In the first part of this paper I point out the reasons in virtue of which human rights discourse was seen with scepticism, in the first half of twentieth century, in its capacity to compel states to act morally in the context of international relations. Then, in the second part, I examine the reasons in virtue of which this kind of scepticism lessened at the end of the Cold War. I argue that an ever growing interaction among actors in international relations – including non-state actors – has contributed to the emergenceof a decentralised system of norms in the context of which the discourse on the concept of human rights may be justified without one’s commitment to such metaphysical ideas as natural laws and natural rights.