Law from a Logical Point of View. Three Basic Questions

Due to the fact that some fundamental laws of logic (such as the principles of non-contradiction and the excluded middle) are usually regarded as necessary features of the foundational principles of law, logic has traditionally been referred to in legal studies to assert the view that law is determinate, in that it has an inner order that can be grasped and applied by means of logical tools and/or that it is a complete and consistent whole. On a second, more recent, view, logic in legal studies should mimic its object of inquiry. The author of this paper defends a stance which runs counter to such views. On the one hand, logic, far from being intrinsic to law, is a tool which helps one demystify the view that law is logically determinate, that it is a “unified, reasonable, whole” (as some authors would have it). On the other hand, logic cannot limit itself to mimicking its object of inquiry, since it would not allow us to spot logical indeterminacies of the law. Within this general compass, the paper explores the role of logic for an analysis of the legal domain by emphasising three points in which the indeterminacy of law is clearly detected (only) by means of logical analysis. More precisely, the paper deals with: (1) the logical form of legal conditionals, (2) the defeasibility of legal norms, and finally (3) the notion of logical consequence in the legal domain. Regarding point (1), the paper surveys some current reconstructions of the logical form of norms and points analytically to some of their shortcomings. By doing so, it shows that there is no current view which can accommodate the forms and treatments of legal norms in a logically satisfactory manner. Concerning point (2), the paper examines the defeasibility of legal norms from a logical perspective. In particular, it is shown that if norms are considered to be defeasible – as they normally are in contemporary jurisprudence and doctrine – either they completely lose their “inferential power”, rendering law widely indeterminate or they are to be regarded as overridable by norms derived from implicit norms. This conclusion leads to point (3): since no clear concept of logical consequence within law and the legal doctrine has been propounded (nor clear concepts of contradiction and implication), the scope and the limits of law are uncertain. In fact, we cannot count on a recursive way of determining which norms are members of legal systems and which are not. This problem is eventually worsened by the fact that the set of norms which belong in a legal system does not constitute the only relevant set for legal application. The main conclusion is that logic, far from being a means to hold that law has an ordered structure, is a powerful tool to show that law has serious logical flaws.