Aristotelian Naturalism and the History of Ethics David O. Brink (bio) terence irwin’s monumental three-volume The Development of Ethics is a masterful reconstruction and assessment of figures, traditions, and ideas in the history of ethics in the Western tradition from Socrates through John Rawls.1, 2 The three volumes weigh in at over 11 pounds and span 96 substantial chapters and over 2,700 densely formatted pages (large pages, small margins, and small font). The Development of Ethics covers not only familiar figures, such as Plato, Aristotle, the Stoics, Aquinas, Hobbes, Locke, Hutcheson, Butler, Hume, Smith, Reid, Kant, Hegel, Mill, Green, and Sidgwick, but also a rich variety of ancient sources (including the Cynics, Cyrenaics, Skeptics, and Church Fathers, including Augustine), medieval, renaissance, and reformation sources (including Scotus, Ockham, and Machiavelli), sources for natural law (including Hooker, Vasquez, Suárez, Grotius, Pufendorf, and Barbeyrac), continental rationalists (including Spinoza and Leibniz), British moralists (including Cumberland, Cudworth, Shaftesbury, Clarke, Balguy, and Price), post-Kantians (including Marx, Schopenhauer, Kierkegaard, Nietzsche, and Heidegger) and twentieth-century English-language sources (including Moore, Ross, Stevenson, Ayer, Lewis, and Hare). This is just a sampling of the more familiar historical sources that Irwin [End Page 813] discusses. He also discusses a wealth of less familiar philosophical and theological figures. For the most part, the chapters are organized chronologically, rather than thematically. Most chapters are devoted to individual figures, and several figures get multiple chapters (Aristotle gets four, Aquinas nine, Scotus two, Suárez two, Hobbes three, Hutcheson two, Balguy two, Butler four, Hume five, Reid two, Kant seven, Hegel two, Mill two, Sidgwick three, and Rawls two). A few chapters discuss traditions and themes. The combination of scope and depth in The Development of Ethics is, as far as I know, without precedent. Existing comprehensive histories of ethics, such as Henry Sidgwick’s Outline of the History of Ethics and Alasdair Macintyre’s A Short History of Ethics, as their titles suggest, are, however valuable, both less comprehensive and less thorough. Even important recent studies that deal with the history of modern ethics in significant detail, such as John Rawls’s Lectures on the History of Moral Philosophy, Stephen Darwall’s The British Moralists and the Internal ‘Ought’: 1640–1740, and Jerome Schneewind’s The Invention of Autonomy, concern only modern philosophy and, even there, have less comprehensive ambitions. The broad scope of Irwin’s inquiry pays various dividends, not the least of which is that he is able to show that some ideas and themes often taken to be distinctive of modern ethics have their origins and antecedents in antiquity. Fortunately, Irwin has the skills necessary to make good on the ambitions of his study. Indeed, it is hard to think of anyone else as well qualified historically, philologically, and philosophically to undertake such an ambitious interpretive and philosophical task and carry it out with such authority. Any reader (or reviewer) of Irwin’s three volumes should find the process humbling. Though Irwin has a keen sense of the context of the figures and ideas he discusses, he is focused on and relentless about understanding and assessing the philosophical content and implications of the texts. Though he provides self-contained reconstructions and assessments of various figures and traditions that make good sense of those figures and traditions on their own terms, two general principles emerge from and guide his discussion. The first principle is a methodological commitment to Socratic dialectic, as refined and practiced by Aristotle (DE §2). As a rough first approximation (but see §1 below), this makes Irwin’s approach to the history of ethics essentially comparative. In understanding and assessing the philosophical claims of a particular figure or tradition, he finds it fruitful to compare the philosophical commitments and resources of that figure or tradition with the commitments and resources of other figures and traditions. This is valuable, Irwin maintains, whether those different figures and traditions were in actual and conscious conversation or not. The second principle is a substantive set of commitments that are perhaps clearest in Aristotle and Aquinas but that Irwin thinks influence, in various ways, much of the history of ethics. This principle Irwin calls Aristotelian naturalism...