This section is from the book "Science Of Legal Method", by Ernest Bruncken. Also available from Amazon: Science of Legal Method.
The contradiction of ideas contained in the two views of custom under consideration is inherent in the very nature of customary law. In such a system of judicial law, as in a system of parliamentary legislation, the judge is called upon to decide the questions submitted to him, not according to his own subjective opinion, but according to a supposedly preexisting rule. He is required to declare, not what seems to him just, but what the law is. He is under a duty to apply a custom, and in theory he may judge only by reference to it. But, to apply a custom he must know it, and it is not known until the moment when he applies it. This vicious circle is the inevitable consequence of a conflict between theory and facts, to be found in all conditions where law develops exclusively or principally through other than parliamentary channels, as is the case to-day in Anglo-Saxon societies.
If we search in English legal literature, which is naturally more authoritative than any other in the matter, for a definition of general custom, we shall meet with many differences, according as we consult the ordinary lawyer or the scientific student. The lawyer (or the author of a treatise on the law who grasps only the traditional view, often made up of fiction) tells us that the judges of his country have never had the power to create law, that their decisions conform to an immemorial custom, every element of which is as ancient as the English nation itself, though many of them have only been recognized and applied for the first time in our day.33 On the other hand, if we consult those writers who have devoted their energy to that higher branch of legal science known in England as "jurisprudence," we hear a very different story. These writers, accustomed to search behind legal dogma for the sociological reality, tell us that the common law has been largely the work of the judges, and that most of its rules originate in legal precedent.34