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<Paper uid="C92-1037">
  <Title>Generic NPs and Habitual VPs</Title>
  <Section position="4" start_page="0" end_page="0" type="metho">
    <SectionTitle>
2 Semantic Framework
</SectionTitle>
    <Paragraph position="0"> The treatment of bare plurals proposed in this paper ntJ within the following general framework.</Paragraph>
    <Paragraph position="1"> * Verbs denote events (subdivided into states, extended actions and instantaneous actions).</Paragraph>
    <Paragraph position="2"> * There is a finite set of thematic roles, such as agent, instrument, target and object. The syntactic sub-categorisation rules of individual verbs allocate sets of items to these roles. These sets often turn out to be singletons, but it seems better to distinguish between singular and plural NPs in terms of the cardinality of some tee of objects than to say that singular NPs denote individuals and plurals denote sets.</Paragraph>
    <Paragraph position="3">  * Tense and aspect express relations between events or sets of events and temporal objects such as instants and intervals.</Paragraph>
    <Paragraph position="4"> * Definite reference and anaphora are treated as PRESUPPOSITION-INDUCING mechanisms. Pre null suppositions are described in terms of formulae each of which is required to pick out exactly one item in the context of an utterance. The semantics of any natural language expression consists of a set of such presuppositions and a matrix, which corresponds to the usual notion of propositional content.</Paragraph>
    <Paragraph position="5"> The dements of this framework ate not universally accepted, but they do at least all have respectable ancestors. The most contentious is the view that definite reference and anaphora should be dealt with in terms of constraints on the situation of utterance. The basic notion here is similar to the use of ANCHORS in situation semantics \[Barwise &amp; Perry 1983\], and to the treatment ofanaphora in DRT \[Kamp 1984\]. The details of our approach are given in \[Ramsay 1990a\]. Very little in the present discussion of bare plurals depends on this treatment of definite reference. Sceptics about this part of our framework are invited to suspend their disbelief while considering the treatment of bare plurals.</Paragraph>
    <Paragraph position="6"> The following analysis of  In order to interpret bare plurM NPs we need the following rule:</Paragraph>
    <Paragraph position="8"> This rule, with quite bit of syntactic detail omitted, says that a plural nominal group (something of category u and bar level 1) may be rewritten as an NP (something of category n and bar level 2). The matrix of the NP consists of a generalised 2 quantifier derived from the matrix of the NN, and the presuppositions of the NN are inherited by the NP.</Paragraph>
    <Paragraph position="9"> This is exactly the rule we need to obtain</Paragraph>
    <Paragraph position="11"> the meaning of the bare plural peaches, and hence to obtain the interpretation given above of (8). It is worth noting that bare plurals as subject have very much the same effect -- that the analysis of (9) Wolves were chasing a deer* says that there was a past instantaneous chasing event whose object was a (singleton set of) deer and all of whose agenfs were wolves:</Paragraph>
    <Paragraph position="13"/>
  </Section>
  <Section position="5" start_page="0" end_page="0" type="metho">
    <SectionTitle>
4 Habituals Revisited
</SectionTitle>
    <Paragraph position="0"> The analysis giveu above seems to provide a satisfactory treatment of the contribution of bare plural NPs in sentences which report simple events. How do we deal with their use in habituM sentences like (1)? We take it that (1) somehow expresses a general tendency, qb say Mar T eats peaches is to say that on suitable occasions she can be found eating peaches.</Paragraph>
    <Paragraph position="1"> The word %uitable n carries a lot weight here* If you say Mary cain Beluga caviar, you probably mean that she eats it whenever she can get it. If you say Mary eats sausages you are more likely to mean that she he~ quently eats thent, probably because she's too poor to afford caviar very often. Indeed, the ehameteri~tttion of Usuitable&amp;quot; is likely to change from situation to situation eveu for the same sentence. You could say She eats sausages lit response to the question Is Mart a funny eater?, iu which ease Usuitable&amp;quot; might mean something like &amp;quot;if she's offered them and there's no other choice&amp;quot;. You could also say it in response to tile question Does Mary \]tare a health v varied diet C/.</Paragraph>
    <Paragraph position="2"> Here, %uitable&amp;quot; would be more likely to memt Son nearly every occasion when site eats anything at all&amp;quot;.</Paragraph>
    <Paragraph position="3"> We suggest that the best way to dam with this h to treat habituals as simply saying that events of the kind iu question exist. The significance oftmying that such events exist will depend on the situation in which it is said. Suppose you say that events in which Mary eats sausages exist in a situation where your hearer wants to know about the existence of events where she eats things that some people might not like (i.e.</Paragraph>
    <Paragraph position="4"> in response to Is Mary a fussy eater~.), in such a case the fact that there are such events is enough to satisfy the heater's curiosity, and there are therefore no grounds for them to assume anything about how often site eats them. Suppose, on the other hand, that you respond to a question about the variety of her diet by simply saying that there are occasions when she eats sausages. Your hearer is then likely to assume that you are implicating that these are MI or most of the &amp;quot;Mary eating something&amp;quot; events that you know about, since if you knew about other things Mary ate then you would know that her diet was reasonably varied, lit other words, hnbituaLs simply posit the existence of sonic set of events of the specified kind.</Paragraph>
    <Paragraph position="5"> Decisious about whether these events are common, about the circumstances in which they occur, can only be made on the basis of extra-linguistic contextuM facts.</Paragraph>
    <Paragraph position="6"> We theretbre analyse the sentence (10) Mary drives a fast car.</Paragraph>
    <Paragraph position="7">  This says that there is a set A of driving events, where A has more than one member; that each member of A has Mary as its agent; and that there is some singieton set B of fast ears (things which are &amp;quot;fast for a cam) which is the object of every member of A.</Paragraph>
    <Paragraph position="8"> How often she drives it, where she drives it, and so on are all questions which can only be answered when we know more about the context in which (10) was uttered. All that (10) actually says is that there is such a set of events.</Paragraph>
    <Paragraph position="9"> This analysis of habituals gives a clue as to why (11) John eats a peach.</Paragraph>
    <Paragraph position="10"> does not seem to admit a habitual reading. The interpretation of (11) as</Paragraph>
    <Paragraph position="12"> says that there is a single peach which is the object of several eating events. Since a given peach can only be eaten once, this seems most unlikely.</Paragraph>
    <Paragraph position="13"> There are, of course, still open questions concerning the interpretation of sentences like: (12) John cats a peach for his lunch cver~ day.</Paragraph>
    <Paragraph position="14"> (12) clearly does require a habitual reading, where each day he eats a different peach. It seems likely that some mechanism such as &amp;quot;Cooper storage n \[Cooper 1983, Keller 1987\] for delaying decisions about quantifier scope will be required here. The exact details of this mechanism do not concern us here. We simply note that something of this kind seems to be necessary anyway for traditional problems of quantifier scope ambiguity. Since we will, for instance, need something like this for obtaining the de re/de ditto readings of (13) John wants to catch a unicorn.</Paragraph>
    <Paragraph position="15"> we will assume that we will be able to rely on it for dealing with the relation between (11) and (12) as well, We end the current discussion by noting that our analyses of bare plurals and habituals do st least provide a sensible formal paraphrase of (1):</Paragraph>
    <Paragraph position="17"> This analysis of (I) says that there are eating events whose agent is Mary and all of whose objects are peaches. This seems to be about as much as you can reasonably expect to get from (1) without some extra contextua! information.</Paragraph>
  </Section>
  <Section position="6" start_page="0" end_page="0" type="metho">
    <SectionTitle>
5 Conclusions
</SectionTitle>
    <Paragraph position="0"> We have argued that the semantics of bare plurals can be captured without any extension to the formal underpinning of our semantic framework. The essential points were that 0) we separated out the effects of the habitual aspect and of the bare plural; (it) we assume that the fillers for thematic roles are always sets of items, with singular NPs denoting singleton sets. This enables us to avoid postulating a systematic polymorphism for verb semantics t with one interpretation in terms of individuals for cases where some argument is supplied by a singular NP and another in terms of sets of individuals for cases where the same argument is supplied by a plural NP; and (iii) we used an event-oriented treatment of verb semantics (see for instance Davidson \[1980\]). It is worth noting that Krit~ \[19901 and Pulman \[1991\] have also developed treatments of complex quantificstional phenomena on the basis of this kind of treatment of verbs.</Paragraph>
    <Paragraph position="1"> The realisation that verbs can denote sets of events in the same way that NPs can denote sets of individuals, and that you can quantify over these as well over the individuals and sets of individuals denoted by NPs, seems to provide n great deal of flexibility without increasing your ontological commitments.</Paragraph>
    <Paragraph position="2"> The analyses of bare plurals and habituals discussed above have been implemented in u version of the system described in \[Ramsay 1990a\]. This system includes a left-corner chart parser, lexical entries containing subcategorisation frames, disjunctive unification of the kind described in \[Ramsay 1990b\], ACTES DE COLING-92, NANaT.S, 23-28 bOUT 1992 2 3 0 PROC. OF COLING-92, NANTES, AUG. 23-28, 1992 etc., etc., etc. All of the example semantic analyses were derived by this system. I would in fact say that unless you have a working implementation of your grammar and semantics, including automatic /f-reduction of applications of A-abntractioas t then the sheer complexity of the semantic formulae that arise will overwhelm you. Deciding, for instance, that using A(A,-~B VC' member(C',B) -4 D.C A IBI = 1 A A.A(E,E.B)) for the matrix of a led to more satisfactory analyses of indefinite NPs than X(A,A.X(E, 3B VC memher(C,B)-~ D.C A IBI=</Paragraph>
  </Section>
  <Section position="7" start_page="0" end_page="0" type="metho">
    <SectionTitle>
1 A (E.B))) would have been a great deal more te-
</SectionTitle>
    <Paragraph position="0"> dious than it was if I had not had a system which would show me the consequences of the two choices in n variety of settings.</Paragraph>
    <Paragraph position="1"> AcrEs DE COL1NG-92. NAm'rs. 23-28 Aot~r 1992 2 3 1 PROC. OF COLING-92, NAtCrEs, AUG. 23-28, 1992</Paragraph>
  </Section>
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