In [1a] the pronoun binds to John, because that delivers the most coherent interpretation of the two-sentence discourse as a whole. In [1b], by contrast, the pronoun is bound to Bill. This difference corresponds to a difference in the kind of coherence relations exemplified by the two discourses: [1a] exemplifies a coherence relation known as Elaboration, while [1b] is an instance of Result. That discourse relations play an important role in discourse interpretation is shown by examples like   [2] (again from Hobbs 1979).