It is an honor to be part of this volume and to appraise the influence of Charles Tilly’s Durable Inequality. When I was just a doctoral student, attempting to navigate the rough waters of a department whose approach to comparative historical work ranged from the indifferent to the hostile, I went on a research trip to “interview” the archives, seeking a way to formulate a dissertation project on working class formation in nineteenth century America. Carol Connell, one of Tilly’s students from his time at the University of Michigan, was then a junior professor at Stanford and she encouraged me to start my trip with a visit to Tilly’s workshop at the University of Michigan. When I got there, I found a better vision for how academic work could be done, as well as both practical help and moral support from Tilly. Then, after I began an assistant professor position at Berkeley, I went to spend a semester’s leave at Tilly’s center at the New School, where I was able to participate in the sort of workshop setting I had so admired in Ann Arbor. Those experiences have profoundly shaped not only my work but also my teaching and mentorship. It was a great gift and I’m happy to have the opportunity to credit Charles Tilly’s influence and help.

In areas like the study of contentious politics, those of us influenced by Tilly’s work have the advantage of being able to track the development of his thinking and theorizing from structure to agency in his many books and articles. We can assess Dynamics of Contention, for example, in light of not only his theoretical work on collective action, From Mobilization to Revolution, but also his many empirical studies of contention in France and Britain. However, in the case of Durable Inequality (Tilly 1999), we do not have this large body of earlier work. Oh, we do have an article on proletarianization (Tilly 1984), which in retrospect foreshadows some of the approach. But we have nothing like the early, careful, empirically rich studies of collective action, where Tilly articulated alternative theoretical arguments and provided the kind of persuasive evidence that led so many of us to believe that he had better answers for how to understand contentious politics. Instead, Durable Inequality is Tilly’s first major work on inequality and it draws very little on empirical work that Tilly did before his turn to agency.

Durable Inequality opens with a critique of the vast majority of research on stratification. It is an appreciative critique in that it notes that previous research has clearly identified the empirical reality that analysts of inequality should be able to explain (for example, by showing how much male female pay differences spring not from unequal pay within the same jobs but from job segregation). However, it is also a sharp critique for Tilly indicts stratification scholars for having done a poor job of actually explaining the extensive inequality they document. They have done a poor job, he suggests, because they have relied on an individualistic framework that identifies in one way or another “powerful agents or institutions that sort individuals whose attributes vary significantly into positions whose rewards differ greatly” (Tilly 2000b: 783–4). Such explanations are unsatisfactory he contends because categorical differences in advantages among human beings are much larger than individual differences in “attributes, preferences, or performances”. And they endure much longer. So any satisfying explanation for inequality must begin by confronting the fact that categorical differences in advantages swamp individual differences.Footnote 1

The bulk of Durable Inequality sketches a set of processes that Tilly suggests underlie the many and varied forms of inequality that historians, sociologists and anthropologists have uncovered and described. Two powerful processes are fundamental in his view: exploitation and opportunity hoarding. Exploitation is the process by which powerful connected people have control over resources and use those resources to enlist others in production of value while excluding them from the full value added by their efforts, using any of a number of means, such as legislation, work rules, and outright repression. Opportunity hoarding occurs when members of a categorically based network confine the use of the value-producing resource to others in the in-group. Tilly is careful to note that elites engage in opportunity hoarding but most of his examples are of non-elites who make peace—more or less—with a categorical distinction and look for ways to advance within it rather than breaking down the distinction. Behind his understanding of exploitation, as both Erik Olin Wright (2000) and Michael Mann (1999) have argued, prowls Marx’s labor theory of value. And his notion of opportunity hoarding owes much to Weber’s idea of social closure.

Two more processes help to cement inequality in Tilly’s model: emulation (in which established organizational models are copied in new settings) and adaptation, or the creation of everyday procedures and practices that people use to cope with and so reproduce the categorical distinctions in their daily interactions. Here, of course, are echoes of the new institutionalism.

Tilly’s model rests on these four processes. The model is both relational and interactional and it identifies organizations, broadly defined, as the key sites for the creation and maintenance of durable categorical inequalities. Tilly insists that the approaches of prior scholars who focus on human capital or on labor market scarcities or on discrimination, are not wrong so much as simply drawing attention to the by-product of the four processes he identifies.

With a dazzling array of examples and stunning erudition, Durable Inequality attempts to flesh out this abstract model and to make it plausible enough to inspire stratification scholars to shift their research program away from examining individuals and social mobility to instead focus on studying different combinations of mechanisms, settings and categories. Yet Durable Inequality did not have that immediate effect.

The initial reaction to the book was respectful and there was widespread agreement that it was an important theoretical contribution. But several objections were also raised, one of which is especially relevant for thinking about Tilly’s role and influence in the history of social science: what constitutes an explanation? Michael Mann (1999) articulated a critique that I believe many others share: mechanisms aren’t causality he implied, noting that although Tilly claimed to explain inequality, his focus on mechanisms left the cause of inequality unaddressed.Footnote 2 Mann wrote, “Since in [Tilly’s] theory causes must obviously concern very long run processes whereby exploitation and hoarding are “installed”, we require historical analysis of their emergence.” He didn’t find an account that explained why modern societies are dominated by the categories discussed in the book (gender, racial, ethnic, occupational), and thus came away from the book believing that it’s conceptual reach far exceeded Tilly’s grasp. Others complained that it underplayed agency and focused too much on the role of organizations in producing inequality (Laslett 2000; Morris 2000).

However, the most distressing critique for Tilly’s himself was almost certainly that the book did not have a big impact on stratification scholars. Tilly tried in different venues to engage his critics and to more clearly lay out the research implications of his work—in Comparative Studies in Society and History (Tilly 2000a) and also in Contemporary Sociology (Tilly 2000b) —but to little immediate effect. In 2001, he published one of the best pieces on Durable Inequality in the journal, Anthropological Theory (Tilly 2001). He hoped, it seems to me, that having had less success than he would have liked with sociologists, he might find a more receptive audience with anthropologists.

I don’t know if that will prove to be the case or not, but I do know that the impact in sociology has grown over time, and that recent work suggests that the influence of Durable Inequality on stratification researchers is growing to be something closer to what Tilly wished.

In 2005, in the Journal of Social History, the American historian Michael Katz along with Mark Stern and Jamie Fader analyzed a century of data on gender inequality in the United States and, inspired by Tilly, asked directly about the mechanisms that have reproduced it in modern U.S. history. They argue that durable gender inequality across the 20th century was paradoxical rather than relentless, as Tilly’s book suggests. By this they mean that Tilly’s model does not account for the paradox of group mobility that coexists with structural inequality and ends up reproducing it. They also suggest that a similar process of internal differentiation has been characteristic of other categorically unequal groups in American history, most notably African Americans and many ethnic minorities. Katz and his collaborators thus assert that their work offers a crucial supplement to Durable Inequality.

Doug Massey’s Categorically Unequal (2007) builds even more ambitiously on the edifice of Durable Inequality. It offers a systematic account of the American stratification system in the twentieth century and relies heavily on the framework elaborated in Durable Inequality to get at the mechanisms that have sustained racial, gender, and class inequalities in the United States. But it also tackles the origins of inequality in a most un-Tilly like fashion, drawing on social cognition studies and neuroscience to argue that humans have a natural tendency to think in categorical terms and, most controversially, that distinctions based on age, gender, race, and ethnicity are more or less hard-wired. This is a step that Tilly steadfastly rejected (2001: 363 1998: 64–5), and there are tensions in Massey’s analysis that follow from his effort to marry Tilly’s relational analysis with a social psychology of categorization. For example, some of the distinctions he sees as hard-wired, like age, never became an organizing principle of durable inequality in the US, while other distinctions that have no obvious basis in hardwiring, like class, do. Yet, Massey’s use of Tilly ‘s central mechanisms (exploitation, opportunity hoarding, emulation, adaption) to illuminate the varying institutional processes that make different categorical inequalities more and less persistent over time does yield an important empirical finding, to wit, that progress in breaking down one dimension of categorical inequality often goes together with increased disadvantage for other categorically unequal groups. Most significantly, Massey shows that the shrinking of the class divide in the period form 1933 to 1974 went hand in hand with racial and gender inequality while progress on the gender divide over the last 30 years has been coupled with an increasing pervasiveness of class division. This finding, of course, runs smack up against Katz et al’s suggestion that paradoxical inequality operates similarly for women, African Americans, and most ethnic groups in the United States, and also challenges Katz et al’s argument that when group mobility coexists with structural inequality it can often end up reproducing the very categorical inequality it seems to challenge.

Both Massey’s and Katz et al’s analysis of inequality rely on the kind of data that has been central to the scholarly exploration of stratification for decades: individual and occupational data from surveys or from the census. Such data is often the only kind available, especially for historical studies. However, as Tomaskovic-Devey et al. (2009) and Avent-Holt and Tomaskovic-Devey (2010) have recently noted, survey and census data on individuals is abstracted from its organizational context and is thus problematic for investigating the interactional and relational contexts of inequality that is fundamental to the theory advanced in Durable Inequality. Sociologists have known since Bielby and Baron (1986), for example, that the finer the data we are able to gather on jobs within workplaces (i.e. within their organizational context), the greater the inequality we are likely to detect. In two recent articles that significantly advance Tilly’s relational model, Tomaskovic-Devey et al. (2009) and Avent-Holt and Tomaskovic-Devey (2010) use data collected on organizations in the United States and Australia—including large and small for-profit firms, non-profit workplaces, and government agencies—to investigate inequality patterns in wages. Reasoning that wage distributions within firms result from actors negotiating and contesting who should receive greater and lesser rewards for their work, both articles examine whether earnings inequality is amplified when categorical distinctions are mapped onto positional differences inside the organizations. Looking specifically at wage disparity between two different groups: mangers and core production workers on the one hand, and core workers and the lowest paid workers on the other, they find that both in the U.S. and Australia, inequality is greater when categorical differences like gender, education, race (in the U.S.) and linguistic group (Australia) can be used by categorically advantaged groups to extract greater rewards for the positions they hold in the organization. They further find that while the generic processes in which actors attempt to exploit and hoard opportunities from categorically distinct others in work organizations are similar in the United States and Australia, status distinctions tend to produce larger wage inequalities in the US, largely because of its extremely decentralized wage bargaining system. They interpret the larger wage inequalities in the US as evidence that Tilly’s generic relational model is enhanced when it is contextualized, as he would no doubt have agreed.

These demonstrations of the explanatory power of Durable Inequality in the work of Tomaskovic-Devey and his collaborators have appeared in key journals of mainstream stratification research and can be expected to generate new analyses and further questions. Thus, although Durable Inequality may have been less influential initially than some of Tilly’s other works, that is clearly beginning to change. Another important development is that scholars are beginning to connect Tilly’s ideas about the processes that drive inequality with the kinds of contentious politics that might potentially undermine them. For example, Gibson and Woolcock’s (2008) study of development projects in rural Indonesia borrows from Durable Inequality to reconceptualize the meaning of “empowerment.” They argue that empowerment can most usefully be thought of in terms of marginalized groups developing routines of contestation that expose and weaken at least one of the four causal mechanisms that drive durable inequality. They then use this reconceptualization to explain outcomes of struggles over local power relations.

In this article, I have concentrated on scholarship that engages deeply with the specific processes and mechanisms laid out in Durable Inequality. The book’s influence, however, can also be seen in the increasing number of studies that find its title to be a useful metaphor or that cite it when emphasizing the stubborn persistence of categorical differences and the boundary maintenance such persistence entails (Sampson and Morenoff 2006; Sampson and Sharkey 2008; Schneider 2008; Light 2009; Stainback and Tomaskovic-Devey 2009). These, too, attest to an enduring legacy.

Let me conclude by relating something Tilly told me when I spent a leave at the New School. I asked him how he was so productive. He told me that he procrastinated on his “A-list” priorities by working on his “B” and “C-list” priorities. He added that although that was key to his ability to publish so many books and articles, he worried that it would mean that at the end of his life he would have never gotten to his “A-list.” I like to think that his turn from structure to action in the 1990s was not only a matter of stocktaking and reformulation after years of denial as other contributions collected here so eloquently suggest, but also of finally allowing himself to tackle his “A” priorities. After all, he wrote a phenomenal amount in the 1990s, like someone not only with a lot to say but also with the joy that must come from finally letting yourself embark upon your top priorities if you have always put them on hold in the past. The result was a huge treasure trove of ideas and research questions. It’s gratifying to see that at least when it comes to his work on Durable Inequality, others have finally taken up his ideas and are pursuing the kind of research questions he urged us to ask. In short, I like to think that this recent work using, extending, and challenging the theory in Durable Inequality is advancing one of Tilly’s “A” priorities.