This paper intends to throw light upon some aspects of the debate on the characterization of legal principles and on their differences when compared to rules. Particularly, this analysis proposes differentiating principles from rules by considering the functions they perform in law instead of their structural differences. To achieve this, we distinguish between the functions of guidance and justification that legal principles fulfill. From that distinction, we observe that the attempt to characterize legal principles based on the way in which they guide conduct does not seem to be the most appropriate either. In contrast, this paper tries to show that all the different types of precepts known as principles perform a justifying function in legal reasoning.
