Prioritized norms in formal argumentation

Abstract

To resolve conflicts among norms, various nonmonotonic formalisms can be used to perform prioritized normative reasoning. Meanwhile, formal argumentation provides a way to represent nonmonotonic logics. In this paper, we propose a representation of prioritized normative reasoning by argumentation. Using hierarchical abstract normative systems, we define three kinds of prioritized normative reasoning approaches, called Greedy, Reduction, and Optimization. Then, after formulating an argumentation theory for a hierarchical abstract normative system, we show that for a totally ordered hierarchical abstract normative system, Greedy and Reduction can be represented in argumentation by applying the weakest link and the last link principles respectively, and Optimization can be represented by introducing additional defeats capturing the idea that for each argument that contains a norm not belonging to the maximal obeyable set then this argument should be rejected.

Representation, justification, and explanation in a value-driven agent: an argumentation-based approach

“…Other related works are those based on argumentation. Among others, Liao et al [22] introduce an argumentation-based formalism for representing prioritized norms, but do not consider the origin of these priorities, while in this paper, the priority relation between the ethical consequences of different actions is learned from a set of cases, guided by the judgement of ethicists. Cocarascu et al [14] introduce an approach to construct an AAF in terms of highest ranked features.…”

From Classical to Non-monotonic Deontic Logic Using ASPIC $$^+$$

“…In the direction of using argumentation to represent various non-monotonic logics, Young et al [25] proposed an approach to represent prioritized default logic by using ASPIC`. Liao et al [14] represented three logics of prioritized norms by using argumentation. While existing works use argumentation to represent existing non-monotonic logics or non-monotonic reasoning, this paper uses argumentation to define new logics.…”

Arguing about constitutive and regulative norms

“…In this paper we use the last link principle, which gives the normative detachment the priority of the last applied norm. However, we could have used the weakest link principle as well, which would give the normative detachment the minimum of the current value and the priority of the last applied norm, or any other way (Liao, Oren, van der Torre, & Villata, 2016, 2018.…”

“…More properties can be proven for the argumentation theory introduced in this paper. In particular, Dung introduced his abstract argumentation theory to represent existing non-monotonic logics and logic programming, and Liao et al (2016) gave various representation results for prioritised normative systems. Extending these representation results to the argumentation theory introduced in this paper is another challenge for further research.…”