Counterfactuals in logic programming

Counterfactuals capture the process of reasoning about a past event that did not occur, namely what would have happened had this event occurred; or, vice-versa, to reason about an event that did occur but what if it had not. In this chapter, we innovatively make use of LP abduction and updating in an implemented procedure for evaluating counterfactuals, taking the established structural approach of Pearl as reference. Our approach concentrates on pure non-probabilistic counterfactual reasoning in LP, resorting to abduction and updating, in order to determine the logical validity of counterfactuals under the Well-Founded Semantics. Nevertheless, the approach is adaptable to other semantics, too. Even though the LP technique introduced in this chapter is relevant for modeling counterfactual moral reasoning, its use is general, not specific to morality.