Carles Boix has written a very impressive book, full of novel sources of data and insights about the intertwined processes of economic and political development. In it he draws heavily on prior work like his 2003 Democracy and Redistribution, but combines those arguments with highly innovative approaches to the empirical study of early societies that existed prior to the advent of writing and historical records.

While much of the development field has focused on randomized experiments that necessarily consider micro issues, Boix is unafraid to take on the largest of macro questions. He is writing very much in the tradition of two other recent efforts to present a unified theory of development that encompasses the phenomenon’s economic and political dimensions: Violence and Social Orders: A Conceptual Framework for Interpreting Recorded Human History (Douglass North, John Wallis, and Barry Weingast, 2009) and Why Nations Fail: The Origins of Power, Prosperity, and Poverty (Daron Acemoglu and James Robinson, 2012).

Political Order and Inequality both builds on and goes considerably beyond these neoinstitutionalist writers. Boix argues that North, Wallis, and Weingast overemphasize parliaments, formal property rights, and constitutional settlements like the Glorious Revolution of 1689 in their account of the rise of modern “open access” orders. They neglect military competition and the way that evolving military technologies favor specific social groups; thus, the use of the horse and the iron stirrup increased inequality by giving military advantages to the aristocracy. Boix points out that there were actually two equilibria that emerged in the early modern period, the monarchical one emphasized by North, Wallis, and Weingast and a republican one that existed in Italy, the Netherlands, and of course North America, where power was held by a broader oligarchy. Which form ended up prevailing depended on the balance of power between “looters” (i.e., the predatory armed aristocracy) and “producers” (i.e., merchants and early capitalists, p. 65) as they made use of military technologies from the gun to the trace italienne. While military dominance is related to general economic growth, it is not coterminous with it; hence, mounted predators from Central Asia could dominate richer agrarian societies for many centuries.

With regard to Acemoglu and Robinson, Boix notes quite properly that their definition of good institutions is so broad that “instead of explaining (the absence of) growth, it turns the outcome that we can explain … into the explanation itself” (p. 221).

One of the great virtues of Political Order and Inequality is its creative use of new data sets to illuminate several important historical transitions. Thus, for example, in explaining the rise of states out of “foraging societies,” Boix makes use of the Ethnographic Atlas that covers more than 1,100 early societies, and is able to correlate political outcomes like state formation and social hierarchy against a wide variety of biogeographical variables, such as population density, domesticatible animal species, and exogenous technological shocks. Similarly, he uses data on height distributions in primitive societies as a proxy for income inequality in societies for which no recorded income data is available, making use of Franz Boas’s famous data set gathered from living Native Americans early in the twentieth century. Boix shows that in primitive societies, inequality increased with the introduction of agriculture and the growth of early states, and decreased with the spread of republican governments in the modern era, as well as being affected by the introduction of certain military technologies like the horse. This analysis mostly confirms what anthropologists have believed for some time, placing these findings on a much broader empirical foundation.

The book thus usefully critiques and extends existing rational choice models of political development, adding as a separate independent variable the evolution of military technologies, and demonstrating the possibility of alternative equilibrium outcomes—particularly the republican one—as a result. Unlike either the North-Wallis-Weingast or Acemoglu-Robinson volumes, which do not explain change over time, Boix presents a developmental theory in which endogenous change in both production and military technologies drives the major political and economic transitions in human history.

The limitations of this approach are related to its rational choice framework more broadly, that is, a framework that assumes that human behavior can be explained as the result of interactions of selfish but rational individuals seeking to maximize their utilities. Boix’s first chapter, entitled “Tabula Rasa,” begins deductively from the assumption that early human beings lived in a state of anarchy, and began to spontaneously organize their interactions through rational calculation of self-interest. This assumption is contradicted by much of what is now known about evolutionary psychology and early primate and human behavior. As noted by Melvin Konner (The Tangled Wing: Biological Constraints on the Human Spirit, 1982), Carl Degler (In Search of Human Nature: The Decline and Revival of Darwinism in American Social Thought, 1991), and Steven Pinker (The Blank Slate; The Modern Denial of Human Nature, 2002), the human mind was never the blank slate imagined by John Locke or contemporary neoclassical economists. Rather, it is filled with evolved structures that promote social cooperation, not as a matter of rational choice but through faculties rooted in the emotions. Kin selection and reciprocal altruism are hard-wired into primate brains; early human groups as well as the higher primates from which they evolved never lived in a state of anarchy. It is true that rates of violence have decreased over the 50,000 or so years that behaviorally modern human beings have existed (Norbert Elias, ed. [1978], The Civilizing Process: The History of Manners; Lawrence Keeley [1996], War Before Civilization; Steven Pinker [2011], The Better Angels of Our Nature: Why Violence Has Declined; and Ian Morris [2014], War: What Is It Good For?). However, this has been the product of successive forms of social organization that simply increased the scale on which societies could be pacified.

By lumping all prestate-level forms of social organization into a single “forager” category, Boix misses one of the most important transitions in early human social organization, the shift from band-level societies to tribal ones, or, in anthropological terms, to societies based on segmentary lineages. In the latter type of society, individuals trace their descent to a common ancestor who could be several generations removed; this allowed the vast scaling up in the size of social organizations and is the reason why lineage-based or tribal societies could overwhelm band-level groups that usually consisted of no more than 50 to 100 closely related individuals.

The development model presented in Political Order and Inequality is relentlessly materialistic: Boix asserts that “self-interest dominates the external or social behavior of individuals in stateless societies” (p. 249) and dismisses Weber’s theories about the role of religion in the transition to modernity (pp. 206, 255). The words “religion” and “legitimacy” do not appear anywhere in the book’s index. Yet while specific theories like those of Weber may be contested, ideas are critical to understanding all political transitions.

For example, the shift from band- to tribal-level societies, which occurred in virtually every human society around 10,000 years ago, was based on a religious idea, that is, the power of dead ancestors and unborn descendants to affect one’s happiness in the present. Absent this ideational framework, it is not obvious why one should prefer cooperating with a third or fourth cousin one has never met over a friendly stranger. Indeed, loyalty to kin, based partly on human biology and partly on deeply embedded norms of fictive kinship, meant that human societies stuck with lineage organizations long after they ceased to be functional. The transition to state-level societies, therefore, required extraordinary institutional arrangements in order to overcome this inertia, such as the Arab-Ottoman practice of capturing young non-Muslim boys and raising them to be soldiers and administrators precisely because the indigenous population could not be shaken of tribal loyalties. This is a problem that continues to inhibit legitimate state formation in the contemporary Middle East.

Similarly, the transition to modern liberal democracy cannot be explained without reference to ideas, in particular the idea of the universality of human dignity (Tocqueville [1835] 2000, Democracy in America). The material self-interest of different social classes—the old landowning oligarchy, the bourgeoisie, and rising proletariat—were of course critical social determinants of the spread of democracy. Boix’s earlier theory of the importance of mobile versus fixed capital (Democracy and Redistribution) is a relevant part of this story. But the perceived self-interest of a social class is not simply determined by its economic position or by technology. In nineteenth-century Europe, proletarian class consciousness was undermined by an alternative form of mobilization based on the idea of nation, leading to two devastating world wars. As a result of this disaster, the way was paved for a fuller normative commitment to democracy in Europe after 1945. As Ernest Gellner (Nations and Nationalism, 2006) suggested, religion today plays a similar role in the Middle East, where Islam has displaced class self-interest as the dominant form of social mobilization.

Political Order and Inequality commendably bucks the trend toward the ever more micro study of development, and brings new data to bear on many of the classical problems of social theory. It would be better, however, if the author saw the rational choice framework as a starting point for theory, rather than as a self-contained system capable of explaining the whole of human development.