The Toulmin model has been proved useful in law and argumentation theory. This model describes the basic process in justifying a claim, which comprises six elements, i.e., claim (C), data (D), warrant (W), backing (B), qualifier (Q), and rebuttal (R). Specifically, in justifying a claim, one must put forward ‘data’ and a ‘warrant’, whereas the latter is authorized by ‘backing’. The force of the ‘claim’ being justified is represented by the ‘qualifier’, and the condition under which the claim cannot be (...) justified is represented as the ‘rebuttal’. To further improve the model, (Goodnight, Informal Logic 15:41–52, 1993) points out that the selection of a backing needs justification, which he calls legitimation justification. However, how such justification is constituted has not yet been clarified. To identify legitimation justification, we separate it into two parts. One justifies a backing’s eligibility (legitimation justification 1 ; LJ 1 ); the other justifies its superiority over other eligible backings (legitimation justification 2 ; LJ 2 ). In this paper, we focus on LJ 1 and apply it to the legal justification (of judgements) in hard cases for illustration purposes. We submit that LJ 1 refers to the justification of the legal interpretation of a norm by its backing, which can be further separated into several orderable subjustifications. Taking the subjustification of a norm’s existence as an example, we show how it would be influenced by different positions in the philosophy of law. Taking the position of the theory of natural law, such subjustification is presented and evaluated. This paper aims not only to inform ongoing theoretical efforts to apply the Toulmin model in the legal field, but it also seeks to clarify the process in the justification of legal judgments in hard cases. It also offers background information for the possible construction of related AI systems. In our future work, LJ 2 and other subjustifications of LJ 1 will be discussed. (shrink)

In this paper, I set out a new Kantian approach to resolving conflicts between moral obligations for highly autonomous machine agents. First, I argue that efforts to build explicitly moral autonomous machine agents should focus on what Kant refers to as duties of right, which are duties that everyone could accept, rather than on duties of virtue (or “ethics”), which are subject to dispute in particular cases. “Moral” machines must first be rightful machines, I argue. I then show how this (...) shift in focus from ethics to a standard of public right resolves the conflicts in what is known as the "trolley problem" for autonomous ma-chine agents. Finally, I consider how a deontic logic suitable for capturing duties of right might meet Kant’s requirement that rightfully enforceable obligations be consistent in a system of equal freedom under universal law. (shrink)

The challenges that normative redundancies and normative conflicts pose to legal theory have been traditionally addressed by either altering the rules that trigger them, or by including preference rules that deactivate them. As an alternative to these routes, this paper argues that the problems with both redundancies and conflicts only arise as a consequence of a mistaken understanding of legal reasoning that ignores the material relations between the rules at issue. By resorting to inferential semantics, this material dimension is taken (...) into account and the challenges met without having to introduce new rules nor altering the original ones. (shrink)

This article discusses C. E. Alchourrdn and E. Bulygin's ideas regarding the distinction between strong permission and weak permission. The author takes for granted that the distinction between the two terms should be placed at the level of the assertive metalanguage about norms. But the symbolizations and the definitions of strong and weak permissions offered by Alchourrdn and Bulygin, as well as their thesis concerning the relations between the two concepts are challenged.

Much has been said about the logical difference between rules and principles, yet few authors have focused on the distinct logical connectives linking the normative conditions of both norms. I intend to demonstrate that principles, unlike rules, are norms whose antecedents are linguistically formulated in a generic fashion, and thus logically described as inclusive disjunctions. This core feature incorporates the relevance criteria of normative antecedents into the world of principles and also explains their aptitude to conflict with opposing norms, namely (...) that their consequents are fulfilled to varying extents more frequently than those of rules. I conclude that the property of genericity should be predicated to the norm antecedent of principles, more precisely to the hypothetical action. This is of paramount importance to explain, in terms of logical implication and exclusion, the expansibility of competing principles, in contrast with the exclusive character of conflicting rules. (shrink)

This article discusses C. E. Alchourrdn and E. Bulygin's ideas regarding the distinction between strong permission and weak permission. The author takes for granted that the distinction between the two terms should be placed at the level of the assertive metalanguage about norms. But the symbolizations and the definitions of strong and weak permissions offered by Alchourrdn and Bulygin, as well as their thesis concerning the relations between the two concepts are challenged.

This paper investigates whether or not cases of in concreto antinomies (ICAs for short, also called indirect antinomies, accidental antinomies, normative conflicts due to the facts, predicaments, or paranomies) can be predicted. I distinguish two main theoretical positions: “Prodetection” argues that we can predict in concreto antinomies; “unpredictability” argues that we cannot predict them.I exemplify the two positions by relying on a disagreement found in the literature; then, after reviewing that disagreement, I (i) provide arguments for both positions; (ii) highlight (...) the problematic issues for a definition of in concreto antinomy based on conceptual independence; (iii) point out some problems in Martínez Zorrilla’s threefold conception of normative conflicts; and (iv) advocate the need to introduce a case for “practically unpredictable” normative conflicts. (shrink)

In this paper, I set out some basic elements of a deontic logic with an implementation appropriate for handling conflicting legal obligations for purposes of programming autonomous machine agents. Kantian justice demands that the prescriptive system of enforceable public laws be consistent, yet statutes or case holdings may often describe legal obligations that contradict; moreover, even fundamental constitutional rights may come into conflict. I argue that a deontic logic of the law should not try to work around such conflicts but, (...) instead, identify and expose them so that the rights and duties that generate inconsistencies in public law can be explicitly qualified and the conflicts resolved. I then argue that a credulous, non-monotonic deontic logic can describe inconsistent legal obligations while meeting Kant’s demand for consistency in the prescriptive system of public law. Finally, I propose an implementation of this logic via a modified form of “answer set programming,” which I demonstrate with some simple examples. (shrink)