Abstract
This article explores the common points and the differences between Hans Kelsen’s and Robert Alexy’s application theories. Although Kelsen subscribed to moral relativism and denied the idea of a practical reason, while Alexy criticised moral relativism and defended the idea of a communicative reason, it is argued that the two theories share important common features, such as denying that interpretation can point one single answer as the right one and acknowledging that interpretation is comprised by both knowledge and will. The article acknowledges that there are differences between both theories, analyses whether these differences are qualitative or quantitative and, in the end, concludes that between the two theories there is not disruption, as one might believe, but rather continuity.