A Causal Theory of Speech Acts

Chiaki Sakama

in: Proceedings of the 6th International Conference on Logic, Rationality and Interaction (LORI VI), Lecture Notes in Artificial Intelligence 10455, Springer-Verlag, pages 658-663, 2017.


In speech acts, a speaker utters sentences that might affect the belief state of a hearer. To formulate causal effects in assertive speech acts, we introduce a logical theory that encodes causal relations between speech acts, belief states of agents, and truth values of sentences. We distinguish trustful and untrustful speech acts depending on the truth value of an utterance, and distinguish truthful and untruthful speech acts depending on the belief state of a speaker. Different types of speech acts cause different effects on the belief state of a hearer, which are represented by the set of models of a causal theory. Causal theories of speech acts are also translated into logic programs, which enables one to represent and reason about speech acts in answer set programming.

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