….there is nothing that we know of in prehistoric Egypt or Mesopotamia or anywhere else in Western Asia to compare with the well-built baths and commodious houses of the citizens of Mohenjo-daro. In those countries, much money and thought were lavished on the building of magnificent temples for the gods and on palaces and tombs of kings, but the rest of the people seemingly had to content themselves with insignificant dwellings of mud. In the Indus Valley, the picture is reversed, and the finest structures are those erected for the convenience of the citizens. Temples, palaces, and tombs there may of course have been, but if so, they are either still undiscovered or so like other edifices as not to be readily distinguishable from them.

-Sir John Marshall, Preface to Mohenjo-daro and the Indus Civilization, 1931, p. vi

The archaeologists who first investigated the Indus civilization thought it diverged sharply from contemporary societies in Egypt and Mesopotamia (Marshall 1931, p. xi). For nearly a century, archaeologists have made a concerted effort to close this gap and make the Indus seem more “normal” in comparison with other complex societies. This is especially true with respect to inequality—specifically, stratification in the distribution of wealth and hierarchies of political power. In my view, these efforts have been largely unsuccessful. Marshall’s observation was basically correct; attempts to refute it have been based on the theoretical assumption that all social complexity entails stratified social relations, rather than a critical interpretation of the empirical evidence. I argue that the widespread distribution of production activities and wealth in Indus cities indicates that the stratification of wealth and power, particularly in the hands of a ruling class who monopolized resources and dictated the production activities of everyone else, was absent from the Indus civilization.

Indus cities (c. 2600–1900 BC) were expansive and planned, with large-scale architecture and sophisticated early technologies—writing, metallurgy, weights and measures, and seals—that matched those from contemporaneous societies in Egypt and Mesopotamia. And yet, it has long been noted that Indus cities lack the tombs, palaces, and aggrandizing art that characterize other early complex societies (e.g., Fairservis 1967). These lines of evidence are essential to the comparative study of complex societies and particularly to the analysis of past inequalities in wealth and power (e.g., Feinman 1995; Feinman and Marcus 1998; Smith 2012). Their absence in the Indus suggests that the forms of inequality that we would expect to find if a class of ruling nobles managed society were limited or absent in Indus cities. Given that complex societies have often been defined by the presence of such stratification (e.g., Trigger 2003, p. 46), the perception that the absence of a ruling class in the Indus civilization risked its omission from comparative debates about the emergence of social complexity gained ground. In response, there arose an implicit argument that the Indus was indeed exceptional, not because it lacked a ruling class, but because to fully appreciate its political economy required an exceptional set of criteria (e.g., Kenoyer 1998). Ironically, this exceptionality led to its exclusion from comparative studies anyway (e.g., Cork 2011; Petrie 2019; Wright 2010). This is unfortunate, because the theoretical challenges brought about by Indus egalitarianism foreshadowed broader problems with traditional assumptions about distributions of wealth, hierarchies of power, specialization, and urbanism that have plagued comparative research on social complexity.

Despite considerable growth in our knowledge of Indus technologies (e.g., Kenoyer 1996; Miller 2007; Prabhakar 2018; Vidale 2000; Wright 1991) and environments (e.g., Madella and Fuller 2006; Petrie et al. 2017; Wright et al. 2008), no clear evidence of a ruling class has been recovered. Mohenjo-daro’s first excavators explicitly grappled with empirical patterns that contradicted the idea that the Indus was under the control of a political hierarchy, such as the widespread availability of luxuries (e.g., private bathing platforms and commodious houses) that in Egypt and Mesopotamia were restricted to palace contexts (Marshall 1931, p. vi); for subsequent researchers the problem of Indus inequality largely receded from view. This is unfortunate, because there had been a time when the archaeology of the Indus had a significant influence on the broader comparative literature on social complexity. In the original edition of The Most Ancient East, Childe (1929) argued that the Indus civilization may have been the world’s primary font of urbanization, perhaps based on impressions of Marshall’s excavations at Mohenjo-daro in the 1920s. Following these brief experiments with the idea of Indus egalitarianism, scholars acted quickly to normalize the Indus within the evolutionary typologies that came to play such a strong role in comparative archaeology over the 20th century. Wheeler (1968) famously installed a ruling class in Indus cities by suggesting that its robust urban environment was evidence not of a prosperous, albeit relatively egalitarian, citizenry but instead the product of a homogenous and conservative military state—led by “priest-kings.” This hypothesized hybrid of monarchy and theocracy was supposedly transplanted from Mesopotamia. As neo-evolutionary theories of social change arose in comparative archaeology during the 1960s, Indus scholars responded by focusing on whether or not the Indus civilization was a “state,” the imagined endpoint of social evolution. However, proponents of the “stateless” (e.g., Possehl 1998) and “state-level” (e.g., Kenoyer 1994) paradigms suffered from the same thorny theoretical problems that have always accompanied the categorization of societies based on trait lists. It is telling that the 17.5-cm statuette commonly called the “priest-king”—one of the few pieces of evidence of their supposed existence—is now believed to be evidence of interaction with neighboring societies, not the talisman of a military elite (e.g., Vidale 2018a). In this article, I review the empirical evidence for a ruling class in the Indus civilization, finding that the traditional assumption that there was a simple correlation between complexity and hierarchy, and between simplicity and egalitarianism, can no longer be sustained.

In brief, no. Since the mid-20th century, archaeological attempts to explain the origins of complex societies were heavily indebted to evolutionary theories of social change based on historical or ethnographic research, which posited that societies progress through a series of universal stages that culminate in what are thought to be present-day social conditions (Trigger 1989).

These traditional theories of social complexity made two major claims: that all social trajectories converge on a common and universal evolutionary outcome—the “state,” and that all states comprise more or less the same social phenomena—namely urbanism, political hierarchy, long-distance intercultural trade, and, importantly, political and economic stratification. The first claim has been thoroughly dismissed, but disentangling the agency of a ruling class from narratives of increasing social complexity is an ongoing project. While the presence or absence of a ruling class has rarely been addressed so directly, the strong tendency of scholars of complex societies to accept the role of a “ruling class,” or coercive elites who directed past societies through disproportionate control of their wealth and power, deserves critical scrutiny.

Childe’s (1950) widely cited article on the “urban revolution” was a touchstone for the study of social complexity. Childe sought to explain cross-cultural patterns in early excavation data from Egypt, Mesopotamia, and South Asia, famously offering a list of traits that he believed brought about a “revolutionary” process of urbanization. He mixed observable empirical phenomena, such as increases in settlement size, large buildings, and evidence of administrative technologies like writing, with theoretical assertions that were heavily influenced by Marx’s speculations about what social relations were like in pre-capitalist societies. Among these theoretical assertions was the idea that the urban revolution was driven by a ruling class, who, through the state, exerted control of society by redistributing food surpluses. Childe’s traits, as well as the pace of change thought to have characterized the urban revolution, have undergone considerable revision since the article’s initial publication (e.g., Smith 2009); however, the core idea—that economic stratification and the emergence of a ruling class separate complex urban societies from those that predate them—has had a profound and continuing influence.

Childe’s assumptions about a ruling class percolated into the substratum of archaeological thinking about complex societies. In early processual models, urbanization was used to explain the emergence stages of class relations by concentrating people and resources in space. This concentration is thought to have allowed an inchoate ruling class to reinforce its high status in society by employing specialists—artisans, soldiers and bureaucrats—to undertake various projects of legitimation and administration (e.g., Childe 1950; Flannery 1972; Service 1975; Trigger 1974; Wright 1977; Wright and Johnson 1975). Thus, we find a division between a ruling class who exercised power and subordinated classes who were subject to that power. Economic specialization, an observable pattern in archaeological data that was thought to result from the subordination of artisans, was thus closely associated with social complexity (e.g., Costin 1991; Eerkens and Bettinger 2001; Roux 2003; Schortman and Urban 2004). Artisans came to be conceptualized purely in terms of their attachment to a ruling class who managed the surplus food and materials necessary for craft production (e.g., Brumfiel and Earle 1989). In this way, Childe’s “ruling class” was rebranded to the more generalized concept of “elites,” who were defined by their high positions in a stratified social order. Elites and their artisans are thought to have tapped long-distance exchange networks to bring in exotic raw materials for specialists to transform into prestige goods that signify and cement their dominance over other social classes (e.g., Helms 1993).

Following the rise of elite-centered views of social complexity, there have been profound changes in the way archaeologists conceptualized the interrelationship between politics, hierarchy, production, and how the three come together in forms of early governance. Drawing on a cross-section of Mesoamerican complex societies, Blanton et al. (1996) argued that the different ways past elites could legitimize and reinforce their positions fall along a continuum between network strategies—those that involve creating alliances within exclusionary power networks—and corporate strategies—those that involve more subtle investments in public goods to minimize the perceived distinction between elites and the people over whom they exerted power. Corporate political strategies were often undertaken by decentralized and “egalitarian” political forms that were dis-embedded from exclusionary elite networks (Blanton 1998). Egalitarian in this sense was mainly political, associated with diffuse and distributed forms of power thought to accompany decentralized governance. Thus, where once archaeologists had imagined a relatively restricted cadre of ruling elites, there has been growing recognition of a vast range of varied political and economic strategies (Feinman 2011). Recognizing this political variability raised fundamental questions about how societies that lacked despotic ruling elites managed themselves.

The degree of “collective action” apparent in premodern societies is closely related to other characteristics of their political economies (Blanton and Fargher 2008). While the concept of collective action was originally borrowed from institutional economics (e.g., Olson 1965; Ostrom 2000), archaeologists have used the term to describe all forms of joint endeavor among people who share a particular resource. All societies exhibit some degree of collective action (otherwise we would not be able to recognize them as societies), but some societies appear to have been more willing to invest in collective endeavors that benefit broader society. The capacity for collective action has thus been recognized as a valuable variable for comparing complex societies, and it appears to be associated with other processes, such as the degree to which a society relies on bureaucracy (Blanton and Fargher 2016). Societies that fall on the collective end of this continuum tend to offer a greater range of public goods and make investments in open and accessible infrastructures. Collective societies also tend to take on more representative political institutions that divide power (Feinman and Carballo 2018), such as the republic identified at Tlaxcallan in prehispanic Mesoamerica (e.g., Fargher et al. 2011). This appears to be related to the fact that more collective societies rely on “internal” resources, such as taxes on agrarian surplus, as opposed to “external” resource such as exotic raw materials acquired through trade (Feinman 2018). There thus appears to be positive feedback between the growth of collective action and political representation and, importantly, inclusion. This makes sense, as the production of public goods, such as large-scale infrastructure or civil administrative systems that are accessible to a relatively wide cross-section of people, necessarily requires collective labor and thus produces more collective forms of governance, which in turn potentially include more diffuse and varied political organizations. While it is certainly conceivable that Childe’s despotic ruling class could coerce society into collectivity, such a strategy would be at odds with the political inclusion that appears to be commensurate with collective action. This relationship between political inclusion and collective action may explain its occurrence in the absence of individual rulers, such as during the long period of neighborhood expansion at Teotihuacan in Mesoamerica (Cowgill 2015, p. 190). To understand how the world’s complex societies emerged, we must get beyond “elite-centered” and “exotics-fueled” models of social change (Chirikure 2020, p. 141). Past societies clearly achieved remarkable feats of collective action in the absence of a ruling elite. How did these relatively egalitarian complex societies organize their collective action?

Such egalitarian complex societies would have to organize their collection action without recourse to a fixed and immutable hierarchy. Heterarchy, wherein social elements are either unranked or have the potential to be ranked in different ways (Crumley 1995), must therefore play a more important role in societies that lack a ruling class. While hierarchy has long been associated with social complexity, the often unexamined dynamics of heterarchy were often as essential to, or perhaps even the causal driver of, many social transformations (DeMarrais 2013; McIntosh 2005a). For example, the first states in Mesopotamia were the outcome of social and economic processes far removed from the establishment of political hierarchies (e.g., Algaze 2008; Porter 2012; Stein 1998; Ur 2010). Collective forms of social organization instead required a rigorous process of consensus building across large cross-sections of society. These processes of consensus making, and the cooperation it engenders, are what make collective action possible in the absence of a coercive political hierarchy (DeMarrais 2016; DeMarrais and Earle 2017; Feinman and Carballo 2018; Halperin 2017). Collective action may thus be more likely in contexts where people engage in a particular activity as a result of emergent decision making, such as we would expect in a society without a ruling class. Using cooperation and consensus to undertake collective action is very different from the network-based exclusionary strategies employed by a ruling class. While cooperation and consensus could potentially have involved a single group of elites, but there is no theoretical reason to assume this as a prerequisite.

If a ruling class is not a prerequisite for cooperation and consensus, it is reasonable to theorize that both can be achieved in relatively egalitarian political economic contexts. This is important because comparative studies indicate that an increasing capacity for collective action shapes long-term trajectories of social change in many parts of the world, so there must be a wide range of powerful social mechanisms for maintaining both cooperation and consensus (Carballo 2013). Certain forms of collectivity appear to mitigate the ability of leaders to engage in egregious acts of coercion and accumulation (Blanton and Fargher 2016; Feinman 2018; Feinman and Carballo 2018). This is likely to lead to the production of public goods and infrastructures that benefit society at large, creating a strong positive relationship between egalitarian social relations and collectivity. Might reproducing specifically egalitarian social relations be a powerful way of maintaining consensus and cooperation, in turn fostering increasing levels of collectivity?

Though archaeologists should not be shy about questioning the role of a ruling class in early complex societies, they have tended to be. It has long been unclear whether the economic differences apparent in early complex societies were analogous to divisions between the working and capitalist classes that Marx (1976) defined by their differing relations to the means of production in industrial economies. There has been considerable effort to study the origins of these classes (e.g., Wurst 1999), and to understand archaeology’s role within capitalist class dynamics (e.g., McGuire and Walker 1999), but the deep history of class remains undertheorized. In response to Crone’s (1989) claim that classes did not really exist prior to the industrial revolution, Trigger (2003, pp. 45–46) suggested that, in fact, a range of prehistoric classes are apparent in “stratified” societies, even defining “early civilization” as “…the earliest and simplest form of class-based society.” In deep history, then, classes can be usefully considered stratified networks of corporate groups collectively defined by their economic status. And yet, archaeologists who compare early complex societies have been hesitant to argue that collective action and collectivity can emerge in the absence of elites.

What is left of Childe’s trait list if we remove a stratified ruling class of managerial elites? Craft specialization appears in a very wide range of societies and is not universally associated with inequality (Clark 1990; Costin 1991; Costin and Wright 1998; Flad and Hruby 2008). It has been well established that markets and merchants appeared earlier than predicted by traditional models of social complexity (e.g., Algaze 2008; Broodbank 2013; Hirth and Pillsbury 2013). Far from being restricted to political economies rife with hierarchy and coercion, trade has commonly occurred in contexts where a ruling class is absent (Oka and Kusimba 2008). Indeed, even standardized systems of weights and measures, clear evidence of people attempting to develop commensurate quantities of goods, have been recovered in contexts that lack significant wealth differentiation (e.g., Rahmstorf 2019).

Can there be states in the absence of a ruling class? This is a thorny question, as even when neo-evolutionary models were at their height, the “state” was a contested concept. In archaeology, the early state has since undergone a long process of redefinition and revision, and archaic polities are now understood to take a range of political and economic forms far removed from what Childe imagined (e.g., Feinman and Marcus 1998; Pauketat 2007; Robb et al. 2013; Wengrow 2010; Yoffee 2005). While there are certainly examples of complex societies where despotic kings made bombastic claims to power and authority (e.g., Smith 2003), there are at least as many instances of early states that cycled through periods of centralization and disintegration (Lawrence and Wilkinson 2015; Stein 1998; Ur 2010), or where formal political hierarchies were fragile and unstable (Yoffee 2016, 2019). Many societies, moreover, tended to favor cooperative and representative forms of governance (e.g., Fargher et al. 2011; Feinman and Carballo 2018; Halperin 2017; Wright 2018). Understanding how different political and economic formations emerge and disintegrate is an ongoing project, but it would appear that political coercion carries with it a range of higher costs and may make social formations more prone to disintegration, while cooperation avoids some of those costs. A collective state based on cooperation may in fact require no coercion, and therefore lack a ruling class to do the coercing.

Cities easily survive the theoretical excision of a ruling class. This is one of the reasons that urbanization has become increasingly untethered from the social complexity trait list, and indeed there is a considerable literature surrounding its definition and characteristics (Cowgill 2004; Smith 2009, 2014; Wright 2002). Social complexity is relatively independent of population size and concentration (Feinman 2011). Instead, urbanization refers to the aggregation and concentration of large numbers of people and things within particular settings (e.g., Gyucha 2019; McIntosh 2005a, b; Smith 2014; Trigger 2003; Wright 2002). Jennings and Earle (2016) compared the archaeological records of the world’s first cities and concluded that urbanization is only loosely associated with state formation and may have often occurred in direct resistance to efforts to build political hierarchies. Later cities certainly became entangled within large political projects, mainly at the behest of a ruling class seeking to take advantage of the economic growth stimulated by urbanization (e.g., Schortman and Urban 2011). Cities indeed appear to produce lots of things by concentrating people and resources, but they do so whether or not they also have a ruling class.

The relationship between a ruling class of managerial elites and wealth disparity could benefit from further research. It had been simplistically assumed that the concentration of power within a constrained ruling class would likewise lead to their acquiring a disproportionate share of wealth; however, archaeologists have found that social relations that increase the production of things often operate in ways that can be quite distinct from those that shape the flow of power. Wealth disparity can appear under social and economic conditions in which it should not, such as in the prehistoric Mediterranean’s low-growth environments (Leppard 2019). Thus, not all kinds of inequality are the same, and it is worthwhile to evaluate the relationships between processes that lead to economic changes and those that create political hierarchies. Through careful attention to how different kinds of political and economic inequality relate to social relations and property, it has also become clear that specific social changes do not necessarily co-occur in monolithic and all-inclusive shifts into social complexity. Indeed, there are different kinds of elites that emerge at different times, such as billionaires, who appear long after the advent of cities. It is certainly true that urbanization can sharpen economic differences, but this does not appear to be a universal law.

This is all to say that archaeologists have honed an excellent set of theoretical tools for examining the processes that bring about a ruling class and separating these processes from those that bring about social complexity. Collectivity, specialized production, long-distance exchange, and urbanization have all occurred in different combinations in different societies, whether or not at the behest of a privileged cadre of managerial elites. And yet, the assumption that the political economy of complex societies will inevitably stratify remains firmly entrenched, even in settings where there is no empirical evidence for a separate group of rulers who are better off than everyone else. For example, a popular argument is that there is a causal link between urbanization, increasing agricultural labor demands, and wealth disparity (Bogaard et al. 2018, 2019; Fernández-Götz and Krausse 2017; Fochesato et al. 2019; Porčić 2019; Smith et al. 2018). Even in contexts where archaeologists are confident that power is diffuse and collectivity predominates, it is often assumed that wealth stratification lies behind large societal endeavors. Large-scale investments in labor are then used to infer the concentration of wealth in the hands of a ruling class, whether or not there is evidence for that class. This is doubly unfortunate, as the best lesson to be derived from collectivity in the archaeological record is that there appear to have been many different ways of governing complex societies.

It is therefore theoretically feasible for complex societies to lack a ruling class, so how should archaeologists go about identifying the presence of ruling class in the past? Given the prevalence of collective action in the archaeological record, we should be skeptical of a simple positive relationship between monumental architecture and social complexity (e.g., Smith 2009), a position that has been repeatedly strengthened by the discovery of labor-intensive monuments that predate cities, states, and ruling classes, such as the ritual center of Göbekli Tepe in Anatolia (e.g., Dietrich et al. 2012). Rather, large investments of labor only indicate the presence of a ruling class when they clearly benefit a restricted subset of people. Elaborate tombs, aggrandizing monuments, or large and restricted temples and palaces are the best evidence of a ruling class in the past (e.g., Pollock 1999). Such structures not only materialize the labor of the many but also clearly benefit the few (e.g., Hayden 1998; Trigger 2003).

Monumental tombs are therefore perhaps the best examples of evidence for  the emergence of a ruling class. Each of the Old Dynasty Egyptian pyramids at Giza materializes the toil of thousands of individuals over decades to convey a single dead king to the afterlife (Wenke 2009, p. 297). These pyramids constitute large investments of the labor—and in some instances, lives—of many different people into structures that directly benefit only a single individual or their family. Retainer sacrifice is also strong evidence of a ruling class. The practice of killing and interring people upon the death of a ruler clearly reinforced the subordinate status of other classes—from specialists to commoners to prisoners (e.g., Campbell 2014; Morris 2014). Such sacrifices are seen in the Royal Tombs of Ur (Baadsgaard et al. 2011), which was constructed by the Indus civilization’s contemporaries in Mesopotamia. When clear evidence of this sort is absent, evidence for craft specialization, long-distance exchange, and even relative wealth differences in residential contexts cannot serve as a substitute.

When their access was clearly restricted to a small subset of individuals, palaces and monumental temples also offer strong evidence of a ruling class. Each kind of structure restricts access to private spaces—protected places to interact with the divine in the case of a temple (e.g., Delougaz 1940) or the private domiciles of a privileged household in the case of a palace (e.g., Preziosi 1983). Clear facilities for craft production are sometimes attached to these structures, an indication that the occupants of a privileged place levied control over the labor of the specialists who worked in the attached facilities. Fewer indices of inequality are available outside of palaces or temples, and developing methods for quantifying economic inequality from broader settlement assemblages is a worthwhile endeavor. However, this goal has not yet been realized (Oka et al. 2018). Gini coefficients of the distribution of space among a sample of domestic structures have been offered as a cross-cultural measure of wealth inequality (Kohler et al. 2017; Kohler and Smith 2018). However, structure size alone is not a reliable measure of inequality because it is not always clear how many structures a corporate group owns and not all structures had the same social functions.

Whether or not Indus society had a ruling class has rarely been the explicit focus of debates about the political organization of the Indus civilization. The significance of the relatively equitable distribution of luxuries in Indus assemblages was lost in the mid-20th century argument that Indus cities were built by invaders, whose military regime was thought to have imposed a high degree of conformity, homogeneity, and conservatism on the people over whom they reigned (Piggott 1950; Wheeler 1953, 1968). This paradigm was popular until researchers began asking about the presence or absence and number and nature of Indus polities in the mid-20th century (Possehl 2002). There are now many different views about whether the Indus civilization was a cohesive polity, a collection of interacting polities, or even whether it shared a unified material culture at all (Agrawal 2007; Chakrabarti 2000; Chase et al 2014a; Cork 2011; Kenoyer 1997a; Petrie 2019; Possehl 1998; Ratnagar 1991; Shinde 2016; Wright 2010, 2018). However, many of these discussions are hampered by the trait-based social definitions researchers inherited from neo-evolutionary archaeology. While all of the current interpretations offer major improvements over the invader paradigm, Indus archaeology often suffers from theoretical assumptions about what should be present in a complex society, privileging these assumptions over actual evidence for what was present. This is particularly clear in the debate surrounding whether or not the Indus civilization was a “state.” Here scholars have leaned most heavily on neo-evolutionary trait lists, which they believed could be used to determine whether or not Indus society had achieved a particular evolutionary level. The Indus state debate involved numerous scholars, and a comprehensive review of each position is not possible here. Instead, I offer a summary based on two particularly well-known positions within the debate.

Fairservis (1961, 1967) was an early proponent of the “stateless” paradigm, arguing that the Indus civilization was not a state based on an absence of political centralization and hierarchy. He contended that the Indus civilization was an amalgam of complex chiefdoms (Fairservis 1989). In response to critiques of neo-evolutionism in the 1990s, Possehl (1998) updated and reiterated Fairservis’ argument, reasoning that because the Indus civilization lacked clear evidence of a political hierarchy, it should not be classified as a state, even if its large populations, cities, and sophisticated architecture undoubtedly made it a “complex society.” The lack of a particular trait—in this case elites and sharp political hierarchies—justified the omission of the Indus civilization from the neo-evolutionary “state” category, implying adherence to the idea of progression through a sequence of social types but excluding the Indus civilization from the highest evolutionary category. Emphasizing categorization obscured important considerations of social process that were evident in specific patterns in the archaeological data.

The stateless argument prompted a strong reaction, which I call the “state-level” paradigm. Kenoyer (1994, p. 76) advocated the state-level position, critiquing the “stateless” paradigm’s reliance on trait lists developed in other social contexts but suggesting that a lack of evidence for a ruling class in the Indus civilization was the result of vagaries in archaeological excavation and recording, not the actual absence of a ruling class. In his view, the presence of craft specialization was enough to place the Indus civilization into the state category and to infer stratification without direct evidence, a position that was foreshadowed in a growing body of work on craft production at Mohenjo-daro (e.g., Vidale 1989). By inferring a ruling class from evidence of craft specialization, adherents of the state-level paradigm implicitly adopted the same static, neo-evolutionary trait list, substituting what would be considered clear evidence of a ruling class in other parts of the world—palaces, tombs, and aggrandizing individuals—for sophisticated craft technologies and extensive interaction networks.

By the late 1990s, the concept of heterarchy had been adopted by Indus archaeologists in both the stateless and state-level paradigms to explain patterns in Indus city planning and the high number of social groups involved in Indus craft production (Kenoyer 2006; Possehl 2002). In both paradigms, Indus political organization emerged through the heterarchical interaction of many different social groups. It remains unclear how heterarchy impacted other aspects of social organization, such as the distribution of wealth, or to what extent Indus heterarchy formed an alternative to hierarchy. Still, it is now widely argued that multiple groups contributed to the construction of Indus cities and the economic activities undertaken within them, and none seemed to dominate the others (e.g., Petrie 2013a, b, 2019; Vidale 2010, 2018b; Wright 2010, 2018). This is, of course, true of most cities, which are rarely controlled by a sole centralized authority. However, again, it is important to address the relationship between heterarchy and the presence or absence of a ruling class. While it is often counterposed to hierarchy, heterarchy is found in otherwise extremely unequal societies (Brumfiel 1995), characterizing the elite interactions between powerful political hierarchies in early medieval Ireland (Wailes 1995) or competition between imperial elites in different parts of the Roman Empire (Tainter and Crumley 2007). A comprehensive consideration of the relationship between heterarchy and governance is beyond the scope of this paper, but I do not think there is sufficient evidence to support the view that a ruling class of managerial elites—heterarchical or otherwise—directed the political organization of Indus society.

In this review, I focus on the kinds of evidence of inequality that would be sufficient to identify a ruling class from a comparative perspective. To avoid assumptions about stratification, I conceptualize social units in the Indus civilization without assuming they were stratified into different political and economic classes. The anthropological term, “corporate group,” is thus an appropriate concept for thinking about Indus political organization. A corporate group is made of up people who enjoy shared access to common property (e.g., Goodenough 1978; Hayden and Cannon 1982; McIntosh 2005a). All societies include different kinds of corporate groups—quintessentially households but also palaces, temples, guilds, governments, militaries, and other kinds of associations. The degree to which corporate groups restrict production and have uneven access to wealth is what determines whether they differentiate into classes, wherein a particular corporate group monopolizes a specific relationship to the means of production that places its members in a different stratum than other corporate groups.

The Indus civilization emerged across a larger area than many other early complex societies, and its substantial geographical extent is considered one of its defining characteristics (Kenoyer 1997a; Petrie 2013a, b; Possehl 2002; Shinde 2016; Sinopoli 2015; Wright 2010, 2018). Differences in environment and material culture divide the Indus civilization into five regions: northwest India, the Upper Indus Valley, Cholistan, the Lower Indus Valley, and Gujarat (Chakrabarti 2009; Kenoyer 1997a; Possehl 1999; Sinopoli 2015; Wright 2010) (Fig. 1). By around 3300 BC, people in each region began building permanent settlements—each maximally around 10 ha—that had large architectural features, such as rectilinear mud-brick architecture and mud-brick walls surrounding a portion or the entirety of the settlement (Fig. 2) (e.g., Ajithprasad 2002; Ajithprasad and Sonawane 2011; Bisht 2015; Joshi et al. 1984; Lal 2003; Possehl 1999; Rajesh et al. 2013). At Kalibangan, for example, thick walls enclosed a complex of smaller “houses” that were arranged in neat rectilinear blocks (Lal 2003). Kot Diji’s early plan includes a major wall that separated two clusters of smaller houses that do not differ significantly in size or available amenities (Khan 1965). Similar patterns are reported from Harappa (Kenoyer 2008; Wright 2010), Dholavira (Bisht 2015), Farmana (Shinde et al. 2011), Rehman Dheri (Durrani et al. 1991), and Surkotada (Joshi 1990). Despite evidence of large-scale construction—a significant form of collective action—none of these structures appear to have had features associated with a particular corporate group. Indus egalitarianism thus originated long before Indus settlements became cities.Fig. 1

Map of the Indus civilization and some contemporary neighboring material cultures. Five main regions are highlighted, as are the size and location of sites discussed in the text. Data are projected in WSG 1984 on version 4.0 of the Natural Earth Basemap using QGIS 3.10

There are different views regarding what prompted the growth of Indus cities around 2600 BC. Some have argued that the urbanization process was propelled by migrations from urban centers into different parts of the Indus zone (e.g., Possehl 1999). More common is the view that the Indus civilization emerged through multiregional interaction (e.g., Agrawal 2007; Chase et al. 2014a; Kenoyer 1998; Shaffer 1992; Shinde 2016; Shirvalkar 2013; Wright 2010). This latter view would make sense if the Indus civilization grew through consensus and cooperation, and not military expansion. Only five sites—Harappa, Rakhigarhi, Mohenjo-daro, Ganweriwala, and Dholavira, one in each region—are typically identified as cities. Many of the hundreds of other reported Indus sites are, in fact, smaller than 30 ha (e.g., Fairservis 1989). As a result, there has been a concerted effort to integrate these “satellite” or “rural” settlements into theories of Indus urbanization, with some scholars identifying patterns of specialization at small settlements (Wright 2010, p. 143) and others suggesting that small settlements materialized the “rural complexity” of Indus civilization (Parikh and Petrie 2019).

After ~1900 BC, major changes impacted nearly every aspect of life in the Indus civilization. Still, many scholars have noted the continuation of many elements of Indus material culture in the wake deurbanization, suggesting that the process was a complex transformation (e.g., Petrie 2017). As landscape datasets have grown especially since 2000, it has become increasingly apparent that environmental changes played an important role in Indus deurbanization (Giosan et al. 2012; Madella and Fuller 2006; Petrie et al. 2017; Wright 2010). There is an apparent correlation between Indus deurbanization and a weakening of the Indian summer monsoon associated with the broader 4.2k event (Dixit et al. 2014a, b). There also are clear correlations between shifting settlement locations and deurbanization that resulted in an eastward shift in population (e.g., Green and Petrie 2018; Madella and Fuller 2006; Petrie et al. 2017; Teramura and Uno 2006; Wright 2010). Surveys have revealed many concentrations of sites in northwest India with Indus material (Chakrabarti and Saini 2009; Dangi 2018; Joshi et al. 1984; Kumar 2009; Parmar et al. 2013; Pawar 2012; Sharan et al. 2013; Singh et al. 2010, 2011, 2018, 2019). This was perhaps due to the fact that summer and winter rainfall systems overlapped in the region, which ensured that alternative sources of water were available (Petrie et al. 2017).

Aside from the excavation of ephemeral “Late Harappan” layers at Harappa and Dholavira, few clear excavation data are available from the post-Urban phase (c. 1900–1300 BC). Only two major post-Urban sites—Bhagwanpura (Joshi and Madhu 1993) and Hulas (Dikshit 1984)—have been extensively excavated, and neither produced the clear site plans or structure foundations analogous to those found in Indus cities. It would thus appear unlikely that there were palaces in the post-Urban phase. Post-Urban ceramic vessel forms are clearly related to early urban forms, but many signature elements of Urban phase material culture disappeared (Wright 2012). With deurbanization, writing, seals, weights, long-distance exchange, and large nonresidential architecture all disappeared (Petrie 2017, 2019). However, small settlements continued and even increased in many parts of northwest India, which may be evidence of rural resilience that carried through urbanization and deurbanization (Petrie 2019). There was a significant increase in the quantity of faience ornaments produced in northwest India (Shinde et al. 2008; Uesugi et al. 2013), which may reflect the application of specialized knowledge to the mass production of objects that do not require raw materials from long-distance exchange networks.

Visceral evidence of the social impact of deurbanization is apparent in skeletal material from Harappa’s post-Urban cemeteries. With the loss of Indus cities there appear to have been deterioration in overall health and increases in physical violence that affected some portions of the Indus population more than others (Robbins Schug et al. 2013). The health of the post-Urban population at Harappa sharply declined, with pronounced increases in the frequency of diseases like tuberculosis and leprosy (Robbins Schug et al. 2013, p. 4). There may also have been a hardening of social boundaries. At Harappa, a distinction in burials appears in the differential treatment of sick and healthy individuals (Robbins Schug et al. 2013). Individuals with leprosy were confined to Area G, outside of the city walls, suggesting that sufferers had perhaps been singled out and confined to particular cemeteries. Worse still, there is evidence of a considerable increase in interpersonal violence, especially toward biological females and immature individuals. Dental lesions and increased vascularization indicate that the post-Urban population of Harappa faced vitamin C deficiency, anemia, and metabolic disorders, a dramatic change from the Urban phase (Robbins Schug and Blevins 2016). These changes certainly raise questions about a larger process of deurbanization that may have ended Indus egalitarianism. Indus cities may have acted as a possible brake on inequality, which increased sharply in their wake. This hypothesis is worthy of further investigation.

The relative egalitarianism of the Indus civilization has been evident since the earliest excavations at Mohenjo-daro, but there has since been remarkable reluctance to investigate it. This is true both of scholars who assumed the Indus civilization was led by priest-kings and by those who thought that the Indus lacked a state. The inability to account for Indus egalitarianism has resulted in the omission of Indus civilization from comparative discussions of social complexity, which now acknowledge a much broader range of nonhierarchical, noncoercive, and nonelite-centered social formations (e.g., Feinman and Carballo 2018). Indus archaeology has much to contribute to this area of study, and my aim in this article is to encourage a deeper exploration of the implication that complex societies can be egalitarian. However, to grow the critical role for Indus civilization in comparative archaeology, Indus archaeologists need to lose some bad habits.

Foremost among these is the tendency to lament the lack of data from the Indus civilization, or to argue that Indus datasets are unusable because they were collected so long ago. Sure, the Indus civilization could use more research, but the same could be said for most early complex societies. This kind of argument has promoted the view that we simply do not know enough about Indus civilization to explore the implications of what we do know. While there have probably been more surveys and excavations in Mesoamerica, Mesopotamia, and the Mediterranean, the last century of Indus archaeology in South Asia has been an enormously rich and successful endeavor. Building on the talents of the network of researchers cultivated in the Archaeological Survey of India, Marshall rediscovered one of the world’s earliest Bronze Age societies (Lahiri 2005). Mackay’s (1938, p. xvi) excavations at Mohenjo-daro, which incorporated a subdatum in an effort to meticulously track changes in material culture through time, were far more methodologically advanced than many contemporary excavations in Mesopotamia. Subsequent generations of South Asian archaeologists redrew the map of the ancient world. Excavations at numerous Indus settlements, such as Lothal (Rao 1979), Dholavira (Bisht 2015), Kalibangan (Lal 2003; Lal et al. 2015), and Kot Diji (Khan 1965), have greatly enhanced our understanding of the Indus civilization. A strong tradition of survey has revealed hundreds of small settlements and produced distribution data that rival many contemporary archaeological datasets (Chakrabarti and Saini 2009; Green et al. 2019; Green and Petrie 2018; Joshi et al. 1984; Kumar 2009; Mughal 1997; Mughal et al. 1996; Parmar 2012; Pawar 2012; Possehl 1999; Rajesh 2011; Shaffer 1987; Sharan 2018; Singh et al. 2010, 2011, 2018, 2019; Suraj Bhan 1969, 1975; Wright et al. 2003, 2005). Like all archaeological evidence, Indus datasets have their limitations, but it is evident that palaces, elaborate tombs, and individual-aggrandizing monuments are not present at Indus sites. This lack of stratification does not diminish the role of Indus civilization in the study of social complexity; in fact, it does the opposite. Rather than following the general rules proposed for other complex societies, the Indus civilization challenges us to rethink the fundamental connections between collective action and inequality. Sometimes an absence of evidence is indeed evidence of absence, especially when you have spent a century looking for it.

Collective action can increase without the guidance of a managerial ruling class. Indus communities devised ways of building a neighborhood platform or wall, incorporating labor from multiple corporate groups, with minimal coercion or exclusionary politics. They maintained a standardized system of weights and measures across the broad extent of the Indus civilization over centuries, which likely entailed the consent of generations of corporate groups. However, none of these corporate groups appear to have used these standardized systems to establish permanent dominance over the others. Indus communities were likely home to people with a wide range of identities (e.g., Clark 2003; Kenoyer 1998; Rizvi 2011). Thus, the emergent nature of Indus collective action may explain the materialization of identities that crosscut local social groups, be they in the cities (e.g., Davis 2018) or in rural Gujarat (e.g., Chase et al. 2014a). These corporate groups drove the urbanization process, which required the production of many generalized “public goods”—streets and drainage systems, large and small buildings with public access, and informational and regulatory technologies like weights and seals that would have facilitated exchange among different corporate groups (e.g., Green 2020).

The absence of a ruling class and relative egalitarianism does not necessarily indicate that there were no other forms of inequality in Indus society. Indeed, differences in the treatment of young and old (Robbins Schug n.d.), the noted heterogeneity in Indus material culture (Petrie et al. 2018), along with the likely presence of at least three genders (Clark 2003, 2016) and differences in the mortuary treatment of people belonging to different biological sexes (Robbins Schug et al. 2012), and possible social hierarchies based on potential differences in urban infrastructures (Rizvi 2011; Wright 2010; Wright and Garret 2018) all suggest that there were a range potential cleavage planes in Indus society. While many differences became more pronounced with deurbanization (Robbins Schug et al. 2013), relative equality may have prevailed across a wide range of identities when Indus cities were at their height. These other potential loci of inequality deserve further research; however, none provide evidence of a ruling class.

If a ruling class is not a prerequisite for collective action, then collective action must have been an emergent outcome of interactions among heterarchical corporate groups. Comparative archaeology reveals that cooperation, as opposed to coercion, is a key mechanism for generating collective action (Carballo 2013; DeMarrais 2016). It is reasonable to theorize that Indus corporate groups devised means of governing collective action without permanently elevating one over the others, such as agreeing to standardized protocols for craft production. One way may have been through the creation of specialized spaces for exchange, negotiation, and interaction at the spatial interstices between corporate groups, such as between neighborhoods or along important streets and roads. I have argued that such “small public structures” are evident at Mohenjo-daro, where urbanization appears to have resulted from the initial aggregation of larger corporate entities, represented in the large structures constructed in Block 1 and 11 of Mohenjo-daro’s DK-G area (Green 2018). These initial large corporate compounds were replaced over time by houses organized along the streets’ grid at a time when economic specialization was increasing and “small public structures” appeared between neighborhoods. Corporate groups that began the Urban phase as generalists who, over time, divided into smaller more specialized corporate entities, nonetheless maintained a high degree of consensus. The construction of specialized spaces may even have ensured that none of Mohenjo-daro’s increasingly specialized corporate groups was able to accumulate wealth at the expense of others (Green 2018).

Egalitarianism thus appears to have been a boon to collective action in the Indus civilization. Corporate groups may simply be more willing to invest in collective endeavors if benefits are not constrained to a restricted subset of elites. At the same time, the efforts of a subset of elites to exact labor from everyone else may restrict collective action by placing boundaries between the corporate groups that make decisions and those whose labor materializes those decisions. A positive relationship between egalitarianism and collective action can also explain certain heterarchical dynamics. In societies with a ruling class, heterarchy among ruling groups may restrict the overall scope for collective action by dividing efforts to exact labor from the same pool of commoners. However, when heterarchy expands the number of unstratified corporate groups in an egalitarian society, it theoretically increases the potential for emergent, consensual, and cooperative collective action. Heterarchy, then, may potentially act as a brake on coercive power among social groups, and societies with a larger number of heterarchical social groups may inculcate more such brakes, restricting coercive authority among different groups on the whole. Rather than arguing that the Indus civilization was heterarchical, we should ask whether heterarchical corporate groups were more numerous in the Indus civilization than in early societies with exclusionary elites, and if so, why? Exploring these questions may reveal how the same social processes, like urbanization and economic growth, can result in different social outcomes.

The increase in economic activity that accompanied Indus urbanization supports the idea that concentrating human activities and fostering specialization drives economic growth. A major indicator of this growth is craft specialization, but it has long been clear that there was not a simplistic relationship between specialization, exchange, urbanism, states, or other traditional harbingers of social complexity (Costin 1991; Inomata 2008; Schortman and Urban 2004; Sinopoli 2011). The lack of a ruling class in Indus cities supports the argument that early cities were not invariably seats of elite power (e.g., Jennings and Earle 2016). It would be worthwhile to explore the connection between specialization and egalitarian growth in the Indus, which may reveal different forms of economic attachment. Certain crafts are associated with one another at Indus sites, and production facilities are occasionally found in association with large structures (e.g., Green 2018; Sher and Vidale 1985), a form of attachment that is curious given the lack of a ruling class. Though the notion of attached specialization has been repeatedly critiqued (e.g., Costin 1991), it remains a common assertion that the control of attached specialists is a key indicator of social complexity (e.g., Nash 2019). By definition, such attachments can exist only in a society divided into ruling and specialist classes. Indus artisans may have instead formed attachments to many different kinds of corporate groups. The nature of these attachments between different kinds of heterarchical corporate groups remains an important topic for future research.

Research on Indus wealth and value suggests that people in the Indus valued distinct kinds of things differently (Kenoyer 1992, 2000; Miller 2008a; Rissman 1988). However, the same can probably be said for all societies. Ethnographic research on many societies that lack a ruling class rely on different forms of value in different situations. Some devised entire currencies to “…arrange marriages, establish the paternity of children, head off feuds, console mourners and funerals, seek forgiveness in the case of crimes, negotiate treaties, [and] acquire followers” (Graeber 2011, p. 130). Though certain categories of objects are rare in the Indus, their distribution does not appear to be particularly restricted, at least within the cities, strongly suggesting that little fell within the exclusive control of a particular ruling class. While some Indus graves contained more ceramic vessels than others, no Indus graves featured retainer sacrifice or monumental aggrandizements of a single ruler or family, such as Pepy’s pyramid in ancient Egypt (Wenke 2009, p. 2) or the Shang China tombs (Campbell 2014, p. 99). The absolute range of wealth distributions in the Indus civilization has not been directly compared to other early complex societies, without which it is difficult to ascertain whether wealth differentials in the Indus were commensurate.

One of the most positive developments in Indus archaeology has been the dramatic increase in data and interest in the small settlements of the Indus civilization. In southern Mesopotamia, settlements of different sizes exhibited qualitative differences; towns, cities, and villages all performed different roles in the broader landscape (e.g., Adams 1966). In the Indus, it is unclear the degree to which small settlements were distinct from the cities. Wright et al. (2003, 2005) have argued that the small settlements in the Upper Indus Basin were “satellites” of urban communities and as such exhibited the same degree of complexity as the cities. On the other hand, Parikh and Petrie (2019) have argued that the small settlements of northwest India were “rural” in character, and although their communities appear to have had access to exotic goods, it has not been established that they hosted a population of craft specialists. It remains an open question whether small settlements were qualitatively different from one another or from the cities; until this question is resolved, it will be difficult to ascertain if Indus egalitarianism extended across its broader landscapes.

The Indus civilization lacks evidence of palaces, elaborate tombs, aggrandizing monuments, and significant discrepancies in grave goods. At the same time, Indus cities boast considerable evidence of sophisticated technologies, commodious houses, large-scale nonresidential architecture, and long-distance interaction. The Indus civilization was perhaps the world’s most egalitarian early complex society, defying long-held presumptions about the relationships between urbanization and inequality in the past. Residents of Indus cities enjoyed a relatively high standard of Bronze Age living. Unfortunately, generations of archaeologists have largely overlooked this phenomenon, focusing instead on contextualizing the Indus within a rigid trait-driven set of evolutionary categories. Some have argued that the Indus was an empire, some that it was stateless, and others that it was a state-level society led by competitive merchant elites. None of these arguments satisfactorily addresses the extent, diversity, and variability of the Indus civilization as a whole. Archaeological data from South Asia have greatly improved since the Indus state debate that culminated in the 1990s (e.g., Petrie 2019; Ratnagar 2016; Shinde 2016; Wright 2018); numerous Indus sites are now known to archaeologists, and the environmental contexts in which South Asia’s first urbanization and deurbanization occurred are now much clearer. To identify inequality, and class in particular, archaeologists have honed a strong set of arguments about mortuary data, palace assemblages, aggrandizing monuments, and written records (Feinman 1995), and efforts are underway to develop similar indices for household data as well (Kohler and Smith 2018). In a century of research on the Indus civilization, archaeologists have not found evidence for a ruling class that is comparable to that recovered in many other early complex societies. It is therefore time to address the egalitarianism of Indus civilization. Urbanization, collective action, and technological innovation are not driven by the agendas of an exclusionary ruling class and can occur in their total absence. The priest-king is dead. The Indus civilization was egalitarian, but this is not because it lacked complexity; rather, it is because a ruling class is not a prerequisite for social complexity.