Rogers Brubaker’s work has been a touchstone for the study of ethnicity, nationalism, and politics for more than a quarter-century. In this symposium, four prominent historical sociologists come together to discuss his recent book, Grounds for Difference (Brubaker Reference Brubaker2015). The book represents a continuation (in some respects, a culmination) of Brubaker’s long-standing interests in the politics and organization of cultural diversity. It is also an incredibly timely work; although it was published before Brexit and the 2016 American presidential election, it provides essential tools for understanding the major factors invoked to explain those political earthquakes: inequality, race, religion, and globalization. Grounds for Difference helps us understand how to think about how growing diversity and inequality are transforming the politics of difference, and thereby politics.

Grounds for Difference interrogates three increasingly salient contexts (termed the return of inequality, the return of biology, and the return of religion) that are transforming our understanding of diversity, and that have altered the stakes and contours of the politics of difference. Regarding the return of inequality, Brubaker argues for a return to a more structural analysis of economic inequality that at the same time connects it to important cultural dimensions of difference. Thus, the growing importance of economic inequality should be understood as intimately linked to the politics of citizenship, gender, and ethnicity. Brubaker theorizes these linkages in terms of social processes: categorical inequalities contribute to inequality by allocating persons to positions, socially producing persons, and socially defining positions. In so doing, Brubaker productively regrounds culturalist analyses of difference and identity in increasingly politically salient material conditions.

The second context, the return of biology, sees Brubaker grapple with the increasing prestige and power of the biological sciences, which has spilled over into the social sciences—visible, within sociology, as a number of recent efforts to forge a rapprochement between sociology and biology. Brubaker astutely notes that this move has important implications for the study of race and ethnicity, particularly insofar as genomics-based arguments about race pose a strong challenge to currently dominant social constructivist accounts of race. Brubaker argues that we must take these biological arguments seriously, but offers a spirited defense of constructivism in the face of these revived biological and naturalist arguments.

The return of the sacred, Brubaker’s third context, is epitomized in politics by the rise of public religion and in the academy by the eclipse and reformulation of the secularization thesis. Brubaker’s laudable goal is to bring religion back in as a fundamental form of diversity that scholars should focus on alongside race, ethnicity, gender, and sexuality. In a pair of chapters, Brubaker examines the parallels, divergences, tensions, and interconnections among religion, race, and nationalism. Comparing religion and language as bases for difference, Brubaker argues that their particular features give them different political purchase, and that their relative salience has accordingly shifted at different historical moments. Examining religion and nationalism, meanwhile, Brubaker disaggregates their relationship and offers four productive paths forward for examining the relationship between the two. In general, Brubaker’s response to the return of the sacred is to acknowledge similarities and analogies between religion and other politically salient forms of cultural difference, but to insist on religion’s autonomy—diving beneath surface similarities to illustrate how religion functions as a shifting axis of difference across time and space.

Taken together, these “grounds for difference” constitute a “categorical infrastructure of modernity” (Brubaker Reference Brubaker2015: 8) that has institutionalized, at a global scale, how states and societies organize diversity. Everywhere, nation, race, religion, and citizen are the fundamental categories through which we “see” difference, and which serve as the basis for identity construction and political mobilization. This flexible, adaptable categorical infrastructure is always historically situated and deeply contested, but through it, modern societies achieve much of their dynamism. Categories of difference structure the politics of belonging and exclusion, providing affordances for claims making, the basis for projects of group construction, and various cultural and political practices.

This politically grounded vision of cultural diversity, as Brubaker shows, complicates a variety of popular arguments in global and transnational sociology. Building on his work in Ethnicity without Groups (Brubaker Reference Brubaker2004), Brubaker critiques the spread of “diaspora” talk as failing to take into account that ethnic, religious, and other group claims are political projects, and not already-existing natural categories. Similarly, extending arguments introduced in Citizenship and Nationhood in France and Germany (Brubaker Reference Brubaker1992), he critiques the argument that the movement of peoples facilitated by contemporary globalization is undermining the nation-state, arguing instead that the transcendence of the idioms of nation, ethnicity, and religion should be understood as evidence for the expansion of the logic of the nation-state, rather than its eclipse. Most broadly, Brubaker argues that there is no need for the fashionable “multiple modernities” thesis. Instead, a single-modernity theory is perfectly sufficient, provided that it be appropriately reconstructed to take the global permutations of politics and diversity into account. Ultimately, then, Grounds for Difference represents both a synthesis of many of Brubaker’s long-standing interests, and also a bold new framework for understanding the politics of difference in a globalizing world.

As the four responses in this symposium attest, Grounds for Difference is a provocative and generative book, whose wide-ranging analysis holds important normative, political, and methodological implications. In their responses, Volker Schmidt and Ann Morning focus on the book’s normative and political implications (which they see as closely intertwined). Schmidt situates the central problematic of difference in a broader historical and philosophical perspective, and focuses on citizenship as the most puzzling form of durable inequality—puzzling because, unlike other axes of inequality, it is still widely seen as legitimate. Schmidt uses Brubaker’s analysis to critique the special status of citizenship, arguing that logic and legitimacy suggest we should replace the concept of “national citizenship” with one of “global citizenship,” although he acknowledges that this would come “at considerable cost.” His critique shows the productive philosophical possibilities of applying Brubaker’s approach to questions of global justice. Morning, for her part, unpacks the normative implications of Brubaker’s understanding of biology for how sociologists should approach the return of biology. Biology and sociology, she points out, are not implacable antagonists, but biology does have public prestige that sociology lacks. Consequently, she emphasizes the need for social scientists to attend both to public and disciplinary politics in deciding how to respond to biological arguments. Normatively, Morning argues that social scientists should worry less about marginalizing themselves by ignoring biological arguments, and more about figuring out a positive approach to engaging biology while continuing to promote constructivist insights among the public at large.

While Schmidt and Morning draw out the political and normative implications of Brubaker’s analysis, Philip Gorski and Matthias Koenig each consider the methodological implications of the book. Koenig lauds Brubaker’s domain-comparative approach as a major strength of the book, but questions how it can be applied in a more thorough-going historical manner when the content of some domains—such as “religion”—have themselves been subject to political reconstruction over the longue durée. He also champions the insights Grounds for Difference provides into the mechanisms that link difference and inequality, while suggesting they need to be contextualized and concatenated to maximize their utility for comparative and historical work. Gorski, by contrast, in a more critical take, focuses on how Brubaker’s conceptualizations of “religion” and “language” shape his conclusions. Arguing for a “thicker” understanding of language and a “broader” understanding of religion, Gorski questions whether the two bases of nationalism are really as different as they may seem.

For historical social scientists, Grounds for Difference offers several appealing features. It provides a framework for analyzing cultural difference that allows us to historicize many contemporary visions of modernity and globalization. Doing so not only reveals that many of the claims of novelty and rupture that pepper the literature on globalization are historically suspect, but also uses that history to critique and reconstruct the present (both politically and scholastically) in ways that reverberate beyond the global studies canon. Similarly, the theoretical approach Brubaker advances provides future scholars with new sensitizing tools to help think about how the politics of difference has been transformed over time. Yet as Koenig notes, there are questions about how the culturally constructed “grounds for difference” Brubaker analyzes will scale back in time. Grounds for Difference should be thought of, then, as both a theoretical statement and an invitation for future research.