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Law is about many things, but at base it is about rights and obligations. That jural correlation is established and sustained by means of reasoning. We hold that an actor has a right or obligation by virtue of reasoning that classically occurs in one of two forms. An obligation creates a right by means of inductive logic that rests on the conviction of similar instances in the past and the need for proof. It can also create an obligation by means of deductive logic, that is, the process of reasoning from one or more statements (premises) that are used to reach a logically certain conclusion. The matched pairing of induction and deduction has been present in law and international law for a long time. The pairing is attractive because it infers a certain symmetry and logical harmony. What has intrigued some commentators surveying the dualism in legal reasoning is the possibility of some other form of reasoning, a third order of logic. A number of commentators are prone to regard deduction and induction as co-terminous, essentially exclusive and exhaustive. Some commentators, however, have identified something additional. It stands to reason that if there are conventionally two modes of logic operating in any one moment, then their combined operation across all moments should create a third thing, or tertium quid, as their product. This product, I suggest, is abductive reasoning. WTO law contains some marked examples of the interaction of deductive and inductive logic that culminate in abduction. The experience suggests that, at the end of the day, reasoning – and indeed knowledge – are provisional. It also explains some of the open-endedness of comments made in WTO decisions, such as the observation in Japan – Alcoholic Beverages II that “WTO rules are not so rigid or so inflexible as not to leave room for reasoned judgements in confronting the endless and ever-changing ebb and flow of real facts in real cases in the real world.”


Discussion Draft Prepared for the Third “Sociological Inquiries into International Law” Conference, Copenhagen, Denmark, April 28-29, 2017 sponsored by iCourts, The Danish National Research Foundation’s Centre of Excellence for International Courts