Richard Melson

December 2005

Turchin Empires:  book

War and Peace and War: The Life Cycles of Imperial Nations

by Peter Turchin



Editorial Reviews:

From Publishers Weekly

Ranging freely from the founding of Rome to 17th-century North America, this provocative essay in "cliodynamics" ("the study of processes that change with time") searches for scientific regularities that underlie history. Ecologist and mathematician Turchin grounds his theory of preindustrial empires in the Arabic concept of asabiya, meaning a society's capacity for collective action. Empires germinate, he contends, along "meta-ethnic frontiers" where conflict between starkly alien peoples—Roman farmers vs. Celtic tribesmen in the fifth and sixth centuries B.C., say—fosters the social solidarity and discipline that empire building requires. Success, he continues, leads inexorably to decline: stability and prosperity produce overpopulation and a Malthusian crisis in which the struggle for scarce resources undermines social solidarity and triggers imperial collapse. Turchin's straining for scientific exactitude occasionally overreaches, yielding a proliferation of historical "cycles" of fuzzy periodicity, riddled with fudge factors like "mathematical chaos." Still, Turchin's focus on social cooperation as the key to history is a fruitful one, and his ideas generate many fascinating discussions of a wide variety of historical episodes, rendered in lucid, vigorous prose. The result, much in the vein of Jared Diamond's Guns, Germs and Steel, is a stimulating revisionist overview of world history. Maps. (Oct.)


"So Peace Brings Warre and Warre Brings Peace"

The empire has unified all the civilizations at last. After generations of battles, the last enemies have been defeated. Citizens of the empire can, it seems, look forward to permanent peace and prosperity. But a maverick mathematician named Hari Seldon has disturbing news. His new science of psychohistory, built from equations that integrate the actions of myriads of individuals, predicts large-scale social trends. When the equations are run forward, they foretell the decay and eventual collapse of the central power, rebellions by regional barons and rogue generals, and finally a bitter civil war that will transform the capital of the empire from a teeming metropolis of hundreds of billions into a ghost town with a few thousand survivors eking out a miserable living among the ruins. The decline and fall of the empire over the ensuing centuries unfolds precisely as the humble mathematician said it would.

This scenario from the Foundation trilogy of Isaac Asimov occurs in the future on the planet Trantor, the capital of a mighty galactic empire. In Asimov's fantasy, human history can be understood and predicted in the same way that physicists understand and predict the trajectories of planets, or biologists the expression of the gene. The key to the prediction of human societies is psychohistory, the "branch of mathematics which deals with the reactions of human conglomerates to fixed social and economic stimuli." The ability of psychohistorians to make accurate forecasts, however, is not absolute. Psychohistory cannot accurately predict actions of a single individual. Furthermore, the knowledge of the prediction must be withheld from the people whose collective behavior is predicted. As Hari Seldon explains, "By knowledge, your freedom of action would be expanded and the number of additional variables introduced would become greater than our psychology could handle." Prediction of human societies might also prove impossible for another reason: Complex dynamic systems are inherently unpredictable in the long run because of "the butterfly effect." Small causes might produce large effects. For example, a butterfly fluttering its wings in Australia might cause a hurricane in the Atlantic. Or, as a children's rhyme has it, "For want of a nail... the kingdom was lost." Asimov, however, could not know about the butterfly effect because he wrote the trilogy in the early 1950s, before the discovery of mathematical chaos.

Asimov's trilogy captured the imagination of millions of readers, among them quite a few scientists and historians. However, his vision flies in the face of the view held by most professional historians and scientists, a view generally accepted in our culture. For centuries, philosophers have mulled over the prospects of a scientific study of history. Despite some dissenting voices, the consensus has been that scientific study of human societies is impossible because they differ too much from physical and biological systems. They are too complex. They consist not of simple identical particles, such as atoms and molecules, but of human individuals, each unique, endowed with free will, and capable of purposeful action. The verdict has been that any sort of scientific history must remain science fiction rather than a real science. And some might believe that this is for the best.

A science of history sounds cold and hard—wouldn't it destroy our enjoyment of the wonderfully rich tapestry of the past? On a darker side, might not such a science enable some shadowy cabal to manipulate societies to a nefarious purpose? But have we ceased to enjoy the blue sky of a brilliant summer day, or the play of colors in a glorious sunset? After all, the physicists, beginning with Newton and ending with Einstein, worked out exactly how colors of the sky result from the interaction of sunlight with the atmosphere. As to the nefarious uses of a science of history, it is true that any knowledge can be turned to good or bad ends. But Asimov's notion of a Second Foundation—a group of psychohistorians pulling the strings from some secret center—was always the least credible part of his vision.

War and Peace and War addresses the question raised by Asimov (and many other people before him, including Marx and Tolstoy): Is a science of history possible? Can we design a theory for the collapse of mighty empires that would be no worse than, say, our understanding of why earthquakes happen? Seismologists have made great strides in understanding earthquakes. They can even make some limited predictions as to which areas of the earth are likely to be hit next by an earthquake. However, forecasting the precise timing and magnitude of an earthquake eludes them. Can a science of history, similarly, explain why states crumble, and perhaps predict which societies are in the danger of collapse?

This book focuses on empires. Why did some—initially small and insignificant—nations go on to build mighty empires, whereas other nations failed to do so? And why do the successful empire builders invariably, given enough time, lose their empires? Can we understand how imperial powers rise and why they fall?

An empire is a large, multiethnic territorial state with a complex power structure. The key variable is the size. When large enough, states invariably encompass ethnically diverse people; this makes them into multiethnic states. And given the difficulties of communication in pre-industrial times, large states had to come up with a variety of ad hoc ways to bind far-flung territories to the center. One of the typical expedients was to incorporate smaller neighbors as self-contained units, imposing tribute on them and taking over their foreign relations, but otherwise leaving their internal functioning alone. Such a process of piecemeal accumulation usually leads to complicated chains of command and the coexistence of heterogeneous territories within one state.

Empires are not the only objects of study for a science of history. Historians such as Arnold Toynbee wrote volumes on the rise and fall of whole civilizations. Others have been fascinated with the spread of world religions, evolution of art styles, progress in science and technology, or economic and demographic changes. All of these subjects are worthy. However, it is impossible to encompass them all in one book. The rise and fall of empires is a fine place to start.

Unlike such entities as civilizations, territorial states are easier to define and demarcate from each other, as well as from other comparable units (city states, tribal confederations, and so on). Historians continue to argue about how to distinguish one civilization from another. Different authorities place Achaemenid Persia as part of the Syriac, Iranian, or Mesopotamian civilization. In contrast to this multitude of contending notions, were you to consult any historical atlas, you would find the boundaries of the Achaemenid Empire drawn in pretty much the same places.

Although the doings of empires dominate the historical records, we should not conclude that they are the norm in human history. Prior to the nineteenth century most (and until six thousand years ago all) of the habitable space on Earth was divided among small-scale, stateless societies, not empires. Historical empires themselves, as often as not, were in the state of decline or even disintegration. A large stable empire, internally at peace, is a rarity in history. Looked at from this point of view, the most fundamental question requiring an explanation is not why empires decline and collapse, but how they manage to get going in the first place. How are empires possible?

The stories of empire are irresistible. Imagine the feelings of an eighteenth-century Englishman, on his world tour, standing among the fairly well-preserved 2,000-year-old ruins of ancient Rome (before the modern metropolis engulfed them). Today one can have a similar experience in Chichen Itza in Mexico. (Be sure to get there early in the day before the tourist buses arrive.) Who were the people who built these magnificent temples and pyramids? Why aren't they around anymore? From Shelley's "Ozymandias" to Darth Vader, stories of empires fascinate us.

As a road map to what follows, here is a very terse outline of the central theoretical argument of the book.

Many historical processes are dynamic—empires rise and fall, populations and economies boom and bust, world religions spread or wither. The field of historical dynamics investigates such dynamic processes in history. Most research has been done on agrarian societies, those in which the majority (and often more than 90 percent) of people are involved in producing food.

The theoretical framework I have been developing for several years focuses not on human individuals, but on social groups through time. Ultimately, the behavior of a group is determined by the actions of its individual members. However, social groups are not simple collections of identical particles, readily described by statistical physics; they have complex internal structures.

One important aspect of group structure is that different people have access to differing amounts of power and wealth. A small number of members of an agrarian society (typically around 1 or 2 percent) concentrates in its hands most of the power and wealth; this group consists of the elites or aristocracy. Commoners make up the rest of the population.

Another important aspect of social structure is ethnicity. Ethnicity is the group use of any aspect of culture to create internal cohesion and differentiation from other groups. An imaginary boundary separates the members of the ethnic group from the rest of humanity. For example, Greeks drew a boundary between themselves and barbarians, non-Greek speakers. The ethnic boundary can use a variety of symbolic markers—language and dialect, religion and ritualistic behaviors, race, clothing, behavioral mannerisms, hairstyles, ornaments, and tattoos. The important thing is not which markers are used, but the distinction between in-group and out-group members, between "us" and "them."

People usually have multiple ethnic identities nested within each other. An inhabitant of Dallas can be simultaneously a Texan, an American, and a participant in Western civilization. The broadest groupings of people that unite many nations are usually called civilizations, but I prefer to call such entities metaethnic communities (from the Greek meta, "beyond," and ethnos, "ethnic group" or "nation"). My definition includes not only the usual civilizations—the Western, Islamic, and Sinic—but also such broad cultural groupings as the Celts and Turco-Mongolian steppe nomads. Typically, cultural difference is greatest between people belonging to different metaethnic communities; sometimes this gap is so extreme that people deny the very humanity of those who are on the other side of the metaethnic fault line.

Historical dynamics can be understood as a result of competition and conflict between groups, some of which dominate others. Domination, however, is made possible only because groups are integrated at the micro level by cooperation among their members. Within-group cooperation is the basis of inter-group conflict, including its extreme versions such as war and even genocide.

Different groups have different degrees of cooperation among their members, and therefore different degrees of cohesiveness and solidarity. Following the fourteenth-century Arab thinker Ibn Khaldun, I call this property of groups asabiya. Asabiya refers to the capacity of a social group for concerted collective action. Asabiya is a dynamic quantity; it can increase or decrease with time. Like many theoretical constructs, such as force in Newtonian physics, the capacity for collective action cannot be observed directly, but it can be measured from observable consequences.

Each empire has at its core an imperial nation. (Some empires had more than one imperial nation for a time, but this structure appears to be unstable.) The ability of an empire to expand territory and to defend itself against external and internal enemies is determined largely by the characteristics of its imperial nation, especially its asabiya. Because only groups possessing high levels of asabiya can construct large empires, the question is how do they gain it, and why do they eventually lose it?

Groups with high asabiya arise on metaethnic frontiers. A meta-ethnic frontier is an area where an imperial boundary coincides with a fault line between two metaethnic communities. metaethnic frontiers are places where between-group competition is very intense. Expansionist empires exert enormous military pressure on the peoples beyond their boundaries. However, the frontier populations are also attracted to the imperial wealth, which they attempt to obtain by trading or raiding. Both the external threat and the prospect of gain are powerful integrative forces that nurture asabiya. In the pressure cooker of a metaethnic frontier, poorly integrated groups crumble and disappear, whereas groups based on strong cooperation thrive and expand.

To match the power of the old empire, a frontier group with high asabiya—an incipient imperial nation—needs to expand by incorporating other groups. On a metaethnic frontier, integration of ethnically similar groups on the same side of the fault line is made easier by the presence of a very different "other"—the metaethnic community on the other side. The huge cultural gap across the frontier dwarfs the relatively minor differences between ethnic groups on the same side. Empirical evidence shows that large aggressive empires do not arise in areas where political boundaries separate culturally similar peoples.

My main argument, therefore, is that people originating on fault-line frontiers become characterized by cooperation and a high capacity for collective action, which in turn enables them to build large and powerful territorial states. I develop this argument in Part I and illustrate it with examples of Russia and America (Chapters 1 and 2), the Germans and Arabs on the Roman frontier (Chapters 3 and 4), the origins of Rome (Chapter 6), and the rise of the European great powers (Chapter 7).

The critical assumption in my argument is that cooperation provides the basis for imperial power. This assumption is at odds with the fundamental postulates of the dominant theories in social and biological sciences: the rational choice in economics and the selfish gene in evolutionary biology. However, recent developments in the nascent fields of experimental economics and multilevel selection show that the standard model, based on the self-interest hypothesis, is deeply flawed. It cannot explain the puzzle of human ultrasociality—our ability to combine into cooperating groups consisting of millions of unrelated individuals. Moreover, it is refuted by behavioral experiments.

Two key adaptations enabled the evolution of ultrasociality. The first one was the moralist strategy: cooperate when enough members in the group are also cooperating and punish those who do not cooperate. A band that had enough moralists to tip its collective behavior to the cooperative equilibrium outcompeted, or even exterminated, bands that failed to cooperate. The second adaptation, the human ability to use symbolic markers to define cooperating groups, allowed evolution of sociality to break through the limits of face-to-face interaction. The scale of human societies increased in a series of leaps, from the village and clan to the tribe and tribal confederation, and then to the state, empire, and civilization. Chapter 5 examines this new science of cooperation.

Whereas Part I is devoted to imperiogenesis—the factors that explain the rise of empires—Part II switches focus to imperiopathosis—why empires decline.

The very stability and internal peace that strong empires impose contain within them the seeds of future chaos. Stability and internal peace bring prosperity, and prosperity causes population increase. Demographic growth leads to overpopulation, overpopulation causes lower wages, higher land rents, and falling per capita incomes for the commoners. At first, low wages and high rents bring unparalleled wealth to the upper classes, but as their numbers and appetites grow, they also begin to suffer from falling incomes. Declining standards of life breed discontent and strife. The elites turn to the state for employment and additional income, and drive up its expenditures at the same time that the tax revenues decline because of the growing misery of the population. When the state's finances collapse, it loses the control of the army and police. Freed from all restraints, strife among the elites escalates into civil war, while the discontent among the poor explodes into popular rebellions.

The collapse of order brings in its wake the four horsemen of the apocalypse—famine, war, pestilence, and death. Population declines and wages increase, while rents decrease. As incomes of commoners recover, the fortunes of the upper classes hit bottom. Economic distress of the elites and lack of effective government feed the continuing internecine wars. However, civil wars thin the ranks of the elites. Some die in factional fighting, others succumb to feuds with neighbors, and many simply stop trying to maintain their aristocratic status and quietly slip into the ranks of commoners. Intra-elite competition subsides, allowing the restoration of order. Stability and internal peace bring prosperity, and another cycle begins. As a sixteenth-century commentator put it, "So peace brings warre and warre brings peace."

The typical period of a complete cycle, which consists of a benign integrative phase and the troubled disintegrative phase, is around two or three centuries. I call these majestic oscillations in demographic, economic, and social structures of agrarian societies secular cycles. The demographic-structural theory that explains secular cycles is developed in Chapters 8 and 9, in which it is illustrated with French and English history during the medieval and early modern times.

The phase of a secular cycle affects a trend in economic and social inequality, which in turn affects the dynamics of asabiya. Incipient imperial nations are relatively egalitarian. Great differences in wealth among group members undermine cooperation, and such groups succumb to rivals with higher levels of asabiya. In addition, metaethnic frontiers tend to be underpopulated, so there is enough land (the main form of wealth in agrarian societies) for all who are willing to work it. The success of an imperial nation at territorial expansion, however, results in the movement of frontiers far away from its core, thus removing an important force holding up the growth of inequality. Imposition of peace results in population growth, and overpopulation brings with it the impoverishment of peasant masses. As the poor grow poorer, the rich grow richer—this process is called the Matthew principle. The growing disparity between the rich and the poor puts the social consensus under strain. At the same time, the gap in the distribution of wealth grows not only between the aristocrats and commoners, but also within each social group. Intra-elite competition for diminishing resources results in faction and undermines national solidarity. During the disintegrative phase of the secular cycle, regional and sectarian identities acquire greater saliency than the national or empire-wide identity, and the asabiya of the imperial nation is corroded. Thus, the Matthew principle plays an important role in imperiopathosis, the decline of empires.

Decline of asabiya is not linearly uniform. During the integrative phases of secular cycles when inequality is moderate, intra-elite competition and conflict between elites and commoners subside; the empire-wide identity regains its strength, for a time. As discussed further in Chapter 10, it takes the cumulative effect of several disintegrative phases to reduce asabiya of a great imperial nation to the point where it cannot hold together its empire.

A life cycle of a typical imperial nation extends over the course of two, three, or even four secular cycles. Every time the empire enters a disintegrative secular phase, the asabiya of its core nation is significantly degraded. Thus, several secular cycles are nested within the great cycle of the rise and decline of asabiya. However, disintegrative phases are also not uniformly grim. A civil war begins like a forest fire or an epidemic—violence leads to more violence in an escalating spiral of murder and revenge. Eventually, however, people become fed up with constant fighting, and a civil war "burns out." Both the survivors of the civil war and their children, who had direct experience of conflict, are reluctant to allow the hostilities to escalate again. They are, thus, "immunized" against internecine violence. The next generation, the grandchildren of the civil warriors who did not experience its horrors at first hand, is not immunized. If the social conditions leading to conflict (the main one being elite overproduction) are still operational, the grandchildren will fight another civil war. As a result, civil war tends to recur during the disintegrative phase with a period of 40 to 60 years. I call such dynamics the fathers-and-sons cycles. The fathers-and-sons cycles are nested within secular cycles, which in turn are nested within asabiya cycles. I illustrate these "wheels within wheels within wheels" dynamics with the decline of the Roman Empire in Chapter 11.

In this book, therefore, I discuss three central concepts: the meta-ethnic frontier theory, which explains asabiya cycles; the demographic-structural theory, which explains secular cycles; and the social-psychology theory, which explains the fathers-and-sons cycles. These theories comprise part of a new science of historical dynamics, or as I prefer to call it cliodynamics (from Clio, "muse of history," and dynamics, "the study of processes that change with time").

Cliodynamics borrows heavily from two disciplines in the natural sciences. The focus on groups rather than individuals is akin to the approach of statistical mechanics, which integrates over motions of myriads of particles to predict such properties of the ensemble as temperature or pressure. However, the study and prediction of human groups is a much more challenging task because people vary (among other things, for example, in power and ethnic identity). Humans also possess free will. I discuss the implications of these complicating factors for the study of human societies in Chapter 12.

Cliodynamics owes an even greater debt to the discipline of nonlinear dynamics. Human societies and states can be modeled as dynamic systems, consisting of parts that interact with each other. Furthermore, states are part of an international system, which adds another level of complexity. The key concept here is dynamic feedback. A change in the state of one component of the system has an effect on another, but the change in the second might in turn affect—feedback on—the first. When a dynamic system contains within it such circular nonlinear feedback, it becomes highly susceptible to oscillation. Stated succinctly, "So peace brings warre and warre brings peace."

Cycles exhibited by historical societies and states, however, are not the same as highly periodic, repeatable phenomena in physics, such as planetary motions or pendulum oscillation. Social systems are much more complex. It is well known from the science of nonlinear dynamics that two or more perfectly cyclic behaviors superimposed on each other may combine to produce noncyclic dynamics—in other words, chaos. Interactions between the asabiya, secular, and fathers-and-sons cycles can lead to such complex, chaotic dynamics. In a chaotic system, a small action of one of its elements—a human being exercising his or her free will—can have huge consequences. External sources also play a role—for example, variations in climate leading to crop failure, random mutations giving rise to new frightful epidemics, and cataclysmic volcano eruptions. The dynamics of real human societies cannot be accurately predicted far in the future because of the nature of chaotic behavior, free will, and natural disasters. Hari Seldon was wrong.

Although prediction far in the future is impossible, given what we know about societies and nonlinear dynamics, it does not mean that improved understanding of how societies function is purely academic knowledge. An understanding of the processes that bring a society to the brink of civil war might suggest policies to avert such a war. Such social engineering, of course, is still far in the future. Our understanding of the dynamics of even agrarian societies is far from perfect, and highly complex modern industrial and postindustrial societies present an even greater challenge for sociologists. Many processes that played a determining role in the functioning of agrarian societies are of much less or even no importance in modern societies. For example, famine has been largely eliminated in modern Western societies. On the other hand, human nature has not been completely changed by the Industrial Revolution. In the last two chapters of this book, I speculate on what lessons cliodynamics might have for us and our future times of war and peace and war.

Product Details:

Peter Turchin book Empires

December 7, 2005