How to Agree to Disagree: Managing Ontological Perspectives using Standpoint Logic

TL;DR

This paper introduces Standpoint Logic, a multi-modal logic framework that enables the representation and reasoning of conflicting perspectives within ontologies, compatible with existing reasoners and ensuring decidability.

Contribution

It presents a novel logic extension for ontologies that manages conflicting viewpoints without merging or detaching them, with efficient reasoning capabilities.

Findings

Polytime translation into standpoint-free logic

Decidability for expressive logic fragments

Compatibility with OWL 2 DL reasoners

Abstract

The importance of taking individual, potentially conflicting perspectives into account when dealing with knowledge has been widely recognised. Many existing ontology management approaches fully merge knowledge perspectives, which may require weakening in order to maintain consistency; others represent the distinct views in an entirely detached way. As an alternative, we propose Standpoint Logic, a simple, yet versatile multi-modal logic "add-on" for existing KR languages intended for the integrated representation of domain knowledge relative to diverse, possibly conflicting standpoints, which can be hierarchically organised, combined and put in relation to each other. Starting from the generic framework of First-Order Standpoint Logic (FOSL), we subsequently focus our attention on the fragment of sentential formulas, for which we provide a polytime translation into the standpoint-free version. This result yields decidability and favourable complexities for a variety of highly expressive decidable fragments of first-order logic. Using some elaborate encoding tricks, we then establish a similar translation for the very expressive description logic SROIQb_s underlying the OWL 2 DL ontology language. By virtue of this result, existing highly optimised OWL reasoners can be used to provide practical reasoning support for ontology languages extended by standpoint modelling.