Scott Shapiro has recently argued that Ronald 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 but disagree that it has not been met.
Positivism cannot 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, that is, a dispute about what judges are doing, and how many of them are doing it (since it is the actual practice of officials and their attitudes towards that practice that fixes the criteria of legal validity according to the positivist). Positivism, however, has two other explanations for theoretical disagreement, which “explain away” rather than preserve the “Face Value” disagreement. According to positivists, theoretical disagreements are either (1) disingenuous, in the sense that the parties, consciously or unconsciously, are really trying to change the law—they are trying to say, as Dworkin puts it, “what it should be” not “what the law is,” or (2) simply predicated on error because parties to the disagreement 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. This Article explores the “Disingenuity” and “Error Theory” accounts of theoretical disagreement, with attention to the theoretical desiderata (for example, simplicity, consilience, methodological conservativism) 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.