Kenneth Waltz famously claimed that anarchy—i.e., the absence of a global sovereign—is the ordering principle of world politics, and much International Relations (IR) scholarship since then has aimed to debunk the claim that anarchy defines IR as a subject. Today, some aim to do so by offering new conceptual foundations for IR.

This post is not a relitigation of the “paradigm wars” of the 1980s and ‘90s that Waltz’s work did much to provoke. Rather, what I am interested in noting here is that some seem to think that whether it is anarchy or otherwise, we need some conceptual foundation for the discipline—some unifying concept that provides common ground for IR and that distinguishes IR from other fields.

Over the past decade, at least three contenders for this new conceptual foundation have emerged—hierarchy, heterarchy, and multiplicity.

(I discuss heterarchy and multiplicity in a recent review of Barry Buzan’s Making Global Society: A Study of Humankind Across Three Eras, which is framed as an attempt to “revive a ‘grand theory’ project” through a tightening of connections between IR, Global Historical Sociology, and Global History, not through a new conceptual foundation.)

“Multiplicity” has largely been the project of Justin Rosenberg, whose intervention begins from an anxiety about a perceived “crisis of intellectual confidence” in IR stemming from the aforementioned paradigm wars that produced no clear consensus on the right way to theorize world politics.

Rosenberg offers a new conceptual foundation to cure this malaise: “IR rests upon a fundamental fact about the social world which is full of implications for all the social sciences and humanities. This is the fact that the human world comprises a multiplicity of co-existing societies.”

Rosenberg outlines the implications of multiplicity, the payoff of which is essentially an affirmation of Leon Trotsky’s theory of “uneven and combined development,” or the notion that “modern world development was not uni-linear but was rather multiple and interactive”. We can expect continued “dialectical change” accordingly.

Like multiplicity, “heterarchy” has primarily been the project of a single scholar. For Philip G. Cerny, heterarchy entails “the coexistence and conflict between differently structured micro- and meso- quasi-hierarchies that compete and overlap not only across borders but also across economic-financial sectors and social groupings”.

This view of a heterarchical world has much in common with IR theory that has portrayed world politics as increasingly “disaggregated,” characterized by various modes of “differentiation,” and subject to the influence of international institutions, regimes, and non-state actors, but it seeks to move even further away from state-centrism.

The payoff for Cerny is a “fundamental paradigm shift”. We can expect the near future to be increasingly heterarchical insofar as international society will be characterized by “durable disorder,” disaggregated governance across “complex, uneven issue-areas,” and “a more uneven and unstable form of transnational capitalism unfolding that will increasingly be dominated by complex special interests”.

The promotion of “hierarchy” as a new conceptual foundation for IR has been less the project of a single scholar and more the product of a diffuse “new hierarchy studies”. (Paul Musgrave and Dan Nexon seem to have coined this phrase in a description of such scholarship in a 2015 draft of a later article.)

Indeed, the push to center “hierarchy” in IR has come in part from those who have identified a view of IR as characterized by hierarchy as a sometimes-implicit premise of much work that was being produced in the 2000s and 2010s.

Janice Bially Mattern and Ayşe Zarakol helped to crystallize this trend toward “hierarchy” in a review essay: “[H]ierarchy-centered approaches to IR promise to deliver what anarchy-centered approaches have not: a framework for theorizing and empirically analyzing world politics as a global system rather than just an international one.”

A focus on hierarchy “reveals that arrangements of super- and sub-ordination,” Waltz’s own definition of hierarchy, “emerge in two different kinds [of] IR scholarship: research that discloses within world politics relations of legitimate authority…and research that discloses within world politics structures of inequality”.

Similarly, going beyond asymmetries in military and economic capabilities, John Ikenberry and Dan Nexon classify research on “an assortment of forms of social stratification along, analogous to, or informed by, for example, racial, class, and gender hierarchies” as part of the new hierarchy studies.

The new hierarchy studies can thus be rather capacious. Nonetheless, this literature represents a growing effort to create a new conceptual foundation for IR in the same way that multiplicity and heterarchy offer potential replacements for the purportedly shaky ground of anarchy.

Whether these concepts offer firmer disciplinary foundations than anarchy—whether we as a discipline are indeed living “after anarchy”— is one open question. Whether IR even needs a conceptual foundation is another. Whether it’s anarchy, hierarchy, multiplicity, heterarchy, or some other common ground, to what extent do we need shared foundations from which to theorize?