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<Paper uid="P85-1008">
  <Title>Ontological Promiscuity</Title>
  <Section position="3" start_page="0" end_page="0" type="intro">
    <SectionTitle>
1 Motivation
</SectionTitle>
    <Paragraph position="0"> The real problem in natural language processing is the interpretation of discourse. Therefore, the other aspects of the total process should be in the service of discourse interpretation. This includes the semantic translation of sentences into s logical form, and indeed the logical notation itselPS Discourse interpretation processes, as ! see them, are inferential processes that manipulate or perform deductions on logical expressions encoding the information in the text and on other logical expressions encoding the speaker's and helper's background knowledge. These considerations lead to two principal criteria for * logical notation.</Paragraph>
    <Paragraph position="1"> Criterion I: The notation should be as close to English as possible. This makes it easier to specify the rules for translation between English and the formal language, mad also makes it easier to encode in logical notation facts we normally think of in English. The ideal choice by this criterion is English itself, but it fails monumentally on the second criterion.</Paragraph>
    <Paragraph position="2"> Criterion lh The notation should be syntactically simple.</Paragraph>
    <Paragraph position="3"> Since discourse processes are to be defined primarily in terms of manipulations performed on expressions in the logical notation, the simpler that notation, the easier it will be to define the discourse operations.</Paragraph>
    <Paragraph position="4"> The development of such a logical notation is usually taken to be a very hard problem, i believe this is because researchers have imposed upon themselves several additional constraints to adhere to stringent ontological scruples, to explain a number of mysterious syntactic facts ms a by-product of the notation, and to encode efficient deduction techniques in the notation.</Paragraph>
    <Paragraph position="5"> Most representational difficulties go *way if one rejects these constraints, and there are good reasons for rejecting each of the constr~nts.</Paragraph>
    <Paragraph position="6"> Ontological scruples: Researchers in philosophy and lint~uistics have typically restricted themselves to very few (altho*Igh * strange assortment of) kinds of entities - physical objects, numbers, sets, times, possible worlds, propositions, events, and situations - mad all of these but the first have been controversial. Quine has been the greatest exponent of ontological chastity, ills argument is that in any scientific theory, &amp;quot;we adopt, at \[east insofas* as we are reasonable, the simplest conceptual scheme into which the disordered fragments of our experience can be fitted and arranged.* (Quine, 1953, p. 16.) But he goes on to say that &amp;quot;simplicity ... is not a clear and unambiguous idea; and it is quite capable of presenting a double or multiple standard.&amp;quot; (Ibid., p. 17.) Minimising kinds of entities is not the only way to achieve simplicity in a theory. The aim in this enterprise is to achieve simplicity by minimizing the complexity of the rules in the system. It turns out this can be achieved by multiplying kinds of entities, by' allowing as an entity everything that can be referred to by a noun phrase.</Paragraph>
    <Paragraph position="7"> Syntactic explanation: The argument here is easy. It would be pleasant if an explanation of, say, the syntactic behavior of count nouns and mass nouns fell out of our underlying ontological structure at no extra cost, but if the extra cost is great complication in statements of discourse operations, it would be quite unpleasant. In constructing a theory of discourse interpretation, it doesn't make sense for us to tie our hands by requiring syntsctie explanations as well. The problem of discourse is at least an order of maguitude harder than the problem of syntax, and syntax shouldn't be in the driver's seat.</Paragraph>
    <Paragraph position="8"> Efficient deduction: There is * long tradition in artificial intelligence of building control information into the notation.</Paragraph>
    <Paragraph position="9"> and indeed much work in knowledge representation is driven by this consideration. Semantic networks and other notational systems built ,round hierarchies (Quillian, 1068; .~immons, 1973; Hendrix, 1975) implicitly assign a low cost to certain types of syllogistic remmning. The KL-ONE representation language (Schmolze and Brat.brunn, 1982) has a variety of notational devices, each with an associated efficient deduction procedure.</Paragraph>
    <Paragraph position="10"> Hayes (1979) has argued that frame representations (Minsky, 1975; Bobrow and Winogrsd, 1977) should be viewed am sets of predicate calculus axioms together with a control component for drawing certain kinds of inferences quickly. In quite a different vein, Moore (1980) uses a possible worlds notation to model knowledge mad action in part to avoid inefficiencies in theoremproving. null By contrast, l would argue against building etSSciencies into the notation. From a psychological point of view, this allows us to abstract away from the details of implementation on a particular computational device, increasing the generality of the theory. From a technological point of view, it reflects a belief that we must first determine empirically the must common classes of inferences required for discourse processing and only then seek algorithms for optimizing them.</Paragraph>
    <Paragraph position="11"> In this paper I propme s flit logical notation with an ontologically promiscuous semantics. One's first naive guess as to how to represent a simple sentence like A boy builds s boat.</Paragraph>
    <Paragraph position="12"> is as follows:</Paragraph>
    <Paragraph position="14"> This simple approach seems to break down when we encounter the more ditcuit phenomena of natural language, like tense, intensional contexts, and adverbials, as in the sentence A boy wanted to build a boat quickly.</Paragraph>
    <Paragraph position="15"> These phenomena have led students of language to introduce significant complications in their logical notations for representing sentences. My approach will be to maintain the syntactic simplicity of the logical notation and expand the theory of the world implicit in the semantics to accommodate this simplicity.</Paragraph>
    <Paragraph position="16"> The representation of the =hove sentence, as is justified below, is (::lCl, C/Z, el, Z, V) Past(el )AwnnLl(et, Z, ez)Aquiekl(e2, us) Abmld~(es, z, g) A bey(z) A boat(g) That is, el occurred in the peat, where el is z's wanting e~, which is the quickness of us, which is z's building of y, where z is a boy and y is a boat.</Paragraph>
    <Paragraph position="17"> In brief, the logical form of natural language sentences will be a conjunction of atomic predications in which all variables are existentially quantified with the widest poesible scope. Predicates will be identical or nearly identical to natural language morphemes. There will be no ftmctious, funC/*ionals, nested quantifiers, disjunctions, negations, or modal or inteusional op erators.</Paragraph>
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