Claims about causality are a key feature of much of the scholarship in political science generally, and international relations specifically. The identification of cause is what separates description from explanation. And yet, for all the claims made about causal relationships across both the social and natural sciences, the concept of causality itself remains both poorly understood and highly contested. What do we mean when we say x causes y, and how do we know that the relationship between the two is in fact causal? Such questions have generated an increasing literature in international relations over the past decade, and it is into this literature that Ned Lebow’s book Constructing Cause in International Relations fits.

Lebow begins the book with a review of how causation has been understood in the philosophy of science. He argues that there is no consensus on this question in the practice of the contemporary natural sciences; different specific subfields within the sciences approach cause in fundamentally incompatible ways. For example, some subdisciplines of physics follow Hume in understanding cause as correlation. Other subdisciplines create intellectual constructs that cannot be empirically identified directly, but to which they impute causal powers—an approach to causality that philosophers of science call scientific realism. Yet others, such as some areas of quantum theory, eschew causality altogether. If physics, the hardest of the hard sciences, cannot agree on a concept of causality, Lebow argues, it should be no surprise that social scientists contest the concept among themselves as well.

The historical review begins with Aristotle, who identifies four kinds of causes, one of which—efficient causation (the proximate source of an outcome)—is what scientists, both natural and social, most often mean when talking about cause. David Hume attempted to specify the idea of efficient causation by associating it with what he called “constant conjunctions,” or observed regularities in relationships among entities (p. 25). It is this Humean understanding of causality that Lebow is principally arguing against (although he also distances himself from various other understandings of cause, including scientific realism). His answer to Hume, and the positivist social science tradition that builds on Humean logic, is what he calls inefficient causation, a play on Aristotle’s efficient causation.

The idea of inefficient causation builds on a Weberian epistemology, in which the analytical categories through which we construct data are intellectual impositions on the empirical world rather than inherent features of that world. It also builds on a constructivist approach to international relations, which sees the political world as socially constructed rather than materially given, and as contingent on social context that cannot be reduced to generalized assumptions about behavior such as rational choice. The combination of two starting points yields an understanding of causation that is singular rather than generalizable; Lebow argues that we should study the causes of single events rather than looking for the cause of a general category of event. For Lebow “cause makes sense of the social world in a manner consistent with evidence in a way that has some social value beyond its internal structure” (p. 6). Attribution of cause in this understanding helps us to understand the world rather than being intrinsic to the world, and should be judged on the extent to which it succeeds in doing so.

Lebow devotes two chapters to developing a methodology for the study of inefficient causation. He begins with the idea of cognitive frames and potential causal links between frames and individual behavior. He then discusses the aggregation of behaviors into outcomes as a separate set of mechanisms and processes, often yielding outcomes very different from what individuals intended to achieve through their behavior. At each of these levels, causal relationships can be traced forward (from cause, looking for effect) or backward (from effect, looking for cause). Inefficient causation allows for multiple causes, at various levels of inquiry and degrees of remove from effects; it “is a multi-step process that involves searching for connections between and among causes” (p. 65).

The final substantive chapter of Constructing Cause is devoted to a case study that illustrates Lebow’s methodology for addressing inefficient causation. It focuses on visual frames, particularly the transition, beginning in the late medieval and early renaissance eras, to linear visual frames that emphasize perspective and an individual viewpoint. He argues that this change, which reflected the development of an individualist frame of reference across European thinking in the middle of the last millennium, was a cause of the evolution of the modern territorial state. He associates it with the concepts of both demarcated borders and sovereignty as an individual possession.

Constructing Cause is both an ambitious book and a short one. This combination has both pros and cons. The pros are that it is intellectually engaging, and covers a broad range of intriguing ideas in areas ranging from the philosophy of social science to the relationship between painting and the modern state. The cons are that individual ideas are not always developed, and individual claims are not always supported as well as they might have been. An example can be found with Lebow’s dismissal of Aristotle’s four kinds of causation in a single paragraph (pp. 64–65), and his similar dismissal of scientific realist accounts of causality. Given that much of the recent literature on causality in IR draws explicitly on both scientific realism and Aristotelian causality, a deeper engagement with these ideas would have been useful.

Similarly, he dismisses the utility of the idea of efficient causation in IR by claiming that all the interesting events are unique, and that cases of efficient causation are uninteresting. He supports this with a few examples of major wars or changes in the international system. IR scholars looking at more quotidian international relations (for example, at the politics of trade or the functioning of international organizations) might have a different interpretation of what is and is not interesting. He also does not locate himself adequately in the constructivist literature. He has, it is true, done so at greater length in his other books, but this book neither refers to, nor cites those discussions. He claims in Constructing Cause to speak for constructivism in general, without locating claims about things like co-constitution and identity within the constructivist literature, and without acknowledging that other self-identified constructivists might disagree with his interpretations. Nor does he address the question of how the dialectical logic that informs some constructivist methodology relates to the arguments about causality that he develops.

A final question is that of the purpose, or to use Lebow’s definition of cause, the “social value” of a methodology of inefficient causation. For positivists, the purpose of understanding causation is to predict. For critical theorists (or at least those critical theorists interested in using the concept of causation), the purpose is to change how we understand, and perhaps practice, contemporary politics. Singular causation allows neither. A discussion of what it offers to us, not as historians interested in understanding the past in its own terms, but as political scientists interested in moving the future, would have been helpful. Having said that, Constructing Cause is both a useful introduction to discussions of causality in international relations and an impassioned and effective argument for a broader understanding of causality than that offered by the narrow positivism that dominates so much of the discipline.