Beyond But-for Test: Counterfactual Explanation in Abstract Argumentation via Actual Causality (Extended Version)
For researchers in abstract argumentation, this work provides a more expressive and reliable method for counterfactual explanation, addressing limitations of existing but-for test approaches.
The paper introduces an intervention-based counterfactual reasoning framework for abstract argumentation that goes beyond the but-for test, enabling more refined counterfactual conditions. The method correctly identifies causes in argumentation structures like Preemption and Overdetermination, surpassing prior methods in expressiveness and reliability.
Counterfactual explanation in abstract argumentation calls for an answer to the what-if query: would the topic argument still be accepted if the status of certain other arguments were changed? Existing approaches are limited to the but-for test and fail to accommodate more refined counterfactual conditions. To overcome these limitations, we introduce an intervention-based counterfactual reasoning framework in abstract argumentation. Our approach encodes the acceptance conditions of arguments as equations, then defines an intervention operator that supports (1) changing sets of arguments simultaneously, and (2) fixing witness arguments to their actual labels. Guided by the refined counterfactual condition introduced in the Halpern-Pearl definition, our method goes beyond the but-for test, thereby correctly identifying causes in argumentation structures such as Preemption and Overdetermination. Through comparison, we show that our method surpasses prior methods in both expressiveness and reliability.