Soft law appears to be the ‘bastard child’ of law. Because of its dubious origin, soft law is not officially recognized, in positivist conceptions of law, as legally valid law. At the same time, the legal relevance of soft law is hard to deny. Soft law does generate rights and duties which the parties at hand, and even sometimes state officials too, perceive as legally binding. How to make sense of soft law? Is it law or non-law, or something in between, law that is emerging or not yet law? Is it really soft and, if so, in what sense? In this chapter, two different approaches to legal validity and soft law will be confronted with each other. Firstly, we will present Kelsen’s conception of legal validity, which still is one of the prevailing...