ABDUCTION AS COMPUTATION

Abstract

Our logical analysis of abduction in the previous chapter is in a sense, purely structural. It was possible to state how abductive explanatory logic behaves, but not how abductive explanations are generated. In this chapter we turn to the question of abduction as a computational process. There are several frameworks for computing abductions; two of which are logic programming and semantic tableaux. The former is a popular one, and it has opened a whole field of abductive logic programming [KKT95] and [FK00]. The latter has also been proposed for handling abduction [MP93] and [AN04], and it is our preference here. Semantic tableaux are a well-motivated standard logical framework. But over these structures, different search strategies can compute several versions of abduction with the non-standard behaviour that we observed in the preceding chapter. Moreover, we can naturally compute various kinds of abducibles: atoms, conjunctions or even conditionals. This goes beyond the framework of abductive logic programming, in which abducibles are atoms from a special set of abducibles.