Most advocates of individual liberty who are fond of Hayek`s work usually show disregard for the value of written bodies of laws and praise the judge-made law systems. In fact, Hayek, at the beginning of chapter 5 of Law, Legislation and Liberty, stated that “the ideal of individual liberty seems to have flourished chiefly among people where, at least for long periods, judge-made law predominated.”
But this citation is moderated by the whole book which it is taken from. What Hayek posited was a matter subject to probability. Laws emerging from judiciary precedent are more likely to be purposeless and oriented to fulfill expectations of what is to be regarded as just conduct. Since the written law is sanctioned by a legislator, the temptation to provide the law with a certain purpose and a social design is hard to be resisted.
Nevertheless, Hayek admitted that the legislation must act in order to prevent judges from obeying certain interests of a particular group or class –in which case a judge-made law would be purpose-oriented and a menace to individual liberty. Furthermore, Hayek stated that it is possible for codified system of law to articulate a set of norms of just conduct so long as they were not orientated themselves towards any particular aim.
As we have said, this is not a problem of essences but of probabilities.