Secular Cycles

From P2P Foundation
Jump to navigation Jump to search

= book and concept

Contextual Quote

"Secular means long term. While there are disagreements among economists as to the duration and dynamics of such long-term trends, there is little doubt about their existence. Only in the past decade have quantitative analyses of history progressed to the point that they might be understood in terms of complex dynamic systems models, as suggested by Wallerstein and operationalized by Turchin."

- Zak Stein [1]


“The most common pattern he presents is “an alternation of integrative and disintegrative phases lasting for roughly a century”. His predictions have a special urgency because western societies, and particularly America, are, he suggests, very near the end of that latter disintegrative phase, which makes the likelihood of civil war or potential systemic collapse far more likely. His model attempts to weight certain factors to predict this social meltdown. Key among them are rapidly growing inequality of wealth and wages, an overproduction of potential elites – children of wealthy dynasties, graduates with advanced degrees, frustrated social commentators – and an uncontrolled growth in public debt. In the US, he suggests – and by association the UK – these “factors started to take an ominous turn in the 1970s… The data pointed to the years around 2020 when the confluence of these trends was expected to trigger a spike in political instability. And here we are.”

- Peter Turchin, paraphrased by Tim Adams [2]

The Book

* Book: Secular Cycles. By Peter Turchin and Sergey A. Nefedov. Princeton University Press, 2009


Contextual Quote

"This is the basic thesis of Secular Cycles. Pre-industrial history operates on two cycles: first, a three-hundred year cycle of the rise-and-fall of civilizations. And second, a 40-60 year cycle of violent disorder that only becomes relevant during the lowest parts of the first cycle."

- Scott Alexander [3]


1. Mark Koyama:

"The leading modern day cyclical theorist is undoubtedly Peter Turchin. For my money Turchin’s best book is Secular Cycles (co-authored with Sergey A. Nefedov). Their innovation (building on an argument made by my GMU colleague Jack Goldstone in his 1991 book Revolution and Rebellion in the Early Modern World) is to take the Malthusian model of economic cycles and add to it a model of elite competition.

Tuchin and Nefedov show that periods of demographic expansion are often associated with the growth of elite incomes and inequality (as population growth causes rents to rise and wages to fall). More elites competing over the surplus, however, puts fiscal pressure on the surplus-extraction machine that we call the state. Elite overproduction thus brings about a political crisis. Secular Cycles applied this model to medieval and early modern England and France, Russia and ancient Rome. Turchin’s most recent book applies it to the United States." (

2. From the publisher:

"Many historical processes exhibit recurrent patterns of change. Century-long periods of population expansion come before long periods of stagnation and decline; the dynamics of prices mirror population oscillations; and states go through strong expansionist phases followed by periods of state failure, endemic sociopolitical instability, and territorial loss. Peter Turchin and Sergey Nefedov explore the dynamics and causal connections between such demographic, economic, and political variables in agrarian societies and offer detailed explanations for these long-term oscillations--what the authors call secular cycles.

Secular Cycles elaborates and expands upon the demographic-structural theory first advanced by Jack Goldstone, which provides an explanation of long-term oscillations. This book tests that theory's specific and quantitative predictions by tracing the dynamics of population numbers, prices and real wages, elite numbers and incomes, state finances, and sociopolitical instability. Turchin and Nefedov study societies in England, France, and Russia during the medieval and early modern periods, and look back at the Roman Republic and Empire. Incorporating theoretical and quantitative history, the authors examine a specific model of historical change and, more generally, investigate the utility of the dynamical systems approach in historical applications.

An indispensable and groundbreaking resource for a wide variety of social scientists, Secular Cycles will interest practitioners of economic history, historical sociology, complexity studies, and demography."

3. Andrey Korotayev:

"We believe that one of the most important recent findings in the study of thelong-term dynamic social processes was the discovery of the political-demo-graphic cycles as a basic feature of complex agrarian systems' dynamics. The presence of political-demographic cycles in the pre-modern history ofEurope and China has been known for quite a long time and already in the 1980s more or less developed mathematical mod-els of demographic cycles started to be produced (first of all for Chinese "dynastic cycles") (Usher 1989). At the moment we have a very considerable number of such models. Recently the most important contributions to the development of the mathematical models of demographic cycles have been made by Sergey Nefedov, Peter Turchin and Sergey Malkov. What is important is that on the basis of their models Nefedov, Turchin and Malkov have managed to demonstrate that demographic cycles were a basic feature of complex agrarian systems (and nota specifically Chinese, or European phenomenon). Nefedov (2004) starts with the population model developed by Raymond Pearl (1926) and described by the logistic equation suggested by Verhulst(Verhulst 1838).

Starting from this basis Nefedov developed his mathematical model of pre-industrial sociodemographic cycles. The basic logic of these models looks as follows: after the population reaches the ceiling of the carrying capacity of land its growth rate declines toward zero values and the system experiences significant stress with decline of the living standards of common population, increasing severity of famines, growing rebellions etc. most complex agrarian systems had considerable reserves for stability, however, within 50–150 years these reserves usually got exhausted and the system experienced a demographic collapse, when increasingly severe famines, epidemics, increasing internal warfare and other disasters led to a considerable de-cline of population. As a result of this collapse, free resources became available, per capita production and consumption considerably increased, the population growth resumed and a new demographic cycle started. It has turned out to be possible to model these dynamics mathematically in a rather effective way. It seems necessary to stress that a new generation of models has moved far beyond this basic logic. For example, models now describe effects of class structure and elite overproduction; the new models predict dynamics of a great number of variables like food prices, urbanization levels, growth of wealth differentiation and so on. These models have achieved a rather close fit with observed data.

Using such indirect data, as well as his system of qualitative indicators of various phases of demographic cycles Nefedov has managed to detect more than 40 demographic cycles in the history of various ancient and medieval societies of Eurasia and North Africa, thus demonstrating that the demographic cycles are not specific for Chinese and European history only, but should be regarded as a general feature of complex agrarian system dynamics."



1. Donald J. Zeigler:

"The shadows of Thomas Malthus and David Ricardo loom large over Turchin and Nefedov's search for history's motive force. Neo-Malthusian demographers will feel vindicated by the theory of secular cycles. Classical economists will relish eight case studies demonstiating Ricardo's law of diminishing returns. Marxists, however, will avert their gaze from a theory that is predicated on a symbiotic relationship between elites and peasants, and a competitive relationship between elites and the state. Secular cycles seem to explain more variation over time in power relationships than does class struggle. Geographers and ecologists will recognize the important role of the biophysical environment in influencing the course of history. Malthus predicted catastrophe when the size of a population reached the carrying capacity of that population's territory. The theory of secular cycles incorporates Malthus's "positive checks" on population grouch by identifying them as ti-iggers of the disintegrative phase. When carrying capacity is exceeded, the stagflation phase of a secular cycle begins. Then, when a famine or epidemic stiikes, the disintegrative phase begins. This pattem is demonsti-ated consistently in England, France, Russia, and ancient Rome. To identify secular cycles in their regional contexts, Turchin and Nefedov mine deeply the annals of history. Out of their thorough literature review, they have pulled the quantitative data needed to test their theory. They have presented it, whenever possible, in the form of tables and graphs, of which there are well over a hundred. As one might expect, the availability of data is greatest for England and least for ancient Rome, yet in each case study the authors present a persuasive argument that the model of secular cycles holds for agrarian societies over time."


2. Reviewed for EH.NET by Harry Kitsikopoulos, Department of Economics, New York University.

"This book is an audacious and ambitious attempt to promote the viewpoint that historical progression runs according to certain regular patterns. In its effort to prove this hypothesis it lays out a number of predictions testing them against empirical time series for four countries during different epochs: Rome (350BC-285AD), France (1150-1660), England (1150-1730) and Russia (1460-1922). The argument is constructed on the basis of measuring (sometimes speculating) four fundamental variables: actual population figures contrasted against ?ideal? population levels, i.e., upper limits defined by agricultural productivity; social structure measured by numbers and consumption levels of elites as well as annual budgets of typical peasant households; the power of the state measured by its fiscal health; and socio-political instability reflected in relevant events (e.g., uprisings, rebellions, civil wars) or, used as a proxy, in coin hoards.

According to Turchin (University of Connecticut) and Nefedov (Institute of History and Archaeology of the Russian Academy of Sciences, Ural Branch) each secular cycle lasts for several centuries and unfolds through the following phases: 1) An expansion phase characterized by relatively stable prices and modest wage declines (if any). 2) As population density tends to approach the limits imposed by the productive capacity of agriculture, we enter a stagnation or stagflation phase. A typical Malthusian scenario develops with an increase in the price of land and its products and a cheapening of labor. The ranks of the elite grow both due to biological reproduction and upward mobility and, simultaneously, its members get accustomed to higher levels of consumption. Gradually, however, we encounter a state of elite overproduction, so to speak, which leads to a relative (but not absolute, as in the case of commoners) decline of their living standards. Intensified oppression of peasants ensues as well as increased competition among members of the elite and between the elite and the state whose growth rate of revenues slows down. 3) A general crisis unfolds either abruptly or gradually which, in theory, can be addressed by raising productivity through technological innovations but more often than not it leads to military expansion into new territories and is resolved through the visitation of pandemics, extreme episodes of famine, or state collapse followed by intense civil war (or a combination of such events). The crisis lasts for a prolonged period. 4) It is followed by a depression phase during which resources per capita increase but fail to lead to population recovery due to the continuation of civil wars. This phase can be prolonged, particularly if the state continues to be dysfunctional, or it can lead to the beginning of a new cycle if the ranks of the elite are sufficiently pruned.

Secular cycles can acquire a periodic character but in societies with complex characteristics the dynamic may incorporate elements of sensitive dependence and non-linear feedback loops which lead to outcomes envisioned by chaos theory. The latter scenario is particularly plausible in the event of exogenous disturbances relating to geopolitical factors and the ecological environment as well as through the reaction of individual actors which can be portrayed ?as a stochastic process, a kind of Brownian motion that also results in erratic, unpredictable changes in the macrosocial trajectory? (p. 22).

The book relies on data drawn from the secondary literature but the authors? handling is not always as refined as it could be nor are they always accurate. For instance, in reconstructing the annual budgets of peasant households in pre-plague England, the authors neglect to include spending on the purchase of consumption goods not produced by the household or investment goods; the typical rent per acre was less than 1s and seigneurial dues at over half of the value of annual output exaggerate typical peasant obligations; gross yields of wheat were not at 10 and 8 bushels per acre before and after the Black Death but 10.5 and 11.9 bushels respectively (based on extensive demesnial records analyzed by Campbell), and when all grains are taken into account yields remained stationary between the two periods. In referring to seigneurial dues of French peasants during the same period, the authors take into account only the terrage and the tithe in reconstructing peasant budgets. But additional dues included the cens (a fixed cash payment), the taille (demanded both by lords and the state), and various payments stemming from the judicial and administrative authority of lords, conventionally known as seigneurie banale. Some of these payments may have been of nominal value, others irregularly imposed, but they amounted collectively to a significant draining of peasant resources; the authors are aware of their existence, since they mention them in other contexts, but for whatever reason they do not take them into account when reconstructing peasant budgets. Including such information is important in defining the acreage necessary to ensure subsistence and estimate the proportion of the population which fell below such thresholds.

Such issues may be deemed minor quibbles given the impressive breadth of evidence considered by the authors. But I found a little more problematic the lack of reference to publications presenting viewpoints inconsistent with the typology outlined in this book. Campbell (English Seigniorial Agriculture, 2000), for instance, argues that grain output per capita remained stable during the thirteenth century (corresponding to the stagflation phase in Turchin?s and Nefedov?s typology), hence challenging the notion of a growing immiseration of the peasantry."



James Quilligan:

"The first chapter of Secular Cycles describes the general historical cycle of a civilization lifting itself out subsistence into greater social complexity and prosperity, then undergoing bitter class inequality, completely misunderstanding the need to manage economics and society by measuring resources according to population, and then undergoing a massive crisis when it is no longer able to support its complex support systems. In this cycle, society ascends through a long period where there appears to be endless resources in which population, growth and demand will increase forever; then descends through a long era when human demand crosses the sustainability threshold of its ecosystems, and energy and resource depletion drastically limit population growth. After the first chapter, the rest of the book provides historical case studies of civilizations tracing this rise and fall."

The book made me more aware of several things. No major civilization has EVER practiced carrying capacity as a basis for political and economic self-governance; carrying capacity has only succeeded in small communities. Of course, we know this from the modern Ostrom view of the commons; but Ostrom never put her finger on the pulse of carrying capacity as the *self-organizing principle between a species and its environment*. Nor has the commons movement recognized the importance of an *empirical way of measuring the metabolism of society* through the cooperative activities of people using resources to meet their biological needs. In other words, Ostrom and the commons movement have yet to define the dynamic equilibrium which they seek as the balance between two opposing forces - population and resources - which continually counteract each other. Instead, the commons movement is more focused on counteracting the Market and the State than on measuring the replenishment of renewable and non-renewable resources and managing them to sustain their yield. In short, the commons movement does not seem to be producing alternative indicators for the productive and provisioning which can be used to guide policy.

Secular Cycles made me realize that the commons, as Ostrom viewed it and as others are now envisioning it, is too informal and small-scale to work in a way that establishes empirical targets that will bring down exponential growth to arithmetic growth levels; and thus organizing society according to the dynamic equilibrium between population and the availability of food, water and energy. Instead, what we get in the commons movement is a general opposition to quantitative analysis because it reminds people too much of the metrics of unbridled capitalism. My point is that if we don't know how to develop evidence-based policy for a soft landing toward a reasonable level of subsistence -- and I've seen very little of this in the commons movement -- then I don't know how we expect to create a long-term system for meeting human needs through sustainable yields. I would hope that the commons movement begins to create the basis for a viable new society by actually focusing on the optimum rate at which a resource can be harvested or used without damaging its ability to replenish itself. That would be something."


The two drivers of the secular cycle, according to Peter Turchin


Tim Adams, paraphrasing Peter Turchin:

The driving forces of negative trends in all societies are broadly twin-engined, he argues. One is the presence of a perverse “wealth pump” which, after years of more equitable wealth distribution, takes from the poor and gives to the rich. In 1983 there were 66,000 households worth at least $10m in the US. By 2019, that number had increased in terms adjusted for inflation to 693,000. But while those numbers of the super-rich increased so the income and wealth of the typical American declined.

This trend has coincided with the second major destabilising factor, what Turchin defines as the “overproduction of elites”, in which an ever greater number of people compete over a finite and increasingly corrupt structure of privilege and power. He offers four factions between which this competition for status is perennially played out: militaristic, financial, bureaucratic and ideological. As societies decline the balanced equation of these factions falls wildly out of balance. The forces of capital seek to destroy the voices of ideology – one “elite” arms itself against another in a series of real wars or culture wars – and things fall apart. “



From: Chapter 1, Introduction: The Theoretical Background

From the reading highlights by Michel Bauwens.

1.1 Development of Ideas about Demographic Cycles

Peter Turchin et al.:

"The modern science of population dynamics begins with the publication in 1798 of An Essay on the Principleof Population by Thomas Robert Malthus. Malthus pointed out that when population increases beyond the means of subsistence, food prices increase, real wages decline, and per capita consumption, especially among the poorer strata, drops. Economic distress, often accompanied by famine, plague, and war, leads to lower reproduction and higher mortality rates, resulting in a slower population growth (or even decline) that, in turn, allows the subsistence means to “catch up.” The restraints on reproduction are loosened and population growth resumes, leading eventually to another subsistence crisis. Thus, the conflict between the population’s natural tendency to increase and the limitations imposed by the availability of food results in the tendency of population numbers to oscillate.

By the 1930s the empirical material had accumulated to the point where it became very clear that European prices had gone through a number of very slow swings between 1200 and 1900 (Simiand 1932, Griziotti-Kretschmann 1935, Abel 1980).

The most striking pattern to emerge was the wavelike movement of grain prices (expressed in terms of grams of silver). There were three waves or “secular trends” (Abel 1980:1):

1. An upward movement during the thirteenth century and early fourteenth century, followed by a decline in the late Middle Ages

2. Another upsurge in the sixteenth century, followed by a decline or apparent equilibrium (depending on the country) during the seventeenth century

3. A third increase during the eighteenth century, followed by irregular fluctuations during the nineteenth century, eventually converging to an early twentieth-century minimum.

By contrast, population moved more or less in the same direction as the food prices and in an inverse ratio to wages (Abel 1980:292–93). Abel concluded that the Malthusian-Ricardian theory provided a better explanation of the data than the monetarist theory.

Furthermore, the Malthusian-Ricardian theory predicted that an increasing population would result in a specific progression of effects. Rents would rise first, with grain prices lagging behind rents, the price of industrial goods lagging behind grain prices, and workers’ wages bringing up the rear. The evidence showed that this was precisely what happened (until the whole system was dramatically changed in the nineteenth century).

Speaking in 1973, he (LeRoy Ladurie) said, “it is in the economy, in social relations and, even more fundamentally, in biological facts, rather than in the class struggle, that we must seek the motive force of history” (quoted in Hilton 1985:4).

Such a radical Malthusian position could not but provoke a reaction from scholars working within the Marxist tradition.

In an influential book first published in 1946, Maurice Dobb argued that the cause of the crisis was the inefficiency of feudalism as a system of production, coupled with the growing needs of the ruling class for revenue (Dobb 1963:42–47).

One interesting contribution to the theory was Paul Sweezy’s proposition that the growing extravagance of the feudal ruling class was a result of the rapid expansion of trade from the eleventh century onward, which brought an ever-increasing variety of goods within its reach (Sweezy et al. 1976:38–39).

Brenner did not deny that the Malthusian model had a certain compelling logic (Brenner 1985a:14). However, its attempt to explain long-term trends in economic growth and income distribution was doomed from the start because it ignored (“abstracted away”) the social structure, the most important part of which was the surplus-extraction relationship between the direct producers and the ruling class (Brenner 1985a:10–11).

One deficiency of the Malthusian theory, according to Brenner, was the empirical observation that different societies within Europe, starting from similar demographic and economic conditions obtaining after the Black Death, subsequently followed divergent trajectories. For example, serfdom completely disappeared from certain Western European countries (England, France) while making a strong comeback in Central Europe (Poland, Prussia).

On the other hand, the extreme version of the Marxist thesis (perhaps found in the purest form in Sweezy), which assigns class relations the alldetermining role in the economic development of medieval and early modern Europe, would also fail to account for empirical facts.

What we need is a synthetic theory that encompasses both demographic mechanisms (with the associated economic consequences) and power relations (surplusextraction mechanisms). In the dynamical systems framework, it does not make sense to speak of one or the other as “the primary factor.” The two factors interact dynamically, each affecting and being affected by the other.

There is, however, a significant movement among historical sociologists “to bring the state back in” (Skocpol 1979). States are not simply created and manipulated by dominant classes; they are agents in their own right, and they compete with the elites in appropriating resources from the economy.

Historians have long recognized that there were recurrent waves of state breakdown and political crises in European history: the “calamitous” fourteenth century (Tuchman 1978), the “iron century” of 1550–1660 (Kamen 1971), and the “age of revolutions” of 1789–1849 (Hobsbawm 1962). Each of these periods was preceded by a period of sustained and substantial population growth. In a pathbreaking book, Jack Goldstone (1991) argued that there is a causal connection between population growth and state breakdown.

For this reason, Goldstone refers to his theory as demographic-structural: demographic because the underlying driving force is population growth, structural because it is not the demographic trend itself that directly causes the state crisis but its impact on economic, political, and social structures (Goldstone 1991:xxvi). We discuss this theory in more detail in the next section, but here we should mention that the verdict on Goldstone’s work among historical sociologists has been highly positive (see, e.g., Collins 1993, Wickham-Crowley 1997, Li 2002).

To summarize, it is becoming increasingly clear to specialists from very diverse fields—demographers and historical economists, social historians, and political scientists—that European societies were subjected to recurrent long-term oscillations during the second millennium CE (Braudel 1988, Cameron 1989, Fischer 1996). Furthermore, the concept of oscillations in economic, social, and political dynamics was not discovered by the Europeans. Plato, Aristotle, and Han Fei-Tzu connected overpopulation to land scarcity, insufficient food supply, poverty, starvation, and peasant rebellions (Parsons 2005).

In this book we examine the hypothesis that secular cycles—demographicsocial-political oscillations of very long period (centuries long)—are the rule rather than the exception in large agrarian states and empires." (

1.2 A Synthetic Theory of Secular Cycles

"It is clear that neither purely demographic nor purely class conflict explanations of secular cycles work very well when confronted with data. On the other hand, a synthetic theory that incorporates both of these (and some other) processes may provide us with a viable hypothesis that can be tested with data. The idea is that secular cycles can only be understood as a result of the interaction between several interlinked variables—economic (including demography), social structure (particularly, how the elites interact with the producing population and the state), and political (state stability or collapse).

The key variable is the population density in relation to the carrying capacity of the local region.

Carrying capacity is defined as the population density that the resources of the habitat can support in the long term (for an excellent discussion of human carrying capacity from an ecologist’s point of view, see Cohen 1995).

Carrying capacity thus is an upper ceiling on population growth. From the point of view of economics, this limit arises because labor inputs into production suffer from diminishing marginal returns. It is clear that the carrying capacity of a specific region is strongly affected by its physiographic features (the availability of land suitable for agriculture, water supply, soil characteristics, length of the growing season, and so on). It is also affected by year-to-year fluctuations in the temperature and the amount of rainfall, as well as by gradual changes in the climate. In other words, carrying capacity is a variable that changes in both space and time. Finally, and most important, carrying capacity is affected both by the existing level of agricultural technology and by how this technology is employed. As Ester Boserup (1966, 1981) famously argued, population growth can have a positive effect on economic innovation.

Thus, adverse effects of population growth on the standard of living can provide strong inducements for the adoption of new means of production.

A society that approaches the current limits of population growth can invest in clearing forests, draining swamps, irrigation, and flood control. All these measures will result in an increase in the carrying capacity. However, at some point there are no more forests to cut or swamps to drain.

As population density approaches the carrying capacity, a number of related changes affect the society. There are shortages of land and food, and an oversupply of labor.

Economic distress leads to lower reproduction and higher mortality rates, resulting in a slower population growth.

Other factors not taken into account by a purely demographic model would preclude the emergence of a stable equilibrium.

Population growth in excess of the productivity gains of the land has a fundamental effect on society’s structures. The typical changes accompanying population growth are high rents and land prices, increasing fragmentation of peasant holdings or high numbers of landless peasants.

However, as long as the elites are united and the state maintains control of the military, such popular uprisings have small chance of success.

This fundamental point was recently reiterated by Jack Goldstone:

- It is a profound and repeated finding that the mere facts of poverty and inequality or even increases in these conditions, do not lead to political or ethnic violence (Gurr 1980, Goldstone 1998, 2002b). In order for popular discontent or distress to create large-scale conflicts, there must be some elite leadership to mobilize popular groups and to create linkages between them. There must also be some vulnerability of the state in the form of internal divisions and economic or political reverses. Otherwise, popular discontent is unvoiced, and popular opposition is simply suppressed.

Surplus is the difference between the total production and what is needed for subsistence.

The amount of resources needed for subsistence increases linearly with population, while the total product grows slower than linearly as a result of the law of diminishing returns (figure 1.1a). As a result, at a certain critical population density, which we have defined as the carrying capacity, the two curves intersect.

Thus, when population increases from a low level, initially the amount of surplus increases (more peasants means more surplus). At some intermediate density, however, the surplus reaches a maximum: this is where the effects of diminishing returns on labor inputs into agriculture begin to be felt.

One important dynamic is that the elites are usually able to extract a larger amount of surplus during the late stages of population growth.

During the late stages of population growth, when commoners are already suffering from economic difficulties, the elites are enjoying a golden age. Both the reproduction of the existing elites and the recruitment of new elites from commoners will be fastest when the amount of extractable surplus is greatest.

The peak of elite numbers often lags behind that of the general population.

Such a happy state of events (for the elites) cannot continue for long. First, expansion of elite numbers means that the amount of resources per elite capita begins to decline. This process would occur even if the total amount of surplus stayed constant. But, second, as general population grows closer to the carrying capacity, surplus production gradually declines.

Modern studies of consumption level expectations suggest that people generally aim at matching (and if possible exceeding) the consumption levels of their parents (Easterlin 1980, 1996). Thus, what is important is not the absolute level of consumption but the level in relation to the previous generation.

Should their level of consumption decrease in relation to the pre­vious generation’s, the elites would be expected to react vehemently to this development.

The deteriorating economic conditions of the elites during the late stagflation phase of the secular cycle do not affect all aristocrats equally.

Poor aristocratic lineages tend to get poorer because they attempt to maintain their elite status on an inadequate economic basis.

A wealthier lineage, by contrast, can maintain the level of consumption necessary for preserving its elite status and have some resources left over to acquire land from its impoverished neighbors. As a result, the poor get poorer while the rich get richer.

The same dynamic operates on peasants during the stagflation phase. During periods of economic hardship, poor peasants must sell land or starve.

As a result, at the same time that the majority are sliding into absolute misery, a small percentage of thrifty, hardworking, or simply lucky peasants are able to concentrate increasing amounts of land in their hands.

During the stagflation phase, thus, economic inequality increases within each social stratum—peasants, minor and middle-rank nobility, and the magnates. Growing inequality creates pressure for social mobility, both upward and downward. Increased social mobility generates friction and destabilizes society. The growing gap between the poor and rich also creates a breeding ground for mass movements espousing radical ideologies of social justice and economic redistribution.

The declining incomes of the majority of aristocrats have two important consequences: intensifying oppression of the peasants by the elites and increasing intraelite competition for scarce resources.

If successful, elites may not only deprive the commoners of the surplus but may also cut into the subsistence resource, resulting in a negative growth rate for the commoner population.

It appears that this stage in the secular cycle may be what is known among dynamicists as a “bifurcation point,” a point at which the system may follow one of several alternative trajectories. A classic example of such divergent trajectories is the disappearance of serfdom in post-medieval England and France and, during the same period, the rise of new serfdom in Prussia and Poland.

This thesis is illustrated by the recent study of Stuart Borsch (2005), which compared the effects of the Black Death in England and Egypt. In post–Black Death England wages rose, rents and grain prices dropped, unemployment decreased, and per capita incomes grew.

The consequences of depopulation in Egypt were profoundly different. Wages dropped, land rents and grain prices rose, and unemployment levels increased. No economic recovery was anywhere in sight by 1500.

Borsch argues convincingly that the persistent stagnation of post–Black Death Egypt is explained by structural factors.

English peasants could resist elites by hiding in the hills and forests, of which there was an abundance in a depopulated England.

By contrast, Egypt’s narrow strip of arable land between uninhabitable desert left no room for evasive tactics. After the Black Death, Mamluks were able to use their tremendous coercive power to maintain the preplague level of resource extraction from a greatly diminished rural population. Extremely high levels of exploitation of individual peasants precluded any demographic revival. The system, thus, was caught in a “vicious equilibrium” .

The second consequence of plunging elite incomes is increased intraelite competition. The forms that this competition takes will depend (again) on the structural characteristics of the society. Probably the most important factor is the capability of the state to suppress overt violence. Here we consider the forms of intraelite competition in the presence of the state when internal order is maintained. The situation after the state collapses or is seriously weakened is considered later.

One recourse for elites facing declining incomes from agriculture was to seek employment with the state or church bureaucracy.

Impoverished elites could also improve their incomes by attaching themselves to the retinues of powerful magnates.

Limits on available land, civil and ecclesiastical offices, and royal patronage lead to increasingly polarized factional battles between patron-client groups for available spoils.

Because there are not enough resources for everybody, certain segments of elites, or groups aspiring to elite status, inevitably end up as the losers. We refer to them as the counterelites, or dissident elites. Usually, the counterelites do not constitute a true sociological group.

Social trends resulting from demographic growth—declining surplus production, popular immiseration, and intraelite competition—have a profound impact on the ability of the state to maintain internal order.

After a certain lag time, the negative effects of population expansion begin to affect the elites, who become riven by increasing rivalry and factionalism. Another consequence of rapid population growth is the expansion of youth cohorts. This segment of the population is particularly impacted by lack of employment opportunities.

Finally, growing economic inequality, elite competition, and popular discontent fuel ideological conflicts. For example, in early modern Europe, dissident elites and dissatisfied artisans were widely recruited into heterodox religious movements. As all these trends intensify, the end result is state bankruptcy and consequent loss of the military control.

On the ideological level, the feeling of social pessimism is pervasive and the legitimacy of the state authority is at its lowest point. The society approaches a condition that may appropriately be called “Hobbesian”.

In the previous sections we focused on the manifold effects of population growth on various structures of the society, including a bundle of variables that we call sociopolitical instability. Here we consider the feedback effect: how does instability affect population dynamics? We can envision two general (and, actually, interrelated) ways: by affecting demographic rates and by affecting the productive ability of the society.

International trade expands in the precrisis period (stagflation phase) and then gradually declines after the society has descended into anarchy. Thus, the rise of widespread epidemics—pandemics—is most probable during the late stagflation phase. In fact, the arrival of a pandemic is one of the most frequent triggers of the demographicstructural collapse.

Finally, political instability causes lower reproduction rates, because personal consumption plummets as a result of lowered production capacity.

In addition, during times of uncertainty people choose to marry later and to have fewer children.

The second and perhaps even more important effect of sociopolitical instability is on the productive capacity of the society (the carrying capacity). Vigorous states often invest in increasing the agricultural productivity by constructing irrigation canals and roads, implementing flood control measures, clearing land from forests, organizing the colonization of underpopulated regions, and so on. The end result of these measures is mainly an increase in cultivated area, although some measures also increase the productivity of land.

The other general mechanism is that the state offers protection. In a stateless society, people can live only in natural strongholds or in places that can be made defensible, such as walled cities.

After the collapse of Rome, settlements were moved to hilltops.

In other words, lack of effective suppression of internal violence by the state imposes a “landscape of fear,” in which a large proportion of agriculturally suitable lands is abandoned because they are too far from a place of security. By contrast, the strong state protects the productive population from external and internal (banditry, civil war) threats, and thus allows the whole cultivable area to be put into production.

Sociopolitical instability affects elite numbers in a fashion that is similar to its effect on commoners, although the relative importance of specific mechanisms can be quite different. Thus, the elites may be little affected by subsistence crises. They also tend to escape more lightly the effect of epidemics.

On the other hand, by virtue of their more active participation in politics, the elites ran a much higher risk of violent death. The death toll in some conflicts was extraordinary. For example, Dupaˆquier et al. (1988a:342) quote an estimate by Philippe Contamine that around 40 percent of the French elite may have been slaughtered in the Battle of Poitiers (1356), and the same proportion at Agincourt (1415). During the Wars of Religion in the late sixteenth century, 20,000 Huguenots were killed in just one day, the St. Bartholomew’s Day massacre (Kamen 1971:39).

Loss of life or elite status could also result from state purges. For example, the first Ming emperor purged 100,000 Chinese officials (Tignor et al.

2002:62). Sulla’s proscriptions eliminated a third of the Roman ruling class, senators, and another third was eliminated by proscriptions following Caesar’s death (see chapter 6).

A much less spectacular but perhaps ultimately more important process reducing the elite numbers is downward mobility. The plunge in elite incomes, which begins in the precrisis period and is greatly exacerbated by the general population decline, affects most strongly the status of the lowest noble stratum. A specific example is given by Christopher Dyer for late medieval England.

In summary, a number of social mechanisms exist by which elite surpluses can be reduced:

(1) deaths resulting from civil war,

(2) deliberate purges of elites by new rulers,

(3) limitations imposed on heir production (celibacy, primogeniture),

(4) downward social mobility, voluntary or forced by the state,

(5) increased material resources resulting from conquest or improvements in agricultural productivity, and

(6) the development of a new political order that directs a greater share of resources to the elites. Several such mechanisms are usually operating in combination; the specific mix depends on cultural peculiarities of societies and historical accidents.

Because the three main factors driving the rise of sociopolitical instability are general overpopulation, elite overproduction, and state insolvency, all these trends must be reversed before the disintegrative phase can end. S\

The last stages of the secular cycle are particularly rife with bifurcation points.

The problem of overpopulation is usually “dealt with” during the crisis phase. One of the most common proximate mechanisms of population collapse is disease, but not all population declines are accomplished by catastrophic epidemics. Prolonged periods of civil war can also cause drastic drops in population levels.

An alternative to population collapse is an increase in the carrying capacity.

The carrying capacity can increase as a result of technological progress. This is probably what happened in early modern England.

The carrying capacity may also increase as a result of the conquest of new underpopulated territories. An example is the conquest of the Kazan and Astrakhan khanates by Muscovy in the sixteenth century.

The manner in which elite overproduction is abated depends very much on the military strength of the aristocracy. A nonmilitarized ruling class can be expropriated en masse by warlords, such as rebel generals or even peasant bandits. A rapid and comprehensive elite turnover results in a relatively short period of sociopolitical instability that follows state collapse.

A rapid elite turnover can also result when there is a ready external source of potential elites, as was the case in the Maghreb described by Ibn Khaldun.

For a new secular cycle to get going, the pressures of the general population on resources and of the elites on commoners must be substantially reduced from their precrisis levels.

It is entirely possible for the civil warfare to gradually die out but a centralizing, integrative trend nevertheless failing to take hold. In this case, the area in question may persist indefinitely (or until it is conquered from the outside) in a fragmented state as a collection of small-scale polities.

Oscillatory dynamics do not go through truly discrete phases with clearly marked breakpoints, but for convenience in talking about each secular cycle, we need to divide it in phases.

Most broadly the cycle can be divided into two opposite trends. In the literature these are sometimes called the positive “A phase” and the nega­tive “B phase,” but we prefer the more descriptive terms integrative and disintegrative trends. Politically the integrative phase is characterized by a centralizing tendency, unified elites, and a strong state that maintains order and internal stability. Internal cohesion often results in the vigorous prosecution of external wars of conquest, which may result in the extension of the state territory (assuming there are weaker neighbors at whose expense the state can expand). The disintegrative phase, by contrast, is characterized by a decentralizing tendency, divided elites, a weak state, and internal instability and political disorder that periodically flare up in civil war.

More frequently it is the external enemies that profit from the internal weakness of the state and society, resulting in an increased frequency of raids, invasions, and loss of territory.

The population tends to increase during the integrative phase and decline or stagnate during the disintegrative one.

During the disintegrative phase, by contrast, population losses due to epidemics, famines, or wars are not made up by sustained population growth.

It is useful to further divide the broad integrative and disintegrative periods into subphases. Population growth is particularly vigorous during the first, expansion phase of the integrative trend. This is a time of relatively stable prices and modest real wage declines (if any). However, as the population density begins to approach the limits set by the carrying capacity, price increases or wage declines accelerate—this is the “stagnation” or “compression” or even more descriptively stagflation (stagnation plus inflation) phase. Although the majority of commoners experience increasing economic difficulties during the stagflation phase, the elites enjoy a golden age, and their numbers and appetites continue to expand.

The stagflation phase (and the overall integrative trend) is succeeded by a general crisis. Whereas expansion grades smoothly into stagnation, the transition between stagflation and crisis is often (but not always) abrupt.

The crisis grades smoothly into a depression phase, characterized by endemic civil warfare. The population may grow during the intervals between intense civil wars, but such increases typically do not last and are followed by declines (although not as a catastrophic as those typical of the crisis phase). The depression phase ends when the ranks of elites are pruned by internal conflict to the point where the disintegrative trend can reverse itself, and a new secular cycle begins. Alternatively, if no functioning state can get going, then the depression phase grades smoothly into an intercycle of indeterminate length.

We wish to emphasize again that the classificatory scheme we propose is an ideal type.

1.3 Variations and Extensions

"The theory should, in principle, be applicable to any agrarian society.

one of the most important characteristics of oscillatory dynamics, (is) the average period of a cycle. Secular cycles are not periodic in the strictly mathematical sense, in which each succeeding cycle repeats exactly the preceding one.

Macrosocial dynamics of agrarian states cannot be strictly periodic. There are at least three reasons for that. First, nonlinear dynamic feedbacks can in theory generate not only strictly periodic (cyclic in the mathematical sense) dynamics but also aperiodic chaos.

Social systems are complex and feedback loops are nonlinear, so the possibility of chaos cannot be discounted (Turchin 2003b).

Second, the dynamics of agrarian states are affected not only by their internal workings but also by exogenous forces, such as changes in their geopolitical and ecological environment. Exogenous factors, unlike endogenous ones, are those that are not part of feedback loops.

Finally, individuals possess free will and can act in unpredictable ways. In principle, even the act of a single person, if it takes place in the right place at the right time, may be able to influence the trajectory of a whole society.

For all these reasons, we do not expect a strict periodicity in secular dynamics. Instead, dynamics should have an average period, a characteristic time scale, with a substantial degree of variation around this average.

Thus, the typical length of the expansion phase is primarily determined by

(1) the per capita rate of population increase and

(2) the population density in relation to carrying capacity at the beginning of the cycle.

For example, if population grows at the rate of 1 percent per year, it takes seventy years for it to double.

Abnormally long expansion phases result from successful territorial conquest, especially when it is accompanied by colonization of conquered territories, which serves to reduce population pressure in the metropole.

The length of the crisis phase is much less predictable, because while there is a definite biological limit on how fast a human population can grow, there is no comparable limit on how fast it can decline.

The characteristic lengths of the stagflation and depression phases depend more on the state and, particularly, on elite dynamics than on what the general population does.

Models tailored to the characteristics of Western European societies (largely monogamous elites enjoying a preponderance of military power over their internal and external enemies) suggest that the typical periods of secular cycles in these societies should lie in the range of two to three centuries.

Ibn Khaldun Cycles

The Maghrebin states differ from Western European states in two important respects:

(1) these Islamic societies permitted polygyny and

(2) there was a ready source of militarily powerful counterelites nearby.

Because aristocratic males could afford to support several wives and concubines, the rate of elite population growth in Islamic societies was (and is today) much greater than that for elites in Christian societies.

The fact remains that the biological reproduction rate of Islamic elites was several times higher than that of Christian elites.

The second factor is the location of Maghrebin societies in the rather thin strip of arable land squeezed between the Mediterranean Sea and the desert.

As soon as a Maghrebin society experienced state collapse, it became extremely vulnerable to conquest from the desert.

When demographic-structural models are modified to account for these two factors they exhibit very different dynamics (Turchin 2003b). High reproductive rate of the elites means that they increase much faster than the general population.

As a result, the integrative trend of the secular cycle is over much faster than in the standard model.

As a result of a shortened integrative trend and a missing depression phase, models predict a much faster secular cycle for Maghrebin-type societies, on the order of one century, rather than the two to three centuries for Western European states. This prediction is in agreement with the observation of Ibn Khaldun that the dynastic cycle in the Maghreb extends, on average, over four generations (a generation time in humans is typically twenty to thirty years).

Islamic societies that controlled the elite growth rates in one way or another are predicted to exhibit slower cycles, with periods similar to those observed in Western Europe. For example, in the Ottoman Empire the sultans had access to an essentially unlimited supply of wives and concubines. However, when the old ruler died, only one son was allowed to replace him; all others were killed. Furthermore, top levels of bureaucracy and army leadership were recruited not from native elites but by means of devshirme. In other words, the state, not biology, controlled the size of the high-ranking elite stratum. Only lower-rank landed elites were permitted to increase “biologically,” and, being not very wealthy, they could not afford too many wives.

The Mamluk polity in medieval Egypt: Its ruling class was recruited entirely from the slave markets. Children of Mamluks could not be Mamluks, and thus automatically dropped out of the ruling class.

The Fractal Nature of Historical Dynamics

Different social processes operate at a variety of temporal scales.

Different questions require approaching an analysis at different time scales.

Turning now to population dynamics, we observe that population changes also occur on a variety of scales: monthly (female menstrual periods), yearly (subsistence and epidemic cycles), generational (somewhere between two and three decades), and secular (one, two, or three centuries, according to the theory of secular cycles).

If we want to understand how secular cycles unfold, on the other hand, we certainly do not need to know how mortality fluctuates on a weekly or monthly time scale.

The appropriate time step is one human generation and we need to average over smaller-scale fluctuations. We also need to do something about very long trends driven by social evolution. This requires some kind of removal of millennial trends.

By smoothing within-decade fluctuations and removing millennial trends, we retain two temporal scales of interest. The longer one is the average period of the secular cycle—this is what needs to be explained. The shorter one is the human generation time.

Generation Cycles

The main hypothesis of this book is that demographic-structural processes are very important in historical dynamics, but we would be the last to argue that they are the only thing that goes on.

One particular process that is not part of the demographic-structural theory but has to be taken into account when studying secular cycles is the “fathers-and-sons” dynamic.

The empirical observation is that disintegrative trends are not periods of continuous civil war; in fact, there are periods when sociopolitical instability is particularly high, interspersed with periods of relative pacification.

To illustrate this dynamic, during the disintegrative trend of late medieval France (“the Hundred Years of Hostility”), good reigns alternated with bad ones. The reign of John II (1350–64) was a period of social dissolution and state collapse, while that of his son Charles V (1364–80) was a time of national consolidation and territorial reconquest.

This is a general dynamical pattern of alternation between very turbulent and relatively peaceful spells that is observed again and again during the secular disintegrative phases.

A possible explanation of such swings in the collective mood lies in the social psychology.

Episodes of internal warfare often develop in ways similar to epidemics or forest fires. At the beginning of the conflict, each act of violence triggers chains of revenge and counter-revenge. With time, participants lose all restraint, atrocities become common, and conflict escalates in an accelerating, explosive fashion. After the initial explosion, however, violence drags on and on, sometimes for decades. Sooner or later most people begin to yearn for the return of stability and an end to fighting. The most psychopathic and violent leaders are killed off or lose their supporters. Violence, like an epidemic or a forest fire, “burns out.”

The peaceful period lasts for a human generation—between twenty and thirty years.

As a result, periods of intense conflict tend to recur with a period of roughly two generations (forty to sixty years).

These swings in the social mood may be termed “generation cycles” because they involve alternating generations that are either prone to conflict or not.

Another example of such social mood dynamics has been noted, for example, by Arthur M. Schlesinger Jr. (1986). Furthermore, generation cycles keep cropping up in other contexts. The birth rates in twentieth century America oscillated with a period of approximately fifty years (Easterlin 1980, Macunovich 2002). Many economic indicators oscillate with roughly the same period, a phenomenon known as the Kondratieff Cycle (Kondratieff 1984). The Kondratieff and Schlesinger cycles may be related to each other; at least, they often seem to oscillate in synchrony (Berry 1991, Alexander 2002). The Kondratieff wave may also be correlated with the war cycle (Goldstein 1988). Our understanding of Easterlin, Schlesinger, and Kondratieff cycles is very deficient, and many researchers doubt the reality of these dynamics.

Exogenous Forces

Here is a more systematic discussion of the important external forces:

• Geopolitical environment. Strong and aggressive neighbors may take advantage of internal weakness of the state during the disintegrative phase of the cycle.

• Disease environment. Some pandemics, such as the Black Death, originate in distant parts of Eurasia and then spread over the whole continent. ... A dense population is highly vulnerable to a pandemic, and a severe drop in population numbers could result in a longer and deeper cycle of disintegration.

• Global climate. Its effects are similar to those of social evolution, inasmuch as long-term fluctuations in temperature and rainfall affect the productivity of crops and the carrying capacity.

• In addition to the recurrent exogenous factors discussed above, we often need to take into account singular events, or historical accidents that may have significant long-term consequences. A good example of such a singular event is the discovery and colonization of the Americas by Western Europeans.

1.4 Empirical Approaches

The main goal of this book is to determine how well the predictions of the demographic-structural theory map onto empirically observed patterns in the studied historical societies. The synthetic theory, described in section 1.2, has four fundamental variables: population numbers (in relation to the carrying capacity), social structure (specifically, the numbers and consumption levels of the elites), state strength (typically measured by its fiscal health), and sociopolitical instability. These variables are fundamental in the sense that it is the reciprocal interactions among them that generate secular cycles.

The demographic-structural theory is about dynamics, that is, change with time, and it is impossible to measure change with a single time slice."

Summary of the phases predicted by the model (from Table 1.1. pp 33-34)

  • Integrative Secular Trends (1) Expansion phase (growth) 2) Stagflation phase (compression)
  • Disintegrative Secular Trends: 3) Crisis phase (state breakdown) 4) Depression/intercycle


The Roman Secular Cycle

Scott Alexander:

"Eight chapters are case studies of eight different historical periods and how they followed the secular cycle model.

For example, Chapter 7 is on the Roman Empire. It starts with Augustus in 27 BC. The Roman Republic has just undergone a hundred years of civil war, from the Gracchi to Marius to Sulla to Pompey to Caesar to Antony. All of this decreased its population by 30% from its second-century peak. That means things are set to get a lot better very quickly.

The expansion phase of the Empire lasted from Augustus (27 BC) to Nerva (96 AD), followed by a stagflation phase from Nerva to Antonius Pius (165 AD). Throughout both phases, the population grew – from about 40 million in Augustus’ day to 65 million in Antonius’. Wheat prices stayed stable until Nerva, then doubled from the beginning of the second century to its end. Legionary pay followed the inverse pattern, staying stable until Nerva and then decreasing by a third before 200. The finances of the state were the same – pretty good until the late second century (despite occasional crazy people becoming Emperor and spending the entire treasury building statues of themselves), but cratering during the time of Marcus Aurelius and Commodus (who debased the denarius down to only 2 g silver).

Throughout expansion and stagflation, the Empire was relatively peaceful (the “Pax Romana”). Sure, occasionally a crazy person would become Emperor and they would have to kill him. There was even one small civil war which lasted all of a year (69 AD). But in general, these were isolated incidents.

Throughout the expansion phase, upward mobility was high and income inequality relatively low. T&N measure this as how many consuls (the highest position in the Roman governmental hierarchy) had fathers who were also consuls. This decreased throughout the first century – from 46% to 18% – then started creeping back up during the stagflation phase to reach 32% at the end of the second century.

The crisis phase began in 165 AD at the peak of Rome’s population and wealth. The Antonine Plague ravaged the Empire, killing up to 30% of the population. Fifteen years later, the century-long dominance of the Good Emperors ended, and Commodus took the throne. Then he was murdered and Pertinax took the throne. Then he was murdered and Didius Julianus took the throne. Then he was murdered and Septimius Severus took the throne.

Now we are well into the disintegrative trend, and the shorter 40-60 year cycle comes into play. Septimus Severius founds a dynasty that lasts 41 years, until Septimius Alexander (the cousin of the grandson of Septimius Severus’ sister-in-law; it’s complicated) was assassinated by his own soldiers in Germany. This begins the Crisis Of The Third Century, a time of constant civil war, mass depopulation, and economic collapse. The Five Good Emperors of the second century ruled 84 years between them (average of 17 years per emperor). The fifty year Crisis included 27 emperors, for an average of less than 2 years per emperor.

Finally, in 284, Emperor Diocletian ended the civil wars, re-established centralized authority, and essentially refounded the Roman Empire – a nice round 310 years after Augustus did the same. T&N mark this as the end of a secular cycle and the beginning of a new integrative trend.

T&N are able to tell this story. But they don’t just tell the story. They are able to cite various statistics to back themselves up. The Roman population statistics. The price of wheat and other foodstuffs. The average wages for laborers. They especially like coin hoards – the amount of buried treasure from a given period discovered by treasure-hunters – because they argue you only bury your money during times of instability, so this forms a semi-objective way of measuring how unstable things are."


The Topic


Andrey Korotayev:

"We would like to discuss in some detail three approaches to modeling of demographic cycles: Turchin's (2003) models, another by Chu and Lee (1994),and finally, the model of Nefedov (1999e, 2002a; 2004).

The "demographic-fiscal" model developed by Turchin

The "demographic-fiscal" model developed by Turchin connects population dynamics, state resources and internal warfare. In this model the elites controlling the state are not assumed to be selfish. It is rather assumed "that the state has a positive effect on population dynamics; specifically, it increases k[the carrying capacity]" (Turchin 2003: 122). "There are many mechanisms by which the state can increase the carrying capacity… The strong state protects the productive population from external and internal (banditry, civil war) threats, and thus allows the whole cultivable area to be put into production… The second general mechanism is that states often invest in increasing agricultural productivity by constructing irrigation canals and roads, by implementing flood control measures, by clearing land from forests, etc. Again, the end result of these measures is an increase in the number of people that can be gainfully employed growing food, i.e., the carrying capacity". Thus the depletion of state resources and state break-down are assumed to be leading to the decline of the carrying capacity and, thus, demographic collapse. As in all the other demographic cycle models the per capita rate of surplus production is assumed to be a declining function of population numbers, whereas the state expenditures are assumed to be proportional to population size. Within this model "the rate of change of S [state re-sources] is determined by the balance of two opposing forces: revenues and expenditures. When N [population] is low, increasing it results in greater revenues(more workers means more taxes). The growth in state expenditures lags be-hind the revenues, and the state's surplus accumulates. As N increases, however, the growth in revenues ceases, and actually begins to decline. This is a result of diminishing returns on agricultural labor. However, the expenditures continue to mount. At population density N = N , the revenues and expenditures become (briefly) balanced. Unfortunately, population growth continues toward the carrying capacity, k , and the gap between the state's expenditures and revenues rapidly becomes catastrophic. As a result, the state quickly spends any re-sources that have been accumulated during better times. When S becomes zero, the state is unable to pay the army, the bureaucrats, and maintain infrastructure: the state collapses", which leads to a radical decline of the carrying capacity of land and demographic collapse (Turchin 2003: 123). Turchin has also developed a number of elegant models of population dynamics, where the peasant-elite interaction plays the role of the main mechanism of state breakdown. When the population size becomes large, food sup- plies are exhausted and the elite multiplies out of control – then state collapse is observed, followed by a significant decrease in the number of peasants. A large number of elite cannot be supported by a shrunken population, so eventually the elite decreases, and the cycle of growth starts over. A resulting feature isthat we do not observe the population to climb up to its carrying capacity and saturate at a certain level before a collapse . Also, the elite behaves in a strictly selfish man-ner; it does not play a role in food redistribution (e.g., to provide food for starving people during time of famine); this mechanism, however, is important whenm odeling Chinese demographic cycles."

The model of Chu and Lee

"The interesting model of Chu and Lee combines elements of mathematicalmodeling and statistical analysis/best fit approach. The main idea is very attrac-tive. The population consists of rulers, peasants and bandits (rulers being equat-ed with soldiers, drafted every year at a constant rate). The population has someintrinsic growth rate, that is, the rate at which it increases given unlimited re-sources. As the density increases, the resources get scarce, and the growth ratedecreases (this is an effect of overpopulation). At the same time, there is a fluxof people from peasants to bandits and vice versa. Each person faces a choice of either working in the field or "defecting" and getting his food by means of force. The soldiers are supported by taxation and they fight the bandits. The rational choice is based on evaluating the "utility function" of peasants and bandits and it depends on external circumstances such as the degree to which agricultural resources are damaged by warfare. The utility function is a combination of the food share received and the probability of survival. As the density of the population grows, it becomes more and more likely that people choose to become bandits and fight for their food instead of grow-ing it. This leads to the reduction in population numbers and the cycle startsover. Chu and Lee did not specify their model to the extent where it can be implemented directly. Instead, they used it as a tool to improve the fitting of real historical data. Information on warfare and winter temperatures was included in the form of exogenous variables, and the frequency of peasant rebellions was modeled based on the expected fraction of the rebels, calculated by the model. This gave an excellent fit to the existing data."


"Nefedov, who incorporated stochastic effects of year-to-year food yields on the population dynamics, has taken another approach. He noticed that as the population reaches the carrying capacity of land, and food storages become depleted, then random effects of good and bad years can play a significant role in the dynamics. As food becomes very scarce because of, say, a bad winter, peo- ple tend to sell their land and leave for cities, or join bands of rebels. In idealized conditions, that is, given a perfectly constant food yield, no cycle is expected. However, a bad harvest triggers a mechanism of collapse with a significant reduction in population number. Nefedov's models have several interesting components. For example, because of the increasing numbers of people leaving the land as population density increases, we expect to see an intense growth of cities, which is confirmed by historical observations. What seems to be missing from Nefedov's models is the direct role of rebellion and internal warfare on the cycle behavior. If only economic factors are taken into account, then there seems to be no inertia in the dynamics, and each demographic catastrophe is followed immediately by a new rise. As we shall see below, this plainly contradicts historical data where "intercycle" periods of variable (but always significant) length are observed." (

Agrarian Secular Cycles vs Industrial Secular Cycles

Agrarian Cycles

Michael A. Alexander:

"Inequality cycles associated with secular cycles have been identified in pre-industrial societies (Turchin and Nefedov 2009:36, 82). A secular cycle is a “demographic-social-political oscillation of very long period (centuries long)” (Turchin and Nefedov 2009:5). They arise from population cycles (Korotayev et al. 2006). In an agrarian economy, demand for labor is ultimately limited by the maximum amount of arable land, while labor supply is proportional to population. As the fraction of arable land under cultivation approaches one, rising population means a rising labor supply relative to an increasingly fixed labor demand which leads to lower real wages and rising economic inequality. Thus, population and inequality trends are correlated, either can serve to define a secular cycle. Several models that describe how population/economic inequality affects elite number, state strength and sociopolitical instability in agrarian societies have been proposed (Turchin 2003:123; Turchin and Korotayev 2006:122; Turchin 2013:251). Some of these have been shown to give a good fit of historical data (Alexander 2016). The empirical and theoretical methods developed for agrarian societies do not apply to industrial societies."


Industrial Cycles

Michael A. Alexander:

"Turchin (2016) has recently tried to apply the secular cycle concept to America. Although there are no population cycles, there are still empirical cycles in economic inequality that may be used to define secular cycles. Turchin uses measures of economic, physical, and social well-being: relative wage (wage/GDP per capita), male stature, life expectancy, and age at first marriage as proxies for inequality. A composite of these measures defines the American secular cycles in terms of inequality (Turchin 2016: 73,fig. 3.7).The composite trends show two secular cycles: the first over 1780–1930 the second from1930 to the present(Turchin 2016: 73).He develops a modified demographic explanation for inequality in which demand for labor is assumed to be independent of labor supply, allowing separate relations for each to be developed and their ratio used to explain real wage trends. Changes in labor supply, chiefly from changes in immigration, depress real wages, causing rising inequality. Given this, he employs percent foreign born as another proxy for inequality."


More information

  • intro the thematic: Korotayev, A., A. Malkov, and D. Khaltourina. Introduction to Social Macrodynamics:Secular Cycles and Millennial Trends. Moscow: KomKniga/URSS, 2006. P. 37