[Prev][Next][Index]

CSLI Calendar, 18 January 1990, 5:13


       C S L I   C A L E N D A R   O F   P U B L I C   E V E N T S
-----------------------------------------------------------------------------
18 January 1990                     Stanford                   Vol. 5, No. 13
_____________________________________________________________________________

    A weekly publication of the Center for the Study of Language and
Information (CSLI), Ventura Hall, Stanford University, Stanford, CA 94305-4115
			     ____________

          CSLI ACTIVITIES FOR THIS THURSDAY, 18 JANUARY 1990

12:00 noon		TINLunch
      Cordura 100	Twenty-five Basic Theorems in Situation Theory
			Ed Zalta
			(zalta@csli.stanford.edu)
			Abstract in last week's Calendar
			     ____________

	  CSLI ACTIVITIES FOR NEXT THURSDAY, 25 JANUARY 1990

12:00 noon		TINLunch
      Cordura 100	The Role of Central Conceptual Structures in the
		        Development of Scientific and Mathematical Thought
			Robbie Case
			School of Education, Stanford University
			(ka.rob@forsythe.stanford.edu)
			Abstract below

 2:15 p.m.
      Cordura 100	CSLI Seminar
			HPSG from Afar
			Paul John King
			CSLI Postdoctoral Fellow
			(pjking@csli.stanford.edu)
			Abstract below
			     ____________

			 NEXT WEEK'S TINLUNCH
	      The Role of Central Conceptual Structures
      in the Development of Scientific and Mathematical Thought
			     Robbie Case

Piaget's structuralist view of human cognition is now considered
outmoded by most developmental theorists, both on rational and on
empirical grounds.  One aspect of the position is still important,
however, and has not been adequately tested.  This is the view that
human thought is both constrained and potentiated by cognitive
structures that do not have their origin either directly in our
empirical experience (as empiricist epistemology would hold), or
indirectly via the internalization of conceptual systems and skills
(as sociocultural epistemology would hold).  According to Piaget,
these cognitive structures have their origin in the structure of
children's spontaneous mental operations, which is then abstracted and
subsequently serves to constrain what children acquire from their
physical or cultural experience.  Some new data are presented that are
of relevance to this general claim, and it is shown that the data are
compatible with a slightly weaker version of the structuralist
hypothesis than Piaget originally formulated.
			     ____________

		       NEXT WEEK'S CSLI SEMINAR
			    HPSG from Afar
			    Paul John King

In this informal seminar, I will outline SRL (Speciate Re-entrant
Logic), a "classical," semantically transparent, and (above all else!)
simple formalism that lets unification-based grammarians work safely
within the bounds of their intuitions.  If time permits, I will
discuss HPSG's existing formalism and throw in a few observations I've
made of the unification-based enterprise.  Please note: the maths
content will (I hope!) be simple, almost to the point of vacuity.
			     ____________

		 SEMINAR ON ISSUES IN LOGICAL THEORY
			    Philosophy 396
		Approaches to the Liar Paradox, Part I
		 John Etchemendy and Solomon Feferman
	  (etch@csli.stanford.edu and sf@csli.stanford.edu)
		 Thursday, 18 January, 3:45-5:30 p.m.
			     Cordura 100
		(Please note new day, time, and room!)

We will explain parts of the work by Kripke, Martin and Woodruff, van
Fraassen, Gupta and Herzberger (a little), Aczel, Feferman, and
perhaps others.  It will not be tied directly to chapter IV.10 of the
_Handbook of Philosophical Logic_. 

Next week's topic is "Approaches to the Liar Paradox, Part II."
			     ____________

			SYMBOLIC SYSTEMS FORUM
		      Affordances for Reasoning
			     James Greeno
			(greeno.pa@xerox.com)
		   Thursday, 18 January, 4:15 p.m.
			Building 60, Room 62A

General concepts are often equated with their abstract
representations, but a representation doesn't provide generality
unless it is interpreted successfully.  An example is the concept of
linear functions, studied in high-school algebra, which is often
taught in a real-life version of Searle's "Chinese Room."  I'll report
progress on some research on situated reasoning about linear
functions, present a theory about how the situation supports the
reasoning, and describe a study about linear equations in this
setting.
         
IMPORTANT NOTE: The Symbolic Systems Forum will be meeting at a new
time and a new place this quarter.  We hope that meeting on Thursdays
at 4:15 p.m. will allow more people to attend.  If you have comments
about the time change, please address them to the forum chair,
Jennifer Cotteleer (jac@jessica).  Room 62A is on the second floor of
building 60.
			     ____________

	       SEMINAR ON ISSUES IN LOGICAL THEORY, II
			Organizational Meeting
			     Greg O'Hair
		  Flinders University, visiting CSLI
		      (ohair@csli.stanford.edu)
		    Friday, 19 January, 2:15 p.m.
 			     Cordura 104

This seminar will consist of an examination of the standard account of
logical consequence by way of a detailed reading of John Etchemendy's
forthcoming book, _The Concept of Logical Consequence_.  The first
meeting will be an organizational meeting to determine an acceptable
meeting time.  If you are interested in attending, but cannot make the
first meeting, get in touch with Greg O'Hair prior to the meeting.

Students will be able to take this seminar for credit.
			     ____________

	    COMMONSENSE AND NONMONOTONIC REASONING SEMINAR
		Logic Programs with Classical Negation
			  Vladimir Lifschitz
		    Department of Computer Science
			 Stanford University
		       (val@sail.stanford.edu)
		    Monday, 22 January, 2:30 p.m.
		       Margaret Jacks Hall 252
		       (Please note new time!)

General logic programs are further generalized by including classical
negation, in addition to negation-as-failure.  The semantics of such
"extended" programs is based on the method of stable models.  We show
that some facts of commonsense knowledge can be represented by logic
programs more easily when classical negation is available.
Computationally, classical negation can be eliminated from extended
programs by a simple preprocessor.  Extended programs are identical to
a special case of default theories in the sense of Reiter.

This is joint work with Michael Gelfond.  If time permits, related
work of Robert Kowalski and Fariba Sadri on "logic programs with
exceptions" will be also reviewed.
			     ____________

			   SYNTAX WORKSHOP
			     Lars Hellan
		    Monday, 22 January, 7:30 p.m.
			     Cordura 100

No abstract available.
			     ____________

		     SITUATION SEMANTICS SEMINAR
			   Informativeness
			  Jonathan Ginzburg
		     (ginzburg@csli.stanford.edu)
		   Wednesday, 24 January, 3:30 p.m.
			     Cordura 100

By postulating his conversational maxims, Grice hoped to be able to
explain why at a given point in a discourse, a given conversational
contribution was made.  In this talk, I will examine two of those
maxims, Quantity and Relevance, focusing on explicating the notion of
"informativeness," which underlies any formulation of the maxim of
Quantity.  I will argue that understandings of the notion of
informativeness, or relevance, in various current pragmatic
frameworks, as entailment, the metric utilized by the "Neo Griceans"
(Horn 1972, Gazdar 1979, Atlas and Levinson 1981, Levinson 1987), or
"relevance," in the sense of Sperber and Wilson 1986 are inadequate
for the task of predicting utterance choice, with concomitant problems
when applied to explain other pragmatic phenomena, such as
implicature.  I will advance an alternative explication of
informativeness, unifying concerns arising both from "relevance" and
"strength of information," and utilizing situation theory as the
underlying logic.  I will argue for the need to recognize a
"two-dimensional" ordering on (information containment of) epistemic
states, that recognizes both "strength of information" and "degree of
anchoring of parameters."  I will illustrate how a revised theory of
implicature can be constructed and show how this could be applied to
deal with cases of polysemy which the classical Gricean theory is ill
equipped to handle.