The ostensible topic of this book is the exchange of views about political liberalism that was initiated by Habermas and Rawls in the Journal of Philosophy in 1995, and pursued by them in subsequent publications. But in fact, the book takes the opportunity presented by this exchange for a wide-ranging comparative discussion of their respective approaches to the modern phenomenon of liberal democracy. The use of the term “debate” in the title may suggest that the book will identify a winner, but Finlayson is clear that this is not his intention. He speaks of a “dynamic complex of arguments stained through by various interpretations and misinterpretations … that affects not just the two disputants but also many critics and commentators” (243), and he notes the difficulty of keeping score. But the book has been written for the English-speaking philosophical community, which—at least in the United States—is more likely to be familiar with Rawls than Habermas. It is thus fortunate that Finlayson is a leading contemporary Habermas scholar and has been able to shed considerable light on the thinking of this difficult philosopher.

The book is divided into two unequal parts. The first, covering the initial 150 pages, is stage setting. Finlayson describes the 1995 exchange as consisting of a book review by Habermas of Rawls's recently published Political Liberalism and a reply by Rawls to the review. He says that the exchange was marred by the fact that Habermas had not had the opportunity to give the book careful examination, and that neither writer had detailed knowledge of the other's philosophical views. In particular, Habermas took Rawls's Original Position and his own universalization procedure for identifying valid moral norms (U) as competing ways of securing the impartial concern for everyone's interests that is definitive of morality.

Finlayson next provides a very helpful overview of Habermas's discourse theory of law, as set out in Between Facts and Norms, which was written shortly before the exchange (with an English translation following shortly after), and which Finlayson takes to have shaped Habermas's perception of Rawls. This is followed by a summary of the main ideas in Political Liberalism. Finlayson emphasizes that in Between Facts and Norms, Habermas takes it to be a distinctive feature of modern, “posttraditional” life that the scope of moral norms has shrunk to such an extent that they are no longer suitable for resolving many conflicts of interest, and that as a result, this function has been taken over by law.

The final one hundred pages of the book examine the 1995 exchange and its aftermath, both in the work of Habermas and Rawls and in that of commentators. Finlayson begins by arguing that the reception of the exchange has been distorted—or more accurately, sidetracked—by the widespread conviction (1) that the dispute between the two philosophers concerns whether (U) or the Original Position provides the best way of interpreting the moral point of view, and (2) that there are no important differences between the two devices, considered as such interpretations. Finlayson appears to accept this conclusion, but argues that to understand what is actually in dispute between Habermas and Rawls, we must cast our net more widely. If we do, he says, we can see that Habermas and Rawls offer sharply different ways of understanding the normative essence of contemporary liberal democracies.

The main difference is that Rawls provides a normative theory of a familiar sort, an account of how things ought to be in such polities. He takes polities of this kind to be characterized by a value pluralism—a diversity of “comprehensive doctrines”—which requires their members to conduct public affairs on the basis of a free-standing political conception of justice implicit in their historically bequeathed background culture, taken to embody the main features of the two principles of justice developed in A Theory of Justice.

By contrast, Habermas's theory, while not purely descriptive, is a sociologically grounded theory of morality that focuses on the complex system of social norms—interpersonal and institutional—that gives structure to the public life in a modern (and thus posttraditional and postmetaphysical) liberal polity. There are a variety of these norms, and they interact in complicated ways to create this public normative structure. An important feature of this picture is the “coorginality” of certain of these elements, most importantly, the norms underlying democratic decision-making procedures and those underlying the civil and political rights characteristic of modern liberal democracies.

According to Finlayson, Habermas takes Rawls to have wrongly given priority to rights. He says that Habermas recognizes two rival traditions in liberal thought, epitomized by Kant and Rousseau, with the Kantian—to which he assigns Rawls—accepting the existence of moral rights that are normatively prior to the laws that seek to codify them. These rights thus constrain the collective lawmaking of citizens that is central to the Rousseauian tradition. Habermas's cooriginality is intended to capture and do justice to both the “private” autonomy associated with the former tradition and the “public” autonomy associated with the latter. Lying in the background is Habermas's continuing commitment to the core idea of discourse ethics, namely, that morally valid norms cannot be injected into a liberal polity from the outside by an expert philosopher, but must be worked out discursively by the members of the community that is to be subject to them.

Another important issue that Finlayson identifies in the Habermas-Rawls debate is Rawls's contention that Habermas's theory is “comprehensive,” and therefore introduces ideas that some members of modern liberal democracy could reasonably reject. As a result, it is unsuitable as an account of the normative structure of such a polity, in which the members must be able to “face one another openly” (where the envisaged “openness” is apparently understood to require invoking only shared values). Finlayson agrees that Habermas's theory can be seen as possessing a “comprehensive” character because he accepts it as a fact that we live in a social world in which traditional religious and metaphysical narratives have become obsolete. But drawing on other commentators, Finlayson goes on to argue that the objection can be blunted by distinguishing comprehensive doctrines that impugn the moral personality of others when proposed as grounds for legislation from those that do not, and he places Habermas's theory in the latter group. Finlayson concludes with a discussion that compares Habermasian and Rawlsian positions on the interesting question, originally posed in connection with Rawls's political liberalism, of whether religious reasons can be advanced in public reasoning.

As noted, this book does not identify a winner of the debate. It rather takes the views of each philosopher on a range of contested issues as an opportunity to explore the views of the other. It is likely to be of most value to readers who want to understand Habermas better than they now do, both because of the valuable exposition it contains of Habermas's overall theory, and because the contrasts established between Habermas and Rawls provide useful points of entry into Habermas's philosophy from Rawls's theory, which will be more familiar to the intended audience. But readers familiar with Habermas who seek a better understanding of Rawls should find the book helpful for the same reason.