Abstract One of the most fascinating developments in the domain of international law in the last few decades is the astonishing proliferation of non-binding legal instruments or soft law, namely, norms or directives explicitly avoiding the imposition of legal obligations on the relevant parties. From a philosophical perspective, this is rather puzzling: how can we explain the idea of a non-binding directive or a non-binding contract? In this article I aim to provide an account of the rationale of soft law from the perspective of the practical reasons in play. First, I analyse the idea of authoritative advice, suggesting that when authorities advise their putative subjects, they purport to give the subject presumptive reasons for action. I explain what presumptive reasons are. Secondly, I suggest the possibility that something very similar is at work in cases of non-binding agreements, coupled with special accountability relations that such agreements invariably constitute.