Frederick Schauer, University of Virginia School of Law, is publishing Second-Order Vagueness in Law in Vagueness in Law: Philosophical & Legal Approaches (G. Keil and R. Poscher, eds., Oxford University Press, 2016). Here is the abstract.
Most of the philosophical literature on vagueness starts with the identification of the term whose vagueness is at issue -- tall, short, night, day, bald, tadpole, etc. But in legal interpretation an additional problem arises, because it is not always obvious which term in a legal text, or even which legal text, is the operative one. H.L.A. Hart's idea of a rule of recognition conceptualizes the way in which some second-order rule is necessary to identify which first-order rule is applicable to some form of conduct, but it is often the case that the second-order rule itself exhibits various forms of vagueness. When that is so, vagueness appears as a distinct problem with important but often unrecognized implications.Download the essay from SSRN at the link.