In his chapter "The Model of Rules I", Ronald Dworkin presents some significant problems with Hart's description of law. Specifically, he asserts that although Hart accounts for rules, he neglects the inclusion of principles within his legal model. The principles judges apply in decision-making in penumbral cases are extra-legal, thus are beyond the scope of legal obligations. This extra-legal discretion allows for judges to make law rather than merely apply it. After presenting this interpretation of Harts account, Dworkin disagrees that judges have a law-making ability and uses the distinction between rules and principles to support his thesis. .
Rules and principles are distinguishable from one another. Dworkin views rules as applying in an all-or-nothing manner. Either a rule applies and is valid, or it is irrelevant. If the former occurs, then the rule effectively determines an answer that must be accepted. Although there may be exceptions to the rule, these possible exceptions must be listed in their entirety of the explanation of the rule. Dworkin gives an example of baseball, where a batter is out if he/she has three strikes. If you get three strikes, you"re out because the rule declares this answer. One cannot claim that they are "not out" when they get three legitimate strikes. Every exception the rule must be intertwined within its definition, as to eliminate argument surrounding the validity of the rule. For example, contracts are void if they are obviously "unreasonable", which would mean that there would be no enforcement of such contracts (Culver 197). .
On the other hand, principles are inapplicable in an all-or-nothing method. They have weight, and provide reasons for a particular decision. The principles of freedom of contract vs. the special obligation of car manufacturers to their customers are competing principles in the case of Henningsen. The heavier principle steers the ultimate decision in a certain way, but does not nullify the weaker principle.
