We begin with Chapter XII of “Natural Law and Natural Rights” because Finnis himself recommends that we do so. This fascinating chapter is divided into four separate subsections (XII.1 through XII.4). In first subsection (XII.1), Finnis makes two important claims. One claim is about the classical natural law maxim lex injusta non est lex (unjust laws are not law). According to Finnis, this famous maxim is, at best, a “subordinate theorem” or “subordinate concern” of natural law theory. Instead,
the principal jurisprudential concern of a theory of natural law is … to identify the principles and limits of the Rule of Law, and to trace the ways in which sound laws, in all their positivity and mutability, are to be derived (not, usually, deduced) from unchanging principles–principles that have their force from their reasonableness, not from any originating acts or circumstances.
In other words, natural law is about distinguishing reasonable laws from unreasonable ones. Say what? Forgive me for raising the alarm and sounding such a skeptical tone at the outset of this review, but let me lay my cards or philosophical priors on the table. Simply put, the criterion of “reasonableness” has to be one of the most amorphous and ambiguous criteria ever devised. Why is “reasonableness” such a useless criterion in practice? Because it is so slippery and subjective, for there is no neutral or impartial standpoint from which to decide how reasonable a law is. That’s why! In short, whether a law is “reasonable” is always going to be in the eye of the beholder.
Finnis makes another important claim in the first section of Chapter XII, a claim about the source of legal authority or political power. According to Finnis, “The ultimate basis of rulers’ authority is the fact that they have the opportunity, and thus the responsibility, of furthering the common good by stipulating solutions to a community’s coordination problems.” For my part, I like Finnis’s original idea of equating the common good (an otherwise vague if not empty concept like “reasonableness”) with a group’s ability to solve co-ordination problems. Why? Because by making an explicit link between co-ordination problems and the common good, we can formulate a fruitful and testable theory of law: laws are good if and only if they are able to solve co-ordination problems.
That said, we can already spot two potential blind spots or gaps in Finnis’s theory of law. One gap is this: how do we define the relevant community? The other blind spot is based on our critique above of Finnis’s slippery “reasonableness” criterion. How do we decide when a solution to a co-ordination problem is “reasonable” or not? Some solutions to co-ordination problems might be effective or efficient, but at the same time such solutions might still be unfair or unjust. (Consider by way of example the quotation by Robert Pirsig below.) If so, we are back to where we started. Nevertheless, we will proceed with our review of Chapter XII in our next post.