As the title suggests, the first chapter of Rogers Brubaker’s (Reference Brubaker2015: 10) book Grounds for Difference focuses on “the relation between difference and inequality.” As members of the human species, people share many characteristics while also differing from each other in certain ways. Some of the differences between them are irrelevant in most respects, others are accorded some—varying—weight in different contexts. Differences of the latter sort include age, skin color and/or race, sex and gender, sexual orientation/preferences, religious creed/affiliation, ethnicity, language, nationality, citizenship, and others. As markers of identification, they sort people horizontally. In and of themselves, they are thus axiologically neutral. This distinguishes them from differences on a vertical plane, which rank people according to some metric, to the degrees in which they possess or control valued qualities such as wealth, income, education, health, positional status and prestige, rights, and so on. These differences are not just differences but also inequalities.

In the real world, the two types of difference are multiply interrelated. Neutral markers of identification become categorical inequalities because falling or being placed into a particular category is typically associated with various privileges and/or disadvantages. Brubaker’s concern is twofold: first, to show that existing links between difference and inequality are not necessary but contingent; and second, to account for the different ways in which they manifest themselves for different categories in different contexts. In other words, not only are these links socially constructed and amenable to change but they also follow different logics of coupling. All categorizations can turn into inequalities, but they do this differently and with different consequences for different groups of people.

To develop his argument, Brubaker (Reference Brubaker2015: 10) invites us to imagine a hypothetical world wherein horizontal categorizations and vertical rankings are “entirely independent of each other.” Vertical or, as I prefer to call them (Schmidt Reference Schmidt, Arjomand and Reis2013a), gradual inequalities would still exist, but they would reflect differences within categories, not between them. So the world Brubaker wants us to visualize is a world without genuine categorical inequalities, a world that was completely category (Brubaker says: difference) blind. How distant from the world we actually inhabit is this scenario?

As it turns out, it is both quite far removed from and close to our world. It is far removed from it insofar as categorical differences of race, ethnicity, gender, sexuality, religion, citizenship, and so forth, do of course have a profound bearing on social inequality. Every sociologist knows this. At the same time, it is remarkably similar to what we believe our world should be like. The hypothetical scenario Brubaker envisions is not some strange, barely conceivable utopia, but a world we are fully familiar with, the ideational world that supplies the very standards by which we daily judge the existing one and often enough find it to be wanting. We are aware of the huge discrepancies between reality and ideal, but this does not lead us to abandon the ideal as sterile. Instead, we insist that the real world be brought closer to it, that it be changed to approach the ideal. Why so?

There is a sociological and a philosophical answer to this question. The sociological answer says that we live in a functionally differentiated society whose economic, political, legal, educational, scientific, medical, and so forth systems have no need for tying their operations to categorical differences among position holders and/or clients, which at best causes no harm to, but at worst subverts, their proper functioning and performance. From the viewpoint of the systems, differences of sex, race, ethnicity, and the like make no difference as long as individual position holders and clients qualify under the terms of the systems in question: as long as they are good at their job and/or participate in market transactions using recognized means of payment; as long as they play by the rules regulating the exercise of political rights and power; as long as they contribute to the creation of new knowledge; as long as they teach or learn adequately; and so on. But it does make a difference when firms are forced to hire insufficiently qualified workers (or prevented from hiring better skilled ones) because social conventions or laws dictate this; when certain defendants must be acquitted or sentenced because of who they are rather than what they have done; and when the value of scientific findings depends on the social status of those who generate them. In short, the emergence of a functionally differentiated society renders obsolete entrenched social hierarchies that form the backbone of the structure of premodern, stratified society that historically precedes it.

The philosophical answer turns on the normative force of egalitarian individualism (Gutmann Reference Gutmann, Willems, Basu, Gutmann, Pollack and Spohn2013). The premise of this liberal principle is that all human beings are born free and equal, thus shifting the burden of proof to those insisting on inequality, who claim that different groups of people constitute qualitatively different types of human beings that cannot be meaningfully compared with each other, let alone judged by, or treated according to, the same standards. But in light of the human rights discourse, which originates in the European Enlightenment and to which the principle gives rise, the “grounds for difference” invoked by the ancien régime to defend graded attributions of social worth, which systematically elevate the noble classes above everyone else, rapidly lose credibility. In their stead emerges a generalized expectation of inclusion and equal respect for all, violation of which is deemed discriminatory and hence requires a strong, case-specific justification rather than being taken for granted. Such justifications are increasingly hard to come by. Hence the delegitimization of categorical inequalities and the call for remedial action whenever and wherever they occur.

The bundle of rights advocated by eighteenth- and nineteenth-century liberals was much more limited than what 200 years later came to comprise the UN Universal Declaration of Human Rights. The liberals of the time pleaded for the civil and political rights of a citoyen, a status for which only a small fraction of the population qualified. The large majority of humankind was thus excluded: the poor and the property-less classes, women and children, in most cases also non-Caucasians, non-Europeans, non-Christians, as well as numerous others, who were either deemed dependents (and hence by definition ineligible) or otherwise found to be lacking.

Most of the exclusions initially seemed self-evident to the contemporaries. But the inclusionary logic of the human rights discourse turned against them from the outset. Aren’t women human beings too? Well, yes but … and here is where the trouble begins. What could one possibly say to defend the curbing of women’s (or some other category’s) rights? Because the liberal case for freedom and equality implied that those subject to (legal) norms are both their putative authors and addressees, the reasons brought forward by any would-be defector had to be publicly presentable and universally acceptable, had to be reasons that nobody could reasonably reject. As it turned out, such reasons don’t exist. Categorical inequality proved indefensible.

So over time, one bastion of (legal) discrimination after another fell. It might take decades, even centuries of struggles before a new social category was admitted to full membership of a political community, but eventually the walls of exclusion had to come down. Critics of liberalism were sometimes more aware of its subversive logic than the liberals. For instance, in a review of John Stuart Mill’s works, published in 1866, a conservative critic claimed that the famous thinker “cannot help claiming the suffrage for the Negro—and the woman. Such conclusions are the inevitable results of the premises whence he started” (cited in Hobsbawm Reference Hobsbawm1977: 294). They are indeed. Mill, as has been frequently noted, was far from consistent in the conclusions he personally drew from these premises, so he could at once be sympathetic to the cause of women’s emancipation and be a strong defender of British colonialism. Similar inconsistencies pervade the work of liberals to the present day. They (and by extension most of us) are still reluctant to draw the full conclusions of the premises to which they (we) ostensibly subscribe. We preach the inviolability of human rights, but when the consequences appear to be “too” radical, too demanding, too uncomfortable, then we quickly back down, maintaining the case in question is “different,” so the human rights logic does not really apply.

Writing in the twenty-first century, Brubaker’s thought experiment serves to illuminate the predicament that the disjunction between firmly held normative convictions whose logic is virtually irrefutable and an everyday reality that strongly diverges from them creates. How can the enduring persistence of categorical inequalities be explained, even though the means for deconstructing them have been available for at least two centuries, and despite their unceasing exposure to critical scrutiny? The inequalities Brubaker pays special attention to are those that systematically link the categories of race, gender, ethnicity, citizenship, and religiosity (in other chapters, also language and nationality) with particular social positions, privileges, and disadvantages. Brubaker shows that and how different mechanisms contribute to the production and reproduction of distinct regimes of what Charles Tilly has called “durable inequality” for each category. To understand durable (categorical) inequality, its causes and effects must therefore be analyzed separately. Brubaker’s analyses are compelling and persuasive in my judgment, so I have nothing to add to them.

Despite their distinctness, most categorical inequalities nonetheless share two commonalities: first, their delegitimization and second, their widespread legal abolishment, at least in the world of liberal democracy (Brubaker Reference Brubaker2015: 22). There is, however, one important exception. That is the case of citizenship, whose exclusionary effects are both widely accepted and backed by law. Is citizenship “special,” then? Do we have good reasons for treating it differently? Apparently not. This is a second predicament Brubaker addresses.

It is also the problem on which I wish to focus in the remainder of my commentary. I will first reiterate the key points of Brubaker’s argument and then add a few considerations of my own. Citizenship, says Brubaker, is internally inclusive but externally exclusive, “an instrument and object of social closure” and opportunity hoarding. The plight of illegal, undocumented residents is widely acknowledged, but their exclusion is “dwarfed by the invisible exclusion of billions of noncitizens” from the territories of rich countries that are magnets for migration. The categorical distinction between citizens and strangers/foreigners is built not only into the basic structure of the modern state but of the “modern state system” as well. As such, it is central to the “segmentary organization” of the world political system (ibid.: 19) from which it cannot be easily detached, and which affords it globally recognized legitimacy. Citizenship “cages” (Michael Mann) the entire world population in bounded territorial spaces, both serving to justify ownership stakes and functioning as a regime of “forced immobility.” In this latter capacity, it “contributes decisively to perpetuating vast social inequalities in life chances” (ibid.: 20).

Exclusion on the basis of citizenship, an ascribed status, continues to be taken for granted as natural—just as other ascribed categorizations that are now widely regarded as dubious (such as race or gender) were before their de(con)struction. Citizenship assigns positions in the world political system that tend to “carry over to subsequent generations,” forming the basis of “inherited privilege” or disadvantage. People ending up with the “wrong” citizenship through the morally arbitrary accident of birth are bound to a subordinate position in a “global structure of unequal positions” (ibid.: 21) that thwarts their opportunities from the start.

But neither citizenship nor the modern state system are “natural,” without any alternatives. They are both outgrowths of a “vast reorganization of political space” (ibid.: 98) whose origins are often traced to the Peace of Westphalia and whose completion arguably took until far into the second half of the twentieth century, when, following the demise of colonial empires, most of the newly liberated territories, now transformed into independent, sovereign states, were finally admitted to the UN system of organizations on a formally equal basis. The external equality granted member states by this system is mirrored internally by the equal status that they are expected to grant their “own” members qua citizenship. The rights of citizenship, on this model, apply only domestically. Internally inclusive, externally exclusive.

This configuration of statutory orders and citizen rights is obviously contingent. That something is contingent does not, of course, automatically render it illegitimate. Could it be that categorical exclusion on the basis of citizenship is justifiable, while other categorical exclusions are not? That has long been the received wisdom of moral and political theory.

There is reason for doubt, though. In addition to the effects on inequality highlighted by Brubaker, the latest wave of globalization that began around the turn of the 1980s has effectively rendered obsolete the nation-state–based model of citizenship by giving rise to the emergence of a world society. Throughout the twentieth century, the terms society and nation-state were essentially used as synonyms. That made some sense as long as the territorial boundaries of the state were more or less coextensive with the boundaries of society’s systemic operations—as long as economies were first and foremost national economies; as long as politics, science, education, medicine, the law, the arts, and just about every other system of society were largely national endeavors—which, however, they had become only in the nineteenth century after sustained efforts by the state to nationalize them (Sassen Reference Sassen2007). Today, the situation is different. Society’s subsystems increasingly project global horizons for their operations, constituting a global society and establishing a supranational regulatory regime that directly or indirectly shapes the living conditions of (almost) every human being (Schmidt Reference Schmidt2014). Unequal life chances in different parts of the world are determined to a significant extent by the daily operations of a world-encompassing society and its (often enough, highly contested) system of governance.

If these inequalities are found to be unfair, then justice requires that the rules that generate them be changed. In keeping with the conventions of methodological nationalism, mainstream philosophy continues to delimit the scope of justice by the boundaries of the nation-state, with citizenship serving as the central lever for grounding demands of justice. But if there is reason to believe that society has gone global, then so must justice (Schmidt Reference Schmidt, Aarni, Hoeren, Paulson, Schulte and Wyduckel2013b) and citizenship. Global citizenship is the conceptual counterpart to a societal reality that can no longer be contained within national borders nor be adequately governed by national institutions and/or actors (alone). And if principles of justice are to be applied to a community of global, rather than national, citizens, then their reach too must be globalized. Global justice is the inevitable corollary of a globalized society, for which a societal exterior has simply ceased to exist. So, citizen rights become global rights, and the normative case for restricting them to the national level collapses.

The implications of this line of reasoning, if accepted, would be far-reaching. Here, I limit myself to a few remarks about migration. As Brubaker points out, the model of the nation-state posits a congruity between the state, territory, and citizenship. This model treats mobility within the nation-state as normal. Mobility between nation-states, however, is understood as anomalous (Brubaker Reference Brubaker2015: 132). It is precisely this model that lends credibility to a system of tightly controlled borders that routinely excludes billions of noncitizens from the territories of rich countries. But if the forces of globalization have undermined this model’s normative foundations, then such exclusion is no longer justifiable. Instead, the borders have to be torn down, opened up to all world citizens who request entry because in a truly global society the distinction between internal and external mobility dissolves, evaporates into thin air.

Even liberal-minded cosmopolitans might get a little nervous at this prospect—just as earlier generations of liberals were wary of drawing the consequences of their premises without reservations and exceptions. It is therefore not surprising that even the rapidly proliferating literature on global justice often clings to whatever reasons seemingly allow us to leave this last big bastion of categorical inequality untouched.

Assuming it turns out, upon thorough investigation and deliberation, that the reasons mobilized in support of territorial (citizenship-based) exclusions are indeed as weak and untenable as the ones that were historically utilized in defense of other kinds of categorical inequality,Footnote ¹ can we still uphold the practice? I think we can, but only at considerable cost.

To explain why, let me end my commentary with another thought experiment, a thought experiment that turns the one proposed by Brubaker squarely on its head. In this hypothetical scenario, once we have liberated ourselves from the demands of consistency in one case, we figure we might as well do the same in other cases. So if we can freely discriminate against foreigners/noncitizens, then why not also discriminate against women, blacks, homosexuals, and so forth? Or to put it differently, if we can get away with acts of xenophobia, then what should possibly stop us from being sexist, racist, and homophobic if and where this suits our interests?

By today’s standards, this is, admittedly, an extreme scenario. It does, however, shed light on a dilemma we face if we are to take the premises of our normative commitments, of egalitarian individualism and the human rights logic, seriously. Sexism, racism, homophobia, and xenophobia are all practices no present-day liberal would openly embrace. The conventional understanding of xenophobia refers to the ill-treatment of noncitizens after they have legally or illegally crossed the borders of a given country. To avoid that, we simply have to grant them negative rights of noninterference, which protect their physical and psychic integrity while under “our” jurisdiction. Most liberals would unambiguously support this. But in a world society, the notion of xenophobia assumes a new meaning. On this, much more expansive understanding, xenophobic behavior begins with the very erection of borders, and the first act of xenophobia is to forcibly prevent anyone from crossing them. The only way to avoid that would be to grant all humankind virtually unlimited mobility. If this is the price for consistency, though, then some of us may well get second thoughts about it. And that is probably the reason why, for the time being, territorial exclusions are far more widely accepted (if not actively endorsed and lobbied for) than the other types of exclusion.

Sociologists’ job is to expose our inconsistencies, demonstrate their consequences, and explain their causes. Rogers Brubaker has done an excellent job at this task. Philosophers’ job is to push us further by pointing out what we do to ourselves when refusing to act on insights that, once they are principally available, won’t go away anymore. As sociologists, we should leave this task to them. But we should also not let them get away with doing less than what we can reasonably expect from them.