Communication and Attitude Revision

Abstract

A theory of communication seeks to explain the effects that communicative acts have on the interlocutors. Typically, communicative acts change the beliefs, desires, and intentions of the dialogue participants. The precise effects on the participant’s mental state depend on the semantic content of the utterance, and the initial beliefs, desires, and intentions that the participants bring to the discourse. The question then arises of how best to construct a formal model of this mental-state revision process. This paper considers two alternatives for such a model: deductive and abductive. A deductive default model starts with a description of the propositional content of the utterance and the original beliefs and intentions of the participants, and describes the conclusions that follow from these premises, provided these conclusions are consistent with the theory. An abductive model begins with an observation of a speech act, and entertains explanations as to why a speaker would produce it. Such explanations consist of hypotheses about the mental state of the speaker that would justify the observed speech act as a rational act. The paper concludes that a deductive model is more suitable for the construction of a competence theory than an abductive model because of the difficulty of accounting for insincere acts within the scope of the abductive theory. Abductive theories, on the other hand, are most suitable for reasoning about causal relationships between hypotheses and observed effects.