Discourse Coherence and Rhetorical Relations

Core Idea

Discourse coherence concerns how sequences of utterances are meaningfully connected through coherence relations (narration, explanation, contrast). These relations constrain interpretation of pronouns, temporal expressions, and other context-dependent elements.

Explainer

From your study of anaphora and discourse dynamics, you know that interpreting a pronoun or definite description requires tracking what is salient in the discourse context — the center of attention, recent referents, entities introduced into the discourse model. Discourse coherence extends this picture: it is not just individual referents that form a context, but the *relations between propositions* that give a discourse its structure. A sequence of sentences hangs together as a discourse only if the listener can identify how successive utterances are connected — and those connections constrain interpretation as powerfully as anything in the sentence itself.

The building blocks of discourse structure are rhetorical relations (also called coherence relations), which include among others: narration (a sequence of events in temporal order), explanation (the second clause gives the cause of the first), elaboration (the second clause says more about the same topic), contrast (the clauses highlight a difference), and result (the second clause is the consequence of the first). Consider the difference between "John fell. Mary pushed him" and "John fell. Mary caught him." The identical first clause receives radically different interpretations depending on which relation links it to the second. In the first, John's fall is presumably caused by Mary's push; in the second, he fell but was then helped. The relation determines the causal structure the reader infers.

This matters for your understanding of anaphora because coherence relations constrain which entities are accessible for pronominal reference. In a narration sequence — "Max walked in. He sat down. He ordered coffee" — each pronoun resolves to the narrative subject, Max, because the narration relation keeps the main event participant salient. But in a contrast sequence — "Max ordered coffee. Bill had tea" — the new entity (Bill) is introduced as a contrastive topic, and the subsequent pronoun "He paid and left" is ambiguous in a way it wouldn't be in pure narration. The coherence relation partly determines the focus structure of the discourse, and focus structure determines pronoun accessibility.

Temporal expressions are equally sensitive to coherence structure. "John entered the room. He had spilled something on his tie" — the past perfect ("had spilled") signals that the spilling is background information, not a narrative advance. This temporal interpretation is not determined by the sentence alone; it depends on recognizing that the second clause is elaborating on background state rather than advancing the narrative sequence. Coherence relations set the temporal frame within which tense and aspect are interpreted. Get the relation wrong and you misparse the timeline.

The deeper implication, relevant to your upcoming work on meaning and convention, is that discourse interpretation involves inferential work well beyond decoding individual sentences. Listeners default to specific coherence relations based on plausibility, world knowledge, and genre conventions. Reading a recipe, you assume each step is a narration; reading a scientific paper's discussion section, you expect explanation and result relations. The pragmatics-semantics boundary you've already studied now extends to discourse level: the coherence relations holding a text together are inferred, not encoded — yet they have concrete semantic consequences for how every constituent part is understood.