Avoiding Pragmatic Oddity: A Bottom-up Defeasible Deontic Logic

TL;DR

This paper extends Defeasible Deontic Logic to address the Pragmatic Oddity problem using a bottom-up approach, enhancing computational efficiency and providing a clearer model for CTD reasoning.

Contribution

It introduces a bottom-up characterization of Defeasible Deontic Logic to improve computational feasibility and reduce non-determinism in handling the Pragmatic Oddity.

Findings

Provides a computational complexity analysis of the logic

Offers a more efficient implementation framework

Addresses the Pragmatic Oddity within a logical CTD reasoning model

Abstract

This paper presents an extension of Defeasible Deontic Logic to deal with the Pragmatic Oddity problem. The logic applies three general principles: (1) the Pragmatic Oddity problem must be solved within a general logical treatment of CTD reasoning; (2) non-monotonic methods must be adopted to handle CTD reasoning; (3) logical models of CTD reasoning must be computationally feasible and, if possible, efficient. The proposed extension of Defeasible Deontic Logic elaborates a preliminary version of the model proposed by Governatori and Rotolo (2019). The previous solution was based on particular characteristics of the (constructive, top-down) proof theory of the logic. However, that method introduces some degree of non-determinism. To avoid the problem, we provide a bottom-up characterisation of the logic. The new characterisation offers insights for the efficient implementation of the logic and allows us to establish the computational complexity of the problem.