Ronald Dworkin, answered from the texts and cited to the page.
The debate between Hart and me runs to the center of what law is and how it works in hard cases. Start with positivism's picture. Hart's version holds that the existence and content of law can be identified by reference to social sources — legislation, judicial decisions, social customs — without reference to morality, except where the law thus identified has itself incorporated moral criteria.1
On that view, when a case arises that no enacted rule clearly governs, the judge exercises discretion in a strong sense: she steps outside the law and legislates freshly. Hart recognized that legal rules have what he called "open texture," and he accounted for troublesome cases precisely this way, by saying judges have and exercise discretion to decide them.2
My objection, developed first in Taking Rights Seriously (1977), is that this picture misdescribes what lawyers and judges actually do in hard cases. When they reason about legal rights and obligations in genuinely difficult situations, they invoke standards that do not function as rules at all — they function as principles. A principle, as I use the term, is a standard to be observed not because it will advance some social goal but because it is a requirement of justice or fairness or some other dimension of morality: the standard that no man may profit by his own wrong is a principle in this sense, not a policy.3
Positivism, as a model of and for a system of rules, and with its central notion of a single fundamental test for law, forces us to miss the important roles these standards play.4 The Sorenson case illustrates the stakes precisely. Mrs. Sorenson was injured by a drug she could not trace to any single manufacturer. How should a judge decide her claim?
On my view, the judge must identify general principles underlying the settled law of product liability and apply them: perhaps the principle that no one is liable for harm he cannot be shown to have caused, or the rival principle that those who profit from an enterprise must bear its costs — and everything depends on which set of principles provides the best justification for the law in this area as a whole.5
On Hart's sources thesis, since no legislature or past judicial decision has made morality pertinent to her case, no moral judgment enters the question at all, and she must lose.6 Legal argument, on my view, is characteristically and pervasively moral argument; lawyers must decide which of competing sets of principles provides the morally most compelling justification of legal practice as a whole.7
Hart's posthumous Postscript to the second edition of The Concept of Law (1994) tried to reframe the disagreement. He insisted that his project was purely descriptive and philosophical — that he was describing legal activities from outside, as a disengaged scholar, while my ruminations about how judges should decide hard cases are moral and engaged because I am criticizing and evaluating those activities.8
I called this view "Archimedean": the philosopher looks down from outside and above on law, distinguishing his second-order meta-discourse from the first-order claims of practitioners.9 My reply is that this separation cannot be sustained. A legal philosopher's theory of law is not different in character from, though it is more abstract than, the ordinary legal claims that lawyers make from case to case; to interpret past law to see what principles best justify it is what both the philosopher and the judge are doing.10
The disagreement is therefore not merely technical. It concerns whether legal reasoning in hard cases is a form of moral reasoning — which I say it is — or whether it is the application of a pedigree test to social facts, with moral judgment entering only when the law itself commands it, which is what Hart's sources thesis says.
According to my theory, the existence and content of the law can be identified by reference to the social sources of the law (e.g. legislation, judicial decisions, social customs) without reference to morality except where the law thus identified has itself incorporated moral criteria for the identification of the law.Justice in Robes, p. 158
Hart, like Austin, recognizes that legal rules have furry edges (he speaks of them as having 'open texture') and, again like Austin, he accounts for troublesome cases by saying that judges have and exercise discretion to decide these cases by fresh legislation.Taking Rights Seriously, pp. 38–39
I call a 'principle' a standard that is to be observed, not because it will advance or secure an economic, political, or social situation deemed desirable, but because it is a requirement of justice or fairness or some other dimension of morality. Thus the standard that automobile accidents are to be decreased is a policy, and the standard that no man may profit by his own wrong a principle.Taking Rights Seriously, pp. 38–39
Positivism, I shall argue, is a model of and for a system of rules, and its central notion of a single fundamental test for law forces us to miss the important roles of these standards that are not rules.Taking Rights Seriously, pp. 38–39
They might find, as the drug companies insisted, that the principle that no one is liable for harm that neither he nor anyone for whom he is responsible can be shown to have caused is so firmly embedded in precedent that Mrs. Sorenson must therefore be turned away with no remedy. Or they might find, on the contrary, considerable support for a rival principle—that those who have profited from some enterprise must bear the costs of that enterprise as well, for example—that would justify the novel market-share remedy.Justice in Robes, p. 158
No legislature or past judicial decision has made morality pertinent in Mrs. Sorenson's case so, on Hart's view, no moral judgment or deliberation enters into the question whether she is legally entitled to what she asked. So far as the law is concerned, he would have said, she must lose.Justice in Robes, p. 158
In my view, legal argument is a characteristically and pervasively moral argument. Lawyers must decide which of competing sets of principles provide the best—morally most compelling—justification of legal practice as a whole.Justice in Robes, p. 158
My own ruminations about how judges should decide hard cases at law are moral and engaged, he said, because I am criticizing and evaluating their activities. But he, on the contrary, simply describes these activities in a general and philosophical way, and describes them from outside, not as an active participant in the legal wars but as a disengaged scholar of those wars.Justice in Robes, p. 155
I have called this view of philosophy 'Archimedean,' and this is Archimedeanism's golden age.Justice in Robes, p. 155
I also argued that ordinary legal argument has the same character: a judge or citizen who has to decide what the law is on some complicated issue must interpret past law to see what principles best justify it, and then decide what those principles require in the fresh case. So a legal philosopher's theory of law is not different in character from, though it is of course much more abstract than, the ordinary legal claims that lawyers make from case to case.Justice in Robes, p. 155