An Argumentation-Based Approach to Generate Domain-Specific Explanations

Abstract

In argumentation theory, argument schemes are constructs to generalise common patterns of reasoning; whereas critical questions (CQs) capture the reasons why argument schemes might not generate arguments. Argument schemes together with CQs are widely used to instantiate arguments; however when it comes to making decisions, much less attention has been paid to the attacks among arguments. This paper provides a high-level description of the key elements necessary for the formalisation of argumentation frameworks such as argument schemes and CQs. Attack schemes are then introduced to represent attacks among arguments, which enable the definition of domain-specific attacks. One algorithm is articulated to operationalise the use of schemes to generate an argumentation framework, and another algorithm to support decision making by generating domain-specific explanations. Such algorithms can then be used by agents to make recommendations and to provide explanations for humans. The applicability of this approach is demonstrated within the context of a medical case study.

Argumentation schemes for clinical decision support

“…On top of this, we developed software that can: (1) combine various inputs (specialised schemes, clinical guidelines, patient facts and so on) represented as a set of ASP facts and rules (Table 13), (2) invoke ASPARTIX to compute the justified arguments, and (3) post-process the results to generate visual representations for the resulting argumentation frameworks. The algorithm that generates an argumentation framework, on which ASPARTIX is run, from the knowledge in the guidelines and the argumentation schemes, was presented in [26]. The algorithm only considers relevant schemes instead of considering all the schemes available, where the relevance of the schemes is decided according to the relations between schemes (i.e.…”

“…In the medical context, we consider clinical guidelines being part of the knowledge base. Moreover, each argumentation scheme is translated into a domain-specific rule that generates arguments and attacks automatically as described in [26]. The information in the knowledge base is static, but can be updated at any time to represent the most up-to-date information such as new clinical guidelines or argumentation schemes.…”

“…The paper also articulates an approach to operationalise the specialised schemes, and illustrates the application of the schemes using case studies related to hypertension treatment as part of secondary stroke prevention [25,26]. We also share details of our implementation which includes the formalisation of the clinical guideline for hypertension, and demonstrates the applicability of the argumentation schemes that we propose.…”

“…An AS is a semi-formal reasoning template that matches common reasoning patterns in real life. More formally [26], an AS = S, c, V is a set of support premises (S) which support the conclusion c, where variables (V) in the AS appear in the premises (S.V) or the conclusion (c.V). These variables can then be instantiated by ground terms to yield a specific argument.…”

“…For example, argumentation schemes can be represented as defeasible rules. Another approach, which allows for a broad range of domain-dependent attacks between arguments, is that described in [26], in which attack schemes can be instantiated so as to identify attack relations. We have also explored the use of metalevel argumentation frameworks (MAFs) [36] to support medical decisions [25,27].…”