The idea of a society founded on a contract among its members is an idea that has captivated political thinkers for centuries. From its origins in the early modern theories of Hobbes, Locke, Rousseau, and Kant to its rebirth in the second half of the twentieth century, the metaphor of the social contract runs long and deep in the tradition of Western political thought. And, although the modern revival of interest in the social contract has spawned a vast scholarly literature, there is remarkably little work that seeks to survey the modern tradition as a whole. In that sense, Albert Weale’s book fills an important, and rather surprising, gap in the literature.

Weale aims to provide an exposition and evaluation of major work in social contract theory from 1950 to the present. Adopting what he terms a “comparative method,” Weale eschews much of the detailed technical debate that has grown around individual thinkers and theories in order to articulate commonalities and points of difference that together clarify the modern tradition. The book is organized around a series of encounters with key theorists, including Barry, Buchanan and Tullock, Gauthier, Grice, Harsanyi, Rawls, and Scanlon. The discussion is divided between what Weale takes to be the two central concerns of contract theory: (1) the “theory of content”—namely, the moral and political principles recommended by each thinker—and the nature of their derivation from the contractual construction (often characterized as the problem of justification); and (2) the “theory of obligation”—namely, the case each thinker makes for the adoption of an obligation to uphold their favored principles (often characterized as the problem of motivation).

Having presented the tradition in this way, Weale proceeds to consider a sequence of prominent criticisms of contract theory: that it is, at best, a superfluous “spare wheel” and, at worst, a tool for the domination of marginalized and disadvantaged groups. Finally, Weale concludes with a relatively brief sketch of his own preferred “empirical” interpretation of the social contract and of some of its implications for the future of the tradition.

At over 400 pages, this is a long and often technical book. The book’s preface exhibits a degree of contrition in its apology for “inflicting on the reader such a long work” (v), but Weale is a fine prose stylist; he communicates the complex ideas under discussion clearly and effectively, and often with considerable elegance. This means that, although its primary audience is undoubtedly that of professional research, the book is also likely to be of interest and value to a somewhat wider readership, including students.

At its best, Weale’s comparative approach yields significant insights. By carefully tracing lines of thought across the tradition, Weale effectively displaces the familiar—though largely unilluminating—subcategorization of theories into “contractarian” and “contractualist” variants. In its place, he introduces a more flexible and nuanced matrix, organizing theories according to both the amount of knowledge they attribute to the contracting parties (do they posit a “veil of ignorance,” and how thick is the veil they specify?) and the type of rationality they ascribe to the contracting parties (do the parties choose according to principles of standard expected utility theory, or to some form of deliberative rationality?). This framework usefully undermines the crude but relatively widespread perception of modern contract theory as emerging in opposition to utilitarianism, when it is more accurate to see it as, in part at least, a continuation—as an attempt to solve problems emerging in utilitarian theory. It also functions to highlight surprising continuities between contract theorists conventionally seen (even by each other) as implacably opposed. For example, although Brian Barry and David Gauthier differ dramatically in their respective understandings of the rationality of the contracting parties and the principles on which those parties would agree, they nevertheless share in their rejection of a veil of ignorance, positing parties who have full knowledge of their endowments, starting place in society, interests, and purposes.

But there is also a fundamental question that Weale’s discussion leaves frustratingly unanswered: why exactly has the social contract proved to be such a powerful and enduring metaphor in our understanding of politics and morality? If there is one question a comparative study of the tradition ought to be able to answer, then it is this. Weale rightly notes that social contract theory constitutes not only an important intellectual construction in its own right but also a cultural phenomenon reflecting a particular “conception of society that forms part of the self-understanding of those who live in the democratic societies that are the product of the enlightenment” (p. 7). Accordingly, in examining social contract theory, “democratic citizens are in various ways holding a mirror up to themselves” (p. 7). I think this is true and important, but Weale’s way of thinking about the contract device is ill suited to the task of showing us what that mirror reveals. Following Barry, Weale differentiates between two interpretations of the contract: the a priori interpretation, on which the contract is conceived as a purely hypothetical, abstract thought experiment; and the empirical interpretation, which “models contractual reasoning by analogy with political representatives deliberating” in the real world (p. 215). But he neglects a third possibility: that the contractual construction might (in contrast to the a priori interpretation) purport to offer a truthful account, but one that does not (in contrast to the empirical interpretation) aspire to empirical validity. To think of the contract in this third mode is to think of it as a kind of fictional genealogy—a story that helps to explain principles of justice by showing how they might have come about.

This way of thinking of the contract might seem to be a capitulation to the “spare wheel” critics, who urge that the contract device is nothing more than a decorative and potentially useful example. But that would be to misunderstand the methodological potential of stories. We may think of the role of stories in moral philosophy not just as a stock of examples but also as a source of reminders. Minimally, our attachment to the social contract story reminds us that we are creatures for whom it is essential that the terms on which we live together can plausibly and without excessive strain be presented as the possible outcome of unforced agreement among those subject to the terms. Of course, there is a far richer story to be told here, and in some ways, it is disappointing that Weale’s extremely long book fails to tell it. But I suspect that the story is not one that can be told anyway from within the conventional resources of analytical political theory alone. If we are to understand these peculiar creatures of contract fully, then we must also investigate their history, anthropology, and fictions.