BGOODMAN%BBNG@sri-unix.UUCP (08/28/84)
From: Brad Goodman <BGOODMAN at BBNG>
[Forwarded from the MIT bboard by SASW@MIT-MC.]
Speech Acts as Summaries of Plans
Phil Cohen
SRI International
and
Center for the Study of Language and Information
Stanford University
BBN AI Seminar
10:30 a.m. on Wednesday, September 5th
Third floor large conference room at 10 Moulton St., Cambridge.
Many theories of communication require a hearer to determine what
illocutionary act(s) (IA's) the speaker performed in making each
utterance. This talk will sketch joint work, with Hector Levesque,
that aims to call this presumption into question, at least for some
kinds of illocutionary acts. Such acts will be shown to be definable
on a "substrate" of interacting plans --- i.e., as beliefs about the
conversants' shared knowledge of the speaker's and hearer's goals and
the causal consequences of achieving those goals. In this formalism,
illocutionary acts are no longer conceptually primitive, but rather
amount to theorems that can be proven about a state-of-affairs. The
important point here is that the definition of, say, a request is
derived from an independently-motivated theory of action, rather than
stipulated. Just as one need not determine if a proof corresponds to
a prior lemma, a hearer need not actually characterize the
consequences of each utterance in terms of the IA theorems, but may
simply infer and respond to the speaker's goals. However, the hearer
could retrospectively summarize a complex of utterances as satisfying
an illocutionary act.
This move of defining illocutionary acts in terms of plans may
alleviate a number of technical obstacles in applying speech act
theory to extended discourse. It formally characterizes a range of
indirect requests in terms of conversants' plans, and demonstrates
how certain conventionalized forms can be derived from and integrated
with plan-based reasoning. Finally, it gives a formal foundation to the
view that speech act characterizations of discourse are not
necessarily those of the conversants but rather are the work of the
theorist.