In contemporary legal thought, it is frequently claimed or simply presumed that reason rules or ought to rule. But if this view is to be more than a conceit, it would be necessary for legal thinkers to address the challenges that reason confronts when faced with a law whose authorities, aesthetics and self-idealization seem resistant to reason. That sort of encounter simply has not happened in any serious way. Based on a close reading of crucial passages in Ronald Dworkin’s Law’s Empire, this chapter shows how instead the ‘partisans of reason’ elide challenges to reason through a characteristic reductionism and purification of law. This rhetorical elision is ultimately a betrayal of reason itself. Predictably, it yields an enchantment of reason.