We have touched on adjudication in many earlier discussions.  The issue arises as a component in any adequate theory of law.  As realists argued, merely defining the rules of law is not enough to account for The law--by which they meant concrete legal rights and duties.  Realists criticized positivism for failing to pay enough attention to the gap between the rules and concrete rights and duties, but realists themselves tended to fill the gap with sociology.  They thought the issue was mainly one of predicting the judge's decisions.  When it came to justifying them, positivists and realists seemed in perverse agreement that one could use some vague "morality" but that it was not part of the law.

Dworkin's early work focused mainly on adjudication.  He argued against the positivist's "model of rules" and insisted that the law includes principles which are necessary to derive particular legal rights and duties from Hart's primary rules. The principles are the same ones used in Dworkin's principle-policy distinction.  The contrast of principles and rules, however, is functional.  Principles are standards for deciding which rule applies.  If a rule applies, then one appeal to it rather than conflicting rules to settle this case.  For example, consider a case where one rule says "no vehicles in the park" and another says "public places must be handicap accessible." A handicapped person, Jones, with a motorized wheelchair rides in the park.  The principles would say which rule applies to the case.  If it is the first, then the person has no right in the park.  If the second then the person has a right to take his motorized wheelchair into the park.  This is what Dworkin means when he says rules "apply in an all or nothing fashion."

Principles, by contrast, pull in many different directions and all apply at once.  So they have Dworkin's vague property of "weight."  In order to get a decision, we have to consider all the principles at stake and treat some as more important than others in this situation.  This combined with the fact that we have no definitive or fixed list of principles or their formulation makes principled reasoning epistemologically complex and underdetermined, but Dworkin argues that it is metaphysically clear. That is, we have no trouble making sense of what it would be for it to be true, even if we have trouble showing how we can know it. 

His claim is that the principles together with their weights yield "one right answer" to legal questions.  Metaphysically, he is saying there is a legal fact of the matter which the judge has the duty to recognize.  He appeals to the principle of excluded middle.  For any legal proposition P, either P or not-P.  Either Jones has a right to go into the park or he does not.  The principles are whatever are necessary to make it the case that one of those is the right answer.

Dworkin focuses on Hart's argument about the penumbra and judicial discretion.  He follows Fuller in casting the issue in prescriptive terms can we justify a rule of law with extensive use of judicial discretion?  His answer is "No, because unlimited use of discretion is the opposite of rule of law." That is rule by intuition or a paradigm case of rule of man.  In such a system (with respect to that sphere of discretion) there would be no answerability, no predictability, and no basis for competitive advocacy because no one could legitimately appeal to objective principles of legal argument to settle the issue.  As we argued before, Hart's position technically makes particular legal duties ex post facto.  The person did not have the duty at the time of action.  The duty came into being with the exercise of judicial discretion that results in his conviction.

Dworkin has to allow that judges do have discretion in some obvious senses, but he distinguishes between weak and strong senses of "discretion."  One weak sense is that in which an order may be "open-ended" or "vague."  As we have seen, the application of principles to legal cases leaves things epistemologically unsettled. An order to a sergeant to "select the five most experienced men for a mission" may be as vague as is the concept of 'experience'.  However, it does not give discretion in the strong sense.  The sergeant is not to use his discretion in choosing the men, he is to choose them for their experience.  He relies on what Dworkin calls a 'conception' (a theory) of the 'concept' and he would not have obeyed the order if he got it wrong (e.g. if he took it to mean 'sexual experience' or merely 'age.')

Other weak senses of 'discretion' are connected with the performative and final features of a judge's authority.  A judge has discretion in the sense that it is her role to "make the finding" but she may still make the wrong finding and her performative authority does not excuse her from the duty to get it right.  Similarly, some judges may be final authorities and have discretion in the weak sense that no one can reverse or change the decision they make.  However, judges do not have discretion in the sense that they could not be criticized for flipping a coin or taking a bribe in deciding the issue.  There is no real unstructured choice with no necessity to justify or apply consistent standards. 

In some legal situations there are specific grants of 'discretion' to judges, for example in sentencing.  There the idea is that there will be no rule, but the judge is still expected to weigh all the factors to find the 'right' sentence.  This kind of discretion, however, does not apply in the case of specific legal findings.

Hart's defenders may insist that he does not allow discretion in these "clear" cases but only in the hard ones--those where the issues are new and complex and equally well qualified judges and legal experts may disagree.  Hart argued for discretion only in cases of the penumbra.  Dworkin claims that even such hard cases are not cases of judge's use of strong discretion because they are questions to which judge must provide an answer and he ought to give the correct one.  Admittedly, there may be many warring theories in the legal community, but the judge in his performative role is charged with choosing the correct one.

Hart also allows that one ought to decide the case in one 'best' way, but that the standards that make it best come from outside the law in those hard cases. Dworkin argues that the principles partly constitute the rule of law.  We can understand this claim alongside Fuller's notion of the "inner morality of law."  The principles help justify the rule of law and flow from the features of law that we value.  He uses analogies to games, for example in American baseball, the rule is a put-out requires the fielder to touch the bag before the runner.  But in practice, umpires tend to allow the second baseman to make a double play without touching the bag because the opposing runner may injure him with his spikes when he slides to the base.  In chess, players are not allowed to blow cigar smoke across the table during a match or hypnotically stare at their opponent.  These rules are not in the books, but emerge in practice and are justified by an implicit appeal to the character of the activity or game. What is the purpose and character? Why play this game?

Raz offers a different defense of Hart's positivism (in the face of Dworkin's challenge).  He says any principles to which Dworkin can appeal in his case-law examples are part of the law in virtue of their being a rule of principle recognition and their being part of the adjudicative secondary rule.  The approximate rule of recognition is that judges do in fact appeal to this principle and other judges would accept that as legitimate. Thus he employs Hart's acceptance/compliance distinction to handle Dworkin's argument.

Dworkin's second and third version of his principles manifest deals with that response.  He draws a distinction between a conventional and a concurrent morality.  He argues that no mere social acceptance can warrant a claim of right or duty. Asserting a duty is not merely presupposing some social rule and signifying acceptance.