[mod.ai] Seminar - Representing Defaults with Epistemic Concepts

VAL@SAIL.STANFORD.EDU.UUCP (02/23/87)

         Commonsense and Nonmonotonic Reasoning Seminar

	 REPRESENTING DEFAULTS WITH EPISTEMIC CONCEPTS

		Kurt Konolige, SRI International
		     Karen Myers, Stanford

		   Thursday, February 26, 4pm
		      Bldg. 160, Room 161K

Reasoning about defaults --- implications that typically hold,
but which may have exceptions --- is an important part of
commonsense reasoning.  We present some parts of a theory of
defaults, concentrating on distinctions between various subtle
ways in which defaults can be defeated, and on the adjudication
of conflicting defaults under hierarchic inheritance.  In order
to represent this theory in a formal system, it seems necessary
to use the epistemic concept of self-belief.  We show how to
express the theory by an almost-local translation into
autoepistemic logic, which contains the requisite epistemic
operators.  Just to be controversial, we also argue that 
circumscription (pointwise, schematic, prioritized, or otherwise)
is insufficient for this task.