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<Paper uid="P86-1030">
  <Title>The detection and representation of ambiguities of intension and description</Title>
  <Section position="3" start_page="0" end_page="192" type="intro">
    <SectionTitle>
1. Introduction
</SectionTitle>
    <Paragraph position="0"> Certain problems of ambiguity and inference failure in opaque contexts are well known, opaque contexts being those in which an expression can denote its intension or underlying concept rather than any particular extension or instance. For example, (1) admits two readings:  (1) Nadia is advertising for a penguin with whom she could have a long-term meaningful relationship. On the transparent (or extensional or de re) reading, there is some particular penguin that Nadia is after: (2) Nudia is advertising for a penguin with whom she could have a long-term meaningful relationship, whom she met at a singles bar last week and fell madly in love with, but lost the phone number of. On the opaque (or intensional or de dicto) reading, Nadia wants any entity that meets her criteria: (3) Nadia is advertising for any penguin with whom  she could have a long-term meaningful relationship. null On this reading, the rule of existential generalization fails; that is, we cannot infer from (3), as we could from (2), that:  (4) There exists a penguin with whom Nudia could have a long-term meaningful relationship Another rule of inference that fails in opaque contexts is substitution of equals; (5) and (6) do not permit the conclusion (7): (5) Nadia believes that the number of penguins campaigning for Greenpeace is twenty-two.</Paragraph>
    <Paragraph position="1"> (6) The number of penguins campaigning for Greenpeace is forty-eight.</Paragraph>
    <Paragraph position="2"> (7) =/~ Therefore, Nadia believes that forty-eight is  twenty-two.</Paragraph>
    <Paragraph position="3"> Although these facts are familiar, little research has been done on how a practical NLU system can detect and resolve intensional ambiguities (which can occur in many constructions besides the 'standard' examples; see Fodor 1980, Fawcett 1985), and control its inference accordingly. The same is true of certain other complications of opaque contexts that are of special relevance to systems that use explicit representations of knowledge and belief. In particular, the interaction between intensional ambiguities  and the beliefs of agents has not been studied. The present work is a first step towards rectifying this.</Paragraph>
  </Section>
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