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<Paper uid="W06-1310">
  <Title>Semantic and Pragmatic Presupposition in Discourse Representation Theory</Title>
  <Section position="5" start_page="69" end_page="74" type="metho">
    <SectionTitle>
3 Agent Presupposition
</SectionTitle>
    <Paragraph position="0"> Speaker presupposition differs from hearer presupposition in terms of three 'information checks' agents are hypothesized to perform when introducing or dealing with presupposition. The checks are (1) clarification check, (2) informativity check, and (3) consistency check. The checks are similar in principle to Purver (2004) and van der Sandt (1992). However, they are developed here as a process which distinguishes speaker generation from hearer recognition, allowing us to differentiate speaker presupposition from hearer presupposition, hence establishing the link between speaker presupposition and sentence presupposition, and between sentence presupposition and hearer presupposition. The three checks apply to both speaker and hearer.</Paragraph>
    <Paragraph position="1"> The clarification check may be used at the beginning of the process of checking. It corresponds to Grice's maxim of manner on the part of the speaker (1989). Nonetheless, as there are different kinds of clarification requests (Purver et al. 2003), clarification can also be initiated at various stages of the check process, indicating a different kind of clarification.</Paragraph>
    <Paragraph position="2"> The purpose of the informativity check is to check whether the presupposition is new or old information to the speaker and the hearer. This check is a modification of Grice's (1989) quality maxim, which has been reworked to include two degrees of beliefs, acceptance and belief (Al-Raheb 2005). In addition, it checks whether the information is new or old to the other agent, based on the beliefs of one agent about the other. The process of checks for the speaker mirrors that of the hearer. However, as the process of recognition is different from the process of generation, the 'information checks' are described for the speaker and hearer individually.</Paragraph>
    <Paragraph position="3"> Similarly, the consistency check determines whether the presupposition is consistent with the agents' beliefs - in accordance with Grice's maxim of relevance (1989). For presupposition, as part of the consistency check, another check is performed, more specifically for the hearer's benefit, which checks whether the presupposition is remarkable or unremarkable. Generally, information can be accommodated, so long as it is 'unremarkable' (Geurts 1999: 36). For example,  (2) The car across the street from my house belongs to my neighbour.</Paragraph>
    <Paragraph position="4"> is less likely to cause problems than (3) The small jet across the street from my house belongs to my neighbour, when the hearer knows that the speaker lives in the city centre.3  The process of 'information checks' influences how speakers make their utterances and how hearers recognize those utterances. Section 3.1 follows the information check process for presuppositions for the speaker, whereas section 3.2 demonstrates that process for the hearer.</Paragraph>
    <Section position="1" start_page="69" end_page="72" type="sub_section">
      <SectionTitle>
3.1 Speaker Presupposition
</SectionTitle>
      <Paragraph position="0"> Speaker presupposition differs from hearer presupposition in terms of checks. When a speaker generates a sentence presupposition (via the communicated utterance), we are assuming that the speaker is bound by Grice's Cooperative Principle (1975, 1989). To utter a sentence triggering a presupposition, the speaker needs to have reason to believe that her presupposition is going to be 'clear' and 'consistent'. The speaker may have previous context in memory that shows her presupposition to be consistent with her beliefs about the hearer's beliefs. However, when such evidence is lacking, the speaker may still make presupposition-triggering utterances (sentence presupposition) and then make the judgement that the presupposition is consistent if there is no negative feedback; alternatively, the speaker might receive evidence that shows the presupposition to be contradictory with her beliefs about the hearer's beliefs.</Paragraph>
      <Paragraph position="1"> The informativity check comes into play when the speaker elaborates on given or known information by packaging it as a presupposition and focusing attention on the assertion part of her utterance, i.e. on the new information. In this case, the  speaker needs to have reason to believe that the hearer is already aware of this presupposed information, therefore, that it is known. For example, (4) My grandchild loves horses.</Paragraph>
      <Paragraph position="2"> To be consistent, the speaker checks her memory to see if the speaker has record that she, the speaker, has reason to believe that the hearer believes that the speaker has a grandchild. The speaker, being in a retirement home, discussing her grandchildren with the carer, and having had previous conversations with the same carer about her family, has reason to believe that the hearer already knows she has a grandchild. She, therefore, presupposes 'I have a grandchild'.</Paragraph>
      <Paragraph position="3"> Another example of elaborating on given information is when the speaker believes the given information has been established, i.e. both the speaker and the hearer believe that the information is part of their mutual or common beliefs. This constitutes a case of strong speaker belief. Consider example (5): (5) Sylvia's will means we have to move out.</Paragraph>
      <Paragraph position="4"> In this case, the speaker and the hearer have been talking about Sylvia's will in their dialogue and both have reason to believe that Sylvia has a will and that they both know the other person has reason to believe Sylvia has a will.</Paragraph>
      <Paragraph position="5"> Generally, if the speaker assumes the information presented in the presupposition to be known to the hearer, the speaker would expect the hearer to accept the information provided by the sentence presupposition by default, or even believe it. This process is generally referred to as binding in dynamic semantics.4 Of course, the hearer may experience some difficulty in understanding and ask for a 'clarification', check 1.</Paragraph>
      <Paragraph position="6"> However, the information presented as a sentence presupposition may be new. The speaker may wish to introduce a topic into the dialogue, knowing that the hearer has no previous knowledge of the topic. The new information (speaker presupposition) is then checked by the speaker for consistency, where it may be remarkable or unremarkable. Here, we follow Geurts's (1999) classification of remarkable and unremarkable presupposition.5 Thus, examples (6) and (7), given a certain situation and agents, are more unusual to accommodate without questioning than example (1), where many people may have sisters.</Paragraph>
      <Paragraph position="7"> (6) I have to pick my personal trainer up from the airport.</Paragraph>
      <Paragraph position="8">  such as having a brother or a sister. An example of remarkable information might be: (8) My private jet arrives this afternoon.</Paragraph>
      <Paragraph position="9"> In social contexts in which it is not expected that everyone owns a private jet, such information will at least raise an eyebrow. Being cooperative, the speaker will assume, unless the hearer indicates otherwise, that the information she provides in the presupposition is unremarkable for the particular hearer in the particular context, and that the hearer will accommodate the information by either accepting it or believing it. Whether something is remarkable depends on the specific participant and type of communicative situation. For example, two film stars talking together would presumably not find example (8) 'remarkable', nor might a journalist interviewing a celebrity.</Paragraph>
      <Paragraph position="10"> The speaker has to be prepared for cases when, despite being cooperative, the hearer might perceive sentence presupposition as unclear and/or contradictory. What this means for the present treatment of presupposition is that generally the speaker believes that the new information presented in the presupposition is unremarkable; therefore, the speaker will expect the hearer to accommodate the new information. However, in case the hearer should find the new information unusual or remarkable, the speaker will, we assume, expect the hearer to check whether the presupposition is consistent with her beliefs or not. The speaker may also expect the hearer to ask for clarification if the sentence presupposition is not clear.</Paragraph>
      <Paragraph position="11"> If clear, the speaker may expect the hearer to accommodate the sentence presupposition and may safely assume that the information has been accepted, unless it is indicated through 'strong positive feedback' that the information is actually strongly believed (Al-Raheb 2005). However, if the presupposition is not clear, the speaker may expect the hearer to ask for clarification and a clarification process takes place, in which the hearer might ask for more clarification if the information is still not clear. When the information is finally clear, the hearer may provide feedback.</Paragraph>
      <Paragraph position="12"> Despite the speaker's best efforts to be cooperative, there are cases where the presupposition contradicts the hearer's previous beliefs. Speakers usually do not expect this to happen, but are generally prepared to produce a clarification or attempt to fix the dialogue when such a problem occurs.</Paragraph>
      <Paragraph position="13"> Figure 2 is a flowchart displaying the speaker's expectations in terms of presupposition according to her beliefs and on the assumption that she is being cooperative. According to this treatment of presupposition, whether the speaker believes the information in a presupposition is new or old, the result is the same in terms of how the speaker expects the hearer to act. The only difference is that new information gets accommodated by the hearer, while known information is 'bound' and either already accepted or believed (Asher and Lascarides 1998; van der Sandt and Geurts 1991).6 It has to be said that this is of course an ideal situation. The speaker does not always have beliefs concerning whether the hearer already believes the presupposed information or not.</Paragraph>
      <Paragraph position="14"> To sum up, when initiating the topic of a presupposition, we can conclude the following: bel(S, P), bel(S, clear(P)), bel(S, consistent(P)), and bel(S, accept(H,P)).7 The speaker may have either the belief bel(S,! bel(H,P)) or the belief bel(S,bel(H,P)). However, in our implementation of the pragmatic and semantic notions of presupposition in DRT, the only beliefs represented after S's utterance are: bel(S, P), or accept(S,P) and if</Paragraph>
    </Section>
    <Section position="2" start_page="72" end_page="74" type="sub_section">
      <SectionTitle>
3.2 Hearer Presupposition
</SectionTitle>
      <Paragraph position="0"> As a result of the speaker's initiating the topic of P indicated through sentence presupposition, the hearer acquires the belief that the speaker believes the presupposition. The first information check to apply to hearer presupposition is the clear/ not clear check. That is to say, upon hearing P, the hearer first checks whether the presupposition is clear (e.g. hearer has no problems with perception). As mentioned previously, there are other types of clarification requested when inconsistency arises. However, what we are concerned with here is whether the hearer has been able to receive the message or not. Other clarification checks may take place after the hearer performs the new/old (informativity) check and the consistency check.</Paragraph>
      <Paragraph position="1"> If the presupposition is not clear in the above sense, the hearer may ask the speaker to clarify her statement. As a simple example, consider an imaginary dialogue between a customer and customer service assistant about a gas heater:  (9) Customer: How long does it take to fix my gas heater? Customer Service Assistant: Your what?  Customer: My gas heater needs fixing.</Paragraph>
      <Paragraph position="2"> After checking whether the information, sentence presupposition, is clear, the customer service assistant asks the customer to clarify. In this particular case, the lack of clarity may be attributed to, e.g. not hearing very well. The hearer expects the speaker to provide an explanation or clarification. The speaker is then obliged to provide a further explanation. If the information is still not clear, the hearer may ask for more clarification and the hearer needs to provide an explanation. Figure 3 incorporates this potentially iterative loop. This is consistent with conversation analysis research, which assumes that information may be cleared up after an explanation is provided, but also allows for further clarification if needed (Schegloff et al. 1977). If the sentence presupposition is cleared up, then the hearer may provide feedback that the information is clear. However, lack of feedback is also considered a case of 'weak positive feedback' (Al-Raheb 2005). Generally, after providing an explanation, the speaker's assumptions are likely to be that the hearer now has no problems with the sentence presupposition.</Paragraph>
      <Paragraph position="3"> Having made sure that the sentence presupposition is clear, the hearer may now move on to perform the informativity check, check 2. If the information the speaker presents as a sentence presupposition is known to the hearer, in the sense of being in his acceptance space, i.e. already a hearer presupposition, the hearer may strengthen that acceptance by now believing the presupposition (cf. Al-Raheb 2005). The hearer may previously hold a strong belief about the presupposition, i.e. the hearer may already believe P. In this case, it is not necessary to add a new belief that P to hearer presupposition. We are assuming here that the hearer's knowledge of a sentence presupposition means that this presupposition does not contradict previous beliefs held by the hearer. Figure 4 shows the hearer's options if the sentence presupposition is already a hearer presupposition, or known to him. The speaker ideally expects the hearer will accept P (i.e. P will have become hearer presupposition), unless negative feedback is provided by the hearer. If strong positive feedback is provided by the hearer, the speaker may thereby form the meta-belief that bel(H,bel(S,bel(H,P))).</Paragraph>
      <Paragraph position="4"> If the sentence presupposition provides new information, the hearer then performs the consis- null Hearer: This can't be! Julia is widowed! When the information presented by the sentence presupposition is consistent with the hearer's belief space or acceptance space, the hearer makes a judgement about whether the information is remarkable (odd or unusual) or unremarkable (cf.</Paragraph>
      <Paragraph position="5"> Geurts 1999). If the information is unremarkable, the hearer accommodates the new information by either accepting it or believing it. In other words, it becomes hearer presupposition. Figure 5 shows presupposition processing from the hearer's perspective when the sentence presupposition contains information new to the hearer.</Paragraph>
      <Paragraph position="6"> If the presupposition is remarkable, the hearer may check for clarity. This is a different type of clarity check from the one performed initially. Clarification checks can arise from different reasons and not just because of difficulty in hearing. This time the hearer requires an explanation for the oddness of the information used as a presupposition. This is when the clarification process starts again. For example, (11) Speaker: My pet lion requires a lot of attention.</Paragraph>
      <Paragraph position="7"> Hearer: Your pet what? Speaker: Oh sorry, I mean one of those virtual pets you take care of.</Paragraph>
      <Paragraph position="8"> Here, we may assume, the hearer has not found the appropriate discourse referent for 'pet lion' and thus goes through 'remarkable' check after the consistency check.8 Again, the hearer may provide feedback concerning whether the explanation has been accepted or not. Unless negative feedback is provided, the hearer is expected to at least accept the presupposition bel(S,accept(H,P)). In addition, the other agent (speaker) may assume that the hearer now has no problem with the presupposition, bel(S,clear(H,P)). If the hearer is not convinced by the speaker's explanation, an attempt at repairing the dialogue is needed.9 To sum up, at the stage of the hearer's receiving the speaker's utterance, the hearer may make the judgement that the speaker believes the presupposition (speaker presupposition). In addition, unless the hearer gives the speaker reason to think that the hearer disagrees with the presupposition, the speaker assumes that the hearer has no problem understanding the sentence presupposition, and further, that the hearer has now come to accept the presupposition (hearer presupposition). It must be pointed out that generally speaking, unless the speaker has introduced as her presupposition a topic perceived to be new and very unusual, the hearer does not need to go through the clarification process for each presupposition, since generally the presuppositions are not the focus of the speaker's utterance (Levinson 1983).</Paragraph>
      <Paragraph position="9">  assumed that if fixing the dialogue is successful, the agent will then continue with the consistency check in order to carry on with the dialogue, unless one of the agents simply gives up.</Paragraph>
    </Section>
  </Section>
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