Treaties and custom are generally regarded as the major sources of international law. They derive their validity more or less directly from the consent of those subjects of the law which also possess the institutional authority to make law. The perceived limitations of the consensual nature of these two sources have resulted in doctrinal controversy concerning, inter alia, the existence of sources of international law which are not essentially consensual. This is the rationale for the inclusion of general principles of law recognised by civilised nations alongside treaties and customary international law in Article 38 of the Statute of the International Court of Justice, as one of the sources of international law to which the Court may refer. Similarly, the phenomenon of ‘soft’ international law is, by and large, a response to the failure to generate the full measure of State consent required for attributing full legal status to the ‘soft’ norms in question, often in relation to developing fields of international concern. It is often said that these non-consensual sources have an inferior status when compared with the consensual ones. The purpose of this paper is to consider critically the basis and the form of the differentiation between these two apparently non-consensual phenomena (i.e., ‘general principles’ and ‘soft’ law) on the one hand, and the paradigmatic (because consensual) types of international law (i.e., treaties and custom) on the other.