Two methodological claims in Hart's The Concept of Law have produced perplexity: that it is a book on “analytic jurisprudence” 1 and that it may also be regarded as an essay in “descriptive sociology.” 2 Are these two ideas reconcilable? We know that mere analysis of our legal concepts cannot tell us much about their properties, that is, about the empirical aspect of law. We have learned this from philosophical criticisms of conceptual analysis; yet Hart informs us that analytic jurisprudence can be reconciled with descriptive sociology. The answer to this puzzle lies in the notion of nonambitious conceptual analysis. The theorist analyzes concepts but accepts the limitations of conceptual analysis and therefore uses empirical knowledge and...