In a series of recent papers Professor Ronald Dworkin has presented a critique of the legal positivist's analysis of law as typified by the work of H. L. A. Hart. Dworkin argues that the “model of rules” provides an incomplete and inadequate characterisation of the nature of legal argument and judicial reasoning and, hence, of law, by virtue of its failure to recognise that judges are bound, in making decisions, not only by rules, but also by principles which have rather different logical properties.