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Doksastichna logika tip logiki predmetom yakoyi ye rozmirkovuvannya pro viru Termin doksastichna pohodit vid starogreckogo slova do3a doksa sho oznachaye vira Tipovo doksastichna logika vikoristovuye poznachennya B x displaystyle mathcal B x dlya vislovlyuvannya viriti v te sho maye misce x displaystyle x i poznachennya B displaystyle mathbb B dlya mnozhini viruvan Doksastichna logika traktuye viru yak modalnij operator B b 1 b n displaystyle mathbb B left b 1 ldots b n right Isnuye povna vidpovidnist mizh viroyu osobi v pevni vislovlyuvannya j formalnoyu sistemoyu sho vivodit ci vislovlyuvannya Vikoristovuyuchi doksastichnu logiku mozhna sformuyuvati epistemichna vidpovidniki teoremi Gedelya pro nepovnotu metalogiki a takozh teoremu Leba ta inshi rezultati metalogiki u terminah viri 1 Zmist 1 Tipi rozmirkovuvachiv 2 Rozmirkovuvachi za zrostannyam racionalnosti 3 Nepovnota za Gedelem ta doksastichna nevishenist 4 Netochnist ta divnist samodura 5 Viruvannya sho stverdzhuyutsya avtomatichno 6 Neposlidovnist viri u vlasnu stabilnist 7 Div takozh 8 Posilannya 9 LiteraturaTipi rozmirkovuvachiv red Shob prodemonstruvati vlastivosti mnozhin viruvan Rejmond Smallian viznachaye taki tipi rozmirkovuvachiv Tochnij rozmirkovuvach 1 2 3 4 ne virit u zhodne neistinne vislovlyuvannya Modalna aksioma T p B p p displaystyle forall p mathcal B p to p nbsp dd Netochnij rozmirkovuvach 1 2 3 4 virit prinajmni v odne neistinne vislovlyuvannya p p B p displaystyle exists p neg p wedge mathcal B p nbsp dd Samodur 1 4 virit sho jogo viruvannya zavzhdi istinni B p p B p displaystyle mathcal B neg exists p neg p wedge mathcal B p quad text quad nbsp abo B p B p p displaystyle quad text quad mathcal B forall p mathcal B p to p nbsp dd Samodur iz racionalnistyu prinajmni tipu 1 divitsya nizhche z neodminnistyu vpade v netochnist Poslidovnij rozmirkovuvach 1 2 3 4 nikoli odnochasno ne virit tverdzhennyu ta jogo zaperechennyu modalna aksioma D p B p B p displaystyle neg exists p mathcal B p wedge mathcal B neg p quad text quad nbsp abo p B p B p displaystyle quad text quad forall p mathcal B p to neg mathcal B neg p nbsp dd Normalnij rozmirkovuvach 1 2 3 4 viryachi tverdzhennyu p displaystyle p nbsp takozh virit sho vin virit p modalna aksioma 4 p B p B B p displaystyle forall p mathcal B p to mathcal BB p nbsp dd Divnij rozmirkovuvach 1 4 virit u tverdzhennya p displaystyle p nbsp i vodnochas virit sho vin ne virit u p displaystyle p nbsp Hocha vin mozhe zdatisya divnim psihologichnim fenomenom divitsya Paradoks Mura divnij rozmirkovuvach z neobhidnistyu netochnij ale ne obov yazkovo neposlidovnij p B p B B p displaystyle exists p mathcal B p wedge mathcal B neg B p nbsp dd Regulyarnij rozmirkovuvach 1 2 3 4 viryachi p q displaystyle p to q nbsp takozh virit B p B q displaystyle mathcal B p to mathcal B q nbsp p q B p q B B p B q displaystyle forall p forall q mathcal B p to q to mathcal B mathcal B p to mathcal B q nbsp dd Refleksivnij rozmirkovuvach 1 4 toj dlya kogo dlya kozhnogo tverdzhennya p displaystyle p nbsp isnuye tverdzhennya q displaystyle q nbsp take sho vin virit q B q p displaystyle q equiv mathcal B q to p nbsp p q B q B q p displaystyle forall p exists q mathcal B q equiv mathcal B q to p nbsp dd Yaksho refleksivnij rozmirkovuvach tipu 4 divitsya nizhche virit B p p displaystyle mathcal B p to p nbsp vin viritime p Ce analog teoremi Leba dlya rozmirkovuvachiv Nestabilnij rozmirkovuvach 1 4 toj hto virit sho vin virit deyakomu tverdzhennyu ale naspravdi vin comu tverdzhennyu ne virit Ce ne mensh divno yak u vipadku divnogo rozmirkovuvacha odnak nestabilnij rozmirkovuvach ne obov yazkovo neposlidovnij p B B p B p displaystyle exists p mathcal B mathcal B p wedge neg mathcal B p nbsp dd Stabilnij rozmirkovuvach 1 4 ne ye nestabilnim Tobto dlya kozhnogo p displaystyle p nbsp yakomu vin virit B p displaystyle mathcal B p nbsp vin virit takozh p displaystyle p nbsp Stabilnist obernena normalnosti Kazhut sho rozmirkovuvach virit sho vin stabilnij yaksho dlya bud yakogo tverdzhennya p displaystyle p nbsp vin virit B B p B p displaystyle mathcal B mathcal B p to mathcal B p nbsp tobto Yakbi ya viriv sho ya viryu p displaystyle p nbsp todi b ya naspravdi viriv p displaystyle p nbsp p B B p B p displaystyle forall p mathcal BB p to mathcal B p nbsp dd Skromnij rozmirkovuvach 1 4 vvazhaye sho dlya bud yakogo tverdzhennya p displaystyle p nbsp v yake vin virit B p p displaystyle mathcal B p to p nbsp tilki todi koli vin virit u p displaystyle p nbsp Skromnij rozmirkovuvach nikoli ne virit B p p displaystyle mathcal B p to p nbsp yaksho tilki vin ne virit p displaystyle p nbsp Bud yakij refleksivnij rozmirkovuvach tipu 4 skromnij Teorema Leba p B B p p B p displaystyle forall p mathcal B mathcal B p to p to mathcal B p nbsp dd Shiblenij rozmirkovuvach 4 ye rozmirkovuvachem tipu G i virit sho vin neposlidovnij ale tut vin pomilyayetsya Sorom yazlivij rozmirkovuvach 4 ne virit u p displaystyle p nbsp boyitsya viriti v p displaystyle p nbsp yaksho virit sho B p B displaystyle mathcal B p to mathcal B bot nbsp Rozmirkovuvachi za zrostannyam racionalnosti red Rozmirkovuvach tipu 1 1 2 3 4 5 povnistyu znaye propozicijnu logiku tobto vin rano chi pizno povirit u kozhnu tavtologiyu bud yake tverdzhennya sho jogo mozhna dovesti tablicyami istinnosti Krim togo mnozhina jogo viruvan minulih teperishnih chi majbutnih logichno zamknuta za modus ponens Yaksho vin virit u p displaystyle p nbsp ta p q displaystyle p to q nbsp todi vin rano chi pizno povirit q displaystyle q nbsp P C p B p displaystyle vdash PC p Rightarrow vdash mathcal B p nbsp p q B p B p q B q displaystyle forall p forall q mathcal B p wedge mathcal B p to q to mathcal B q nbsp dd Ce pravilo mozhna rozumiti yak tverdzhennya sho vira rozpodilyayetsya implikaciyeyu oskilki vono logichno ekvivalentne p q B p q B p B q displaystyle forall p forall q mathcal B p to q to mathcal B p to mathcal B q nbsp dd Rozmirkovuvach tipu 1 1 2 3 4 virit u vsi tavtologiyi jgo viruvannya kolishni teperishni j majbutni logichno zamknuti za modus ponens i dlya bud yakih vislovlyuvan p displaystyle p nbsp ta q displaystyle q nbsp yaksho vin virit p q displaystyle p to q nbsp todi povirit sho yaksho vin virit p displaystyle p nbsp todi vin povirit q displaystyle q nbsp Rozimrkovuvach tipu 1 trishechki svidomishij svoyih viruvan nizh rozmirkovuvach tipu 1 p q B p q B B p B q displaystyle forall p forall q mathcal B p to q to mathcal B mathcal B p to mathcal B q nbsp dd Rozmirkovuvach tipu 2 1 2 3 4 ye rozmirkovuvachem tipu 1 i dlya kozhnih p displaystyle p nbsp j q displaystyle q nbsp vin pravilno virit Yaksho ya koli nebud viritimu yak p displaystyle p nbsp tak i p q displaystyle p to q nbsp todi ya poviryu q displaystyle q nbsp Oskilki vin tipu 1 vin takozh virit logichno ekvivalentnim vislovlyuvannyam B p q B p B q displaystyle mathcal B p to q to mathcal B p to mathcal B q nbsp Rozmirkovuvach tipu 2 znaye sho jogo viruvannya zamkneni za modus ponens p q B B p B p q B q displaystyle forall p forall q mathcal B mathcal B p wedge mathcal B p to q to mathcal B q nbsp dd Rozmirkovuvach tipu 3 1 2 3 4 ye normalnim rozmirkovuvachem tipu 2 p B p B B p displaystyle forall p mathcal B p to mathcal B mathcal B p nbsp dd Rozmirkovuvach tipu 4 1 2 3 4 5 ye rozmirkovuvachem tipu 3 a krim togo virit sho vin normalnij B p B p B B p displaystyle mathcal B forall p mathcal B p to mathcal B mathcal B p nbsp dd Rozmirkovuvach tipu G 1 4 ye rozmirkovuvachem tipu 4 a krim togo virit sho vin skromnij B p B B p p B p displaystyle mathcal B forall p mathcal B mathcal B p to p to mathcal B p nbsp dd Nepovnota za Gedelem ta doksastichna nevishenist red Nehaj pered tochnim rozmirkovuvachem stoyit zavdannya viznachennya istinnosti deyakogo vislovlyuvannya Sered usih vislovlyuvan isnuyut taki shodo yakih rozmirkovuvach musit abo zalishatisya nazavzhdi neviznachenim abo postupitisya tochnistyu Odin iz prikladiv zadayetsya tverdzhennyam S Ya nikoli ne poviryu comu dd Yaksho rozmirkovuvach koli nebud povirit tverdzhennyu S displaystyle S nbsp cej fakt jogo sprostuye i S displaystyle S nbsp stane neistinnoyu viroyu a otzhe rozmirkovuvach viryachi S stane netochnim Otzhe oskilki rozmirkovuvach tochnij vin ne mozhe poviriti S displaystyle S nbsp Tobto tverdzhennya istinne bo vono progoloshuye te sho vidpovidaye dijsnosti Dali rozmirkovuvach nikoli ne matime nepravilnogo viruvannya sho S displaystyle S nbsp neistinne Tozh rozmirkovuvach nikoli ne zmozhe viznachitisya shodo istinnosti S displaystyle S nbsp Ekvivalentna teorema stverdzhuye sho u bud yakij formalnij sistemi F isnuye matematichne tverdzhennya yake mozhna prointerpretuvati yak Ce tverdzhennya ne mozhna dovesti v formalnij sistemi F Yaksho sistema F poslidovna to ni ce tverdzhennya ni protilezhne jomu ne dovoditsya v nij 1 4 Netochnist ta divnist samodura red Nehaj pered rozmirkovuvachem tipu 1 postalo tverdzhennya Ya nikoli ne poviryu comu rechennyu Todi os sho cikavo yaksho rozmirkovuvach virit sho vin tochnij to vin staye netochnim Takij rozmirkovuvach mirkuvatime Tverdzhennya peredi mnoyu stverdzhuye sho ya nikoli jomu ne poviryu otzhe yaksho vono nepravilne ya jomu poviryu Oskilki ya tochnij to moya vira oznachaye sho vono musit buti istinnim tobto yaksho vono nepravilne to ya poviryu comu tverdzhennyu Oskilki ya tochnij vira v tverdzhennya oznachaye sho vono musit buti istinnim Otzhe yaksho ce tverdzhennya nepravda to vono musit buti istinnim Yaksho pripushennya sho tverdzhennya nepravda vede do samogo tverdzhennya to ce tavtologiya otzhe tverdzhennya istinne U cyu mit rozmirkovuvach poviriv u tverdzhennya vsuperech tomu sho vono stverdzhuye Tverdzhennya staye nepravdoyu Tak vihodit sho rozmirkovuvach netochnij viryachi sho tverdzhennya istinne Yakbi rozmirkovuvach ne pripustiv vlasnoyi tochnosti to vin nikoli b ne vpav u taku netochnist Formalno 1 S B S displaystyle 1 S equiv lnot mathcal B S nbsp viznachennya S displaystyle S nbsp 2 S S S displaystyle 2 lnot S to S to S nbsp elementarna tavtologiya 3 B S S S displaystyle 3 mathcal B S to S to S nbsp oskilki S B S displaystyle lnot S equiv mathcal B S nbsp 4 B B S S S displaystyle 4 mathcal B mathcal B S to S to S nbsp rozmirkovuvach virit u tavtologiyi 5 B B S S B S displaystyle 5 mathcal B mathcal B S to S to mathcal B S nbsp rozmirkovuvach nalezhit do tipu 1 6 B B S S displaystyle 6 mathcal B mathcal B S to S nbsp rozimkovuvach samodur 7 B S displaystyle 7 mathcal B S nbsp modus ponens 5 ta 6 8 S displaystyle 8 lnot S nbsp oskilki B S S displaystyle mathcal B S equiv lnot S nbsp Krim togo rozmirkovuvach divnij oskilki virit sho vin ne virit tverdzhennyu u simvolah B B S displaystyle mathcal B lnot mathcal B S nbsp sho sliduye z B S displaystyle mathcal B S nbsp oskilki S B S displaystyle S equiv lnot mathcal B S nbsp navit todi yak vin vlasne virit jomu Viruvannya sho stverdzhuyutsya avtomatichno red Nehaj refleksivnist sistemi oznachaye sho dlya bud yakogo p displaystyle p nbsp movoyu sistemi isnuye q displaystyle q nbsp take sho q B p p displaystyle q equiv mathcal B p to p nbsp dovoditsya u sistemi Teorema Leba v zagalnij formi stverdzhuye sho dlya bud yakoyi reflektivnoyi sistemi tipu 4 yaksho B p p displaystyle mathcal B p to p nbsp dovoditsya v sistemi to p displaystyle p nbsp tezh dovoditsya 1 4 Neposlidovnist viri u vlasnu stabilnist red Yaksho poslidovnij rozmirkovuvach tipu 4 virit sho vin stabilnij vin staye nestabilnim Inshimi slovami yaksho stabilnij refleksivnij rozmirkovuvach tipu 4 virit sho vin stabilnij to vin staye neposlidovnim Chomu Nehaj stabilnij refleksivnij rozmirkovuvach tipu 4 virit sho vin stabilnij Bude pokazano sho rano chi pizno vin povirit usim tverdzhennyam p displaystyle p nbsp i tak stane neposlidovnim Vizmit bud yake tverdzhennya p displaystyle p nbsp Rozmirkovuvach virit B B p B p displaystyle mathcal B mathcal B p to mathcal B p nbsp otzhe za teoremoyu Leba vin povirit B p displaystyle mathcal B p nbsp oskilki vin virit B r r displaystyle mathcal B r to r nbsp de r displaystyle r nbsp stverdzhuye B p displaystyle mathcal B p nbsp tozh vin povirit r displaystyle r nbsp sho ye tverdzhennyam B p displaystyle mathcal B p nbsp Oskilki vin stabilnij vin povirit p displaystyle p nbsp 1 4 Div takozh red Pereglyad viruvan Modalna logikaPosilannya red a b v g d e zh i k l m n p r s t u f h c sh Smullyan Raymond M 1986 Logicians who reason about themselves Proceedings of the 1986 conference on Theoretical aspects of reasoning about knowledge Monterey CA Morgan Kaufmann Publishers Inc San Francisco CA pp 341 352 a b v g d e zh i k l https web archive org web 20070930165226 http cs wwc edu KU Logic Book book node17 html Belief Knowledge and Self Awareness nedostupne posilannya z 01 06 2016 a b v g d e zh i k l https web archive org web 20070213054220 http moonbase wwc edu aabyan Logic Modal html Modal Logics nedostupne posilannya z 01 06 2016 a b v g d e zh i k l m n p r s t u f h c sh sh Smullyan Raymond M 1987 Forever Undecided Alfred A Knopf Inc a b Rod Girle Possible Worlds McGill Queen s University Press 2003 ISBN 0 7735 2668 4 ISBN 978 0773526686Literatura red Lindstrom St Rabinowicz Wl 1999 DDL Unlimited Dynamic Doxastic Logic for Introspective Agents Erkenntnis 51 2 3 353 385 doi 10 1023 A 1005577906029 Linski L 1968 On Interpreting Doxastic Logic Journal of Philosophy 65 17 500 502 JSTOR 2024352 Segerberg Kr 1999 Default Logic as Dynamic Doxastic Logic Erkenntnis 50 2 3 333 352 doi 10 1023 A 1005546526502 Wansing H 2000 A Reduction of Doxastic Logic to Action Logic Erkenntnis 53 1 2 267 283 doi 10 1023 A 1005666218871 Otrimano z https uk wikipedia org w index php title Doksastichna logika amp oldid 38178384