The author proceeds from a brief elucidation of the concept “argumentation” through a more extended account of substantive reasons in pure practical argumentation and of institutional argumentation applying “authority reasons” as grounds for legal decisions to an initial account of the nature and place of legal interpretative reasoning. Then he explores the three main categories of interpretative arguments, linguistic arguments, systemic arguments and teleological/deontological arguments; and he examines the problem of conflicts of interpretation and their resolution. His conclusion is that legal argumentation is only partly autonomous since it has to be embedded within widerelements of practical argumentation.