francisco javier diez bgvpkidiaunedes gzrdaeecsberkeleyedu wrote consider following line reasoning let p proposition ronald born new york p infer q ronald born united states q infer r possible ronald born new jersey hand p infer possible ronald born new jersey arrived contradiction wrong note answer question familiarity modal logic needed dear lofti guess might possible find solution modallogic formalism alternative solution might inspired belief revision default reasoning research ai field instance know q ronald born us conclude r possible born nj conclusion revised might retracted new evidence arrives particular knowing p born ny retract r case conclusions draw must take account available knowledge therefore know q r holds know p q r hold typical example defaultreasoning literature know tweety bird q assume tweety fly r also know tweety penguin p deduce fly r think paradox formally identical tweetys classical example fact subtle difference default reasoning elementary proposition would ronald born new jersey formulation paradox defined r possible ronald born new jersey understood think know ronald born us would possible born nj summary solution paradox might possible mean compatible ie contradictory available evidence therefore possible would contextsensitive ie depending knowledge reason infer using p part available evidence case infer q solve paradox best regards javier díez francisco javier diez phone 34 913987161 dpto inteligencia artificial fax 34 913988895 uned cjuan del rosal 16 email bgvpkidiaunedes 28040 madrid spain httpwwwiaunedesfjdiez _______________________________________________ uai mailing list faqengrorstedu httpssecureengroregonstateedumailmanlistinfouai tue 05 aug 2008 112851 0200 uai paradox