What is meant by the term "rational legal argument"? To what extent can legal theory permit legal reasoning to be rational? Is the demand for rationality in legal affairs justified? What are the criteria for rationality? In addressing these questions, Alexy first develops a general theory of practical discourse based on insights from Anglo-Saxon and German moral and legal philosophy. He then sets out a new theory of rational legal discourse, which will stand as a major contribution to the study of legal reasoning.