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Aporiameansadifficulty.Whentalkingofanaporia,andespeciallyofthe
aporiaofflyingarrow,weshouldstickto“difficulty”andnottogravitetowards
“paradox”or“inconsistency.”Aparadoxinvolvesanelementofsurprise.And
whenitcomestoaninconsistency,wemustprovethatitisone.Theaporiaof
thearrowistroublesomebutnosurprising(Figure1).Wecaneliminateitby
claimingthat,inspiteoftheappearanceofrigor,itsreasoninghasgaps.But
weareawarethatthisargumentisjustadodge.Thisdodgehasbeentriedby
somephilosophers.Theproblemremainsaproblem.
Fig.1.Theflyingarrow
WhenponderingZeno3sdifficulty,thefirstconclusionwearriveatisthat
certainsimplenotionsaboutmotionresistrigorousdescription.Accordingto
ourrulesoflogic,oneshouldfaulttheassumptionsofZeno3sreasoningforthe
resultingdifficulty.Clearly,the“guilty”assumptionistheonethatstatesthat
continua1inthiscaseastraightlineandtime1consistsofpoints.2
SomesaythatwhenZeno1perverselyandnotquiteexplicitly1assumed
therealizationoftheinfinitedivisibilityoftimeorofaroadhewantedto
provetheimpossibilityofmotion.Afterall,hewasaParmenides3sdisciple,and
Parmenides,andanotheroneofhisdisciplesMelissus,arguedthatexistenceis
“unchangeableandmotionless.”
Thisisahalftruth.IfonewantstopresenttheideasofParmenides
andtheEleaticphilosophersinanon-trivializingway,thenonehastogo
deeplyintoconceptsknownonlytophilosophers.InParmenides3ssystem
existencewasclosetowhatwethinkofasabsolutespace,thebasisofall
phenomena,andthisbasiswastobemotionlessinprinciple.Thisguarded
againsttheextremepositionofHeraclituswhoclaimedthat“everything
flows.”TheEleaticphilosophersdidnotdenythepossibilityofmotionof
fragmentsofexistence,althoughtheystipulated1asdidMelissus1that
wearedealingwithan“appearanceofmotion,”3astatementwhosemean-
ingtheydidnotexplain.
Wewillnotderiveconclusionsfromtheaporiaoftheflyingarrow,conclu-
sionswemaybeunabletounderstand.
Motionexists,andwewillseekinmathematicalconventionsaconfirma-
tion,ratherthanadenialofitsexistence.WewilltreatZeno3saporiaasan
2“Itfollowsfromthesuppositionthatthetimeiscomposedfromaseriesof“now.”Ifthis
suppositionisnotassumed,theconclusiondoesnotfollow”1Arystoteles,Fizyka[Physics].
Warszawa1968,p.209,BookVI,239b.TranslatedbyAbeShenitzer.Therulesoflogicare
createdatthattimeinsomemodestformthanours.
3AfterDiogenesLaertius,Żywotyipoglądysławnychfilozofów,Warszawa1982,p.530.
TranslatedbyAbeShenitzer.
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