hammurabi (Mesopotamia) -1700 2
Old Assyria (Mesopotamia) -1800 1
Middle Empire (Egypt) -2000 3
Akadia (Mesopotamia) -2310 1
Old Empire (Egypt) -2800 5
• Category: History, Science • Tags: Anthropology, Cliodynamics, Geography 
🔊 Listen RSS Long time readers know well my fascination with quantitative history. In particular, cliometrics and cliodynamics. These are fields which attempt to measure and model human historical phenomena and processes. Cliometrics is a well established field, insofar as it is a subset of economic history. But clio dynamics is new on the scene. At the heart of cliodynamics is the quantitative ecologist Peter Turchin. I highly recommend his readable series of books, Historical Dynamics, War and Peace and War, and Secular Cycles. Also, see my reviews of the first two books.

With that, I am rather excited by the debut of Cliodynamics: The Journal of Theoretical and Mathematical History. Here’s the description of the brief of the field and the journal:

‘Cliodynamics’ is a transdisciplinary area of research integrating historical macrosociology, economic history/cliometrics, mathematical modeling of long-term social processes, and the construction and analysis of historical databases. Cliodynamics: The Journal of Theoretical and Mathematical History is an international peer-reviewed web-based/free-access journal that will publish original articles advancing the state of theoretical knowledge in this discipline. ‘Theory’ in the broadest sense includes general principles that explain the functioning and dynamics of historical societies and models, usually formulated as mathematical equations or computer algorithms. It also has empirical content that deals with discovering general empirical patterns, determining empirical adequacy of key assumptions made by models, and testing theoretical predictions with the data from actual historical societies. A mature, or ‘developed theory,’ thus, integrates models with data; the main goal of Cliodynamics is to facilitate progress towards such theory in history.

The first issue has an article by Sergey Gavrilets, David G. Anderson, and Peter Turchin. Gavrilets is a familiar face. I know him from his work in evolutionary theory. The paper itself is a readable and plausible model of how “medium scale” societies rise and fall through conflict and consolidation. Basically the stage of human society described in Laurence Keely’s seminal War Before Civilization; after agriculture, but before major literate state systems. Their basic method is to take a mathematical model with a tractable number of plausible parameters and run simulations which give one a sense of how it changes dependent variables of interest. Polities were modeled as being circumscribed hexagons; so they had six neighbors (instead of four which would be the case if they were squares). The area modeled had an “edge,” and polities can exist in a flat hierarchical structure, or eventually aggregate so they exhibit rank order. Additionally, polities varied by economic productivity. Finally, there was a temporal aspect in that there was a potential conflict per generation where the probability of success was conditional upon the strength of the polity. Being more powerful increase the probability of victory, but does not guarantee it. Flukes do happen. The full model can be found in the paper, which is open access. The math isn’t totally opaque, so I’m really not going to distill it down. You can swallow it whole. Rather, let’s look at the list of parameters and statistics:

Most of the above variables are pretty straightforward. You should know that “complexity” refers to the levels of structure above the independent village. Presumably larger polities will have more complex structures, because they have to. Here’s a figure which shows the dependency of the statistics over time on α, the scaling exponent. α = 2 a quadratic, while α = 1 linear. The area of a square grows as a quadratic function. In other words, there are greater gains to to the variable than a linear increase.

As you can see, maximum complexity and polity size seems to be strongly contingent upon the scaling exponent. This makes sense: the powerful get more powerful when the differentials are less swamped out by noise. Remember that the probability of victory in war is dependent in part on the scaling exponent, so when you increase the rate of victory as a function of greater power, you can have longer strings of “wins,” and so more aggregation.

The table to the left shows the big outcomes from their simulations. I’ve underlined what you need to focus on. You can see that α and τ have the big effects on the properties of the system in terms of how they vary over time. Basically the greater returns there are on power differentials, the more large polities will emerge and flourish. This is intuitively obvious. Second, the other major factor which influences the growth and flourishing of large and complex polities seems to be the time of rule of a given chief. The other factors seem less important when it comes to maximum size or complexity, which are probably the two statistics of major interest to us.

So does this tell us something we don’t know? Qualitatively we know this already. The authors choose to focus on pre-Columbian North American societies as well as Sub-Saharan African and Oceanian ones. But they do give the nod to the “big name” civilizations too, which aren’t really modeled here because their scale and complexity is outside of the purview of the parameters given here. To anyone who knows history the importance of the returns to asymmetric power and length of leadership are qualitatively obvious. In the first case, it seems almost tautological that if you reduce the “noise” in wars, and simply allow for victory to go to those who should win “on paper,” there would be a “winner take all” dynamic. Small initial differences could much more quickly snowball into large differences. In some ways this is like evolution; increase population size and selection becomes more efficacious vis-a-vis stochastic forces (drift remains powerful to the same extent, as per neutral theory, selection simply has a larger footprint).

But what about the second variable? It is descriptively a well known fact that polities of massive scope and longevity tend to have a run of long-lived rulers at their inception. Consider the reigns of Augustus and Tiberius for Rome. Akbar, Jehangir, Shah Jahan and Aurangzeb for the Mughals. Kangxi and Qianlong for the Ching. Taizong and Xuanzong of the Tang. And so on. The question though is: are these long reigns the chicken or the egg? In other words, is the length of the reigns at the beginning of a political order simply a function of the endogenous factors which give rise to political units? Or does the length of rule itself impact the nature of the political system? These results seem to point to a causal role for the length of rule. I find this plausible. In the pre-modern era the death of even elites was to some extent a much more random affair than today. The death of Edward VI of England during his teenage years probably had a huge impact on the future trajectory of the culture of the British nation. That death occurred simply through an act of God in the era before modern medicine. Therefore, one of the stochastic aspects of polity size in the pre-modern era was probably simply the necessity for a random run of political leaders who did not die of illness (the second century famously had a run of Roman emperors who had no male heirs, so they adopted competent successors).

The Sui-Tang dynasty of China perhaps hints at a dynamic where structural forces set the preconditions for the emergence of a large and stable polity, but personal rule means that there is still an element of stochasticity in terms of when the rise to power of that polity will occur. There were several “false starts” in the interregnum between the fall of the Latter Han and the rise of the Sui-Tang. This chaotic period was exceptionally long by the standards of later Chinese history. One model, which I find plausible, is that the institutions of Chinese society became more robust, and allowed for more rapid re-integrations after the collapse. But another model could be that the long period between the Latter Han and the Sui-Tang was simply due to a series of long odds. In other words, not only are large and complex political systems due to chance contingent upon the length of reigns, the perpetuation of fragmentation is also the inverse of that result.

Finally, I think of the points that the authors are trying to make needs to be emphasized:

Our model provides theoretical support for a view that the formation of complex polities is “a predictable response to certain specific cultural, demographic and ecological conditions”…Conditions explicitly accounted by our model include warfare, circumscription, variation in productivity between different local communities, ability to generate surpluses, ability to delegate power, and restrictions on the growth of polities due to scalar stress. Once these conditions are present within a particular geographic area, the model predicts rapid formation of hierarchically organized competing polities partitioning available space.

A striking feature of the model output is the fluid nature of “significant” polities, which continuously go through stochastic cycles of growth (both in size and complexity) and collapse. Growth is driven by successful warfare whereas collapse results from defeat in warfare, rebellion of subchiefs, or fragmentation following the death of the paramount chief. The lifetime of chiefdoms observed in our simulation – a few generations – is comparable to those identified by archaeological studies…The model suggests that the rapid collapse of chiefdoms can occur even without environmental perturbations (e.g., drought) or overpopulation.

First, the model has elements of randomness, and, determinism. Complex societies naturally arise given particular structural preconditions, but the long term dynamics exhibit stochasticity. Second, that stochasticity may be a due to endogenous parameters within the system. In other words, randomness in long term dynamcis may not be due to an outside “shock,” like climate change or disease. Rather, it may simply be due to the fact that societies are complex systems which oscillate around equilibriums.

Citation: Gavrilets, Sergey, David G. Anderson, & Peter Turchin (2011). Cycling in the Complexity of Early Societies Cliodynamics: The Journal of Theoretical and Mathematical History

• Category: History, Science • Tags: Cliodynamics, Culture 
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Doing a literature search on the Price Equation for some weblog posts I found that Peter Turchin had written a new paper on world history using Price’s formalism explicitly. A quantitative ecologist by training, Turchin has already written a series of books attempting to model human history in a more formal fashion than is usually the case. Though his work has a tendency to overlap with economic history, in particular cliometrics, Turchin brings a more robust theoretical toolkit from the natural sciences to the table. An ecologist once told me that the ultimate aim of his career was to “count stuff,” and that professional expertise is handy when it comes mapping the distribution & abundance of the human species over time. What David Sloan Wilson is to multilevel selection theory, Peter Turchin is to “cliodynamics”, his attempt to grapple with the general dynamics which characterize the cycles of human history.

Specifically, Turchin focuses the agricultural societies which mark the span between the age of the hunter-gatherers, and the industrial revolution. What I term the “traditionalist transient.” Traditionalist because from our “modern” viewpoint we perceive many of the customs, institutions and values of this age as timeless and traditional. This despite the fact that they emerged in a specific and relatively brief historical transient after the Ice Age & before the Great Divergence. But this period is still important in our modern age, because the basic building blocks of contemporary identities draw from the traditionalist transient. Higher religions invariably date back to this period (Salafi Muslims and some ultra-traditionalist Roman Catholics look back to particular periods during the traditionalist transient as golden ages to be emulated), as do modern lingua francas, and the basic terms of political organization (democracy, republic, etc.). Early modern thinkers of the Enlightenment may have rejected or superseded the orthodoxies of the traditionalist transient as the Quarrel of the Ancients & Moderns was finally resolved to the satisfaction of the latter, but the context of the refutation was still to a large extent on the basis of traditionalist transient assumptions. For example, contemporary secularism, laicism and disestablishmentarianism are intelligible only in light of the fusion of the sacred and temporal which played out in the agricultural societies after the rise of Sumer. Turchin always notes that his conclusions may not, likely do not, apply to the dynamics extant in the present. But I suspect that much of what does go on in the present is intelligible only in light of the phenomena of the past. So his models are not purely abstract intellectual exercises.

Whether you think the project as a whole is worthwhile or not (see Massimo Pigliucci‘s skepticism), I am intrigued by the fact that Turchin focuses on Inner Asia because this is one region of the world which has long been “at the center of it all,” both literally as well as more metaphorically. Some of the inferences from Turchin’s framework illuminate rather well the broad observations and hints presented in Christopher Beckwith’s Empires of the Silk Road. Since Beckwith is a philologist he lacks Turchin’s more robust theoretical toolkit, but he naturally exhibits both more depth and granularity when it comes to the details of the history and ethnography. Setting both against each other is fascinating as one can make out binocular intellectual vision with more subtly than if just one narrative is considered.

As I said, in the paper, Warfare and the Evolution of Social Complexity: A Multilevel-Selection Approach, Peter Turchin uses the Price Equation as a theoretical framework. The reason for this is that Turchin believes that human societies within the past 10,000 years can be viewed as functional units subject to selection; in other words, they’re adapting entities, organisms. The Price Equation allows one to partition variation between and within groups, variation being necessary for selection to operate upon collections of entities. Though the economist Samuel Bowles has suggested that between group genetic variance (FST) and selection (through warfare) may have values high enough in “small-scale societies” to allow for non-trivial biological group level selection, most seem to accept the contention of those who suggest that between group variance only makes cultural group selection plausibly common. Turchin is in the latter camp, in particular because his focus is not on small-scale societies, but larger polities which characterize what we would term “civilization.” In the world of civilization it is clear that between group variance can be much greater culturally than biologically. Consider the example the case of Transylvanian Hungarian Protestants who could get by in late 16th century Oxford by virtue of their common fluency in Latin, combined with shared Calvinist religious precepts with many English Protestants (example from The Reformation: A History). Yet genetically Hungarians are closer to their neighbors, the Orthodox Romanians, than to the British. By intuition and impression it is clear that in relation to gene frequencies religious and linguistic identity tend to exhibit a less clinal pattern of variation. Though genes are discrete units, genetic variation approaches blending dynamics more easily than religious and linguistic variation, where pidgins and syncretisms are often marginalized or absorbed into one of the “parent” traditions.* Because languages and religions vary less gradually, it is easier for one to conceive of a clear and distinct group coherency in a selective framework. Where one entity ends and another begins is not arbitrary, the genes of France blend in to the genes of Germany more gently than do the dialects of French to those of German. It seems that selection between group genetic differences (not reducible to individual level selection) runs up against the problem of “gene flow” overwhelming divergences in frequency (I imagine in pre-modern times this gene flow consisted predominantly of the assimilation of the breeding-age women of conquered tribes). Here’s an example from a primitive people:

31:9 And the children of Israel took [all] the women of Midian captives,
and their little ones, and took the spoil of all their cattle, and all their flocks, and all their goods.

31:13 And Moses, and Eleazar the priest, and all the princes of the congregation, went forth to meet them without the camp.
31:14 And Moses was wroth with the officers of the host, [with] the captains over thousands, and captains over hundreds, which came from the battle.
31:15 And Moses said unto them, Have ye saved all the women alive?
31:16 Behold, these caused the children of Israel, through the counsel of Balaam, to commit trespass against the LORD in the matter of Peor, and there was a plague among the congregation of the LORD.
31:17 Now therefore kill every male among the little ones, and kill every woman that hath known man by lying with him.
31:18 But all the women children, that have not known a man by lying with him, keep alive for yourselves.

In fact, it seems likely that between group genetic differences have been driven by cultural differences. The Jews are a famous case, but this dynamic also crops up in surprising places, such as among Christian & Muslim Arabs in Lebanon. It seems likely that high FST values in small-scale societies tracks their cultural and linguistic diversity; as conventional gene flow through movement of mates between populations which can not communicate or worship different gods is likely to be dampened due to mutual unintelligibility and suspicion. By contrast, the expansive spread of the possible Y chromosomal lineage of Genghis Khan within the last 1,000 years is a testament to the power of cultural prestige and conquest over large areas to generate rapid gene flow.

The ethnogenesis of the Hazara in Afghanistan illustrate the complex interplay between religion, language and lineage. The Hazaras show clear evidence on Structure-based analyses of being an East Eurasian and West Eurasian hybrid population. Y chromosomal lineages tied to Genghis Khan the Mongols are common among them, and there are historical legends that they arose from exactly this group. Their practice of Islam & usage of a Persian dialect likely dates to the time that the Mongol Khans of the Ilkhanate accepted the religion of the local majority in the 13th century. The Mongols who refused to accept Islam emigrated to Inner Asia, while those who remained assimilated, accepting the religion and dominant language of the local populations whom they ruled. Today as a physically distinct Shia Muslim Persian speaking group in Afghanistan the Hazara are now endogamous, their biological distinctiveness a function of broader cultural-historical forces.

Of course that is just a specific concrete illustration of historical dynamics, and an atypical one at that. The general processes which Peter Turchin discusses have an extreme specific case scenario in the form of the Mongols, who left an outsized impact on the World Island. A big shift from small-scale societies to those of agricultural civilizations is the need for complex hierarchies to mediate decision making from the apex of the political pyramid. Like Archimede’s lever with which he could move the world, the functional integrity of these units allowed the decisions of Genghis Khan to affect tens of millions. It is presumed that for small-scale societies primary face-to-face interaction sufficed to coordinate decision making. Interestingly, there is also compelling data which points to relative egalitarianism of material wealth to complement the flat authority structures. By the time history arises to supplement archaeology, meaning that we have records in the form of cuneiform tablets, societies are clearly already quite hierarchical (literacy probably emerged as a more sophisticated form of accounting, so rather complex economies are already necessary conditions). A reliance on rules, heuristics and institutions which coordinate and channel power tracked the crystallization of a powerful and wealthy rentier class (as well as a possible reallocation of power between the sexes). The idea that the poor will always be with us, and that true status and nobility accrue to those who can consume at leisure, as opposed to those who increase productivity, was the norm in the traditionalist transient.** Whereas in small-scale societies alien tribes were subhuman, in civilization the elites would often dehumanize their own subjects as lower orders of a different nature.

It is this last tendency which Turchin examines in this paper, to contrast it with conflicts which emerge on the “meta-ethnic frontiers.” If you have read his earlier work you are familiar with the idea, which basically describes civilizational marchlands. The Muslim Ottomans, Orthodox Cossaks and Buddhist Oirats were all forged in the fires of meta-ethnic frontiers. In opposition to this is the “narcissism of small differences”, whereby societies exhibit cleavage along what may otherwise seem to be marginal differences. Civil wars within polities can often by traced back to these issues, or sides aligned based on internal factions. Consider the divisions between Protestants which resulted in the English Civil War. Turchin wishes to assess the extent of ethnocide and genocide in the former vs. latter cases. Why? Because he believes that it is the former cases which are responsible for the rise of large empires and re-ordering of civilization and historical shifts. Evolutionary theory tells us that selection needs extant variation to operate, and it seems that along meta-ethnic frontiers such variation would would be extant in more copious quantities than in civilizational heartlands. In particular, along the boundaries of civilizations. Within individual societies there should be less variation, so selective forces should have less traction. To assess this he reviews the literature to evaluate the magnitude of depopulation wrought upon cities by victorious armies. This is a classic form of “hard selection”.

Table 1 shows that conflict on meta-ethnic frontiers does have a stronger effect than civil wars. Why? Turchin posits a simple psychological explanation: those of different civilizational character are dehumanized, so empathy is modulated downward (it is notable that during and before the Albigensian Crusade the Cathars were subject to many conventional demonizing tropes, and effectively de-Christianized in the eyes of the rest of Christendom) .This is clear from the history of Christianity and Islam, in the medieval period the religious norms in both civilizations accepted the enslavement and maltreatment of unbelievers to an extent not acceptable for believers. This is the explanation for why some of the Christian military orders in the Baltic, whose original raison d’etre was to Christianize the native peoples, actually were among the last to allow and e
ncourage baptism of their subjects. Baptism imposed constraints on efficient extraction of marginal product. The analogy to New World chattel slavery here is clear, as some plantation owners viewed proselytization among blacks dimly lest economics be modulated by morality. When the crossbow was invented the Roman Catholic Church attempted to ban its usage between Christian powers, though declared it acceptable as a weapon against Muslims. This sort of behavior, constraining and/or ritualizing high stakes competition and conflict within groups, while accepting a more “no holds barred” attitude toward between group conflicts is known from small-scale societies (though perhaps the contrast would manifest more in the extent of extreme barbarism with which outgroups were treated, rather than any particular norm of humanity for ingroups). Civilization simply operationalized this on a grander scale, and scaffolded human nature and channeled it through particular institutions and identities.

Peter Turchin argues, and presents data, that these frontier regions where primitive, and frankly savage, passions are channeled toward outgroups serve as the loci for new empires and mega-polities. In particular, being an ecologist, he focuses on particular ecologies as the exceptional cauldrons for state-formation: the semi-arid steppe. It is here that Turchin aligns with some of Christopher Beckwith’s insights in Empires of the Silk Road. This should not be totally surprising, though we look through the glass darkly nature is fundamentally one, and history is a phenomenon rooted in nature. Beckwith attempts to generate a revisionist history of the world where the rise and fall of nomadic empires are just as salient as the ebb and flow of peasant-based civilizations, where the eruptions from the heartland echo down the centuries. And Turchin, like Beckwith, seems to hold that it is less important or relevant that the movers of history are unlettered nomads, but that they are derived from the marchlands where nomads or part-nomads are prominent on both sides of the frontier, civilized and barbarian. Consider the Cossacks who pushed the frontier of the Russian Empire back against the Tatars from the 16th to the 18th centuries. Loyal to the Russian state, Orthodox Christians, and trailblazers for Slavic culture and society, they certainly were the civilizational antithesis of the Muslim Turks descended from the Golden Horde of the Mongols. But upon closer inspection there were similarities between the Cossacks and Tatars as rough frontiersmen which exposed affinities when set against the lives of Russian peasants, or the more cultured nobility of the Russian heartland. It is known that many Tatars “went Cossack,” abandoning the Muslim religion and eventually shifting toward a Slavic self-identity in the wake of defeats (though this is most notable for elite Tatars who converted to Christianity and were assimilated into the Russian noble class). This is what Turchin would label “ethnocide,” cultural extermination if not physical. The men who expanded the domain of Russian civilization in the early modern era were useful barbarians (this seems especially evident to the more sophisticated and European-oriented Russian rulers of the 18th century, who relied upon and disdained & feared, the Cossack). The Turks who had crushed the first efflorescence of Slavic civilization which ran from Kiev to Novgorod were less useful barbarians. But to Turchin this distinction is not particularly important, as civilization-destroying barbarians such as the Arabs after Muhammad and the Mongols can set the stage for the emergence of a new civilizational-system (in the case of the Mongols there was of course the brief world-system of the Pax Mongolica).

So what do the data say?

If these data & the result, repackaged in a statistically significant form are any surprise to you, I recommend you read some books. The importance of the semi-arid steppe, the rise of the mounted cavalry and utility of the reflex bow are plain in the record of civilized societies. Macedonia, the Zhou & Chin, Persia the Turks are just a few examples of peoples who are barbarian or semi-barbarian, and came blazing out of the marchlands to establish a new order over civilized peoples. Naturally the horse looms large here. It is a truism that the average peasant was never more than 10 miles from where they were born. Even if the exact value on this expectation is off, the general thrust is surely correct, in the Malthusian world the average sedentarist was quite sedentary. In contrast the mounted nomads were highly mobile, with whole peoples such as the Avars migrating en masse from Mongolia to the Hungarian plain on the order of a decade! More mobile units of males operated on the scale of years, as was shown by the Turks and the Mongols whose zone of control spanned the margins of the Pacific to the Black Sea. The Mongols were simply the apotheosis of the terror and savagery which mobile calvary could inflict upon settled populations. In the classical period the Scythians and their fellow travelers ranged widely in their depredations, causing havoc in their wake. It is often forgotten that the Huns who were menacing Gaul in the 450s were strafing Syria ~400, sweeping down through the Caucasus from the plains to the north of the Black Sea. Just as the institutions of the traditionalist transient allowed for individuals at the apex of power to control and affect massive change at a distance, so the rise of the horse and bow gave the nomad a combination of mobility and lethality which was only neutralized with the spread of firearms.

Turchin dates the emergence of the nomadic warrior toolkit, and therefore the potential to wreak havoc on civilized polities, to the period between 1000-500 BCE. This sounds about right. Though the records are sparse because literate civilization was thin on the ground, this is the period when the Scythians battered the Assyrian Empire, and the Medes and Persians finally sacked Nineveh. In China the rise of this sort of nomadic lifestyle and warfare seems to have taken a bit longer, with the Xiongnu making permanent the archetype of the raw nomad beyond the frontiers of Han civilization in the 3rd century BCE. But a more critical point is that there is the suggestion that the Axial Age is a deterministic reaction on the part of civilized peoples to the hammer-blow which nomad polities dealt them (in the case of Persia you have the barbarians overwhelm, assimilate and re-order the civilizations of the Near East in totality). To Turchin this is an evolutionary process, as selection operates upon cultures and polities to give rise to adaptations to a new fitness landscape. In this case, the mounted archer, a combination of lethality and mobility which the more primitive modalities of the Bronze Age were helpless. The choice was clear, adapt or be swallowed.

To me it is notable that the Assyrians are reputed to have been particularly savage, while the Persians who were their eventual successors were depicted as relatively benevolent. Some of this is selection bias, as the Persians treated the Jews with less brutality than the Assyrians, and much of our character/narrative history of this place and period come from the Hebrew Bible. But there are other independent records of the nature of Assyrian rule, which seemed to be rather coarse and overly generous in its application of intimidation and cruelty to the conquered. From what I can tell it is as if the Assyrians were Yanomami in chariots, exhibiting a brutal inchoate savagery more the norm in sm
all-scale societies. In contrast, the Persian system of rule were imperial, but often indirect. Local traditions were respected, but it was under the Achaemedids that the Zoroastrian religion began to develop, which later developed into a state-religion for the Persians in the manner that Christianity was for Rome and State Confucianism in China. It is likely that the ethical aspect of Judaism as an ethical monotheism came to the fore during the period of influence under the Persian Zoroastrians, whose primary deity is, Ahura Mazda, is an explicit force for good, not an angry and jealous god. In Empires of the Silk Road Christopher Beckwith suggests that the synchronous efflorescence of religio-philosophical systems across the ecumene during the Axial Age was promoted by the expansion of nomads, their ideas, and the facilitating role of their trade networks. Turchin’s model would seem to suggest that nomads played a role as well, but more as antagonists for civilized polities (and in some cases the progenitors of new polities and empires), who had to increase in scale and develop institutional and ideological adaptations. The two models are not mutually exclusive. In terms of religion there are many cases of barbarians beyond the limes being influenced and innovating. Most famously with Islam, but in both Scandinavia and the Baltic before the conversion to Christianity the extant records and preserved mythologies are clear enough to show an influence and institutional mimicking of the “Roman religion.” In the latter cases the cult of Baldr and the temple at Arkona were dead-ends, as Christianization eliminated those cultural experiments. A more successful universal religious model is the worship of Tengri, the sky god of the Turks and Mongols who was the focus of worship their “shamanistic” phase. The similarities of Tengri to El, one of the ancestors of the Abrahamic God, can not be a coincidence. Sky gods are portable and plainly omnipresent, looking down from on high, in a way that makes them ideal candidates for the God.

It seems that the model presented here is that from savagery comes civilization. This is basically an evolutionary model of human history, an “arms race” of ideas and institutions between polities and civilizations. Sometimes, as in the case of the mounted warrior with bow, the race was triggered by a technological change. The civilizations of the Near East, from Egypt to Mesopotamia, did not change or adapt fast enough. They became fiefs in a Persian world. It can be argued that the Classical Greeks, descendants of the barbaric city-states which sacrificed humans to placate savage gods as they were falling to the Sea Peoples, did formulate appropriate institutional (the cohesive polis and national identity) and technological (the accoutrements and organization of the hoplite phalanx) responses to the threat. In China the two dynasties which set the tone for Imperial China down to 1900, the Zhou and the Chin, emerged out of the borderlands as semi-barbarian polities. The Zhou introduced the peculiar elite Chinese variant of supernaturalism whereby worship centered around the impersonal “Heaven.” The Chin state was organized around an efficient and utilitarian plan which may have been repudiated in name, but not totally in practice, by subsequent dynasties. Reorganized from within by useful barbarians China was ready to meet the nomad threat in the form of the Xiongnu.

In The Human Web: A Bird’s-Eye View of World History John and William McNeill point out that history seems to have a direction in terms of human complexity. Between 1200 and 800 BCE the Greeks “forgot” how to write in totality, so that the Linear B system of the Mycenaeans has no connection to the Phoenician derived alphabet of the later period. As the ages progressed these sorts of “Dark Ages” when the clock was reset, the slate wiped clean, became less and less frequent. The world of settled humanity, dominated by rentier elites, purporting to justify their domination through transcendent truth, covered the face of the earth. Ray Haung, in China: A Macro History, observes that the interregnums between dynasties exhibits a persistent decline in length. Why? One hypothesis is that the “Chinese system,” as embodied in norms and values passed down through its bureaucratic class, became more robust to the “exogenous shocks” of political chaos. Some, such as Robert Wright in Nonzero: The Logic of Human Destiny, would explain this in generally “microeconomic” terms. Game theory applied through the lens of rational actors. Turchin rejects this view insofar as he seems to be suggest that cultural units are being driven to success because of a process of expansion through the elimination of rivals. Again, there is no need to assume these are exclusive alternative choices. Religions such as Christianity and Buddhism clearly spread through individual action and choice (both seem to have been popular first among cosmopolitan urbanites, and counter-elites). But, they also clearly spread by being adopted as ideological cement for polities, the choice made on high at the apex of the political pyramid and extended down by fiat to the population as a whole. This choice may have conferred upon the polity the benefits which accrue from being members of a meta-ethnic civilizational coalition. The benefits to being members of Christendom for the pagan elites to the north of the post-Roman world were clear. James I of England asserted “No bishop, no King,” to indicate the necessary connection between ruler and the priests. And so it was the arrival of Christianity seems curiously concomitant with the emergence of kings on pagan Europe, one God, one ruler. Pagan peoples who remained relatively disinclined toward joining the Christian Commonwealth were liable to be subject to ethnocide, as occurred with the Wends and the Old Prussians.

A focus on elites is evident in Turchin’s model, and I think in some ways that is a critical piece of information. Group level selection on the scale that he focuses upon, large polities and such, may be a feature of only a small slice of a given polity. The elites, or particularly important military groups, such as the Cossacks. History is written by and for the elites. The gods and languages of the elites, their norms, often percolate down to the masses (though not always, my example above about a Latin speaking Transylvanian in Oxford is obviously extremely elitist, but in terms of international politics they are all who counted!). Greg Clark documented high mortality rates for the military nobility of England in Farewell to Alms, as opposed to the relative fertility of the pacific gentry. This shows how high the stakes for intergroup conflict for elites may have been, as opposed to commoners. Benjamin Franklin reputedly stated that “We must all hang together, or assuredly we shall all hang separately.” Kevin Phllips reports in The Cousins’ Wars that much of the Virginia planter aristocracy, including George Washington and Thomas Jefferson, were in severe debt to English financial houses. Their individual material
stakes illustrate how victory or loss in war can have huge negative or positive outcomes to those at the apex of the power pyramid in agricultural societies. This is where I think the civilizational values which unite and engender a degree of cosmopolitanism among elites within the bounds of that broader meta-ethnic framework serve to dampen the savagery of loss and the gluttony of gain. The world of a defeated king may seem to collapse upon him, but if the foe shares the same civilizational presuppositions the institutions and values remain intact, and some honor and status may be retained by the rules of the game which are enforced by third parties (e.g., in medieval Europe, the Church). By contrast, it is no surprise that when the kingdom of the Visigoths fell to the armies of the Arabs and Berbers the elites either fled, or, more likely converted to Islam to preserve their positions. This was ethnocide. A process which was inverted in 1492, as Granada fell to the armies of Castile and Aragon, and the Muslim elites either had to flee to North Africa, or convert to Christianity. In the former case they lost their wealth and power. In the latter case they lost their identity. These are of course the less savage cases, on occasion elites are simply exterminated by the conquerors so that the snake’s head is removed.

If Peter Turchin turns this most recent paper into a book, I have a catchy title in mind: Civilization: a tale of regicide. It has been said that science can not progress until old ideas die with old scientists, and so it may be that civilization can not proceed until old elites die prematurely thanks to the efforts of new ones. The argument is too broad to be sure, but the history of the evolution of power is a biography of the lives of those in power, so this captures much to a first approximation if it is correct.

* English has a strong influence from the Romance languages via French, but it is still recognizably a Germanic language. Similarly, Sikhism emerged as a new world religion or sect which navigated between the disjoint idea spaces which defined Hinduism and Islam, but it is notable that many Hindus claim Sikhism to be a variant of Hinduism, while no Muslims seem inclined to make this assertion.

** The poor were always with the hunter-gatherers as well, because they were all poor, but a wealthy leisured class who could comment on the plight of the poor did not exist so the observation would have been ludicrous.

Related: Historical Dynamics and contingent conditions of religion, Cliodynamics, the rise & fall of empires and asabiya.

• Category: History, Science • Tags: Cliodynamics, History, Peter Turchin 
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Peter Turchin is at it again, Coin hoards speak of population declines in Ancient Rome (ungated version):

In times of violence, people tend to hide their valuables, which are later recovered unless the owners had been killed or driven away. Thus, the temporal distribution of unrecovered coin hoards is an excellent proxy for the intensity of internal warfare. We use this relationship to resolve a long-standing controversy in Roman history. Depending on who was counted in the early Imperial censuses (adult males or the entire citizenry including women and minors), the Roman citizen population of Italy either declined, or more than doubled, during the first century BCE. This period was characterized by a series of civil wars, and historical evidence indicates that high levels of sociopolitical instability are associated with demographic contractions. We fitted a simple model quantifying the effect of instability (proxied by hoard frequency) on population dynamics to the data before 100 BCE. The model predicts declining population after 100 BCE. This suggests that the vigorous growth scenario is highly implausible.

The figure to the left shows the reasoning. A simple model which related population size (dependent) to coin hordes (independent) was fitted before 100 BCE. The correlation between coin hordes to population size and political stability are well attested for many polities. In any case, using the model and projecting outward with the coin hordes known for the early imperial period a theory which suggests that multiplicative increases in census size during the Julio-Claudian age were a function of a shift in the accounting method (instead of simply males, including the whole household) was supported. The high count was already implausible on other grounds (e.g., if true, that means that Italy never attained the early Roman imperial population size until the mid-19th century), but that the model fits so well with the lower projections previously offered by other scholars is very suggestive. Contra extreme subjectivists some models of the past are probably right, and some are probably wrong.

• Category: History, Science • Tags: Cliodynamics, History 
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Quantitative ecologist Peter Turchin’s Secular Cycles is not available for purchase, but you can get a final draft copy online. His previous books, War and Peace and War: The Life Cycles of Imperial Nations & Historical Dynamics: Why States Rise and Fall, prefigure many of the arguments that are fleshed out in Secular Cycles. Turchin’s aim is audacious. The last paragraph of Secular Cycles lays out the vision:

Our concluding thoughts are these. We believe that we showed that it is possible to obtain quantitative empirical estimates for many variables that are needed to test theories of historical dynamics. Furthermore, our models, and the demographic-structural theory in particular, have matured to the point where they can make quantitative and testable predictions. Many of these predictions are supported by the data; others failed, but often in interesting ways that suggest further development of the theory. The historical process is very complex, we have to live with severe data limitations, but nevertheless it is possible to apply the standard scientific approach to the study of history. We are optimistic about the future prospects of History as Science.

If history is any guide Turchin’s optimism is misplaced, and a general theory of historical dynamics will elude us. But the nature of science is that it is exhibits a strong ahistorical* bent and the past can be a weak guide to the future.  If cliodynamics emerges as a respectable field we would expect it to overturn precedent. As someone trained in the former Soviet Union it should be  no surprise I suppose that Turchin would be the one making an attempt to resurrect theoretical history in the English speaking world. An intellectual who was shaped by a Marxist Zeitgeist would be more easily inclined to consider the possibility that history could be formalized so as to produce systems of non-trivial inferential power.

So what makes this latest effort different from the speculations of Arnold Toynbee and Oswald Spengler? First, as a biological scientist Turchin comes the table with a methodological toolkit which is far superior in precision to that available to historians of the early 20th century. From game theory to systems ecology there are many new formal frameworks which can be brought to bear upon human historical dynamics which were not extant in earlier epochs. Secondly, the data sets are far more extensive than they once were due to the prominence of cliometrics, as well as the greater power of traditional fields such as archaeology due to improvements in method. Finally, Turchin’s ambition is constrained to the pre-modern era when Malthusian parameters were ascendant. This is not to say that I do not think that some of his inferences and conjectures have no contemporary salience, but there is no overarching lesson or ideological implication to be derived from his models (in contrast to Marxism).

Nevertheless, I am obviously somewhat intrigued by Turchin’s attempt to add some quant juice to qual questions & observations. I recently read Niall Ferguson’s The House of Rothschild: Volume 1: Money’s Prophets: 1798-1848. Because of the fact that the House of Rothschild was incomprehensibly wealthy at its peak via its involvement in public bond markets there was naturally a whole genre which emerged exposing their power and malice as conspirators at the center of a vast web of influence (see the Age of Metternich). Ferguson does emphasize that the financial interests of the Rothschild’s, public debt, compelled them to attempt to block conflicts between major European powers. But another reality which has nothing to do with the Rothschild’s is that Europe during the early years of the family’s rise was recovering from the Napoleonic Wars, and nations and elites which have experienced sustained and strenuous conflict tend to be wary of future conflicts. In Turchin’s data sets he present evidence that these qualitative cycles are evident in clear generational terms throughout the historical record for regions where we have good records. He also presents a causal motive force behind the explosions of violence which tend to prune military aristocracies. Ultimately one would also want to explore the neurological basis of memory and its effect on how humans make decisions and weight risks, and how long traumatic events can effect behavior, but the gross patterns and the expected period of the recession of violence are also of interest. The point being that despite their wealth even the House of Rothschild might have been accidental players in broader macrosocial dynamics.

* Though operationally it is historical because of the weakness of human cognitive powers.

• Category: History, Science • Tags: Cliodynamics, History, Peter Turchin 
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