Last time we looked at chiefdoms, which Moffett described as a watershed in the evolution of human societies. Chiefdoms aggregated multiple societies together and, as such, could be seen as analogous to the evolution of multi-cellular organisms out of single cells, except on a societal level instead of a biological one. Like the creation of multi-cellular organisms, natural selection meant that some experiments succeeded while others failed, and the ones we see today are the ones which survived.
Eventually, chiefdoms evolved in to an even larger, more complex organism, something we generally refer to as a state.
States are territorially defined; have complex, specialized economies often centered around market exchange; have tens of thousands or even millions of people; have urban centers with monumental architecture; have formal written laws and law courts backed by a coercive apparatus including armies and police; and have institutionalized leadership including organized bureaucracies which enforce the laws and provide for defense and public welfare. Relations above the family level are no longer centered around blood ties or kinship, and the society contains multiple different ethnicities—something not true of homogeneous tribal or band societies.
In the past, a state was often defined by a checklist originally established by the eminent archaeologist V. Gordon Childe*. However, many features of "Childe's checklist" have subsequently been shown to have existed before the rise of the state, including sedentism, urbanism, hierarchy, figurative art, and monumental architecture. Sociologist James C. Scott describes it as more-or-less a judgement call in his book on early states:
An alert reader might...ask, what is a state anyway? I think of the polities of early Mesopotamia as gradually becoming states. That is, "stateness," in my view, is an institutional continuum, less an either/or proposition than a judgement of more or less. A polity with a king, specialized administrative staff, social hierarchy, a monumental center, city walls, and tax collection and distribution is certainly a "state" in the strong sense of the term.
Such states come into existence in the last centuries of the fourth millennium BCE and seen to be well attested at the latest by the strong Ur III territorial polity in southern Mesopotamia around 2,100. Before that there were polities with substantial populations, commerce, artisans, and, it seems, town assemblies, but one could argue about the degree to which these characteristics would satisfy a strong definition of stateness. 
The sociologist Michael Mann describes civilization as a phase change wherein loose, overlapping social networks ossify into a "social cage" of permanent power relations complete with private property, dynastic wealth, patriarchy, hierarchy, class stratification and a dramatic divergence in life chances of some people relative to others. In a similar vein, archaeologist Colin Renfrew saw the defining feature of civilization as insulation from nature:
[Colin] Renfrew...notes that Childe's list consists of artifacts. They impose human-made objects between human beings and nature. Most attempts to define civilization center on the artifact. Thus Renfrew defines civilization as insulation from nature...Note the similarity of the metaphor to the social-cage metaphor. Civilization was a complex whole of insulating and caging factors emerging fairly suddenly together. 
Unlike tribes and chiefdoms, which emerged more-or-less independently everywhere, the arrival of the state was a rare phenomenon which only occurred in a few select places around the world. The universally agreed-upon locations were: Mesopotamia between the Tigris and Euphrates rivers; Egypt along the Nile River; the north China plain starting around the Yellow River; and the Indus River valley in modern-day Pakistan. Sometimes other regions are included such as Elam, Minoan Crete and the lake region of eastern Africa, but these are less certain. States that formed without any outside influence are called "pristine" states ("bootstrap" states in my terminology), while "secondary" states developed due to contact with existing states.
State formation was not confined to Eurasia. In the Americas the two major locations of bootstrap states were the Olmecs of the tropical lowland Mexico, and the Norte Chico civilization of north-central coastal Peru. These led to successor states becoming established in the Mexican highlands and the Andes mountains. It is obvious that these Precolumbian states could not have been influenced in any way at all by previous state formation in the Old World.
The fact that state formation occurred so rarely has caused many scholars to conclude that they were not a general feature of human societal evolution, but rather came about through regionally-specific circumstances in a few select places. Michael Mann concluded that most of human history was a struggle against the centralization of power in a few hands, and that societies typically cycled between periods of centralization and decentralization throughout history without ever reaching something like a state. That is, most of human history was spent trying to avoid the state:
[G]eneral evolutionary theory may be applied to the Neolithic Revolution, but its relevance then diminishes. True, beyond that, we can discern further general evolution as far as "rank societies" and then, in some cases, to temporary state and stratification structures. But then general social evolution ceased...I...suggest that the further general processes were "devolutions"—movement back toward rank and egalitarian societies—and a cyclical process of movement around these structures.
In fact, human beings devoted a considerable part of their cultural and organizational capacities to ensure that further evolution did not occur. They seem not to have wanted to increase their collective powers, because of the distributive powers involved. As stratification and the state were essential components of civilization, general social evolution ceased before the emergence of civilization. 
Even if it was a rare occurrence, the fact that state-level societies formed independently in both the Old World and the New indicates that on some level they must be a potential social arrangement which arises everywhere out of human social instincts. The fact that civilizations were so strikingly similar across the world also points to this conclusion, which Moffett vividly illustrates with a passage from the book A Short History of Progress by Ronald Wright:
What took place in the early 1500s was truly exceptional, something that had never happened before and never will again. Two cultural experiments, running in isolation for 15,000 years or more, at last came face to face...When Cortes landed in Mexico he found roads, canals, cities, palaces, schools, law courts, markets, irrigation works, kings, priests, temples, peasants, artisans, armies, astronomers, merchants, sports, theatre, art, music and books. High civilization, differing in detail but alike in essentials, had evolved independently on both sides of the earth. (293)
The origin of these bootstrap states is something of a mystery. They formed so very long ago that we cannot directly observe their formation; we can only infer the causes. The fact that all of these early civilizations (excepting possibly Crete) began in irrigated river valleys in a self-evident observation that has long been noted by anthropologists and historians. It can hardly be a coincidence. This fact led to the "hydraulic state" theory proposed by Wittfogel that we discussed last time.
Subsequent scholarship has refuted much of Wittfogel's core thesis (canals were administered at the village—not the state—level, and the earliest signs of urbanization and the state are not seen along the canals). Nonetheless, alluvial agriculture must have played a role. Irrigation agriculture on naturally fertilized alluvial soils allowed for denser, more tightly integrated populations than places which relied on other methods such as slash-and-burn cultivation fed by rainfall. Before the introduction of iron tools, many parts of the world were simply impossible for large-scale agriculture, such as mountains, wetlands and forests.
But alluvial agriculture by itself did not lead to the formation of states. At least two other major factors played a role: militarism and circumscription.
Circumscription refers to the fact that certain regions are surrounded by areas where productivity falls off sharply, trapping their inhabitants in a sort of environmental "cage". Moving away from incipient elites meant abandoning one's way of life altogether. It's possible that some people did exactly that, but the ones who remained for whatever reason eventually became civilization's first underclass.
The few titanic civilizations that emerged generally did so in settings where the societies they took over were packed in a tight space. Under this condition, described by the anthropologist Robert Carneiro as circumscribed, conquest paid off royally. "War appears when mobility is not an option" is how the anthropologist Robert Kelly framed it.
Tribes farming fertile sites encircled by inhospitable regions experienced such circumscription, locking them in a fight from which in time just one would emerge. Think of the Nile Valley hemmed in by deserts, where ancient Egypt took hold or the Hawaiian and Polynesian island chains, specks in an overwhelming ocean, where giant chiefdoms, some containing over 100,000 persons, claimed their domain. Though far from guaranteed by a circumscribed setting, civilizations were far more likely to emerge in such places than elsewhere.
Where there was no circumscription, a chiefdom or state could reach a modest size, then be unable to pursue further expansion as surrounding societies shuffled their locations to escape takeover...That was the situation in New Guinea, where...the island...never supported even a small state society until the country called Papua New Guinea was founded at the eastern end of the island in 1975. Even then it took years for many of PNG's citizens to learn that such a thing as a "country" existed. To the majority of the people, their tribes continue to matter most. (297-298)
Another ingredient in state formation was militarism. Various groups of people came into conflict with one another, leading to conflict between societies. Because so many people were tightly packed into these circumscribed regions, the scale of conflicts ratcheted up engendering the need for more top-down command structures. Battles were now for wiping out one's enemies and gaining control of their territory rather than simply slave raids or small-scale skirmishes. Colin Renfrew called it “peer polity interaction”, and the egyptologist Barry Kemp likened this process to a game of Monopoly, where early advantages compounded until only one winner remained on the “board” of the circumscribed area.
"War made the state, and the state made war," as Charles Tilly aptly observed. There have been no truly pacifist states...Any society larger than a handful of villages is composed of once-independent groups...
The birth of states in conflict, and their obligatory inclusion of people from varied sources, have a simple explanation: by the time states emerged, essentially no unoccupied habitable land remained. Some group—whether roaming hunter-gatherers, a tribe, a chiefdom, or a state—was already there and willing to do whatever it could to retain its independence....When an aggressively expanding society couldn't be escaped, often victory was pulled off without bloodshed…
Any expanding society had to push aside, conquer, or even destroy other peoples whose territories would have been part of an unbroken quilt on a map...Throughout recorded history conquering was followed by consolidation and control, repeated ad infinitum...Just as chiefdoms swallowed tribes and then each other, the pattern of the expansion of the nations and empires that ensued stayed the same. (297-298)
In the case of chiefdoms, authority was centralized in the person of the chief and his retinue. Power relations were still based primarily around affinity and kinship—and thus were inherently fragile. Complex chiefdoms were politically integrated by little more than the personal relationships between paramount chiefs and their subordinates. Chiefs and early kings spent a great deal of time touring their territory maintaining face-to-face relationships. This limited the ability to effectively control and manage large swaths of territory or delegate authority effectively. Many powerful and charismatic chieftains managed to unite multiple tribes to form proto-states throughout history, only to see them disintegrate upon their death (for example Arminius or Shaka Zulu).
By contrast, leadership in true states became institutionalized so that it could survive the death of any particular leader. In states, neither personal relationships nor kinship were necessary for social integration—impersonal relationships between formal office-holders took their place. A permanent bureaucracy could continue to administer a territory during a transfer of power from one leader to another, whether peaceful or not. That is, to some degree, a state is on auto-pilot.
A fatal flaw in the chiefdom was the chief's inability to delegate authority. When the chiefdom grew large, the former chiefs of its subjugated villages could be allowed to retain their position, but the paramount chief had to oversee each of them personally. This kind of flimsy oversight, based largely on the leader's dominance or powers of persuasion, became impractical once the combined territory took more than a day to traverse. (291)
By contrast, heads of state not only asserted the sole right to enact their will, they could back the claim up with the support of a formal infrastructure...It was, then, with the proud birth of bureaucracy that societies came to improve their cohesion and rule great expanses. (292)
The development of bureaucracy, then, is one of the hallmarks of state-level societies. No one ever builds statues or monuments to bureaucrats, yet they were just necessary for states to form as kings, priests and generals. Someone had to make sure those conquering armies were armed, housed and fed, after all.
Such an administrative apparatus was greatly facilitated by the development of the writing. Writing first began in Mesopotamia around five thousand years ago as way for managerial elites to coordinate and manage economic activity; "lists, lists and more lists," is how James C. Scott put it. Only much later was writing pressed into service to represent the sounds of human speech.
Scott argues that writing was key to state formation, quoting the anthropologist Claude Lèvi-Strauss: "Writing appears to be necessary for the centralized stratified state to reproduce itself." To that I would add numeracy, as the two were intimately related. Literacy and numeracy were used to regularize ownership rights over assets and establish creditor/debtor relationships which allowed certain ambitious groups to gain control over the economic output of producers.
Moffett argued earlier that it was the institution of slavery which allowed the incorporation of foreigners into human societies to be a comprehensible notion for the first time. With the arrival of states, that institution ramped up dramatically. Vast amounts of unfree and bonded labor were crucial to the formation of the first states and empires. Entire captive populations were relocated by early states in what Scott refers to as a "late Neolithic multispecies resettlement camp." Societies such as ancient Rome and Sparta were utterly dependent on slave labor to sustain their societies. Unfree labor—including corvée and statutory labor—was necessary to build the massive infrastructure projects which tied early states together such as roads and canals, as well as their defensive walls and public monuments.
Another defining feature of the state are written laws. In states, laws are formally laid down by the rulers and administered by designated officials rather than determined by local custom and administered by village elders. Not only punishment for delict, but also laws specifying property rights, transfers of property, marriage, and inheritance are also set forth. Private property became much more centered around individuals and families rather than corporate kin groups as in tribal societies; that is, it became alienable. The alienation of property from the control of kin groups has long been been pinpointed as the origin of private property as we know it since at least the time of Karl Marx†. Laws—and the coercive force to back them up—established what Max Weber saw as the defining characteristic of the state: the monopolization of the use of legitimate violence.
States are distinct from chiefdoms in a few other particulars as well. For one, laws are truly laid down: while people carried out vigilante justice in societies with weak leaders, in a state those with authority mete out punishments.
In states, too, notions of private property are fully realized, including luxury goods sought after by an upper class. Indeed, while people in chiefdoms could gain prestige and sometimes showed differences in social class, in states inequalities reach extremes. Differential access to power and resources can be either earned or inherited, with some people working for others. (292)
Both of these developments were predicated on the development of ideologies which justified and maintained unequal access to power and material resources on the part of a ruling elite. Religion was designed to confer legitimacy on the early state. Legitimacy can be defined as the right to rule.
In states, ideology, as distinguished from other cultural elements, is not simply generated through human interaction; a significant part of a society's worldview is intentionally created and transformed by a social elite to direct the thoughts and action of subject peoples. State institutions, as part of an ideological apparatus, seek to develop and perpetuate a charter for the institutional order of society. Such strategic charters are a significant source of social power in state societies. 
Legitimacy can be thought of as either rational or irrational. Rational legitimacy is conferred by a deliberative process, and leaders are voluntarily put in charge and can be removed by consensus if they fail to perform. Both band societies and modern democracies (in theory) generally fall into this category. Irrational legitimacy is based around things like charisma, superstition, and personality cults. Religious cults like Scientology and dictatorships like North Korea fall into this category. Business corporations have aspects of both. All of these are sustained by intersubjective realities in the perceptions of citizens and subjects, as Yuval Noah Harari describes:
All these cooperation networks—from the cities of ancient Mesopotamia to the Qin and Roman empires—were 'imagined orders'. The social norms that sustained them were based neither on ingrained instincts not on personal acquaintances, but rather on belief in shared myths...We believe in a particular order not because it is objectively true, but because believing in it enables us to cooperate effectively and forge a better society. Imagined orders are not evil conspiracies or useless mirages. Rather, they are the only way large numbers of humans can cooperate effectively...
Hammurabi’s Code was based on the premise that if the king’s subjects all accepted their positions in the hierarchy and acted accordingly, the empire’s million inhabitants would be able to cooperate effectively. Their society could then produce enough food for its members, distribute it efficiently, protect itself against its enemies, and expand its territory so as to acquire more wealth and better security. 
States levied professional armies in place of ad hoc assemblies of tribal warriors who went back to occupations like herding, fishing, farming and handicrafts once the conflict was over. Individual bravery and initiative were supplanted by regimented units of professional, interchangeable soldiers acting under the orders of senior commanders.
The safeguarding and control of large populations require a heightened level of organization that can be traced back to the first state societies. States assembled armies to put down rebellions and carry out further territorial invasions using offensive strategies than changed as societies grew.
Big Men and chiefs often had to personally lead warriors in order to motivate and maintain their following. Even then each combatant was prone to act alone, with plans breaking down in the heat of the moment with little accountability.
By contrast, the ruler of a state remained safely ensconced on the capital, where he or she could direct attacks and, if the battle was won oversee the takeover of the territory and its survivors. Military tasks could be delegated to specialists.… Disciplined training ensured much greater reliability, and uniformity, among the troops. This uniformity and the sheer scale of wars guaranteed the impersonal nature of the enterprise. All traces of individuality were stifled. Combat between large states took on ant-like qualities in giant anonymous societies...(296)
States are distinguished in particular by the presence of cities—the very word "civilization" comes from the Latin word for city: civitas. Early cities were based around ceremonial centers staffed by a professional priesthood. Goods flowed into these centers from the far-flung corners of the state and radiated outward either through redistribution or markets. This is known as a palace economy, or a palace-temple complex. This is why so many anthropologists saw statehood as developing out of redistributive chiefdoms. They also point to the importance of both local and regional (long-distance) trade in state formation. The revenue-raising philosophy of many early states was, in essence, "if it moves, tax it."
Early civilizations, then, were "cultural interaction zones" where many different and contrasting lifeways encountered each other—farmer and herder; “civilized” and “barbarian”. The tiered hierarchy of urban settlements—with national capitals, regional capitals and administrative centers—is considered to be a hallmark of civilizations and is not found in village societies or in all but the most complex chiefdoms on the verge of statehood.
When one state conquered another, each of the former state's territories was converted into a province, its capital refashioned into an administrative center. Government agents, each master of a particular job, were distributed as needed. This system of oversight meant that societies could be ruled more coercively than before, even if lag times in communication from the capital to the outer reaches continued to be a handicap for early states. In fact, with a strong enough infrastructure, a state could survive the overthrow of its leaders or reign [sic] in their worst impulses. (292)
States—much like chiefdoms—relied on the Tributary Mode of Production that I described last time. In states, however, tribute was often recast as taxes and used to support an army of administrators and bureaucrats who managed the affairs of the state (including the collection of taxes!).
Later, states began to issue various forms of currency (i.e. money) which allowed for decentralized exchange to take place. States claimed a monopoly on the issuance of such tokens. This "abstract layer" superimposed above the real exchange of goods and services in an economy makes it easier for states to transfer resources from the public to themselves, pay soldiers, conduct war, hire expertise, build monuments, maintain public works, enforce laws, and redistribute wealth (which, contra libertarians, all societies throughout history have done to some degree).
Finally, states extract tributes, taxes, or labor from citizens in a more formal way than chiefdoms. In return, they offer infrastructure and services that ensure the members are more dependent on their society than ever before. (292)
There are also improved economies of scale. For instance, it can be easier to feed and house each member, and these lowered costs can lead to a resource surplus that ants invest in warfare and humans in the military, though our species can divert the surplus as well into the sciences, the arts, and such nonessential projects as the Taj Mahal, the pyramids, and the Hubble telescope, which require ant-like levels of coordination and industry. (293)
In addition to fertilized alluvial soil and irrigation, it is notable that all early states (with the possible exception of the Inka) relied on cereal grains as the staple food crop. As James C. Scott notes, “…no "lentil states," chickpea states, taro states, sago states, breadfruit states, yam states, cassava states, potato states, peanut states, or banana states [have] appeared in the historical record…Many of these cultivars provide more calories per unit of land than wheat and barley, some require less labor, and singly or in combination they would provide comparable basic nutrition...” 
Scott argued that the reason was because grains were eminently taxable. Cereal grains all ripen at roughly the same time; they ripen above ground; they can be stored for long periods of time; they can be easily destroyed; and they come in small and divisible units; meaning that they are especially appropriable by incipient elites seeking to impose taxes on a domestic or subjugated population.  Cereals can also easily feed large numbers of soldiers and slaves alike, which are essential for states to form. The earliest accounting units were tied to measures of grain. I would also add that they're especially easy to ferment into alcohol—another ubiquitous feature of all early states that's all too often neglected‡.
Writing, bureaucracy, cities, money, laws, taxes, social classes—all of these can be seen as ways of making society more legible, and thus amenable to top-down management and control by elites at the apex of the social pyramid. The concept of legibility was developed by Scott in his earlier study of the various ways states tried to assimilate tribal and nomadic peoples based on abstract lines drawn on a map:
The more I examined these efforts at sedentarization, the more I came to see them as a state’s attempt to make a society legible, to arrange the population in ways that simplified the classic state functions of taxation, conscription, and prevention of rebellion. Having begun to think in these terms, I began to see legibility as a central problem in statecraft. The pre-modern state was, in many crucial respects, particularly blind; it knew precious little about its subjects, their wealth, their landholdings and yields, their location, their very identity. It lacked anything like a detailed “map” of its terrain and its people. 
Moffett notes that large-scale civilizations and modern states contain ethnicities. In this, they are unique. Managing multiple, overlapping identities of their subjects and citizens was a challenge not faced by the leaders of tribes or simple chiefdoms. Moffett describes two basic approaches taken by states and empires toward integrating vanquished peoples: control and assimilation.
Control basically leaves the conquered population intact without making much effort to integrate them into the dominant society. The subjects remain outsiders and their cultural and ethnic heritage remains mostly intact. In many cases they are left under the supervision of their previous rulers, with those rulers pledging fealty to their new overlords in exchange for allowing them to retain their position. An example Moffett cites are the Inka who controlled a highly diverse population in the Andean highlands of South America:
The peoples subjugated by the Inca essentially retained the identities they had had as an independent society...(311)...obedient local leaders were often kept in place after the society was subjugated. They would be handsomely paid to oversee the extraction of goods and services from their people who received few benefits in return...(312)...the occupants of outlying provinces were beaten into submission, unrests crushed, and unruly villages transplanted to lands other than their own to guarantee their subservience...(311)
Although the conquered peoples received some food and goods from the Inca, the residents of most Incan provinces had no real social status within the empire. They had almost no contact with the regular Incan population, and were prohibited from modeling themselves after their overlords. (311)
If the Inca had instead chosen to allow their subjugated peoples into the broader society, as Rome and the Chinese dynasties eventually did with the populations of many conquered provinces, those people may have come to identify not just with the Inca, but as Incans themselves, taking pride in the empire even if their stature within it continued to be less than equal...(311)
The other approach was assimilation. In this approach, the conquered people are stripped of their cultural identity and forced to take on the markers of the dominant culture. The end goal was to erase any and all distinctions between the dominant people and their subjects. The subordinate people would adopt the language of their conquerors, learn their writing system, read their literature, wear their clothing, live in their houses, and gradually be integrated into the government. Moffett describes this as the strategy taken by the early Chinese rulers, leading to the relative homogeneity seen in China today:
The China subcontinent fascinates in that conquests there began early and to great success, eventually creating a virtual uniformity among what's now regarded as the Chinese, or Han, race, presently amounting to 90 percent of China's people. The scale of this outcome can be attributed to the policy of early dynasties of accepting anyone converting to their culture, writing, and sometimes their language. This tradition traced to Confucius, who promoted the idea that the people could become Han simply by committing to a Han mode of life... (312)
Among the provincials, the wealthiest would be first to realize the desirability of teaching their children Han customs. Over the centuries this education filtered down through the social strata to yield a widespread Han identification by the time of the Ming Dynasty in the fourteenth century.…Unlike the Romans, who exported to their subjects a miscellany of improvements in plumbing, lighting, and other basics, the Chinese dynasties offered few quality-of-life benefits to the outlying masses, depending more on their military presence to crush repeated uprisings...(313)
A hybrid approach was taken by the Roman Empire, which mainly left conquered peoples in place under the rule of client kings but thoroughly assimilated the ruling classes of foreign societies into their way of life through things like language, art, literature, clothing styles, food and drink, theater, games, architecture, and so on. Unlike in China, many of these adoptions led to higher standards of living for the citizens under Roman rule, as memorably satirized by Monty Python in The Life of Brian. If subject peoples revolted, however, they were met with overwhelming force, as seen, for example, in the Jewish and Roman wars.
Eventually states developed concepts like citizenship and state religions to help integrate vast empires. This was greatly facilitated by the establishment of doctrinal religions, wherein a freely-adopted confession of faith took the place of ethnic and tribal affiliations during the Axial Age. Some scholars also point to the establishment of so-called "Big Gods" based around what I call the "Santa Claus model" of religion (“He sees you when you're sleeping; he knows when you're awake. He knows when you've been bad or good, so be good for goodness sake!”). These religions supposedly facilitated increased trust and cooperation between groups of unrelated strangers.
At their roots, Moffett notes, states are ultimately problem-solving organizations. They are complex systems of people and technology which allow vast populations to cooperate on scales which rival those of the social insects. In fact, the biomass of human and ants at the start of the twenty-first century are roughly equal, and our domesticated plants and animals far outweigh their wild counterparts.
States around the world bear similarities not just in such defining features as their administration of power, but also in the organization of those infrastructures and services. Like any society, a state is a problem-solving organization, and its big problems often require complex solutions.
On this point, we discern in states many of the patterns we have already found among the social insects. When a society, human or ant, becomes sizeable, the demands on it to provide for and protect its members grow intricate and diverse. Consequently, so must the means by which these obligations are met. Methods must be found for the transport of supplies, troops, and other personnel when and where goods and services are required. Failing to meet those basic needs will be cataclysmic...(293)
Many states did, in fact, fail to meet the basic needs of their people over time. This leads to another persistent and recurring feature of state-level societies and their associated civilizations that is discussed far less often: dissolution, breakdown, and collapse.
States, empires, and even chiefdoms, were all prone to regular cycles of dissolution and collapse throughout human history. Indeed, collapse is one of the core features of every society that expands beyond the tribal level. The larger human societies grow, the more fragile they become. For such artificial contraptions to be held together, they depend on institutions which are built and maintained by fallible and selfish human beings who are prone to putting their own needs ahead of that of society. When societies expanded beyond a certain point, the costs of controlling subject peoples far outweighed any economic benefits they might reasonably provide:
Conquering chiefdoms and states sprang up the world over after the advent of agriculture. Most were a flash in the pan, this transience a reminder that no level of complexity secures a society's continued existence...(299)...Cycles of conquest and dissolution are evident everywhere. Historical records are replete with chiefdoms and states that gained, then lost, members and property after expanding too far to hold their territory... (300)
Moffett characterizes collapse as more precisely a fracture—societies split along predetermined and predictable lines just as stone, concrete, and pottery crack along certain predictable weak points when exposed to stress:
[A] collapse...is more accurately a fracture. Though band societies and tribes divide, the modus operandi for breaking apart chiefdoms and states has been a complex yet often predictable sort of splintering. These breaks were sure to happen regardless of resource abundance. More specifically, the manner by which chiefdoms and states absorb outsiders makes them likely to sunder along the demarcations on a map that conform roughly to their past military occupations. (299)
...For a secession to succeed, the clashing group typically has to populate a specific portion of the county's territory, which they often claim as an ancient homelend. This means the break ends up falling between stretches of terrain heavily populated by ethnicities that once had societies of their own there...The likelihood that such geographical variation on its own will tear a country apart appears relatively small, however, even when those differences are played up… (303)
Joseph Tainter, an anthropologist who extensively studied societal collapse, argued that societies tend to become more and more complex over time to solve problems they encounter. Eventually, increasing returns to complexity are supplanted by diminishing returns to complexity, and societies undergo a rapid simplification that shows up in the archaeological record as "collapse."
Tainter, among others, has emphasized the essential continuity of such civilizations, however. A "collapse" is not usually a disappearance, but rather a transformation into something else. As James C. Scott notes, "much [of what] passes as collapse [is] rather a disassembly of larger but more fragile political units into their smaller and often more stable components."  He further notes that, "The early states were fragile and liable to collapse, but the ensuing "dark ages" may often have marked an actual improvement in human welfare." 
Societies underwent rapid simplification, with the upper tiers of multilevel societies disappearing and economic and political relations becoming more localized and small-scale. Intensification no longer worked as a strategy due to environmental degradation or political factors, and simplification became the only alternative. As Amos from the television show The Expanse put it, "The more settled things are, the bigger the tribes can be. The churn comes, and the tribes get small again."
Conquering and fractioning alienated through time...when a Maya civilization shattered, its families didn't just slip into the jungle, and certainly not across a wide area or over the protracted time the word "collapse" might suggest. Generally a king lost control. The top tier of society vanished. Former sacred and symbolic objects and public works were often desecrated. Outlying districts, subjugated in a distant era, would thereby break free under leaders who no longer anyone to dictate what they could do...Had the Spaniards made it to Mexico a century later, at a different point in this loop, they may well have been met by another Maya empire like the Mayapan, reborn, or perhaps—if a recent breakdown had been especially harsh—by isolated farming villages.
The Roman Empire foundered, in the end, into smaller states as well. These stayed intact by delegating leadership responsibilities to lords in what became a feudal system, a form of social organization in many way functionally equivalent to a chiefdom. At that point, societies, in the sense of people's identification with a greater group, would seem to have lost their sway across much of Europe. Yet careful scholarship demonstrates that the local lords crippled, but didn't erase, the sense of belonging peasants felt with the region beyond the fiefs... (299-300)
Each rise and fall [of civilization] left its imprint on the population of a region, yielding a fresh medley of cultural ingredients...The imprint of societies past may explain certain curiosities of world geography. Distantly related peoples of the South American rainforest, for example, have similar crafts, traditions, and languages not easily explained by trade. Their hybrid cultures could be a signature of powerful chiefdoms, now vanished, that overpowered and refashioned the identities of many. (301)
On a long enough timeline, all civilizations, empires and states eventually fall. The ones which are around today are simply the ones that have not collapsed yet. While a nation-state may look like stable, durable, and permanent edifice from the perspective of an individual lifespan, from a historical perspective, it is an ephemeral creation—a blip on history's radar. Luke Kemp estimated the average lifespan of a civilization to be around 340 years. As he notes, “Collapse is a tipping point phenomena, when compounding stressors overrun societal coping capacity.” 
Archaeologist Joyce Marcus has found that state societies across antiquity had a finite life span, normally ranging from two to five centuries. This duration suggests states are no more persistent than hunter-gatherer band societies, which the evidence indicates endured for a few centuries as well...(304)...Chiefdoms and early states were more ephemeral, by some measures with the former lasting at most 75 to 100 years. (396 n. 43)
Much of the cobbled structure of a state is grounded in a feeble understanding of of the origins of people's devotion to their country and each other and how these can be managed...No society can persist unless being a part of it is important to its people. Despots keep dysfunctional nations intact for a time, but people with little attachment to a group are less stalwart and industrious. The USSR is one example of a nationality that deteriorated after being imposed on its people not even a century prior. Like Yugoslavia, it balkanized into states to which people felt more committed…
We must ask why nations aren't more stable given the controls they put in place, the services they provide, and the improvements in information flow that expose the citizens to each other's perception of proper behavior.
Despite the benefits of living in a state society, one recurring flaw is that, as an archaeologist proclaimed, states are "ramshackle contraptions, at best half understood by the people who made them." That courts of law, markets, irrigation, and so on had to exist in some form didn't mean people always put them together well. (304)
A description of these dynamics in detail is far beyond the scope of this (already way too long) post. Books such as Peter Turchin's War and Peace and War, William Orphul's Immoderate Greatness, Jared Diamond's Collapse, the aforementioned Collapse of Complex Societies, Ronald Wright’s A Short History of Progress, and many others discuss in detail the causes and circumstances of collapse across multiple human societies over time.
In the end, perhaps no explanation can suffice. We are social creatures, after all, and we do what the people around us are doing. We go along with the flow. If changes happen slowly enough, we will come to accept our circumstances—however miserable or unjust—as just the normal, or even inevitable, way of doing things. Society’s myths become more powerful than lived reality. Once a society becomes large enough, the actions of any single individual no longer matter. Nobody has any control. The Iron Law of Oligarchy takes over.
I'll end with what I think is one of the best summaries of state formation by the anthropologist Marvin Harris:
What I find most remarkable about the evolution of pristine states is that it occurred as the result of an unconscious process: The participants in this enormous transformation seem to have known what they were creating. By imperceptible shifts in the redistributive balance from one generation to the next, the human species bound itself over into a form of social life in which the many debased themselves on behalf of the exaltation of the few. To paraphrase Malcolm Webb, at the beginning of the lengthy process no one could foresee the end result. "Tribal egalitarianism would gradually vanish even as it was being appended, without awareness of the nature of the change, and the final achievement of absolute control would at that point seem merely a minor alteration of established custom. The consolidation of governmental power would have taken place as a series of natural, beneficial, and only slightly (if at all) extra-legal responses to current conditions, with each new acquisition of state power representing only a small departure from contemporary practice." By the time the remnants of the old council finally sank into impotence before the rising power of the king, no one would remember the time when the king had only been a glorified [Big Man] whose exalted status rested on the charity of his friends and relatives.
I urge those who feel that my explanation of the evolution of culture is too deterministic and too mechanical to consider the possibility that at this very moment we are again passing by slow degrees through a series of "natural, beneficial, and only slightly...extra-legal changes which will transform social life in ways that few alive today would consciously wish to inflict upon future generations... 
A lot of people have warned about the coming technological neo-feudalism along with the disastrous effects of climate change—something implicated in the fall of every previous civilization. Will we heed Harris's warning before it's too late? Or will our great-grandchildren find themselves working as serfs on plantations owned by Bill Gates and mining boron on Mars for Elon Musk while all commercial activity is controlled by Amazon?
Next time we'll take a brief look at the potential future of human societies, and recap the essential lessons of The Human Swarm in the final post of this series.
* Childe's checklist (from Early Civilizations of the Old World by Charles Keith Maisels):
1.) Cities that are ‘more extensive and more densely settled than any previous settlements’...
2.) Full-time specialists—craftsmen, transport workers, merchants, officials and priests—who ‘did not secure their share directly by exchanging their products or services for grains or fish with individual peasants’, but instead worked for organizations that could command surplus from peasants.
3.) Concentration of surplus (limited by low productivity) ‘as tithe or tax to an imaginary deity or divine king’.
4.) ‘Truly monumental public buildings [which] not only distinguish each known city from any village but also symbolize the concentration of the social surplus.’
5.) The presence of a ruling class, including ‘priests, civil and military leaders and officials [who] absorb a major share of the concentrated surplus’.
6.) Members of this class develop technical expertise, particularly systems of writing and numerical notation, from which emerge:
7.) ‘Exact and predictive sciences—arithmetic, geometry and astronomy...Calendrical and mathematical sciences are common features of the earliest civilizations and they too are corollaries of the archaeologists’ criterion [separating the historic from the prehistoric], writing.’
8.) Specialists in representative art emerge—‘full-time sculptors, painters, or seal engravers [who] model or draw likenesses of persons or things, but no longer with the naive naturalism of the hunter, but according to conceptualized and sophisticated styles which differ in each of the four urban centres’.
9.) Regular foreign trade, involving comparatively large volumes and long distances, emerges to exchange part of the concentrated social surplus for ‘industrial materials’. ‘To this extent the first cities were dependent for vital raw materials on long distance trade as no neolithic village ever was.’
10.) ‘Peasants, craftsmen and rulers form a community.... In fact the earliest cities illustrate a first approximation to an organic solidarity based upon functional complementarity and interdependence between all its members such as subsist between the constituent cells of an organism. Of course this was only a very distant approximation.’ In apparent contradiction to which:
11.) This social solidarity is represented and misrepresented by ideological means ‘as expressed in the pre-eminence of the temple or sepulchral shrine’.
12.) State organization is dominant and permanent.
The book Lost Civilizations of the Stone Age by Richard Rudgley is dedicated to illuminating the deep history of these things in the Paleolithic era long before they developed in anything that we might call a "civilization" in the traditional sense of the term.
† As described by Friedrich Engels in his book on the origin of the state. In Marxist theory, the state arises primarily to establish, secure and defend the private property and wealth of the elites from commoners—everything else flows from this purpose. Thus states were formed by class conflict. Furthermore, that conflict is still ongoing.
Again, it's worth noting the distinction between personal property and the things a society needs to sustain itself—whether that be land, food, water, housing, energy, or factories. Texans, take note.
‡ As far as I’m aware, every early civilization brewed alcohol from grains on a large scale. In Mesopotamia it was barley; in Egypt wheat and sorghum; In China it was millet; in the Americas it was corn (chincha). This universality between civilizations is less often commented on. I'm struck by the overlap between workaholics, accumulation, and binge drinkers in our own societies—the "work hard play hard" ethos. See for example, Japan's cultural expectation of Stakhanovite working hours and binge drinking with colleagues—something also increasingly seen in the notoriously overworked and materialistic United States. Farmers historically appear to have spent a lot of their time drunk, in contrast to hunter-gathers among whom alcoholism and drug abuse is largely absent. Note also that tribal peoples tend to have a hard time keeping their society intact once alcohol is introduced. In short, are we civilized peoples mostly descended from those who traded freedom for booze?
All citations in parentheses from The Human Swarm by Mark W. Moffett; Basic Books, New York 2019
 James C. Scott; Against the Grain: A Deep History of the Earliest States, p. 35
 Michael Mann; The Sources of Social Power Volume 1: A History of Power from the Beginning to AD 1760, p. 74
 ibid., p. 39
 Timothy Earle; How Chiefs Came to Power, p. 149
 Yuval Noah Harari; Sapiens: A Brief History of Humankind, p. 113-114
 Against the Grain, pp. 113-115
 See: Cereals, appropriability, and hierarchy (VoxEU)
 A Big Little Idea Called Legibility (Ribbonfarm)
 Against the Grain, p. 155
 ibid., p. 11
 Are we on the road to civilisation collapse? (BBC Future)
 Marvin Harris; Cannibals and Kings, p. 122