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CSLI Calendar, May 5, 3:27


       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
_____________________________________________________________________________
5 May 1988                         Stanford                    Vol. 3, No. 27
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     A weekly publication of The Center for the Study of Language and
     Information, Ventura Hall, Stanford University, Stanford, CA 94305
                              ____________
	      CSLI ACTIVITIES FOR THIS THURSDAY, 5 May 1988

   12 noon		TINLunch
     Ventura Hall       Reading: "Connectionism and Cognitive
     Seminar Room  	Architecture: A Critical Analysis"  
			by Jerry Fodor and Zenon Pylyshyn, 
                        "Cognition," March 1988
			Discussion led by Adrian Cussins
			(cussins.pa@xerox.com)
			Abstract below

   2:15 p.m.		CSLI Seminar
     Cordura Hall	Postponed; see announcement below
     Conference Room	
			
   3:30 p.m.		Tea
     Ventura Hall
                             --------------
	     CSLI ACTIVITIES FOR NEXT THURSDAY, 12 May 1988

   12 noon		TINLunch
     Ventura Hall       Harman's and Cherniak's Leniency on Agent Rationality
     Seminar Room  	Readings:  "Change in View: Principles of Reasoning"
			by Gilbert Harman
                        "Minimal Rationality"
			by Christopher Cherniak
			Discussion led by Ron Loui
			(loui@csli.stanford.edu)
			Abstract below

   2:15 p.m.		CSLI Seminar
     Cordura Hall	What is Logic Programming?  What is a Logic?
     Conference Room	Jose Meseguer
			(meseguer@csl.sri.com)
			Abstract below
			
   3:30 p.m.		Tea
     Ventura Hall

			     --------------
			      ANNOUNCEMENT

   This week's seminar has been postponed due to the illness of the
   speaker, John Perry.  His seminar, "What is Information?," will be
   rescheduled for a later date.
			     --------------
			THIS WEEK'S CSLI TINLUNCH
	   Reading: "Connectionism and Cognitive Architecture:
			  A Critical Analysis"
		   by Jerry Fodor and Zenon Pylyshyn
			  Cognition, March 1988
		    Discussion led by Adrian Cussins
			 (cussins.pa@xerox.com)
				  May 5

   Fodor and Pylyshyn try to impale connectionism on the horns of a
   dilemma: either connectionism is a mere implementation theory, or it
   is a false theory of cognition because it cannot capture the
   systematicity of thought.  Once you adopt Fodor and Pylyshyn's
   perspective, their argument is very powerful.  I will run through
   their argument, and then show how to adopt a different perspective on
   connectionist modeling of cognition by showing how to deny their
   assumption that any psychological theory must model cognition in terms
   of its conceptual structure.  Our question must be: Can we make sense
   of connectionism's claim to model cognition subsymbolically?

			     --------------
			NEXT WEEK'S CSLI TINLUNCH
	  Harman's and Cherniak's Leniency on Agent Rationality
	   Readings: "Change in View: Principles of Reasoning"
	   by Gilbert Harman, chaps. 2 and 3 (MIT Press, 1986)
				   and
			  "Minimal Rationality"
		by Christopher Cherniak (MIT Press, 1986)
  		      Discussion led by Ronald Loui
			(loui@csli.stanford.edu)
				 May 12

   In two short chapters of CHANGE IN VIEW, Gil Harman (1) argues against
   the "special relevance" of logic to reasoning, and (2) dismisses
   normative theories that require (probabilistic) degrees of belief.
   Inconsistency is unavoidable, closure leads to clutter, and sometimes
   implication is immediate, but not logical.  There exists
   all-or-nothing-belief, and "it is too complicated for mere finite
   beings to make extensive use of probabilities."

      Christopher Cherniak is more interested in "how stupid can you be"
   while still being describable as a rational agent.  But he has also
   tried to let the agent off the normative hook.  He argues that a
   condition of MINIMAL RATIONALITY must be fashioned for any
   satisfactory cognitive theorizing.  Only inferences that are
   "feasible" and "apparently appropriate" need be made.

      I will focus on the Harman chapters, but will entertain Cherniak's
   blurring of the descriptive/normative distinction as well.

			     --------------
			NEXT WEEK'S CSLI SEMINAR
	      What is Logic Programming?  What is a Logic?
			      Jose Meseguer
			 (meseguer@csl.sri.com)
				 May 12

   During the past few years at CSLI, Joseph Goguen and I have proposed a
   broad view of logic programming that is open to different logics and
   rejects the identification of logic programming with one of its
   instances.  This point of view has led to the design and
   implementation of the purely functional logic programming language
   OBJ, to the design of the Eqlog language that unifies functional and
   relational programming, and to the FOOPS and FOOPlog languages that
   extend OBJ and Eqlog with object-oriented capabilities.  The
   development of natural language systems can be made much simpler by
   adopting this broad view of logic programming.  Joseph Goguen has
   shown how the Goguen-Burstall theory of institutions can be applied to
   formalize logic programming languages and yields design principles for
   such languages.

      In this talk, I will report on some recent work of mine that builds
   on the previous joint work with Goguen and makes this view axiomatic
   by giving general axioms that a language should satisfy in order to be
   called a logic programming language.  The question of what a logic
   programming language is leads us to the more fundamental question
   about how general logics should be axiomatized.  Two main approaches
   to this question are:
       
    1. A model-theoretic approach that takes the satisfaction relation
       between models and sentences as basic, and is exemplified by the
       Barwise axioms for abstract model theory and the Goguen-Burstall
       axioms for institutions.

    2. A proof-theoretic approach that takes the entailment relation
       between sets of sentences as basic and is exemplified by the work
       of Tarski on consequence relations and the entailment axioms of
       Scott.

   Neither of these approaches is by itself sufficient to axiomatize
   logic programming.  In the talk I will present an axiomatization that
   unifies both approaches and yields the desired axioms for logic
   programming.  I will also discuss how languages based on higher-order
   type theory can be included in this framework.