In “Legal Reasons, Sources and Gaps”, Joseph Raz points out that statements of reasons – mainly, conclusive legal reasons – are the most basic category of legal analysis. The conceptual importance of statements of legal reason implies that legal philosophers must use them to explain other legal concepts. In this sense, Raz claims that conclusive reason is a useful analytical tool for dealing with a classic problem of legal philosophy: gaps in the law. Raz defends a particular form of indeterminacy of law, which are ordinary gaps produced by the imprecision of the concepts used in the formulation of legal norms (when the law speaks with an uncertain voice) or by specific conflicting legal reasons (when the law speaks with many voices). In such cases, judges have discretion to resolve legal disputes. However, he denies that the law can have genuine gaps (when the law is silent) and, in those cases, judges lack discretion. In this paper, I criticise Raz’s arguments for denying the existence of genuine gaps in the law and suggest an alternative which partially preserves Raz’s intuitions but does not compromise with their implausible consequences.