This chapter begins by looking at Waltz’s other political ordering principle, hierarchy – which, like anarchy, is not in fact an ordering principle. Saying that a system “is hierarchical” merely indicates that it has some unspecified set of relations of stratification and functional differentiation. “Hierarchy,” rather than a structural ordering principle, is a residual category of non-anarchic orders (that, like most residuals, obscures the diversity of the “things” lumped together). And, as the preceding chapters have shown, most international systems, which by definition are anarchic, are also hierarchical. Therefore, even if anarchy and hierarchy are ordering principles, international systems do not have singular ordering principles. The remainder of the chapter looks critically at recent efforts by Ryan Griffiths and by Mathias Albert, Barry Buzan, and Michael Zurn to develop alternative accounts of political ordering principles. I conclude that the problem is not that Waltz has misidentified the ordering principles of international systems but that international systems do not have ordering principles.

Waltz claimed that although functional differentiation is inherently a feature of the structure of political systems, the units of anarchic systems are functionally undifferentiated. But states clearly perform differentiation functions than nonstate actors. And, as Waltz emphasized, great powers perform managerial functions in international systems that lesser powers do not. Furthermore, his focus on the similarity of great powers ignores this functional differentiation in the system in favor of attention to particular attributes of one type of parts. Turning to the distribution of capabilities, Waltz’s focus on system polarity (the number of great powers) looks not at how capabilities are actually distributed but only where they are concentrated. This is especially unfortunate because the relativity of power means that the places where capabilities are not concentrated is of great structural importance. And Waltz perversely excludes inequalities of power and relations between the strong and the weak from his account of international political structures.

This and the following chapters offer substantive applications of a relational/systemic understanding of international systems. This chapter looks at how international actors are differently placed (and shaped) by their authority, status, and roles; by the principles, norms, and rules that govern their actions; and by the institutions and practices in which they participate. The chapter offers three illustrations. First, I suggest that international systems can profitably be understood as having constitutional structures composed of principles and practices of international legitimacy, principles and practices of domestic legitimacy, foundational functional practices, and hegemonic cultural values. Second, I look at the great variety of types of security systems, including (various types of) systems organized around unit autonomy, systems of hierarchical subordination, and transnational security communities. Finally, I look at the transformation of post-World War II international society through norm-driven processes that abolished aggressive territorial war and overseas colonial empires.

This book explores some implications of studying international relations from a systemic perspective. This chapter takes on the preliminary tasks of defining systems, identifying distinctive characteristics of systemic explanations, and situating systems approaches in a broader context of relational framings. A system is a bounded set of components of particular types, arranged in definite ways, operating in a specific fashion to produce characteristic outcomes, some of which are emergent. The arrangement and operation of the components produce “emergent” “systems effects;” properties and outcomes that cannot be fully understood through knowledge of the parts considered separately. I emphasize the relational character of systemic explanations and their reliance on mechanisms and processes, in order to foster developing a relational processual systemic perspective within a pluralistic IR.

In sharp contrast to dominant (Waltzian) understandings in contemporary IR, I argue that anarchy neither is an ordering principle nor has determinate effects – and therefore is not central to the structures of international societies. Anarchy, understood as the absence of a government, is not an ordering principle. (It tells us one way in which a system is not ordered.) Understood as the absence of hierarchy, anarchy is not the ordering principle of international systems. (For example, great power states systems are defined by the hierarchical superiority of states over nonstate actors and of great powers over lesser powers.) Furthermore, the absence of a government has no determinate effects (which I show both by identifying a wide range of consequences of the absence of a government and by looking at the empirical case of simple immediate-return hunter-gatherer societies). I also show that framing the absence of an international government as anarchy, and making anarchy a core concept in IR, is largely attributable to the impact of Waltz’s Theory of International Politics (1979).

One of Waltz’s major contributions was the idea that political structures can be specified, in a rough first approximation, by ordering principle, functional differentiation, and distribution of capabilities – an understanding that remains largely taken-for-granted in contemporary IR. This chapter shows, however, that this tripartite conception can neither accurately nor fruitfully depict the structure of three simple anarchic systems: the Hobbesian state of nature, immediate-return forager societies, and great power states systems. In fact, Waltz’s depiction of great power states systems, his implicit model of a generic international system, is wildly inaccurate on all three of his dimensions of structure. Great power states systems, rather than lack hierarchy, are structured by the hierarchical superiority of states and great powers. Great powers, states, and nonstate actors perform different political functions. And the standard Waltzian account of the distribution of capabilities as a matter of the number of great powers (“polarity”) is about as useful as depicting the distribution of wealth in a society by the number of billionaires.

IR typically understands levels as levels of analysis that produce analytic/reductionist (rather than systemic/relational) explanations. Causes, separated by levels, are looked at as independent variables understood as distinct sources of explanation. Systemic explanations rely instead on related elements and levels of organization that are (understood to be) in the world (not just convenient epistemic devices). Systems approaches claim that parts on one level are organized into higher-level wholes that are themselves structured parts of still-higher-level wholes. (For example, subatomic particles, atoms, elements, chemical compounds.) The chapter concludes by examining the implications of a levels of organization framing for four important metatheoretical issues: micro–macro relations, the agent–structure problem, the natures of individual human beings and social groups, and the natures of individual and group identities.

The life sciences and social sciences typically study “complex adaptive systems:” nonlinear, self-organizing, adaptive, multilevel, multicomponent systems in which dense interconnections between elements produce irreducible/emergent systems effects. Systems and their components are partially (in)separable: they can be fully understood neither solely in terms of their parts (some outcomes are emergent) nor solely in terms of the whole (the character of the parts is essential to the nature of the whole). Important implications of a complex adaptive systems perspective for IR include a new view of international systems and their structures; a distinctive understanding of social continuity and social change; new perspectives on levels, theory, and explanation; new tools for comparative analysis; renewed attention to hierarchy; and a distinctive understanding of globalization.

Multilevel multicomponent complex adaptive systems are not reducible to the sum of the causal effects of independent variables. Causal inference, which has a privileged place in contemporary IR (and many other social sciences) cannot address systems effects, which arise from interdependent elements and operations (not the impact of independent variables on dependent variables). Systems effects explanations explain why by showing how. They identify mechanisms and processes of causation. They thus are able to establish causal efficacy; that is, show how processes produce – actually cause – outcomes (rather than merely identify some elements that are part of an unspecified causal process). Such an understanding leads us away from a “laws and theories” conception of science, which remains popular in Physics and Chemistry, towards a “models and mechanisms” understanding, which predominates in the life sciences (which, on their face, seem a much better model for the social sciences).

How international (and other social) systems are stratified – how social positions are arranged in ranked relations of super-, sub-, and co-ordination – is obviously central to their structure and functioning. This chapter looks at two broad types of vertical differentiation: single (or convergent) hierarchies and heterarchies (or multiply ranked orders). I begin with a 2x2 typology of hierarchies, based on whether they are restricted to a single issue or institution and whether they have a single axis of stratification. Among multi-layer systems, which are the norm in international relations, I look at various types of “states systems,” which have different types of relations between more or less autonomous polities; “imperial” systems, which have a single axis of super- and subordination; and “heterarchies,” which have multiple axes of stratification. The chapter concludes by considering the distinctive ways in which typologies explain.

This and the following four chapters address the systemic/structural theory of Kenneth N. Waltz. Despite extensive criticisms of its details, Waltz’s account of the nature of system, structures, and systemic/structural theory continues to predominate in contemporary IR. This chapter shows that, despite its systemic starting point, Waltzian structural theory is thoroughly analytic. Waltz replaced components arranged and operating as parts of a structured whole with a reified structure that exerts causal effects on units that interact with one another and with the structure. The resulting one-sided explanation of the actions of “units” by “the system” reduces systems to mere environments of autonomous actors (whose activities are not constituted, generated, or structured by being parts of a system but are simply constrained by external “system-level” forces).