We have been commenting on Professor Stephen Sachs’s scholarly paper “Finding Law.” In brief, we agree with Sachs that law does not have to written down to be “law.” But as we explained in our previous post, we disagree with his elitist discovery and demarcation criteria. Here, then, we will apply Oliver Wendell Holmes’s prediction theory of law to the sphere of unwritten law or natural law. Although Professor Sachs states (p. 34) “the prediction theory fails to say anything interesting about unwritten law,” we beg to differ. In truth, Holmes’s prediction theory applies not only to the domain of positive law; it can also help us illuminate the scope and strength of natural law principles.
So, what is Holmes’s prediction theory, and how can it illuminate unwritten law? To our mind, Holmes’s own statement of the prediction theory is still the best: “The prophecies of what the courts will do in fact, and nothing more pretentious, are what I mean by the law.” (Holmes, 1897, p. 461, quoted in Sachs, 2018, p. 33.) In other words, according to Holmes, we don’t need to resort to a circular or quasi-mystical “internal point of view” to discover what the law is. Instead, if you want to know to what the law is, you just need figure out the probabilities of getting caught (the probability of detection), as well as the probability of getting punished (the probability of punishment), if you are caught.
Although Holmes’s put forth his famous (or infamous, depending on your point of view) prediction theory in the context of positive law (i.e. man-made law such as international treaties, domestic statutes, and judicial precedents), we can also extend this theory into the domain of natural law. As Sachs himself concedes (p. 34), we just want to whether courts and judges will treat unwritten law or natural law as binding on them. After all, since natural law can be just as contested (if not more so) as treaties, statutes, and precedents are, the prediction theory is useful because it is able to capture this inherent uncertainty in both scenarios, whether we are in the domain of positive law or natural law.
As an aside, although this formulation of law can be criticized as cynical, our response is: so what? For example, in The Concept of Law, H.L.A. Hart asks (1961, p. 39): “Why should not law be equally if not more concerned with the ‘puzzled man’ or ‘ignorant man’ who is willing to do what is required, if only he can be told what it is? Or with the ‘man who wishes to arrange his affairs’ if only he can be told how to do it?” But this is not valid objection to Holmes’s prediction theory. The prediction theory applies just as much to the puzzled man or the ignorant man as to the Holmesian bad man. At the end of the day, all three creatures are bogged down by the same legal problem: uncertainty as to what the law is, especially when the law is unclear or contested.
Furthermore, there is no reason in principle why the prediction theory should be limited to courts or judges. By way of example, if a sufficient number of people believe strongly enough that chattel slavery is wrong, it may not matter whether a court (even a nation’s highest court) declares a constitutional right to own slaves, as the U.S. Supreme Court did in the infamous Dred Scott case. The prediction theory will tell us to what extent people will accept a court’s reasoning or abide by its decision.
Finally, the prediction theory is consistent with the most fundamental aspect of natural law theory: the use of reason. For what is probability theory but the use of reason in human affairs?