Abductive problems and their solutions are presented by means of justification logic. We introduce additional meta-constructions in order to generate and compare different solutions to the same abductive problem. Our approach has three advantages: (i) it makes structurally explicit the solution to an abductive problem (as it has a syntactic nature); (ii) it gives a precise meaning to the notion of evidence; (iii) it provides clear definitions and procedures for the comparison of solutions that can be adapted to different needs.

The aim of this article is to analyse the kind of inference used in the reconstruction of proto-languages. Hypothesis is at the core of this reconstruction process and this, together with the structure of reasoning involved, indicates abductive reasoning. We analyse abductive reasoning, and specify its nuances and particularities. The novelty we introduce is the importance of context as we focus on a form of abduction that goes beyond the context in which the scientific work is being developed by incorporating (...) contexts from other sciences. Therefore, an intercontextual chain of inference can be part of abductive reasoning processes and the resulting hypothesis remains provisional. Several disciplines, such as archaeology, history and linguistics, play a cognitive role in the reconstruction of proto-languages, thus requiring more than one context. We use the case of the reconstruction of proto-Semitic and the unexpected fact of the Ugarit and Ebla discoveries (plus Amorite names). This sample may shed light on the use of abduction to explain certain scientific practices. (shrink)

This work proposes an understanding of deductive, default and abductive reasoning as different instances of the same phenomenon: epistemic dynamics. It discusses the main intuitions behind each one of these reasoning processes, and suggest how they can be understood as different epistemic actions that modify an agent’s knowledge and/or beliefs in a different way, making formal the discussion with the use of the dynamic epistemic logic framework. The ideas in this paper put the studied processes under the same umbrella, thus (...) highlighting their relationship and allowing a better understanding of how they interact together. (shrink)

In this article, we first study abduction in human dialogues. Given an utterance, objective abduction produces a hearer’s belief that could explain the utterance, while subjective abduction produces a hearer’s belief that could explain the belief state of a speaker. Different types of abduction are formulated using propositional epistemic logic. We next consider conversational implicature used as pragmatic inference in speech acts. Two conflicting implicatures, Q-implicature and I-implicature, are formulated and contrasted with abduction. We also argue how speakers could use (...) abduction or conversational implicature for the purpose of misleading hearers. (shrink)