법철학에서 관습이 왜 중요한가? ―관습의 본질과 법규성에 대한 새로운 이해―

Today in the so-called ‘post-customary era,’ custom(ary law) has often been neglected and disfavored in both legal theory and practice. Along with the skepticism that customary law is merely a redundancy in the domestic legal system, the role of custom is often called a ‘jurisprudential puzzle.’ In the philosophy of law, in contrast, customary law is an important subject in many dimensions. For legal positivists, the legal status of customary law has been a dilemma that had to be solved in accordance with their concept of law, the outcome which would the theory’s persuasiveness. In a Fullerian non-positivist perspective, conversely, customary law can be a medium which shows the interactiveness and openness of law. Thus how we cope with custom can be decisive in valuating the coherence and validity of a theory of legal philosophy. In this article, the author first examines the history of legal-philosophical arguments concerning the nature and legal status (II.), and focuses on phenomena of ‘customary laws wi thout customs’ and ‘the paradox of customs,’ which were indicated as troubles by positivists adhering to command theory and in the skeptistic tradition, to point out what makes custom so ‘problematic.’ (III.) The author (i) sets forth the formula of “custom = convention * habit(uation) as the basic framework for a new perspective on the nature of custom(ary law), (ii) with an introduction to Postema’s normative practice account (IV.). As a conclusion the author remarks that a properly reconstructed theory on legal customs can work, instead of a troublesome dilemma, as the basis for a inclusive concept of law embracing international customary laws in its sphere, and speculates that customary law can ―instead of being an outdated source of law― be reshaped as a soft-law norm for future society (VI).