{ "paper_id": "H86-1024", "header": { "generated_with": "S2ORC 1.0.0", "date_generated": "2023-01-19T03:35:12.188290Z" }, "title": "Assertions from Discourse Structure", "authors": [ { "first": "William", "middle": [ "C" ], "last": "Mann", "suffix": "", "affiliation": { "laboratory": "", "institution": "USC Information Sciences Institute", "location": {} }, "email": "" } ], "year": "", "venue": null, "identifiers": {}, "abstract": "", "pdf_parse": { "paper_id": "H86-1024", "_pdf_hash": "", "abstract": [], "body_text": [ { "text": "As part of an ongoing study of discourse structure of natural texts, we have identified a particular class of propositions that affect the bearer's perception of the coherence and communicated content of texts. As an example, if the text (spoken in a suitable situation) is: \"I'm hungry. Let's go to the Fuji Gardens.\" then the most natural interpretation is that the Fuji Gardens is a restaurant at which the speaker would like to eat with the hearer. The text is heard as exhibiting a problem-and-solution structure. Consequently, we can say that there is a proposition which says that there is a \"solutionhood\" relation between the two sentences. In this case, going to the Fuji Gardens (partially) solves the hunger problem.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "I nt rod u ction", "sec_num": null }, { "text": "The solutionhood construct is one type of re/ational propositions. Note that the proposition about solutionhood is not stated explicitly in the text.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "I nt rod u ction", "sec_num": null }, { "text": "Although phenomena resembling relational propositions have been recognized, there is no widely accepted explanation of how they arise from text. This paper characterizes relational propositions and presents a theory of discourse structure to explain them. In this Rhetorical Structure Theory (RST), relational propositions arise in direct correspondence to particular elements of the structure of a discourse.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "I nt rod u ction", "sec_num": null }, { "text": "We present Rhetorical Structure Theory progressively during analysis of a published, two-paragraph political advocacy text. The text involves substructures for informing, giving evidence, conceding, requesting an action, justifying a presentation, asserting conditionally, and others.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "I nt rod u ction", "sec_num": null }, { "text": "The two elements that form the basis for this paper, relational propositions and Rhetorical Structure Theory, have both been described in more detail elsewhere. The explanatory relation between them, however, has not [Mann & including implicature, presupposition and indirect speech acts, to see whether they account for the textual properties of relational propositions. It concludes that these constructs do not account for them. The paper also discusses relationships between relational propositions and the work of Grime& Hobbs, van Dijk, Martin, Longacre, Beekman and Callow, and it includes analyses of several texts.", "cite_spans": [ { "start": 217, "end": 224, "text": "[Mann &", "ref_id": null } ], "ref_spans": [], "eq_spans": [], "section": "I nt rod u ction", "sec_num": null }, { "text": "The Fuji Gardens statement and the solutionhood relation have already illustrated that relational propositions need not be signalled explicitly in order to be recognized. 1 Extending the example, we now describe properties relational propositions hold more generally, giving special attention to those properties that can be accounted for by Rhetorical Structure Theory.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "The Phenomenon of Relational Propositions", "sec_num": "1" }, { "text": "In our informal presentations of relational propositions, virtually everyone recognizes that texts such as the political letter analyzed in this paper convey the particular relational propositions that we attribute to them, even though it does not represent them explicitly. If the text author were to deny a particular relational proposition, most readers would be surprised--and puzzled about the status of the part of the text containing that proposition.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Relational Propositions Assert", "sec_num": "1.1" }, { "text": "This general consensus testifies that the relational proposition is conveyed. Further evidence lies in the apparent redundancy or somewhat bizarre markedness that occurs when the relational proposition is asserted explicitly by adding a clause to the text: \"I'm hungry. Let's go to Fuji Gardens. Our going to Fuji Gardens would contribute significantly to solving the problem of my hunger.\"", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Relational Propositions Assert", "sec_num": "1.1" }, { "text": "One way to demonstrate that a relational proposition is coherence-producing is to insert a denial of the relational proposition into the text. Doing so makes some portion of the text a non-sequitur: \"I'm hungry. Let's go to the Fuji Gardens. Of course, going to the Fuji Gardens won't do anything about my hunger.\"", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Relational Propositions are Coherence Producing", "sec_num": "1.2" }, { "text": "1We use constructed examples in this section only, tor expository reasons. RST is a theory of natural text; it was developed entirely on natural texts, such as the political advocacy text analyzed below.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Relational Propositions are Coherence Producing", "sec_num": "1.2" }, { "text": "The second sentence above has become a non-sequitur, and as a result the text as a whole is incoherent.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Relational Propositions are Coherence Producing", "sec_num": "1.2" }, { "text": "Relational propositions are always coherence-producing in this way. We will see later that this is a consequence predictable from RST, particularly from the structural forms that RST posits. Also, relational propositions are always present in coherent multisentence texts.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Relational Propositions are Coherence Producing", "sec_num": "1.2" }, { "text": "The list below names several kinds of relational propositions besides solutionhood, and gives an example of an asserted, coherence-producing proposition for each. These are drawn form the larger collection of [ ", "cite_spans": [ { "start": 209, "end": 210, "text": "[", "ref_id": null } ], "ref_spans": [], "eq_spans": [], "section": "Other Kinds of Relational Propositions", "sec_num": "1.3" }, { "text": "Give her a subscription to Science magazine. She'll be in seventh heaven.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "CONDITION:", "sec_num": null }, { "text": "I'm going to the corner. We're all out of milk.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "REASON:", "sec_num": null }, { "text": "Let me make one thing perfectly clear. I am not a crook.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "JUSTIFICATION:", "sec_num": null }, { "text": "We desire a theory that will answer two questions about relational propositions:", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "JUSTIFICATION:", "sec_num": null }, { "text": "1. What relational propositions are possible?", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "JUSTIFICATION:", "sec_num": null }, { "text": "2We have abundant natural correlates for these constructed examples. They have been designed to illustrate the fact that the relations and relational propositions are identifiable, without any explicit signalling, such as a dause, conjunction, or lexical selection.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "JUSTIFICATION:", "sec_num": null }, { "text": "The answers come from studying discourse.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "What relational propositions does a particular text assert?", "sec_num": "2." }, { "text": "RST has not been developed simply to account for relational propositions; it arose from a much broader desire to understand text and communication and to learn how texts may be created. We identified and began studying relational propositions only after RST had largely assumed its present shape.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Rhetorical Structure Theory", "sec_num": "2" }, { "text": "We wanted a theory of text organization--a way to describe what kinds of parts a text can have, how they can be arranged, and how parts can be connected to form a whole text. We especially valued the following attributes.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Rhetorical Structure Theory", "sec_num": "2" }, { "text": "The theory should apply to many kinds of text.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Comprehensiveness:", "sec_num": "1." }, { "text": "achieves its effects for the writer.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Functionality: The theory should be informative in terms of how text", "sec_num": "2." }, { "text": ". Scale insensitivity: The theory should apply to a wide range of sizes of text and should be capable of describing all of thevarious sized units of text organization that occur in a large text.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Functionality: The theory should be informative in terms of how text", "sec_num": "2." }, { "text": "The theory should lend itself to formalization and computer programming;", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definiteness:", "sec_num": "4." }, { "text": "5. Constructive potential: The theory should be usable in text construction as well as text description.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definiteness:", "sec_num": "4." }, { "text": "We developed this theory primarily in response to small written texts, although it has also been applied to larger texts. We have constructed RST descriptions for a variety of texts, including:", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definiteness:", "sec_num": "4." }, { "text": "-Administrative memos -Personal letters -Advertisements -Editorial letters in magazines -Complete Scientific American articles -Newspaper articles -Public notices in magazines -Research technical reports -Travel brochures -Cookbook recipes To introduce the theory, let us consider the analysis of a text that appeared in a political newsletter, The Insider, Vol. 2.1, July 1982. 3 The Insider is the California Common Cause state newsletter. This text was the \"con\" part of a \"pro\" and \"con\" pair of letters on the issue of California Common Cause's endorsement of the nuclear freeze initiative, which was then on the California state ballot.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definiteness:", "sec_num": "4." }, { "text": "The text has been reformatted, numbered, and divided the text into units. Units are roughly equivalent to clauses, except that that relative clauses and complement clauses are considered to be part of the unit in which their governing item appears, rather than as independent units. As long as the whole text is analyzed, the size of the minimal units can vary without affecting the larger analysis.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definiteness:", "sec_num": "4." }, { "text": "for California CC.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "I don't believe that endorsing the Nuclear Freeze Initiative is the right step", "sec_num": "1." }, { "text": "2. Tempting as it may be, 3. we shouldn't embrace every popular issue that comes along.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "I don't believe that endorsing the Nuclear Freeze Initiative is the right step", "sec_num": "1." }, { "text": "5. we use precious, limited resources where other players with superior resources are already doing an adequate job.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "When we do so", "sec_num": "4." }, { "text": "6. Rather, I think we will be stronger and more effective 7. if we stick to those issues of governmental structure and process, broadly defined, that have formed the core of our agenda for years.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "When we do so", "sec_num": "4." }, { "text": "8. Open government, campaign finance reform, and fighting the influence of special interests and big money, these are our kinds of issues.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "When we do so", "sec_num": "4." }, { "text": "3Le~er used by permission", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "When we do so", "sec_num": "4." }, { "text": "Let's be clear:", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "(New paragraph)", "sec_num": "9." }, { "text": "10. I personally favor the initiative and ardently support disarmament negotiations to reduce the risk of war.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "(New paragraph)", "sec_num": "9." }, { "text": "11. But I don't think endorsing a specific nuclear freeze proposal is appropriate for CCC.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "(New paragraph)", "sec_num": "9." }, { "text": "12. We should limit our involvement in defense and weaponry to matters of process, such as exposing the weapons industry's influence on the political process.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "(New paragraph)", "sec_num": "9." }, { "text": "13. Therefore, I urge you to vote against a CCC endorsement of the nuclear freeze initiative.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "(New paragraph)", "sec_num": "9." }, { "text": "(signed) Michael Asimow, California Common Cause Vice-Chair and", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "(New paragraph)", "sec_num": "9." }, { "text": "How is this text organized? At the most general level, the text as a whole functions as a request to vote in a certain way. At its coarsest level of decomposition, it has two parts. One part presents the request, presented in segment 13, and the remainder supports that presentation.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "UCLA Law Professor", "sec_num": null }, { "text": "The theory has a number of patterns, called rhetorical schemas, that represent organizational information about text. To represent the particulars of two-part decomposition of the text, we use one of these rhetorical schemas, the Request Schema, Figure 1 .", "cite_spans": [], "ref_spans": [ { "start": 246, "end": 254, "text": "Figure 1", "ref_id": null } ], "eq_spans": [], "section": "UCLA Law Professor", "sec_num": null }, { "text": ".._T.~.~a b lem en t Figure 1 : Request Schema A text that instantiates the Request Schema has a nuclear part, called the nucleus, that presents a request. It also has one or more supplementary parts, called satellites, that are functionally related to the nucleus. Satellites are related to the nucleus by a named relation. Here we have relations named motivation and enablement.", "cite_spans": [], "ref_spans": [ { "start": 21, "end": 29, "text": "Figure 1", "ref_id": null } ], "eq_spans": [], "section": "I", "sec_num": null }, { "text": "Let us illustrate the parts of a Request Schema in a short example: \"Call me. I have a surprise for you. My extension number is 110.\"", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "I", "sec_num": null }, { "text": "The nucleus is \"Call me,\" the motivation satellite is \"1 have a surprise for you,\" and the enablement satellite is \"My extension number is 110.\" These elements can be arranged in any order and still be an instance of the Request Schema. Schemas do not encode the order of segments; in this case, the segments can be rearranged freely without disturbing their meaning or structural relation.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "I", "sec_num": null }, { "text": "Satellites are all optional, so we can delete either one in this example and still instantiate the Request Schema-but there must be at least one satellite. The political text has a motivation satellite, segments 1 through 12, but no enablement satellite.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "I", "sec_num": null }, { "text": "We analyze each of the two top-level segments of the political text in the same way. The final segment is a single unit, so we don't try to divide it. The first segment, 12 units long, consists of a claim (unit 1) and two arguments that give evidence for the claim. We analyze this arrangement with the Evidence Schema (Figure 2) , in which the claim is the nucleus and an evidence relation connects the nucleus to the ,satellite. Figure 3 shows the resulting structure. The Upper Structure of the Political Text Both of the nuclei obey what we call the Most Favorable Audience Rule: F.or the most knowledqeable and D0sitivelv Dredisoosed hearer, the nucleus al0n@ would be sufficient to perform the function of the structure; the ~atellit~ function to inCreasE the likelihood that the nuCleus will succeed. This rule is a summary of many observations about the rhetorical structures of texts. It does not always hold, but there is a strong, unexplained tendency for it to hold.", "cite_spans": [], "ref_spans": [ { "start": 319, "end": 329, "text": "(Figure 2)", "ref_id": null }, { "start": 431, "end": 439, "text": "Figure 3", "ref_id": null } ], "eq_spans": [], "section": "I", "sec_num": null }, { "text": "In this case of the Request Schema, presenting the request (to vote in a certain way) to a favorably predisposed hearer would be enough to get that reader to vote as desired; the supporting argument makes the desired vote more likely for most readers.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Evidence", "sec_num": null }, { "text": "This application of the Evidence Schema contains two arguments: One says that the proposal is wasteful, and the other says that better alternatives exist. They make the reader more likely to accept the claim that endorsement is not right. 4", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Evidence", "sec_num": null }, { "text": "The analysis goes on, down to single units. schemas used. They are drawn from through use of about 30 relations. To illustrate the relations used here, we turn back to the text.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Evidence", "sec_num": null }, { "text": "The thesis~antithesis relation connects units 11 and 12. 11: \"But I don't think endorsing a specific nuclear freeze proposal is appropriate for CCC.\"", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "J ~sis~tithesis", "sec_num": null }, { "text": "12: \"We should limit our involvement...\"", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "J ~sis~tithesis", "sec_num": null }, { "text": "The concessive relation connects units 2 and 3: 2: \"Tempting as it may be,\" 3: \"we shouldn't embrace every popular issue that comes along.\" Unit 8 is an elaboration for the Inform Schema; it lists instances, such as open government and campaign finance reform.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "J ~sis~tithesis", "sec_num": null }, { "text": "Unit 9 ,says \"Let's be clear.\" This is in a justification relation to the argument that follows, in 10 through 12. It obtains permission to present a second argument, defending the same conclusion.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "J ~sis~tithesis", "sec_num": null }, { "text": "Finally, units 4 and 5 are in a condition relation. 4: \"When we do so...\" 5: \"we use precious resources...\" Figure 5 shows the structure of the whole text.", "cite_spans": [], "ref_spans": [ { "start": 108, "end": 116, "text": "Figure 5", "ref_id": "FIGREF4" } ], "eq_spans": [], "section": "J ~sis~tithesis", "sec_num": null }, { "text": "How is RST defined? How do claims about particular texts arise from an RST analysis of it? The theory is defined in terms of just three mechanisms: schemas, schema application conventions, and relation definitions.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definition Mechanisms of RST", "sec_num": "2.1" }, { "text": "Schemas are simply sets of relations. There is no schema-specific information beyond the identities of the relations that comprise the schema.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definition Mechanisms of RST", "sec_num": "2.1" }, { "text": "Schema application conventions are descriptions of what it means for a particular span of text to instantiate a schema. Its conventions are easy to state: 1. One schema is instantiated to describe the entire text.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definition Mechanisms of RST", "sec_num": "2.1" }, { "text": "2. Schemas are instantiated to describe the text spans produced in instantiating other schemas.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definition Mechanisms of RST", "sec_num": "2.1" }, { "text": "3. The schemas do not constrain the order of nucleus or satellites in the text span in which the schema is instantiated.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definition Mechanisms of RST", "sec_num": "2.1" }, { "text": "4. All satellites are optional.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definition Mechanisms of RST", "sec_num": "2.1" }, { "text": "5. At least one satellite must exist.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definition Mechanisms of RST", "sec_num": "2.1" }, { "text": "6. A relation that is part of a schema may be instantiated indefinitely many times in the instantiation of that schema. 8. The relation definition must be consistent with the spans of text related by the instantiation of the schema containing the relation.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definition Mechanisms of RST", "sec_num": "2.1" }, { "text": "It is possible for the conventions to apply to a text in more than one way, so that the text is rhetorically ambiguous.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definition Mechanisms of RST", "sec_num": "2.1" }, { "text": "A relation definition specifies three kinds of information:", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definition Mechanisms of RST", "sec_num": "2.1" }, { "text": "1. A characterization of the nucleus.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Definition Mechanisms of RST", "sec_num": "2.1" }, { "text": "span of the nucleus and the conceptual span of the satellite must be plausible.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "A characterization of the satellite. 3. A characterization of what sorts of interactions between the conceptual", "sec_num": "2." }, { "text": "To define, for example, the motivation relation, we would include at least the following.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "A characterization of the satellite. 3. A characterization of what sorts of interactions between the conceptual", "sec_num": "2." }, { "text": "the reader. 2. The satellite describes the action, the situation in which the action takes place, or the result of the action in ways that help the reader associate value assessments with the action. 3. The expected value assessments are positive, to lead the reader to want to perform the action.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "The nucleus describes an action performable, but not yet performed, by", "sec_num": "1." }, { "text": "The relational propositions do not arise independently of the relation definitions. Rather, finding that a relation definition holds is sufficient to establish the corresponding relational proposition. As readers recognize the functional relations of the parts, they are recognizing that the relation definitions hold. The content of the relational proposition is identified in this process. As a consequence, the definition scheme for RST requires no additional definitions in order to specify the relational proposition. In any particular case, the proposition can be derived from the way the relation definition fits.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "The nucleus describes an action performable, but not yet performed, by", "sec_num": "1." }, { "text": "We have found the relation definitions, useful in predicting other facts about the text, such as the kinds of conjunctions that will appear in certain places. We have analyzed a large number of texts, including thousands of clauses, in this way. We are confident that we can perform this analysis, with fairly high reliability, for virtually any small, written, multisentence monologue in general American culture, using only about 25 schemas.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "The nucleus describes an action performable, but not yet performed, by", "sec_num": "1." }, { "text": "Note that these rhetorical schemas are defined in terms of the functions of segments of text. The evidence relation applies when one segment supports another as evidence, Solutionhood applies when we can see one segment as identifying a problem and another as a partial solution to that problem. These are not criteria of form; as one might expect, the relationship of these function categories to form categories is quite loose. The rhetorical structure of text, in these terms, is composed of function-specific units. The structure does not express categories of knowledge or form as much as it expresses the roles of specific parts in relation to the whole text, especially the role of each satellite relative to one particular, immediate portion of the text, the corresponding nucleus.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "The nucleus describes an action performable, but not yet performed, by", "sec_num": "1." }, { "text": "The key observation for the purposes of this paper is:", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "RST as an Account of Relational Propositions", "sec_num": "3" }, { "text": "For every relation of the rhetorical structure of a text, a corresponding relational proposition is asserted.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "RST as an Account of Relational Propositions", "sec_num": "3" }, { "text": "For solutionhood relations, the discourse structure asserts a solutionhood proposition. For evidence relations it asserts an evidence proposition, and so forth. Readers attribute the assertions to the text because they recognize the functional relations of the parts. Now we can explain why relational pi'opositions are coherence-producing.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "RST as an Account of Relational Propositions", "sec_num": "3" }, { "text": "First, RST structures always have the connectivity of trees. The schema application conventions guarantee this, because when a span is decomposed, each of the parts is further decomposed separately.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "RST as an Account of Relational Propositions", "sec_num": "3" }, { "text": "If a portion of the text is to be connected to the whole without being a non-sequitur, some relation must be established. A relation is established through implicit assertion of a relational proposition. Since the relations form a tree, denial of any one relational proposition is sufficient to separate the structure into two parts, thus destroying connectedness, a key attribute of coherence. Now we can also explain why relational propositions are always present in coherent multisentence texts. In regarding the text as a single whole, readers impute rhetorical structure to it, necessarily positing relations between the parts; the relations give rise to assertion of relational propositions.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "RST as an Account of Relational Propositions", "sec_num": "3" }, { "text": "We can also see how to create more precise specifications of relational propositions. They can be developed from the relation definitions of RST. RST tells what sorts of propositions can be relational, gives the conditions under which relational propositions arise, and tells how to alter a text or a situation so that the asserted relational proposition is changed. Rather than simply searching texts for potential relational propositions, we can search rhetorical structures for the necessary relational propositions.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "RST as an Account of Relational Propositions", "sec_num": "3" }, { "text": "Rhetorical Structure Theory provides an attractive basis for explaining relational propositions, although some details need development.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Uses of Rhetorical Structure Theory", "sec_num": null }, { "text": "In addition, RST satisfies some of the attributes identified in section 2, above, as desirable for a descriptive theory of text organization. It is comprehensive enough to apply to many different kinds of text; it is functional, in that it explains what various portions of a text do for the writer. And it is scale insensitive, applying to a wide range of sizes of units, from simple clauses up to whole magazine articles.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Uses of Rhetorical Structure Theory", "sec_num": null }, { "text": "However, RST still lacks two desired attributes: It needs for more detailed expression of each part, and it would be useful to develop a constructive counterpart to the descriptions, a way to select schemas and plan texts.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Uses of Rhetorical Structure Theory", "sec_num": null }, { "text": "In addition to these attributes, benefits of RST.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Uses of Rhetorical Structure Theory", "sec_num": null }, { "text": "we recognize other opportunities for and 1. It gives a partial account of the distribution of interclausal and intersentential conjunctions.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Uses of Rhetorical Structure Theory", "sec_num": null }, { "text": "2. It leads to new observations of text phenomena, including some related to nuclei, such as the most-favorable-reader hypothesis.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Uses of Rhetorical Structure Theory", "sec_num": null }, { "text": "3. The advantages of a recursive theory are obtained for text structure.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Uses of Rhetorical Structure Theory", "sec_num": null }, { "text": "Beyond the phenomena identified above, RST appears to be useful in accounting for other kinds of discourse phenomena. We have found no boundary for its uses; it is like trying to delimit the uses of a grammar. We have identified the following as particularly attractive applications: ", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Uses of Rhetorical Structure Theory", "sec_num": null }, { "text": "The assertion of relational propositions is a hitherto unexplained phenomenon. Rhetorical Structure Theory provides a way to explain such assertions in terms of discourse structure. In addition to explaining relational propositions, Rhetorical Structure Theory can be used to explain other text characteristics as well, and it provides a way to address a wide range of discourse phenomena.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Summary", "sec_num": "5" }, { "text": "[Mann & Thompson 83] Mann, W. C., and S. A. Thompson, Relational Propositions in Discourse, USC/Information Sciences Institute, Technical Report RR-83-115, July 1983. To appear in Discourse Processes.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null } ], "back_matter": [], "bib_entries": { "BIBREF0": { "ref_id": "b0", "title": "Discourse Structures tor Text Generation, USC/Information Sciences Institute", "authors": [ { "first": "W", "middle": [ "C" ], "last": "Mann", "suffix": "" } ], "year": 1984, "venue": "", "volume": "", "issue": "", "pages": "", "other_ids": {}, "num": null, "urls": [], "raw_text": "Mann, W. C., Discourse Structures tor Text Generation, USC/Information Sciences Institute, Technical Report RR-84-127, February 1984. Also appeared in the proceedings of the 1984 Coling/ACL conference, July 1984.", "links": null } }, "ref_entries": { "FIGREF1": { "num": null, "text": "Figure 2: Evidence Schema", "type_str": "figure", "uris": null }, "FIGREF2": { "num": null, "text": "Figure 3:", "type_str": "figure", "uris": null }, "FIGREF3": { "num": null, "text": "shows the additional a larger set of about 25 schemas, defined Other Schemas Used to Analyze the Political Text 4Although the unit begins \"1 don't believe that...,\" the claim here is really about whether this step is right for CCC. The evidence that follows in units 2 through 11 is about what benefits C, CC, not about whether the author believes this claim or not. RST does not represent the indirectness of the form of the claim.", "type_str": "figure", "uris": null }, "FIGREF4": { "num": null, "text": "Full Rhetorical Structure of the Political Text 7. The nucleus and satellites do not necessarily correspond to a single uninterrupted text span.", "type_str": "figure", "uris": null }, "FIGREF5": { "num": null, "text": "Thematization and text development . Distributions of tense selections in text -Lexical selection -Patterned shifts of hypotheticality, identifiability, or conditionality -Patterns of use of conjunctions -Purposeful clause combining . Distribution of topicalization markers -Text ordering (under way) -Relating coherence to cohesive devices", "type_str": "figure", "uris": null } } } }