The aim of this impressive and ambitious book is to make what it calls “a dual intervention” in “both the history of political thought and contemporary political theory” (8). On the former front, it seeks to demonstrate that the political theories of Hume and Smith are both grounded in the concept of “opinion” and represent alternatives to ways of thinking about the state (among other political phenomena) inherited from Hobbes. On the latter front, it aims to recover the approach to political theory taken by Hume and Smith—“a particular style of thinking about politics that has for too long lain overshadowed by its rivals” (240)—and to show how it might serve as a useful antidote to contemporary ideal theory. By and large the book is successful on both fronts.

Sagar divides his book into an introduction and six chapters. After setting out in the introduction the twofold goal described above, the opening chapters focus on the ways in which Hume's science of man and his theory of sociability lay the foundation for a science of politics very different from that which emerges from Hobbes's views on human nature. In chapter 1 Sagar identifies “the control of pride” as the heart of Hobbes's account (35), arguing “the chief goal of Hobbes's science of politics was to offer a solution to the central problems generated for human sociability by that same pride” (37). Hume is then shown to have “resisted Hobbes's vision at a fundamental level” (38), offering an “alternative science of politics” (63). Hume's alternative science is founded on opinion, which, it is argued, offered a better account of “why people submitted themselves to government” than could Hobbes's theory of simple “redirected self-interest” (60). Chapter 2 then extends this comparison of Hobbes and Hume, focusing on Hume's shift away from an “emphasis on contract” to give attention instead to “real history” (72). Here Sagar particularly argues that Hume's “major achievement” was his “marriage of commercial sociability” with “a functioning account of history and the family” (100). Its most striking claim is that Hume's notorious insistence on the artificiality of justice as a supplement for the deficiencies of sympathy and natural sociability culminates in a theory of “naturally artificial sociability” (100). Chapter 3 is the last chapter to focus on Hume, and here we are reminded that Hume, contra Hobbes, “has no theory of sovereignty” (103), which compelled him “to supply an alternative theory of authority that did away entirely with consent,” and also that, contra Locke, Hume aimed to develop his alternative outside “a theistic framework” (123).

Chapter 4 detours from Hume and Smith to consider Rousseau, presented here as defending a theory of sociability that in fact led in “an opposite direction to that pointed out by Hume: back to Hobbes” (141). Rousseau thus serves as an example of an approach that “failed to get past Hobbes” (164), thereby setting the stage for Smith, whom the last chapters present as Hume's torchbearer. Here Sagar argues that what is “of most significance and interest in Smith's political thinking is his acceptance of Hume's prioritization of opinion as the primary item in political-theoretical analysis, alongside his attendant insistence on the centrality of natural authority in explaining and vindicating such arrangements” (167). The acceptance of Hume's core commitment is said to put Smith “firmly outside the Hobbesian legacy of thinking about the modern state” (168), even as Smith is said to go beyond Hume by offering a “substantial correction” to Hume's views on natural sociability (169). Here Sagar rightly notes how Smith's theory of sympathy and sympathetic resentment allowed Smith to bridge the gap between natural sociability and political order without having to take recourse to Hume's controversial insistence on the artificiality of justice (171). Yet otherwise Sagar's Smith is largely in lockstep with Hume, committed to the notion that “all government was founded on the twin principles of authority and utility” (205) and focused on employing “a theory of the opinion of mankind” to account for political order absent any “foundational theory of sovereignty” (207). Chapter 6 then concludes the book with an investigation of some implications of these “theories of the state without sovereignty” (211) for political theory today.

As noted at the outset, Sagar's book is, on the whole, successful on both of the two fronts on which it aims to make an intervention. Through his careful analysis of the texts under review, coupled with his evident familiarity with the larger tradition of which they are a part, Sagar convincingly demonstrates the degree to which Hume and Smith are each committed to developing a political theory of authority very different from Hobbes's. In the end I have only a few relatively minor quibbles with Sagar's arguments on the historical side. First, that Hume's theory of authority and obedience constitutes what is sometimes called “a thoroughly anti-Hobbesian theory of politics” is not yet entirely clear to me (18). Hume's deep philosophical affinities to Hobbes have been emphasized by historians of philosophy such as Paul Russell (among others) in recent years. And Hume's theory of artificial justice has long been regarded—going back to William Wishart and Thomas Reid in the eighteenth century—as an explicit embrace of “Hobbism.” Second, if indeed Hume and Smith's chief innovation is the grounding of politics and indeed political obedience in opinion, one wonders whether this alone entitles them to be seen as “major and original innovators in the history of political thought” (12). I am amenable to this claim, but I expect that many of my colleagues working on Plato are likely to remind us of the degree to which the Republic beat Hume and Smith to the punch on this particular front.

In the end the book's historical arguments strike me as mostly successful. Yet its most important contributions may lie on the more contemporary front. Hume and Smith, Sagar convincingly and compellingly argues, offer not only a set of thoughts about politics that deserve our attention, but a way of thinking about politics that political theorists today would do well to engage. Sagar presents this claim in sometimes arresting if not breathless ways, suggesting that his proposed turn to Hume and Smith is intended in part to induce “a shift in our understanding of what political philosophy is and can hope to achieve” (3) and to induce “a radical reconfiguration of the role and power of political philosophy” (39)—a rethinking of “what political philosophy is and can do” (132). Those are clearly big claims, but Sagar has something very specific and quite useful in mind in making them. What he so admires in Hume and Smith is the effort to develop a political philosophy “better fitted the real world” (134) and its “evident realities” (132). Thus his focus on their reorienting of political philosophy away “from the armchair” to the reality of the world as it is (211), and their efforts to elevate “the importance of history and practice over that of theory” in order to “return political theory to an emphasis on what is, mundanely speaking, politics” (211, 218). This will remind some readers of similar efforts by Cambridge-based thinkers such as Raymond Geuss and Istvan Hont (the latter of whom is a dedicatee of the book and a frequent presence in the notes). It may remind other scholars of Bernard Williams, or Amartya Sen's recent efforts to do something similar with regard to Rawls. But however one regards Sagar's efforts as mapping onto similar contemporary efforts to shift political theory away from idealism and towards realism, they will be welcomed by those amenable to this project.