Cohen seeks to rescue the concept of justice from those, among whom he includes Rawls, who think that correct fundamental moral principles are fact-sensitive. Cohen argues instead that any fundamental principles of justice, and fundamental moral principles generally, are fact-insensitive and that any fact-sensitive principles can be traced back to fact-insensitive ones. This paper seeks to clarify the nature of Cohen's argument, and the kind of fact-insensitivity he has in mind. In particular, it distinguishes between internal and external fact-sensitivity – that is, whether facts are referenced in the content of the principle, or must otherwise be the case in order for the principle to apply at all. Cohen himself seems likely to endorse internally fact-sensitive fundamental principles. This leads to a discussion of Cohen's Platonism about moral principles and the extent to which his arguments cover all its rivals.