Questions, Answers and Presuppositions

The paper deals with empirical questions that come attached with a presupposition. In case that the presupposition is not true, there is no unambiguous direct answer. In such a case an adequate complete answer is a negated presupposition. Yet these simple ideas are connected with a bunch of problems. First, we must distinguish between a pragmatic and semantic presupposition, and thus also between a presupposition and mere entailment. Second, we show that the common definition of a presupposition of a question as such a proposition that is entailed by every possible answer to the question is not precise. We follow Frege and Strawson in treating survival under negation as the most important test for presupposition. But a negative answer to a question is often ambiguous. The ambiguity consists in not distinguishing between two kinds of negative answers, to wit the answers applying narrow-scope or wide-scope negation. While the former preserves presupposition, the latter seems to be presupposition denying. We show that in order the negative answer to be unambiguous, instead of the wide-scope negation presumably denying presupposition, an adequate and unambiguous answer is just the negated presupposition. Having defined presupposition of a question more precisely, we then examine Yes-No questions, Whquestions, and exclusive-or questions with respect to several kinds of presupposition triggers. These include inter alia topic-focus articulation, verbs expressing termination of an activity, factive verbs, the „whys and how comes“ , and past or future tense with reference time interval. Our background theory is Transparent Intensional Logic (TIL) with its procedural semantics. TIL is an expressive logic apt for analysis of questions and presuppositions, because within TIL we work with partial functions, in particular, with propositions with truth-value gaps. These features enabled us to define a general analytic schema of sentences associated with a presupposition. Our results are applicable in linguistics 1 See, for instance, [S, 18, 19, 20, 27]. and artificial intelligence, in particular, in the systems the behavior of which is controlled by communication and reasoning o f intelligent social agents.