Abstract

The purpose of this paper is to consider the frequently held view that since obligation is a rule-dependent concept it can be explicated by reference to rules. H.L.A. Hart's attempt to explicate the normative character of a legal system in terms of rules is examined and it is shown that (A) the notion that obligation is rule-dependent necessitates that there be an ultimate rule in the legal system, that (B) if obligation is rule-dependent and there is an ultimate rule in the legal system it is mysterious, indeed unintelligible how rules themselves can oblige and (C) the attempt to capture the normative character if the legal system fails. The appeal of this analysis of obligation is traced to the tempting but ill-founded supposition that rationality always consists in applying a general rule to a specific case.