?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Formalization+of+two+Puzzles+Involving+Knowledge&rft.creator=McCarthy%2C+John&rft.subject=Artificial+Intelligence&rft.description=This+paper+describes+a+formal+system+and+uses+it+to+express+the+puzzle+of+the+three+wise+men+and+the+puzzle+of+Mr.+S+and+Mr.+P.+Four+innovations+in+the+axiomatization+of+knowledge+were+required%3A+the+ability+to+express+joint+knowledge+of+several+people%2C+the+ability+to+express+the+initial+non-knowledge%2C+the+ability+to+describe+knowing+what+rather+than+merely+knowing+that%2C+and+the+ability+to+express+the+change+which+occurs+when+someone+learns+something.+Our+axioms+are+written+in+first+order+logic+and+use+Kripke-style+possible+worlds+directly+rather+than+modal+operators+or+imitations+thereof.+We+intend+to+use+functions+imitating+modal+operators+and+taking+%60%60propositions''+and+%60%60individual+concepts''+as+operands%2C+but+we+haven't+yet+solved+the+problem+of+how+to+treat+learning+in+such+a+formalism.&rft.date=1987&rft.type=Preprint&rft.type=NonPeerReviewed&rft.format=application%2Fpostscript&rft.identifier=http%3A%2F%2Fcogprints.org%2F427%2F2%2Fpuzzles.ps&rft.identifier=++McCarthy%2C+John++(1987)+Formalization+of+two+Puzzles+Involving+Knowledge.++%5BPreprint%5D+++++&rft.relation=http%3A%2F%2Fcogprints.org%2F427%2F