Amy Allen's The End of Progress: Decolonizing the Normative Foundations of Critical Theory is a careful intervention in the ongoing attempts to establish a critical theory of society associated with the Frankfurt School. Its central concern is the way Critical Theory (capitalized here to indicate the specific tradition of the Frankfurt School), particularly in its latter-day incarnations, has been structured by a stadial philosophy of history that presents European modernity as the apex of progress and as a universal standard from which the rest of the world can be judged. Provoked by decolonial and postcolonial critiques of teleological philosophies of history, Allen seeks to decolonize Critical Theory by showing how current normative theorizing remains ensnared in this essentially nineteenth-century Eurocentric framework. Through a series of close readings of the work of, first, Jürgen Habermas and, later, his successors, Axel Honneth and Rainer Forst, Allen examines the ways critical theorists have grappled with the question of “European modernity”—as a historical moment, geographic location, or epistemic framework—and its relevance for Critical Theory's stated emancipatory aims (Horkheimer 2002). Although these thinkers are certainly aware of the problems of Eurocentrism, Allen is particularly adept at detailing how progressive conceptions of Universal History continue to animate normative justifications in this tradition.Allen's account begins not with the origins of the Frankfurt School in the 1920s and 1930s but with Habermas and his attempt to reconstruct the normative foundations of Critical Theory. Although Habermas has written extensively on globalization, Allen notes his lack of sustained attention to questions of imperialism, postcolonialism, and decolonization. Allen reads the lack as symptomatic of a deeper problem in which a particular account of historical progress continues to play an important role in Habermas's work. This occurs in spite of Habermas's interest in breaking with the Hegelian metaphysics of historical progress in which history marches ineluctably toward reason. Yet Allen shows how a progressive notion of history lurks within Habermas's concepts of social evolution and sociocultural learning. In this context, social evolution refers to the way societies rationally reflect on problems in the process of solving them, a notion articulated in his account of communicative reason. Although Habermas argues that the formal pragmatics of his theory “proceed reconstructively, that is, unhistorically,” the key tension for Allen is that this theory still depends on the “structures of action and structures of mutual understanding that are found in the intuitive knowledge of competent members of modern societies” (Allen 2016, 51, quoting Habermas 1987). Allen's point is that what counts as competency in modern society is not a universal property of humanity, but a specific set of practices and dispositions from a particular historical and geographic social formation connected with European modernity. Habermas, Allen claims, effaces that particularity, presenting European modernism as simply the outcome of a developmental process of learning.Responding to such critiques, Habermas has attempted to distinguish the underlying structures of modern society, which he views as universal, from the various social and cultural responses to modernity, advancing a thesis of “multiple modernities.” On this read, modernity's characteristic elements, including the techno-scientific domination of nature, bureaucratic rule, and capitalist social relations, are presented as a global infrastructure that different societies—or, in his terms, “civilizations” (68)—encounter, respond to, and shape in culturally specific ways. Yet Allen, drawing on the work of Gurminder Bhambra, argues that this approach does little to resolve the problems of Eurocentrism as it continues to present reflexivity, which Habermas connects with Enlightenment reason, as the apex of social evolution.The middle chapters of the book explain Honneth and Forst's differing responses to this basic problematic. Honneth takes a modified Hegelian position in which progress is neither linear nor inevitable but is nonetheless realized by ethical communities as they continually struggle over the conditions limiting freedom. For Honneth, institutions such as the family, the market, and the state gain a sort of legitimacy as individuals opt for certain configurations out of the range of those available. Normative foundations are given in the historical development of institutional forms, as societies pursue the expansion of diverse conceptions of freedom. Allen's critique of Honneth thus comes to center on the way a certain forward-looking notion of progress, what she calls “progress as imperative,” becomes conflated with an assertion that society has itself progressed over time, or what she terms “progress as fact” (12). For Allen, however, “progress as fact” fails to grasp the complexity of unequal societies or the extensive forms of violence coincident with European modernism.Forst, on the other hand, pursues a Kantian response to Habermas, arguing that normativity is grounded not in the historical development of societies but in the formal properties of practical reason. Here too struggles for justice are important, but not because they reveal the normative commitments of an historically specific society. Instead, Forst grounds normativity in a fundamental right to justification, which Allen glosses as requiring “that no one shall be subjected to rules or institutions that cannot be justified to him or her as a free and equal member of society” (127). As to the metaethical question concerning the validity of justifications, Forst treats justifications as valid after they withstand procedures of evaluation characterized by both reciprocity and generality (129). Justifications must be reciprocal—in that similar claims should be treated similarly, and one cannot universalize their own position—and general—in that the interests of all affected parties must also be considered. Yet Allen argues that if we push the metaethical questions back to the normative grounding of the justification procedure itself we return to a conception of the human as a “justifying being” (130), equating humanness with a particular form of practical reason. Here too, Allen finds a problematic Eurocentrism that connects Forst's account to other Kantian and neo-Kantian projects, in which a “Kantian notion of practical reason has been closely bound up with pernicious notions of progress” and has “provided the benchmark with respect to which black, female, queer, colonized and subaltern subjects have been judged” (138).As these brief summaries suggest, Allen's engagement with Habermas, Honneth, and Forst is detailed and extensive. It is clear that hers is a direct intervention in an ongoing debate over the future trajectory of the Frankfurt School (for an earlier skirmish, see Forst 2014). The chapters thus presuppose extensive understanding of the current work of its leading practitioners. For readers coming to the text more interested in a dialogue between Critical Theory and the broader project of anticolonial critical thought, the results might be more mixed. Afterall, Allen owns up to the difficulty in trying to bridge a “gulf” between Critical Theory and postcolonial critique. As she notes in the preface, the project has a quixotic element insofar as she is “criticized vehemently” for “flirting with relativism” by her Frankfurt School colleagues while also looked at askance by her colleagues working in postcolonial traditions for her interest in a “normative foundationalist project at all” (xv).Nonetheless, if the book really does dwell in the gulf between these two traditions, it remains oriented primarily toward the Frankfurt School. This orientation even structures the alternative approach to temporality she maps out in the final chapters, advocating for the forward-looking notion of “progress as imperative” while jettisoning what she sees as the Eurocentric conceptions of “progress as fact.” Where one might have expected a robust engagement with post- or decolonial theory, Allen remains within the Frankfurt School tradition, drawing on the work of Theodor Adorno and Michel Foucault—even going so far as to reposition Foucault within the family as “Adorno's other ‘other son’” (163).Allen finds Adorno and Foucault useful as thinkers who challenge the notion of history as the progressive development of reason, while also maintaining a notion of philosophy as a critique of the present. In a series of inventive readings, she treats them as taking up the basic Hegelian claim concerning the relationship between knowledge and history but destroying the Hegelian story of reason's dialectical self-realization toward the Absolute (177). Her reading of Adorno focuses on his dialectical approach to history, which views the Enlightenment as, at best, a highly ambivalent achievement and full of self-destructive tendencies. Yet rather than reading Adorno as simply a negative thinker bent on showing the irrationality of Enlightenment, she identifies a more limited understanding of progress in his thought. For Allen, the strength of Adorno's work is the way it continues to offer a notion of reason, but one stripped of the teleology of historical development and thus reflects back on its own role in fomenting the disasters associated with European modernity. For this reason, Allen frequently references Adorno's claim that “progress occurs where it ends” (163).Allen finds a similar use in Foucault, particularly his account of the history of reason from the position of unreason. In her account of History of Madness, Allen wrenches Foucault from readings that position him as celebrating unreason or even madness as a space of freedom that is set apart from modernist rationality. Instead, she carefully parses Foucault's uses of unreason as a category within modernity that problematizes or fractures the seemingly smooth surface of reason's self-development. Unlike madness, which might simply be the Other of reason and fully outside of its logic, unreason is useful as a category that exists within but is not fully intelligible by reason's own self-understanding. As she puts it, “the function of the figure of unreason, then, is to create some distance between ourselves and our system of thought” (184).It is this problematization of “our system of thought” that she urges Critical Theory to take up. Allen presents a powerful case for an approach that is more self-critical and modest, suggesting that decolonizing Critical Theory means quieting it down and allowing it to hear and be challenged by the voice of others. As an immanent critique of the role of stadial history in current normative theorizing, the book succeeds in demonstrating the persistent problems posed by the figure of historical progress. Readers of this journal, for instance, should find her reading of progressive history in Habermas's theory of communicative reason and concepts of sociocultural learning insightful, as it poses important questions about the way formal pragmatics, communication, and language are shaped by Eurocentric assumptions of linear development. But the book also raises issues concerning the meaning, content, or practice of decolonization, not only for the narrower category of normative theorizing in Critical Theory that constitutes Allen's focus but also for the broader category of critical thought more generally.For Allen, notions of progress are really the core of what needs decolonizing in Critical Theory. She notes at the outset that the critique of stadial history is “perhaps the major lesson of postcolonial scholarship over the last thirty-five years” and argues, echoing James Tully, that “the language of progress and development is the language of oppression and domination for two-thirds of the world's people” (3). Clearly Allen is right that progressive narratives have been central to the thought and practice of colonization and conquest. And a diverse range of scholars, from postcolonial theorists to critical social scientists, have demonstrated the continuities of progressive readings of history in postcolonial projects of development and modernization (see, for instance, Wainwright 2008). Those literatures also make clear, however, that Eurocentric conceptions of history as progressive development are always part of a larger apparatus of colonial thought and practice. In other words, it is the different ways that progress is mobilized in the thought and practices of, say, private property, secularism and religion, land and resource use, economic regulation, state violence, or the gendered division of labor that constitute just a few of the many techniques by which societies continue to be structured by colonial and postcolonial relations of domination.If that claim is true, it would set a higher bar for what it might mean to “decolonize,” which could also carry some methodological implications for the practice of critique. Specifically, it might suggest an approach to theory that is attentive to the way theory is conditioned by and moves in the world. What is so interesting is that this is one of the things Allen presents as the great strength of the Critical Theory tradition, that it is “rooted in and constituted by an existing social reality that is structured by power relations that it therefore also aims to critique” (xiii). Yet the diversity and complexity of power relations constituting colonization, imperialism, racism, and heteropatriarchy are largely subsumed under the singular category of “progress” in the text. This is useful for Allen's argument, providing a lever to offer critical readings of the texts at hand, but might also attenuate the multiple ways colonial power continues to work and thus the difficulty of decolonization as a practice. Recognizing as much does nothing to limit the enlightening and rigorous critiques of Habermas, Honneth, and Forst or the useful and insightful readings of Adorno and Foucault, situating them as anti-Hegelian Hegelians. But it might also suggest that there is still much to be done in the work of decolonization.