International soft law as a legal metaphor has become part of legal discourse. The author argues not only that the term itself is misleading and contradictory, but that the terminological problem indicates deeper doctrinal difficulties which soft law theories should overcome. Identifying two main streams of these theories, the article provides a short review of the fundamental arguments for the existence of soft law. It distinguishes between two lines of arguments, ie functional arguments and proximity arguments, evaluates their coherence and explanatory power, and finds that these arguments fail to lay a coherent and persuasive foundation for international soft law. The author concludes by pointing out that non-legal norms may have essential regulatory functions in international relations but the law and non-law distinction should be maintained, and separating soft law as a distinct category is unwarranted.