Research on the Judicial Developmental Function of Custom as a Source of Law under the Context of the Implementation of the Civil Code

Abstract

The general recognition of custom as a source of law by the Civil Code provides a normative foundation for judicial practice to introduce diverse social norms into the adjudication process, making the judicial developmental function of custom an issue of both theoretical value and practical significance. This study finds that custom holds a supplementary status within the system of legal sources. Its validity dynamically emerges from factual practices through judicial procedures and can be categorized into three modes of application: interpretative, empowering, and constructive. The judicial application of custom is not automatic but follows a refined pathway from discovery and identification, through normative justification, to preliminary review. This pathway is delineated by the coordinating boundaries of legality, legitimacy, and coherence, achieving development through synergy with the fundamental principles of civil law. The research demonstrates that the judicial development of custom not only serves to fill legal gaps and concretize the interpretation of legal rules but also acts as a dynamic coordinating mechanism. While maintaining the stability of the code, it promotes a flexible, bottom-up evolution of the private law order, ultimately transforming the Civil Code into an open and responsive "framework order." The systematic construction of this function represents a key direction for the future development of civil law methodology.