The Collapse of Complex Societies (Cambridge University Press 1988; paperback 1990, 250 pages, ISBN 978-0-521-38673-9) is Joseph A. Tainter’s magnum opus and deservedly considered a classic. Tainter packs an overview of explanations of collapse, analyses of historical cases, and his own overarching theory into one slim book, soberly argued from quantifiable data yet quite readable. If you’re at all interested in the subject matter Collapse is a must-read, immensely enlightening whether or not you think Tainter’s reasoning exhausts any specific case of collapse. Preparing this post I also found two later articles that summarize and elaborate Tainter’s positions. I’ll discuss them after a short overview of the book itself.
Definitions & Explanations
A society has collapsed when it displays a rapid, significant loss of established sociopolitical complexity [p.4] where “complexity” [p.23] measures how heterogeneous, unequal, interconnected, and generally diversified a society is. On one extreme, hunter-gatherer tribes are small homogeneous groups that feature only a few distinct social roles and utilize few artifacts and resources. On the other extreme, modern industrial societies cover large territories with populations in the millions, contain a hierarchy of sub-units organized along multiple axes, and feature tens of thousands of distinct professions and products.
“Collapse” means that these markers of complexity rapidly decline, causing the society to lose centralized organization and split into multiple independent units that are simpler, smaller, less connected, and more homogeneous. These definitions are general enough to cover all known cases of collapse while also suggesting some easily quantifiable measures for complexity and collapse.
Speculations about the causes of collapse have abounded in Europe for centuries, thanks to the well-documented precedent of the Roman Empire. Tainter reviews this and many other historical cases, as well as the explanations proposed by various scholars. He observes that the usual suspects – resource depletion, natural disasters, military conflict, foolish leaders, etc. – are all by themselves insufficient to explain collapse. For one thing, they all occur often enough without causing societal collapse. Moreover, complex societies tend to be specifically designed to deal with a variety of challenges, e.g. storing grain against shortages and organizing territorial defense. Why do these measures fail at some point?
Marginal Return on Complexity
Tainter explains such failures from an economic perspective: complex societies collapse when they fail to meet new challenges because the cumulative cost of doing so has grown too great. This in turn almost inevitably happens because growing complexity yields a declining marginal return on investment. As a society gains complexity, it will always prefer the simplest and most productive actions at any given point. First one cooperates with one’s nearest neighbors, exploits those resources that are most easily obtained, constructs the most basic buildings and defenses that are better than nothing, and so on. The return on this initial investment in social complexity is very high, and so the growing society tends to continue on this path to greater interconnection and specialization.
Unfortunately that cannot last. Continuing investment, often in response to challenges like competition, population growth, or resource depletion, requires more difficult and less productive actions, as the simplest and most productive ones were already taken. So when surface deposits of some ore are exhausted, ever deeper mines must be dug. With the best land already in use, worse land must be developed at greater cost of labor and infrastructure. Medical research is now much more costly and relatively less effective than when penicillin and hygiene were first discovered. When states are locked in an arms race, ever-increasing military expenses are required merely to avoid being conquered. Bureaucracy also has the well-known habit of multiplying for no purpose whatsoever once established – Tainter cites the examples of British Navy and Colonial Office clerks growing through 1967 and 1954, respectively, even while the actual navy and empire were shrinking!
Ultimately, the cumulative expenses of maintaining the current complexity plus responding to new challenges are so huge that the declining marginal return becomes a declining absolute return. The extra cost of solving some new problem now exceeds the benefit from solving the problem itself. This is when a society will collapse, i.e. abandon some or all centralized organization and decay into smaller units. These will no longer receive the old benefits from central organization, but crucially they no longer have to pay its expenses either. Once expenses exceed benefits, collapse is the rational course of action. Naturally the central organization will attempt to prevent this, through coercion and propaganda, but that too only increases its cost – and so indirectly accelerates the collapse.
Examples of Collapse
Western Roman Empire — Tainter’s inevitable first example, Rome rose and fell as a machine of territorial conquest. While there was rich nearby land to conquer, the legions brought back so much loot that Rome’s expanding military paid for itself. This gradually came to a halt after Caesar when the empire reached the frontiers of oceans and deserts, as well as nations too poor or remote to bother conquering. Decline set in immediately: the emperors were in perpetual financial trouble, frequently resorted to debasing the currency, and eventually instituted an oppressive regime of conscription, serfdom, and absurdly high taxes – just to maintain an army that was by now both corrupt and ineffective.
Unsurprisingly the subjects opted out of this system, turning into bandits, fleeing to a local lord that would protect them from the imperial tax collector, or outright joining the invading Germanic tribes. These eventually divided the Western Empire into smaller independent kingdoms that were both less costly and more successful in defending against the next wave of invaders. We might lament the cultural decline of the “Dark Ages” but for the average peasant (at least outside Britain), the post-collapse situation was generally preferable to the pre-collapse one.
Note that Tainter’s emphasis differs from Luttwak’s strategic analysis which I also recommend on this subject. Both agree that Rome’s downfall was its inability to make new conquests, but Tainter focuses on the economic consequences whereas Luttwak highlights the lack of easily intimidated client rulers for guarding the outer borders. Obviously both factors reinforced each other, as Rome had to pay more to defend its borders just when it could less afford to do so.
Classic Maya — The Maya had inhabited the Yucatán peninsula since at least 2000 BC and still did so when the Spanish invaders arrived in the 16th century, but their monumental urban centers had been deserted and decaying since the 9th century AD. This phenomenon is known as Classic Maya collapse and had at first led to speculation that sites like Palenque and Tikal were mere ceremonial centers, never intended for habitation. However, closer examination showed that these sites had been cities with tens of thousands of residents.
Tainter’s scenario is one of increasing population growth, requiring and facilitated by intensive agriculture with canalization and raised fields, and increasing competition between neighboring groups. Both factors would lead to a growing administrative overhead that organized labor and defense in centralized cities. Much of the remarkable monumental architecture and imagery created in this era served the purpose of deterring attacks through ostentatious wealth and cruelty, as the Maya did not maintain standing armies. This was a classic arms race against competitors as well as population pressure, and after one final building frenzy the stalemated and bankrupt city system reverted to the previous agglomeration of villages, at a much reduced population.
Chaco Canyon — Tainter’s least well-known example concerns the Ancestral Pueblo culture around the Chaco Canyon in New Mexico. Archaeological remains show an explosion of wealth and building activity between 900 and 1200 AD, followed by swift collapse to a much smaller and disorganized population. Tainter once again identifies population pressure as an incubator for social complexity, but here it materialized in the form of collaboration rather than antagonism. The Chacoans appear to have created an interchange network among the most ecologically diverse settlements of the region, ensuring each against poor harvests with the others’ surplus production.
This system was an immense success. “Great Houses” were built with up to 700 rooms and multi-storied masonry, over 300 km of roads were constructed with causeways over drainages and stairways cut into cliffs, and luxury goods were exchanged throughout and beyond the region. More and more settlements joined the network – and ultimately caused its breakdown. Its wealth generation potential was based on the difference between the ecological situation of each participant, especially moisture at any given time of the year. New (and poorer) members whose situation merely duplicated existing ones would cause higher administrative and infrastructure costs without offering commensurate benefits. The network collapsed when rainfall was unusually poor over a 50-year period, and the most productive members withdrew as they decided they were better off no longer paying the costs of membership.
Anthropologist Arthur Demarest (PBS interview) discusses the collapse of ancient civilizations, including the Maya. As in Tainter’s examples above, he notes that collapse usually does not come after a long slow decline but on the contrary rapidly after one last spending frenzy, ostensibly at the peak of success. (This is approximately also true of the Western Roman Empire whose final organization was its most regulated and expensive one.) His viewpoint is primarily political rather than economic: leaders cannot afford to do nothing, yet cannot conceive of necessary structural changes to reduce expenses, so they do more of the same, ever more expensively. If they did not they would be replaced by another leader who did.
Tainter himself has reiterated on the subjects of complexity and sustainability in numerous articles. For example, Complexity, Problem Solving, and Sustainable Societies (1996) summarizes a few key points of Collapse of Complex Societies, so you might want to give it a read for a quick overview. Social Complexity and Sustainability (2006) again reiterates the basics but also introduces some new case studies, namely the recovery (not collapse!) of the early Byzantine empire and the success of industrialism.
Byzantine Empire — In the 8th century, the Eastern Roman (Byzantine) Empire had been nearly destroyed by exhausting wars with Persia followed by invasions of the newly converted Islamic Arabs and various northern tribes. Remarkably and perhaps uniquely in history, the imperial administration responded by preempting rather than causing collapse: it dramatically simplified itself. Soldiers who could no longer be paid were instead granted land in return for hereditary service, civil and military administrations were merged, the economy was reorganized around self-sufficient manors, administration was simplified everywhere to cut costs. Byzantium voluntarily performed the reduction of complexity that Western Rome tried to prevent, and which therefore arrived more forcibly in the form of collapse.
This simplification rejuvenated Byzantium. The peasant-soldiers became producers rather than consumers of the empire’s wealth. By lowering the cost of military defense the Byzantines secured a better return on their most important investment. Fighting as they were for their own lands and families, soldiers performed better. […] The Byzantines went from near disintegration to being [by the 11th century] the premier power in Europe and the Near East, an accomplishment won by decreasing the complexity and costliness of problem solving.
Industrialization — The acquisition of new resources can offset the climbing costs of social complexity. The old-fashioned way is territorial conquest which is how Rome grew large and powerful, until there were no more new lands to conquer. Europe followed this path on a global scale during colonization, but the more important boost was the discovery and exploitation of fossil and later nuclear energy sources. It’s the ever-increasing use of mostly fossil fuels that sustained the rapid, centuries-long increase of every form of consumption and investment in industrialized countries. The anxiety over finding new energy sources, whether nuclear fusion or highly efficient solar cells, is therefore well justified.