Conditional answers and the role of probabilistic epistemic representations (2020)

Abstract: Conditional utterances can be used in discourse as answers to regular, non-conditional questions in situations of partial knowledge of the answerer. We claim that the probabilities assigned to possible epistemic states of A are a measure of the utility of conditional answers. A second criterion that makes a conditional answer ‘if p, then q’ relevant has to do with the dependency between p and q that is conveyed in the statement. A conditional answer counts as relevant when this dependency leads the question asker to shift from a decision problem about q to an alternative, easier, decision problem about p.

## introduction 1.conditionals as answers the study of conditional sentences (if -then sentences) constitutes a vast area within formal semantics. a lot of this work considers the internal structure of conditionals: how do tense, aspect, and modality contribute to the combination of pragmatic and semantic effects observed for conditional utterances? (see e.g. von fintel, 2011 for an overview). the use of conditionals in conversation is relatively less well studied. yet, corpus research shows that conditionals are a very common utterance type @xcite for some preliminary corpus data from the europarl corpus, see @xcite . a prominent view in semantic theories of discourse interaction is to model conversational contexts as a structured collection of (possibly implicit) information requests, and answers to these requests. these requests are called questions under discussion (quds, @xcite , or issues in the framework of inquisitive semantics @xcite . hence, a natural start of a theoretically and computationally robust study of condi-tionals in discourse is to ask how conditional utterances behave as answers to questions. work on conditionals as answers to questions is surprisingly scarce, given that both questionanswer models of discourse, and formal theories of the meaning of conditional sentences, have been major themes in the literature on semantics and pragmatics. i argue that the most important empirical setting to study is when conditionals answer regular, non-conditional questions. indeed, we observe that conditional utterances make good answers to all types of non-conditional questions, including polar questions (1a), alternative questions (1b) and wh-questions (1c): here, the conditional form of the answer was not driven by the form of the question, but newly introduced by b on the basis of conditional knowledge he has. 1 what is worth noting about the cases in (1), is that b's answers are not the maximally informative congruent answers that are typically studied in semantic theories of questions (congruent answers would be 'yes'/'no' to a polar question, 'coffee' or 'tea' in (1b), and a constituent answer such as 'pasta' or 'steak' in (1c)). this is because the conversations in (1) crucially involve partial knowledge. in (1a), b does not know for 1 throughout, i will use a(lice) and female pronouns to refer to the question asker, and b(ob) and male pronouns to refer to the answerer. a fact whether john will come, so the pragmatically most informative answers 'yes' and 'no' are ruled out. however, he is not completely ignorant about the situation, he has conditional knowledge: b knows that if john finishes his work, he will come. ## conclusion i have outlined various reasons for investigating conditional utterances from the perspective of answers to questions: understanding the use of conditionals in discourse, their information-structural properties, and the distribution of conditional perfection. then i outlined some specific examples in which conditional answers are licensed, and argued that interlocutors have representations of each other's epistemic states. they update, and reason probabilistically about these representations in the course of the conversation. the utility of a conditional answer is measured by p b (k a ?p), but there is a second way in which the information conveyed by a conditional utterance counts as relevant, over and above the epistemic condition. learning about the conditional dependency between p and q is relevant for a in the process of resolving her decision problem '?q', when this dependency allows her to switch from the original problem '?q' to an alternative decision problem '?p' that is easier to resolve.