In a world characterized by complex dynamics, Emanuel Adler's World Ordering: A Social Theory of Cognitive Evolution offers an insightful perspective on how international social orders are constructed, maintained and replaced (295). Contributing to the literature on international relations (IR), Adler's book provide a synthesis of his previous work on practices, learning processes, epistemic communities, progress and the construction of social reality.

The book is led by the argument that international social orders are not only multiple and overlapping and cut across boundaries but constantly evolving and simultaneously kept metastable through practices (24)—with metastability understood as “practices’ continuity in a stable state of flow” (3). Furthermore, using his agential, structural, pragmatist and practice-based approach toward social reality, Adler argues that communities of practices are the principal vehicles driving international social orders’ evolution and stability (296). To support this central claim, Adler shows how learning and deliberative processes within and between communities affect their background knowledge and, hence, the propensities for international social orders to stay stable and evolve (120).

Adler's social theory of cognitive evolution offers a novel way to look at the role played by practices in world-ordering processes. Contributing to the recent practice turn in the literature on IR, he places communities of practices—defined as “spatial-organizational platform where practitioners interact, learn, and end up creating and diffusing practices and promoting their adoption by future practitioners” (41)—and their background knowledge at the centre of his analysis (165). By doing so, Adler reinstates the relevance of practices—as material, collective and meaningful—to explain social change processes.

Moreover, IR students and scholars will find in Adler's book an approach that brings to light complementarities between agency and structure, materiality and meanings, stability and change (109), as well as between practice and discourse (266). In doing so, Adler's cognitive evolution theory also breaks rank with Darwinian and Lamarckian conceptions of evolution and offers a distinct explanation of social cognitive evolution (164).

By focusing on communities of practices and the background knowledge that sustains them, Adler also brings agential social mechanisms to the forefront of world politics (chaps. 6 and 7). He further shows that these mechanisms depend on creative variation and selective retention processes of social innovation and of extinction or perpetuation of practices (chaps. 8 and 9). Along with those mechanisms and processes, Adler argues that epistemic practical authority (“the capacity for practical meaning fixation” [236]) and deontic power (“political authority from a practical epistemic perspective” [297]) are key explanatory factors for the selection and retention of practices that eventually constitute social orders (236). In chapter 10, he ventures into normative theorizing by attempting to point to what constitutes better practices and bounded progress (265), which he identifies as those practices based on a sense of common humanity (268). He further highlights the role of practitioners in promoting such practices (271).

While the book is primarily accessible to an initiated audience, it offers an unprecedented contribution to the literature on IR. Resonating with the work of many contemporary scholars—including that of his doctoral supervisor, Ernst Haas (100); the process-oriented ontology of Alexander Wendt (39); and the contributions to practice-based understandings of international orders by his former student and present colleague Vincent Pouliot (138)—Adler's cognitive evolution theory is at the intersection of a rich diversity of perspectives. Contributions of scholars such as Ilya Prigogine, John Searle, John Dewey, Karl Popper, William James, Donald Campbell and Etienne Wenger, in addition to the philosophical stance of the pre-Socratic philosopher Heraclitus, are also mobilized in many instances and are central to this work. As a result, Adler's cognitive evolution theory gains from its carefully chosen diversity of influences and allows the author to propose a theory that rests on evolutionary constructivism along with a “becoming” and pragmatist ontology (36). It is an ambitious attempt to understand the social world (9), accounting simultaneously for the stability and change of international social orders (102) and grappling with the complex dynamics of world-ordering processes (295).

Although the book's theoretical richness offers avenues for advancing into theorizing world-ordering dynamics, it leaves little room for empirical illustrations. Intended to be primarily theoretical (9), the book builds solely on three cases: the evolution of the cyberspace, corporate and European Union social orders (296). Consequently, the book's principal strength may also be its main weakness. For those interested in conceptually grasping complex dynamics such as metastability (3) and nonlinear change (103) and with theorizing the evolution of international social orders and the organization of world politics (25), the rich theoretical discussions sustained in the book can be fruitful. However, for those prioritizing empirical verifications over theory building, Adler's book may only lay the foundations for further empirical research and open a new research agenda.