This chapter analyzes mistakes and proposes a more adequate account of the heterogeneity of reasoning and its implications. It describes legal reasoning by looking at it as a "deliberative practice" and explains the idea of a deliberative practice, implicitly relying on Wittgenstein's insights about reasoning and justification. The chapter demonstrates how the understanding of law as a deliberative practice helps to resolve several key issues concerning the merits and defects of a positivist description of law. It discusses the limitations of antifoundationalism and pragmatism by examining the consequences of their relative inattention to the same two problems, the inside/outside dilemma and the heterogeneity of justification. Characterizing law as a deliberative practice sets on the road to three goals: giving an elastic and convincing description of legal reasoning, building bridges between the old jurisprudence and the new and examining the foundations of critical theory by questioning the way in which it claims to destabilize value, conceptual coherence, and meaning.