Anaphora without indices: Dynamics of centering


Συγγραφέας: Maria Bittner


Maria Bittner: Anaphora without indices: Dynamics of centering (pdf, 316K)
The standard way to represent anaphoric dependencies is to co-index the anaphor with its antecedent in the syntactic input to semantic rules, which then interpret such indices as variables. Dynamic theories (e.g. Kamp’s DRT, Heim’s File Change Semantics, Mus1<ens’s Compositional DRT, etc) combine syntactic coindexation with semantic left-to-right asymmetry. This captures the fact that the anaphor gets its referent from the antecedent and not vice versa. Formally, a text updates the input state of information to the output state. In particular, an indexed antecedent updates the entity assigned to its index, and the output entity is then picked up as the referent by any subsequent co-indexed anaphor. (1) The elephant in the room is that the all-important indices have no audible reflex in any natural 1anguage—e.g. no language contrasts hen vs. hem. Adding to the embarrassment, actual anaphoric contrasts are not interpreted like contrasting variables in formal logics—e.g. zero (i.e. missing argument) vs. pmnnun td in Mandarin Chinese; or proximate vs. obviative 3rd person in languages with grammatical obviation (e.g., -ni vs. -u in Kalaallisut). Yet actual anaphoric systems render anaphora unambiguous (Mandarin, Kalaallisut), or much less ambiguous than predicted (English), by mechanisms that index-based theories have no tools to explicate. A yet another mystery for index-based theories is why anaphora resolution does not get increasingly harder as discourse progresses, since every (2) sentence adds to the set of potential antecedents. Yet, intuitively, in a long novel a pronoun at the end is just as easy to resolve as a pronoun in paragraph one. Intuitively, this is because a pronoun refers to a salient antecedent, and the set of currently salient antecedents changes but does not grow. Previous attempts to implement this common-sense idea (centering theory of Grosz et al 1995 and related work) have been criticized into oblivion (see e.g...