Presuppositions in Spoken Discourse

Between Binding and Accommodation
Within the binding theory of presuppositions, Bos et al. (1995) present a
resolution procedure for bridging NPs that uses information represented in
Pustejovsky’s (1991) generative lexicon to help resolve examples of bridging
anaphors. They illustrate the approach with a few simple examples that they work
out in detail, such as the bridge between bar – barkeeper. This is an approach that is
highly dependent on the information coded in the generative lexicon, which is a
mixture of encyclopedic and lexical information.
Piwek & Krahmer (2000) present a lexically based approach that uses a
reworking of the binding theory in Construction Type-Theory (CTT), a deductive
proof system. It incorporates an enriched definition of context, essentially adding
the same type of lexical or encyclopedic information as the approaches described
above. Piwek & Krahmer’s work is interesting for two reasons.
The first reason is that they make a distinction between two types of
bridging inferences. The first type is straightforward lexical ones, such as example
(5). To resolve these, a lexical relationship is integrated in the CTT context to build
a deductive proof that makes the bridging inference explicit. Examples like (2) are
more complicated and are treated by a procedure that incorporates both binding
and accommodation. Piwek & Krahmer propose treating the presupposition of the
chandelier as decomposable into two parts, the information that the presupposed
object is a light, and the information that the light is more specifically a chandelier.
The information that the object is a light can be bound to the room on the basis of
world knowledge that rooms have lights, and integrated into the CTT context. The
second part of the presupposition, e.g. that the light is a chandelier, needs to be
accommodated. 5 Piwek and Krahmer argue that some type of reasoning
mechanism will be necessary even when bridging relationships can be analyzed in
terms of lexical relationships like the first type in order to calculate the inference.
They also point out that not all bridging references can be analyzed with lexical
information.
The second reason why Piwek & Krahmer’s work is interesting is that they
acknowledge the problem that there may be more than one potential way to infer a
relationship between the anchor and the bridging NP, and they suggest two
conditions that can help make the bridging process determinate, as Clark (1975)
argued it should be. An effort condition, based on the stopping rule presented in
Clark (1975), encourages the shortest, consistent bridging inference defining it
operationally by the complexity of the proof in CTT. In addition, a plausibility
condition helps disambiguate examples when there is more than one potential
anchor and one resolution would be more plausible or consistent with the speaker’s
intentions. In effect, this mechanism is intended to take care of examples where the
lexical approach is faced with an ambiguity in choice of anchors, the same type of
examples that make up the majority of the data that has led to the development of
5 Note that this is all done within the CTT approach in such a way that the descriptive content
that the light is a chandelier is accommodated by adding a new variable to the proof.
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