The evolution of common law and the role of the judge

A central theme in Hayek’s system of thought refers to the interplay between the order of rules and the order of actions. Hayek distinguishes between the legal framework, upon which the relative certainty of expectations is founded, and the system of market exchanges within that framework, in which there is no certainty of expectations.

Moreover, the stability of the legal framework is not absolute. As will be seen, the rules themselves evolve. Hayek’s account of the role of the common law judge is very illuminating in this respect. In Hayek’s theory of the common law and the role of the judge, the emphasis is on the coordination of individual activities through a process of systematic mutual adjustment of expectations (Hayek, 1973, p. 86). The function of the judge is to ensure a maximal coincidence of (legitimate) expectations, that is, to create a situation in which the chance to form correct expectations is as great as possible. But the chance of as many expectations as possible being fulfilled will be best enhanced if some expectations are allowed to be systematically disappointed.

Thus the judges, by upholding those rules which make it more likely that expectations will match and not conflict, are consciously trying to give greater internal coherence to the law. However, they do not need to know anything about the nature of the resulting overall order which they serve, beyond the fact that the rules are meant to assist the individuals in successfully forming expectations in a wide range of circumstances. They are unintentionally playing a part in the formation of a spontaneous order: a system of rules of conduct conducive to the efficient operation of the order of actions which rests on it. The body of the common law constitutes a spontaneous order, which evolves as an unintended consequence of the following of meta rules. One of the most fundamental meta rules is that, when deciding a difficult case, the judge’s task is to try to make the law as a whole a little more coherent: he is required to think only about the internal logic of the law. Hayek quotes a famous statement by the great eighteenth-century judge Lord Mansfield, who stressed that the common law ‘does not consist of particular cases, but of general principles, which are illustrated and explained by those cases’, thus highlighting the fact that a law based on precedent is more rather than less abstract than one expressed in verbal rules (ibid., p. 86).

The judge assists in the process of selection of rules. In fact, three distinct evolutionary mechanisms are involved in Hayek’s account of the modus operandi of the judiciary. If there were no variation, evolution could not get started as a result of selection. At first sight, however, there seems to be little room for a variation or mutation mechanism in Hayek’s account of the judge’s task. The judge will merely assist in ‘the process of articulation of pre-existing rules’ (ibid., p. 78). The judge ‘is committed to upholding the principles on which the existing order is based’ (ibid., p. 120). He discovers the rules ‘presumed to have guided expectations in many similar situations in the past’ (ibid., p.

How then does variation arise? ‘Experience will often prove that in new situations rules which have come to be accepted lead to conflicting expecta­tions’ (ibid., p. 115). And further: ‘Since new situations in which the established rules are not adequate will constantly arise, the task of preventing conflict and enhancing the compatibility of actions. is of necessity a never-ending one, requiring. the formulation of new rules necessary for the preservation of the order of actions’ (ibid., p. 119). Thus variation is generated. However, ‘This will in some measure always be an experimental process, since the judge. will never be able to foresee all the consequences of the rule he lays down, and will often fail in his endeavour to reduce the sources of conflicts of expectations’ (ibid., p. 102); and: ‘The judge may err’ (ibid., p. 119).

By what mechanism are errors, that is, unfit rules, eliminated?

[It is] only by their effects on that order of actions, effects which will be discov­ered only by trial and error, that the adequacy or inadequacy of the rules can be judged. (Ibid., p. 102)

Like most other intellectual tasks, that of the judge is. one of testing hypotheses at which he has arrived by processes only in part conscious.. he must stand by his decision only if he can rationally defend it against all objections that can be raised against it. (Ibid., p. 120)

As in all other fields advance is here achieved by our moving within an existing system of thought and endeavouring by a process of piecemeal tinkering, or ‘immanent criticism’, to make the whole more consistent both internally as well as with the facts to which the rules are applied. (Ibid., p. 118)

Thus a learning process of trial-and-error elimination accounts for the selection mechanism.