Cultural Multilevel Selection
"I draw a parallel between Scheidel’s central argument and recent developments in cultural evolution (Richerson and Christiansen 2013), the most relevant of which is Cultural Multilevel Selection (CMLS). The logic of CMLS, applied to the evolution of western European polities, is simple and quite compelling. Cooperation within a polity imposes costs on all parties. Rulers prefer to wield absolute power over the nobles and commoners, which leads to despotism. Selfish elites oppress commoners but would rather de-cline contributing resources to the rulers. Commoners just want to survive and are disinclined to pay taxes or provide recruits for wars. Intense interpolity competition, however, compels rulers and their constituencies to cooperate and compromise. Those polities that fail to achieve at least some degree of cooperation are eliminated and replaced with others that are internally more cooperative. This is what happened to early modern Poland-Lithuania, which lost its capacity for internal cooperation and was carved up by its neighbors in a series of “partitions” in the eighteenth century. As time unfolds, the level of intrapolity cooperation needed for survival grows, as only the most cohesive ones survive. This is the essence of CMLS: polity-level beneficial traits can evolve despite their costs for intrapolity constituencies, but only under the conditions of intense interpolity competition (Turchin 2016). Note that “polity-beneficial traits” include not only cooperative social norms and institutions, but also military technologies, economic innovations, prosocial religions, and cultures of knowledge. Furthermore, elimination of uncooperative and dysfunctional polities is only one mechanism of CMLS, if the most powerful. Equally important, and perhaps more common in action, is selective imitation of successful polities. This was most clearly visible in the realm of military innovations. Under the conditions of intense interstate warfare following the Military Revolution of the fifteenth and sixteenth centuries (Roberts 1956), new models of firearms and cannon, innovations in tactics and drill, and developments in fortification and siege warfare were eagerly sought after and copied. Similar processes were involved in other realms—econo-mics, finance, technology, and science, of which many examples are discussed in Escape from Rome. Interpolity competition is a special case of a more general process, cultural group selection, which is still a controversial subject among evolutionary scientists (see the programmatic article by Richerson et al. 2016 and the commentaries on it). Curiously, however, the mechanism of cultural group selection is the core of many theories in economics, archaeology, and other social sciences, although they do not use this particular term. Examples include the “creative destruction” of Joseph Schumpeter, “peer-polity interactions,” first introduced by Morton Fried (1967)and later formalized by Renfrew and Cherry(1986), and, of course, the central argument in Escape from Rome."