Positive Law vs. Natural Law
Suppose that the federal government enacts a bill with the purpose of “weaning us from the dependence on foreign oil” ordering everyone, instead of going by car, to fly to where they want to go by flapping their arms. Is this law valid? Legal positivism would say yes. It is made by the legitimate sovereign, using the proper procedures, it does not seem to be contrary to the Constitution or any “higher” positive law, so what’s the problem? Of course it is valid and therefore commands obedience.
The obvious absurdity of this law, however, can be picked up on by natural law theorists. Interpreting “natural law” literally as “all the causal regularities put in service to human ends,” they will say that it is impossible for humans to fly around in the prescribed manner, and since ought implies can, they ought not to fly. Now if the positive law is higher than natural law, then natural law is to be set aside and positive law, enforced. But this opinion begins to look suspect when prisons start running out of room for new law-breakers. It is more plausible to suppose that natural law outranks positive law, and therefore the requirement to fly by flapping one’s arms is no law at all.
Ludwig von Mises said that the chief function of an economist is telling the government what it can’t do. Now this lack of ability does not mean any kind of legal limitation on the power of the state, useful as such things are, but the limitations of the economic law itself. For example, the government supports a banking industry which generates credit expansions. But if we want to be prosperous, credit expansion leading to business cycles is precisely the wrong thing to allow. The question is, then, must we obey the (1) legal tender laws, (2) laws forbidding banks from issuing their own notes, (3) laws giving banks immunity for keeping fractional reserves? These artifices fail to lead us to what we want, namely, a successful society. The connection is a bit more subtle than in the case of flying by flapping the arms about, but it is essentially the same. The means to our common end are inappropriate, and therefore not even the state can override the natural law linking the means to the end. The laws in question therefore lose their status as valid laws. They remain in power only because most people do not perceive them to be contrary to reason, impoverishing society and them personally, and because of the government’s ability to crush those few who do realize their pernicious nature.
Finally, consider a new law ordering all the redheads to report to concentration camps where they are to be gassed. Must the redheads obey like lambs to the slaughter, and must the police round up those who will not go voluntarily? Positive law, knowing no limit other than, perhaps, the laws of physics, must needs say yes. But everyone not corrupted by legal positivism will say that the moral law, “Thou shalt not kill,” overrides the government dictate, making it null and void.
I agree with the positivists, however, that in all these cases, while the laws being evaluated are wicked and invalid and ought to be repealed, they retain their character as human laws. It’s just that whichever non-man-made laws we pick, natural (physics, chemistry), social (economics), or moral (self-ownership, the Golden Rule), it is clear that they sit in judgment over the human law and its makers. In other words, nature, in order to be commanded, must be obeyed.