The importance which the certainty of the law has for the smooth and efficient running of a free society can hardly be exaggerated. There is probably no single factor which has contributed more to the prosperity of the West than the relative certainty of the law which has prevailed here. This is not altered by the fact that complete certainty of the law is an ideal which we must try to approach but which we can never perfectly attain. It has become the fashion to belittle the extent to which such certainty has in fact been achieved, and there are understandable reasons why lawyers, concerned mainly with litigation, are apt to do so. They have normally to deal with cases in which the outcome is uncertain. But the degree of the certainty of the law must be judged by the disputes which do not lead to litigation because the outcome is practically certain as soon as the legal position is examined. It is the cases that never come before the courts, not those that do, that are the measure of the certainty of the law. The modern tendency to exaggerate this uncertainty is part of the campaign against the rule of law, which we shall examine later.

The essential point is that the decisions of the courts can be predicted, not that all the rules which determine them can be stated in words. To insist that the actions of the courts be in accordance with pre-existing rules is not to insist that all these rules be explicit, that they be written down beforehand in so many words. To insist on the latter would, indeed, be to strive for an unattainable ideal. There are “rules” which can never be put into explicit form.

Many of these will be recognizable only because they lead to consistent and predictable decisions and will be known to those whom they guide as, at most, manifestations of a “sense of justice.” Psychologically, legal reasoning does not, of course, consist of explicit syllogisms, and the major premises will often not be explicit. Many of the general principles on which the conclusions depend will be only implicit in the body of formulated law and will have to be discovered by the courts. This, however, is not a peculiarity of legal reasoning.

Probably all generalizations that we can formulate depend on still higher generalizations which we do not explicitly know but which nevertheless govern the working of our minds. Though we will always try to discover those more general principles on which our decisions rest, this is probably by its nature an unending process that can never be completed.