Issues in Linguistic

This paper addresses discourse structure from the perspective of understanding. It would perhaps help us understand the nature of discourse relations if we better understood what units of a text can be related to one another. In one major theory of discourse structure, Rhetorical Structure Theory (Mann & Thompson 1988; hereafter simply RST), the smallest possible linguistic units that can participate in a rhetorical relation are called units, and \are essentially clauses, except that clausal subjects and complements and restricted relative clauses are considered as parts of their host clause units rather than as separate units" p. 248]. But both Dale and Meteer (in these proceedings) point out that rhetorical relations can appear within clausal units. (Dale's argument will be discussed at the end of this paper.) For example, the relation that is expressed in two clauses in (1.2) is expressed in only one clause in (1.1) (from Meteer, these proceedings): (1) 1.1 My icking the switch caused the light to turn on. 1.2 Because I icked the switch, the light turned on. Similarly, Hwang & Schubert (1992), in their work on recognizing temporal relations among episodes in discourse, argue for a \\ne structure" of discourse, in which temporal relations can be established even among episodes of subordinate clauses. This paper points out another discourse phenomenon that calls for a \\ne structure" of discourse. In passages containing attitude reports|reports of agents' beliefs, knowledge, intentions, perceptions, etc.|rhetorical relations can hold such that one or more of the linguistic units involved in a relation is only part of a sentence. 1 In some cases, such a unit may be smaller than the smallest possible unit in RST. Speciically, only the complement of an attitude report, rather than the entire sentence, might be involved in some particular relation. (An example is (2) below, which will be discussed shortly.) To make matters more concrete, we will consider short passages in which an attitude report participates in a relation indicated by the cue phrasèbut', wherèbut' is being used to connect clauses. 1 Note that this paper is meant to illustrate some complexities that I believe require attention. Undoubtedly, similar discourse structures occur that do not involve attitude reports.