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<Paper uid="E91-1045">
  <Title>HELPFUL ANSWERS TO MODAL AND tlYPOTHETICAL QUESTIONS</Title>
  <Section position="3" start_page="0" end_page="0" type="intro">
    <SectionTitle>
Keywords:Semantics, Pragmatics
2.0 INTRODUCTION.
</SectionTitle>
    <Paragraph position="0"> Answers people give to questions have two basic properties: they may vary dependitig on the situation a question is asked in, and, especially if the answer is negative, they aim to be &amp;quot;helpful&amp;quot;. The context-sensistivity of answering seems obvious and in no need of further demonstration. What precisely constitutes &amp;quot;helpfidness&amp;quot; is harder to pin down. Modal and hypothetical questions offer an interesting mea for investigating &amp;quot;helpfulness&amp;quot;. Suppose A and B are going to a party and are discussing how they might travel. Suppose A asks B Cat, youdrive.? B is correct but perverse to respond ~ if he knows how to drive, has a valid licence but has no car, or if he has a car but he has lent it to someone. A more helpful answer might be No. because 1 haven't got a car. Note here that there is a range of &amp;quot;correct&amp;quot; answers, some of which are Ye___~s: for instance Yes, I hww how to drive, Yes, ! lutve a licence, even Yes, I have a car', and some of which are N._oo, as in No, I haven't got a car&amp;quot; tonight. The range includes No, but ! cat, ask tO borrow my wife's car, or even Yes, ill .can get mF car back which establishes a link with hypothetical questions. Note also that, for each of these &amp;quot;correct&amp;quot; aqswers, we can imagine contexts in which they would be &amp;quot;helpful&amp;quot;.</Paragraph>
    <Paragraph position="1"> Little is known ahout the nature of questions and their relationship to appropriate answers, or about how ,such answers can be computed given some information about what the answerer knows. Some theories, mainly emerging from the Men*ague tradition (see Groeneudijk and Stockhof 119841), attempt to define &amp;quot;sema,tic&amp;quot; answerhood (see section 2.2), but fall short when tackling the pragmatic aspect of helpful answers. Other theories lSperber &amp; Wilso, 19861 offer interesting pragmatic insights but their formulation does not allow for a straightforward hnplemenration. Furthermore, the problem of answering modal and hypothetical questions is a compounded one which touches on a host of issues including quantification, intensionality, partiality, belief revision, propositional attitudes, etc.</Paragraph>
    <Paragraph position="2"> Our research aimed to draw up a formally specified and compurationally feasible pragmatic theory which could accommodate formal semantic views on answerhood as well as intuitive insights into &amp;quot;helpfulness&amp;quot; and its dependence on context (such as offered by Relevaoce Theory \[Sperber and Wilson 19861). Furthennore, the model is rigourously constrained as it must be tested by an implementation over some knowledge base representing what an agent knows.</Paragraph>
    <Paragraph position="3"> This paper is intended as an overview of the computational model. As such it (Ices not provide an in-depth account of all aspects of the investigation; in particular, it does not attempt to give a formal account of a basic theory of pragmatics, which is avail, able elsewhere \[Ball et al 19901. Rather, we sketch the background to the problems involved in providing helpful answers tO modal and hypothetical questions as a review of the relevant literature aml its perceived shortcomings. We will then proceed to outline the intuitions behind our approach to a model of pragmat.</Paragraph>
    <Paragraph position="4"> ics aod its in~plementation, and explain how it accommodates helpful answers to modal and hypothetical questions. An example is presented.</Paragraph>
  </Section>
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