Prior to the publication of Hart's The Concept of Law, it was not uncommon for legal philosophers to identify jurisprudence with the quest for a definition of “law.”The subject of this paper is “law” as it pertains to systems of governance of human conduct. Therefore we are not offering an analysis of “law” as it pertains to regularities in nature and thus we do not explore the semantic or metasemantic relations between the two.See, for example, Herman Kantorowicz, THE DEFINITION OF LAW (Cambridge University Press, 1958). In a similar vein, see Lewis Zerby's suggestion that “the most famous definition of law [sic]… is that made by Justice Holmes when he said: ‘The prophecies of what courts will do in fact, and nothing more pretentious, are what I mean by law.‘” Some Remarks on the Philosophy of Law, 46 J. PHIL. 773–779 (1949). Hart explicitly resisted this characterization of the ambition of jurisprudence; the subject matter of jurisprudence is law, not “law.” Notwithstanding Hart's assertions to the contrary, in Law's Empire Ronald Dworkin argues that Hart's own legal positivism as well as other familiar jurisprudential theories (like natural law) are semantic theories: that is, accounts of the meaning of “law.” Dworkin further identifies semantic theories with criterialism, according to which the meaning of a term is given by shared criteria for applying it. The meaning of the expression “law” on this view is given by a rule or set of criteria specifying the conditions that must be satisfied in order properly to employ that expression, and the project of a semantic jurisprudence is to identify that rule.