Brian Leiter

Shapiro has recently argued that Dworkin posed a new objection to legal positivism in Law's Empire, to which positivists, he says, have not adequately responded. Positivists, the objection goes, have no satisfactory account of what Dworkin calls “theoretical disagreement” about law, that is, disagreement about “the grounds of law” or what positivists would call the criteria of legal validity. I agree with Shapiro that the critique is new, and disagree that it has not been met. Positivism can not offer an explanation that preserves the “face value” of theoretical disagreements, because the only intelligible dispute about the criteria of legal validity is an empirical or “head count” dispute, i.e., a dispute about what judges are doing, and how many of them are doing it. Positivism, however, has two other explanations for theoretical disagreement, which “explain away” rather than preserve the “face value” disagreement. According to positivists, either theoretical disagreements are disingenuous, in the sense that the parties, consciously or unconsciously, are really trying to change the law, that is, they are trying to say, as Dworkin puts it, “what it should be” not “what the law is”; or they are simply in error, that is, they honestly think there is a fact of the matter about what the grounds of law are, and thus what the law is, in the context of their disagreement, but they are mistaken, because, in truth, there is no fact of the matter about the grounds of law in this instance precisely because there is no convergent practice of behavior among officials constituting a Rule of Recognition on this point. The “Disingenuity” and “Error Theory” accounts of theoretical disagreement are explored, with attention to the theoretical desiderata at stake in choosing between competing explanatory theories. Particular attention is given to the best explanation for Riggs v. Palmer in light of the actual historical context of the decision and other opinions by the Riggs judges in contemporaneous cases

Both an introduction to Nietzsche’s moral philosophy, and a sustained commentary on his most famous work, On the Genealogy of Morality, this book has become the most widely used and debated secondary source on these topics over the past dozen years. Many of Nietzsche’s most famous ideas - the "slave revolt" in morals, the attack on free will, perspectivism, "will to power" and the "ascetic ideal" - are clearly analyzed and explained. The first edition established the centrality of naturalism to Nietzsche’s philosophy, generating a substantial scholarly literature to which Leiter responds in an important new Postscript. In addition, Leiter has revised and refreshed the book throughout, taking into account new scholarly literature, and revising or clarifying his treatment of such topics as the objectivity of value, epiphenomenalism and consciousness, and the possibility of "autonomous" agency

The “naturalistic turn” that has swept so many areas of philosophy over the past three decades has also had an impact in the last decade in legal philosophy. Methodological naturalists (M-naturalists) view philosophy as continuous with empirical inquiry in the sciences. Some M-naturalists want to replace conceptual and justificatory theories with empirical and descriptive theories; they take their inspiration from more-or-less Quinean arguments against conceptual analysis and foundationalist programs. Other M-naturalists retain the normative and regulative ambitions of traditional philosophy, but emphasize that it is an empirical question what normative advice is actually useable and effective for creatures like us. Some M-naturalists are also..