Legal theory has failed to fully explore the rhetorical in the judicial decision and, in doing so, has misunderstood the key role played by reasons that seek to legitimate and justify while expressing emotion and commitment. This thesis sets out to understand why legal theory has failed to do so and what role rhetoric plays in the judicial decision. Three legal theorists, Chaim Perelman, Bernard Jackson and Neil MacCormick are used to show that it is seeking to be philosophically acceptable that has led legal theorists to avoid the emotional and character-based aspects of the judicial decision. Two historical studies, of the Talmud and Aristotle's Ars Rhetorica, demonstrate that rhetoric can be seen as closely related to the limits of authority in the system and the character and identity of the decision-maker. These insights are then applied to the common law, exemplified by six cases from the law of negligence. This highlights the importance of the commitment of judges to their own sense of role and the way limitations on reasoning help to create this sense. The thesis concludes by considering the relationship between philosophy and judgement and argues that they can be seen as different forms of understanding and that there are strong ethical reasons for rejecting attempts to see either as a paradigm for all understanding.