Scott J. Shapiro (University of Michigan Law School) has posted The "Hart-Dworkin" Debate: A Short Guide for the Perplexed on SSRN (U of Michigan Public Law Working Paper No. 77). This is the abstract:
For the past four decades, Anglo-American legal philosophy has been preoccupied - some might say obsessed - with something called the 'Hart-Dworkin' debate. Since the appearance in 1967 of 'The Model of Rules I,' Ronald Dworkin's seminal critique of H.L.A. Hart's theory of legal positivism, countless books and articles have been written either defending Hart against Dworkin's objections or defending Dworkin against Hart's defenders. My purpose in this essay is not to declare an ultimate victor; rather it is to identify precisely the core issue around which the debate is organized. Is the Hart-Dworkin debate, for example, about whether the law contains principles, as well as rules? Or does it concern whether judges have discretion in hard cases? Is it about the proper way to interpret legal texts in the American legal system? Or is it about the very possibility of conceptual jurisprudence?
Although trying to capture the essence of a philosophical debate can be tricky, I think that there is an important unity to the Hart-Dworkin debate that can be described in a relatively straightforward manner. I suggest that the debate is organized around one of the most profound issues in the philosophy of law, namely, the relation between legality and morality. Dworkin's basic strategy throughout the course of the debate has been to argue that, in one form or another, legality is ultimately determined not by social facts alone, but by moral facts as well.
This contention directly challenges, and threatens to undermine, the positivist picture about the nature of law, in which legality is never determined by morality, but solely by social practice.As one might expect, the response by Hart and his followers has been to argue that this dependence of legality on morality is either merely apparent or does not, in fact, undermine the social foundations of law.
The Hart-Dworkin debate, I also try to show, is not a monolithic entity. In the second half of the paper, I describe how Dworkin modified his critique to circumvent the responses of Hart's followers, thereby inaugurating a new phase in the debate. Virtually no attention, however, has been paid to this latter challenge, which is especially surprising given that none of the previous positivistic defenses are helpful against it. I then sketch out a possible response positivists might offer to this extremely powerful objection.