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Forthcomingin:PacificPhilosophicalQuarterlyThedefinitiveversionwillbeavailableatwww.wileyonlinelibrary.com
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ILLUSIONSOFOPTIMALMOTION,RELATIONISM,ANDPERCEPTUALCONTENT
BY
SANTIAGOECHEVERRI
Abstract:Austererelationismrejectstheorthodoxanalysisofhallucinationsandillusionsasincorrectperceptualrepresentations.Inthispaper,Iarguethatillusionsofoptimalmotion(IOMs)presentaseriouschallengeforthisview.First,Isubmitthataustere-relationistaccountsofmisleadingexperiencescannotbeadaptedtoaccountforIOMs.Second,IshowthatanyattemptatelucidatingIOMswithinanaustere-relationistframeworkunderminestheclaimthatperceptualexperiencesfundamentallyinvolverelationstomind-independentobjects.Third,IdeveloparepresentationalistmodelofIOMs.Theproposedanalysiscombinestwoideas:Evans’(1981)dynamicmodesofpresentationandFine’s(2007)relationalsemanticsforidentity.
Keywords:Perceptualcontent,naïverealism,illusion,hallucination,phiphenomenon,apparentmotion,objectperception.
Acentralquestionincontemporaryphilosophyofperceptioniswhether
representationalcontentsmustfigureinananalysisofthestructureofperceptual
experiences.Therearetwoprominentresponsestothisquestion.Austererelationism
holdsthatrepresentationalcontentsareunnecessaryforanalyzingthestructureof
perceptualexperiences.Italsoholdsthatperceptualexperiencesfundamentallyinvolve
relationstomind-independentobjectssuchastrees,tables,andstones(Antony2011;
Brewer2011,forthcoming;Campbell2002,2009,2014;Genone2014;Johnston2014;
Raleigh2015;Travis2004).Representationalism,bycontrast,holdsthat
representationalcontentsarenecessaryforanalyzingthestructureofperceptual
experiences(Burge2010;Byrne2009;Peacocke1992;Searle1983;Siegel2010;Pautz
2010,2011).1
Misleadingexperienceshaveoftenbeencitedinsupportofrepresentationalism.
Onthisaccount,misleadingexperiencesareincorrectperceptualrepresentations.
Defendersofaustererelationismhavechallengedthisassumption,though.Somehave
arguedthatrepresentationalismprovidesaninadequateaccountofhallucinationsand
illusions(Brewer2011;Campbell2014;Johnston2014),whileothershaveclaimedthat
itmischaracterizesthephenomenologyofperceptualexperiences(Raleigh2015;Travis
2004).Anumberofphilosophershaveevenputforwardaccountsofmisleading
experiencesthatdonotintroduceperceptualcontents(Antony2011;Brewer2011,
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forthcoming;Campbell2014;Fish2009;Genone2014;Kalderon2011;Martin2004,
2006).2
Thegoalofthispaperistoexaminearatherneglectedclassofmisleading
experiencesthatpresentsaseriouschallengeforaustererelationism.Icallthem—
followingMaxWertheimer(1912)—‘illusionsofoptimalmotion’(IOMs).Theseare
experiencesofapparentmotioninwhichsubjectsreportoneobjectmovingfromone
locationtoanotherwhen,infact,therearetwostationaryobjects.Interestingly,these
casesdonotclearlyfitintotheorthodoxphilosophicaldichotomyofhallucinationsand
illusions.
IshallarguethataustererelationismcannotadequatelyaccountforIOMs.In
addition,anyattemptataccountingforthesecaseswithoutintroducingperceptual
contentsthreatenstheaustere-relationistclaimthatrelationstomind-independent
objectsconstitute“themostfundamentalcharacterizationofourexperience”(Brewer
2011:92;seealso:62-3).Iprovidethreeargumentsinfavoroftheseclaims.
First,theaustere-relationistaccountofhallucinationscannotbegeneralizedto
IOMsbecauseitisonlytailoredfortotalhallucinations.Indeed,ifoneappliesthe
austere-relationistaccountofhallucinationstoIOMs,oneisledtoneglector
mischaracterizethecontributionoftheexternalworldtotheirphenomenalcharacter.
Second,theaustere-relationistaccountofillusionscannotbegeneralizedtoIOMs
becauseperceptualrelationstophysicalobjectsdonotconstituteanadequatebasisto
groundtheirphenomenalcharacter.Indeed,therearegoodreasonstoholdthatthe
itemsinvolvedinIOMsarenotsuccessfullyperceived.
Third,ifoneinsistsonprovidinganaustere-relationistaccountofIOMs,onehas
tocharacterizethesubjectasbeingperceptuallyrelatedtoentitiesotherthanmind-
independentobjects.Withsomeadditionalassumptions,thisconclusionunderminesthe
austere-relationistclaimthatrelationstomind-independentobjectsofferthemost
fundamentalcharacterizationofperceptualexperiences.
Intheremainderofthepaper,Idevelopanaccountofperceptualcontent
designedtoaccountforIOMsand,moregenerally,forourexperienceofobjectsas
persistingovertime.Ontheproposedview,whenasubjectispreytoanIOM,she
misrepresentsphasesofnumericallydifferentobjectsasphasesofthesameobject.By
contrast,whenasubjectperceivesanobjectaspersistingovertime,shecorrectly
representsphasesofoneobjectasphasesofthesameobject.Thisaccountcombinestwo
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ideas:Evans’(1981)insightthatperceptualtrackingrequiresdynamicmodesof
presentationandFine’s(2007)relationalsemanticsforidentity.Asitturnsout,the
proposedviewdiffersfromotherFregeanaccountsthatintroducedereordedicto
modesofpresentation.
Thepaperfallsintosevensections.Sections1to3setoutthetermsofthedebate:
IintroduceIOMs(Section1),defendmydescriptionofthem(Section2),anddefine
austererelationism(Section3).Next,Iexaminethetwomainstrategiesavailableto
austererelationismtoaccountforIOMs:accountsthattreatthemashallucinations
(Section4)andaccountsthatassimilatethemtoillusions(Section5).InSection6,I
sketchanaccountofperceptualcontentthatelucidatesIOMsand,moregenerally,our
experienceofobjectsaspersistingovertime.Iconcludewithsomeimplicationsofthe
proposedaccountforthebroaderdebateonthestructureofperceptualexperiences
(Section7).
1. IllusionsofOptimalMotion
Illusionsofoptimalmotion(IOMs)belongtothebroadclassofexperiencesof
apparentmotion.Intheso-calledϕphenomenon,twonumericallydifferentimagesa
andb(e.g.twodots)areprojectedatdifferentlocationslaandlbatdifferenttimes.
Wertheimer(1912:32-3)introducedϕasavariableforanyeventthattakesplace
betweenlaandlbduringthetemporalintervalthatmediatesthepresentationofaandb.
Withlongintervals,observershaveanexperienceasofthesuccessionoftwodifferent
images.Withveryshortintervals,theyhaveanexperienceasoftwoimagespresented
simultaneously.Theinterestingphenomenaoccurwhentheintervalsliebetweenthe
longandtheveryshortones.Inthesecases,mostobserversreportanexperienceasof
movementbetweenlaandlb.Sincethereisnomovement,allthesecasesinvolve
apparentmotion.Apparentmotioncantakedifferentforms.Insomecases,the
movementis‘dual’:onecanhaveanexperienceasofamovingalittlebittowardb,then
disappearing,andthenanotherexperienceasofbstartingitsmovementjustafterthe
midpointthatseparatesafrombuptolb.Inothercases,observersreportanexperience
asofwhatWertheimercalls‘optimal’or‘definite’motion.Ashemakesclear,thesecases
are“exactlyaswouldbeexperiencedwhenviewinganobjectthatactuallymovesfrom
onelocationtoanother”(Wertheimer1912:7).3
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OnereasonwhyIOMsaretheoreticallychallengingisthattheydonotseemtofit
intothephilosophicaldichotomyofhallucinationsandillusions.Indeed,theyseemto
havefeaturesofbothtypesofmisleadingexperiences.4
Ontheorthodoxview,ahallucinationisacaseinwhichasubjecthasan
experienceasofanitemandthatitemisnotthere.Thus,FionaMacphersonwrites:
Whenphilosopherstalkofhallucinations,theytypicallyimaginecasesinwhichone’sperceptual
experienceiscompletelyhallucinatory.Thatis,theyimaginethatoneisseeingnothingandthat
eachelementofone’sperceptualexperienceishallucinatory(Macpherson2013:8).
Similarly,JohnCampbellpointsout:
Thephilosophers’ideaofahallucination(asopposedtotheempiricalphenomenonof
hallucination)istheideaofamentalstatethatisintrinsicallyjustlikeseeingsomething,but
withouttheexternalworldbeingthere(Campbell2014:92).5
Consideraparadigmaticexampleofaphilosophicalhallucination.Supposethat
Macbeth’svisualcortexisstimulatedinexactlythesamewayinwhichitisactivated
whenheisseeingadaggerinfrontofhim.Inthiscase,hecouldhaveanexperiencethat
exactlymatchesasuccessfulvisualexperienceasofadaggerinfrontofhim.Contraryto
thiscase,however,IOMsarenotproducedbydirectlystimulatingtheperceptualsystem
butbypresentingsomedistalitemsatsomelocationsandseparatedbysometemporal
intervals.Thus,thereisasenseinwhichtheseexperiencesarenotcompletely‘empty’.
Theworldoutthereseemstoplayadecisiverole.Whatgoeswrongisthecardinalityof
theitemsthatseemtobepresentedinthescene.Insteadofhavinganexperienceasof
twodots,thesubjecthasanexperienceasofonedotmovingfromonelocationto
another.
Theorthodoxviewalsotellsusthatanillusionisanexperienceinwhicha
perceivedobjectseemstoinstantiateapropertyitdoesnotinstantiate.Thus,Bill
Brewerwrites:
Inanillusionaphysicalobject,o,looksF,althoughoisnotactuallyF(Brewer2011:64).
Similarly,MichaelTyesubmits:
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[I]ncasesofillusiontheperceivedobjectappearsotherthanitis.Insuchcases[…]theobjectis
notasitappearstobe(Tye2011:172-3).6
TheMüller-Lyerdiagramisanillusioninphilosophers’sensebecausethetwo
mainsegmentsseemtoinstantiateapropertytheydonothave.Thesegmentwith
outward-extendingslashesseemstobelongerthanthesegmentwithinward-extending
slashes.Yet,theformerdoesnotinstantiatethepropertyofbeinglongerthanthelatter.
InIOMs,subjectscertainlyexperienceatleastonepropertythatisnotinstantiatedin
theworld:motion.Nevertheless,thisdoesnotseemtobesufficienttoclassifyitasan
illusioninthetraditionalsenseofthattermbecauseitisunclearwhattheobjectof
perceptionis.WhileBrewer’sandTye’sdefinitionsrequirethataperceivedobjectlook
orappearotherthanitis,thisconditiondoesnotseemtobesatisfiedinIOMs,wherethe
subjectgetsthenumericalidentityofthedotswrong.7
Althoughthefirststudiesontheϕphenomenonwerecarriedoutmorethana
centuryago,thisphenomenonhasplayedarathermarginalroleincontemporary
philosophyofperception.8ItcertainlyplayedaroleinGoodman’s(1978)argumentfor
constructivismandinDennett’s(1991)defenseofthemultipledrafttheoryof
consciousness.Illusionsofapparentmotionhavealsoplayedaroleinrecentworkon
temporalexperience(e.g.,Dainton2000;Grush2008).Nevertheless,thefactthatthey
donotseemtofitintothephilosophicaldichotomyofhallucinationsandillusionshas
notreceivedsufficientattentionincontemporaryworkonthestructureofperceptual
experiences.Idothink,however,thatthisveryfactmakesthemideallysuitedtotestthe
availableviewsonthestructureofperceptualexperiences.9
Iwillarguethataustererelationismlacksthetheoreticalresourcestoaccountfor
IOMswhileremainingfaithfultoitsmainmotivation:toassignafundamentalroleto
perceptualrelationstomind-independentobjectsinanaccountofthephenomenal
characterofperceptualexperiences.Hence,wehavegoodreasonstorevisethisclaim
andpositperceptualcontents.BeforeIpresentmyarguments,letmedefendthe
previousdescriptionofIOMsasinvolvingnumericalidentity.
2. TheIdentityInterpretationDefended
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Inthissection,IdefendmydescriptionofIOMsasinvolvingnumericalidentity.
Tothisend,Iexamineandrejecttwoalternativecharacterizations.
2.1. IllusionsofOptimalMotionDoNotInvolveObjects
OnemightgrantthatIOMsconstituteasuigenerisclassofmisleading
experiences,yetdenythattheyarerelevanttoassessaustererelationism,whichis
mainlyconcernedwiththeperceptionofobjectssuchastrees,tables,andstones.Inthe
presentcase,therelevantitemsarenotobjectsbutdotsorflashespresentedin
succession.
Ifindthisrestrictionontheitemsofperceptionunmotivated.Afterall,wedonot
merelyperceiveobjectsbutalsorainbows,soapbubbles,flames,explosions,andmany
otherentities.Moreover,althoughcasesofapparentmotiondonotinvolveobjectslike
trees,tablesorstones,theyinvolveitemsthatdisplaysomeofthemainsignature
propertiesofobjects.AsPalmer(1999:498)pointsout,themechanismsthatcompute
apparentmotionaresensitivetohigh-levelphenomenasuchaspositionconstancy,
objectrigidity,andocclusion/dissoclusionevents.10Moreover,asGoodman(1978:80)
rightlyindicates,pathsofapparentmotiondonotcross.Aplausibleexplanationisthat
theydonotcrossbecausetheentitiesinvolvedareparsedasobjects,andobjectsdonot
crosstheirowntrajectories.
2.2. IllusionsofOptimalMotionConcernQualitativeIdentity
OnemightgrantthatIOMsarerelevanttoassessaustererelationismbutdeny
thattheyinvolvenumericalidentity.Tothisend,onemightre-describethosecasesas
involvingaqualitativesimilaritybetweentwoobjects.Hence,incasesofoptimalmotion,
thereisnoexperienceasofoneobjectmovingfromlatolb.Instead,thereisan
experienceasoftwoqualitativelysimilarobjectsatlaandlb,accompaniedbya
connectingmovementinbetween.
Althoughthislineofreplyisrelativelypopularamongphilosophers,Ihavenever
encountereditamongpsychologistsandnon-philosophers,whograntthatIOMs
concernnumericalidentity.11Interestingly,thereisexperimentalevidenceinfavorof
thenumerical-identitydescription.KolersandPomerantz(1971)comparedtwo
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scenarios.Inthefirstone,twodotswereflashedatanintervalthatwouldnormallylead
toanIOM.Hence,observersreportedthefirstdotasfollowingastraighttrajectory
towardthelocationoftheseconddot.Inthesecondone,avirtualbarrierwas
interposedbetweenlocationslaandlb,andthedotswereflashedatthesametemporal
interval.Theyfoundthat,ratherthanexperiencingthedotaspassing‘through’the
barrierinastraightline,mostobserversreportedthefirstdotasmovingindepth
aroundit.Theseexperimentsprovidecompellingevidenceinfavorofthenumerical-
identitydescription.IfIOMsmerelyconcernedthequalitativesimilarityoftwoobjects,
itwouldbedifficulttoexplainthechangeofdirectioninthepresenceofabarrier.12
Thisverdictisconfirmedbyadditionalexperimentsinwhichobserversreportan
objectchangingqualities.OnecanhaveIOMsinwhichagreendotfollowsareddotora
longlinefollowsashortline.Inthesecases,observersreportanexperienceasofone
objectchangingcolororsize(Goodman1978;KolersandvonGrünau1976;Sekuler
2012;Wertheimer1912).
IconcludethatwehavegoodreasonstouseIOMsasalitmustestforaustere
relationismandinterpretthemasinvolvingnumericalidentity.Inthenextsection,I
offeraprecisecharacterizationofaustererelationism.
3. NaïveRealismandAustereRelationism
Naïverealismcharacterizesperceptualexperiencesasfundamentallyinvolving
relationsbetweensubjectsandmind-independententities(Martin2004,2006;Soteriou
2010).Therearetwoinfluentialversionsofthisview.Oneofthemtakestherelevant
entitiestobemind-independentobjectslikestones,tables,andtrees(Brewer2011,
forthcoming;Campbell2002,2009,2014;Genone2014;Johnston2014).Anothertakes
themtobecomplexentitieslikefactsorstatesofaffairs(Dokic2000;Fish2009;
McDowell1996).Althoughmyconclusionsapplytobothviews,mymainfocuswillbe
onversionsofnaïverealismoftheformersort.Brewer(2011,forthcoming)callsitthe
‘objectview’andCampbell(2002,2009,2014)the‘relationalview’.13
LetusfollowBrewer,andcharacterizetheobjectviewastheconjunctionoftwo
claims:
(I) Physicalobjectsaremind-independent.
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(II) Physicalobjectsarethedirectobjectsofperception.
Thesetwoclaimsarticulatetheideathatphysicalobjectsprovide“themost
fundamentalcharacterizationofourexperience”(Brewer2011:92;seealso:62-3).In
otherwords,thephenomenalcharacterofperceptualexperiences—‘whatitislike’to
havethem—istobecharacterizedbycitingmind-independentobjectsintheworld(see
alsoCampbell2014:33,41,51;Genone2014;Soteriou2010).14
AsBrewerinterpretsit,claim(II)turnstheobjectviewintoaradicalformof
naïverealism.By‘direct’hemeansthatperceptualexperiencesdonotfundamentally
involverepresentationalcontents(orsensedata).Thus,representationalcontentsare
unnecessaryforanalyzingperceptualexperiences.Theobjectviewisthereforeaformof
austererelationism.
Thereisonedialecticalreasonwhyaustererelationismistheoretically
interesting.Defendersofthisviewoftenadvertiseitasthebestarticulationofour
commonsenseviewofperceptualexperiences.Whereascommonsensetakesfor
grantedthatwearepresentedwithstones,tables,andtreesinperceptualexperiences,
theexistenceofperceptualcontentsisunobvious,soitshouldbeestablishedby
argument.Inthisrespect,thestatusofperceptualrepresentationsisarguablysimilarto
thatoftheoreticalentitieslikesensedata,qualia,andnon-existentobjects(Campbell
2014:20-2,42-3,88;Cassam2014:136;Raleigh2015).Intheremainderofthispaper,I
shallgrantthatperceptualcontentsaretheoreticalentities.
Whatismeantby‘representationalcontent’?Therearemanydifferentwaysof
developingthisidea(Brogaard2014;Pautz2011;Schellenberg2014;Siegel2010).For
mypresentpurposes,Iwillpresupposeaminimalandrelativelyuncontroversial
analysis.Arepresentationalcontentwillbeunderstoodasanabstractentity.Typical
examplesofcontentsarepropositions.Ishallsaythatrepresentationalcontents
determinecorrectnessconditions.Thelatteraresituationsunderwhicha
representationalcontentiscorrectorincorrect.Theproposition<<John>,beingadog>
iscorrectifandonlyifJohnexemplifiesthepropertyofbeingadog.Itisincorrect
otherwise.Iwillusetheadjective‘correct’asagenerictermcoveringavarietyof
evaluationsliketruthandaccuracy.Mypositiveclaimisthatentitiesthatdetermine
correctnessconditionsofferaplausibleexplanationofIOMs.Whethertheseentitiesare
propositionsisaquestionIwillnotaddresshere.
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Ithasbeenpointedoutthatonecanassociateperceptualcontentswith
perceptualexperiencesand,still,thoseperceptualcontentsneednotoffera
fundamentalcharacterizationofthoseexperiences(Brogaard2014;Pautz2011;
Schellenberg2014;Siegel2010).Agoodwayofshowingthatperceptualcontentsare
nottriviallyassociatedwithperceptualexperiencesistoarguethattheyhavesome
explanatoryrolestoplay.Myaimispreciselytoshowthatperceptualcontentsoffera
plausibleexplanationofIOMs.
HowcouldaustererelationistsaccountforIOMswithoutintroducingperceptual
contents?Giventhatcurrentproposalshavemostlyfocusedonphilosophers’
hallucinationsandillusions,theymighttrytoreduceIOMstoanyofthesecategories.I
willarguethatneitheroftheseapproachesisplausible.
4. TheEpistemicAccountofHallucinations
RecallthatIOMsdonotseemtofitintothephilosophicaldichotomyof
hallucinationsandillusions(Section1).Nevertheless,austererelationistsmightinsist
thatIOMsareplausiblycharacterizedashallucinationsasofonemovingobject.
Arguably,thisviewdoesnotneedtointroduceanon-existent,intentionalobjectbecause
thephrase‘onemovingobject’appearsaftertheintensionalexpression‘hallucinationas
of’.IwillsubmitthattherearedecisiveasymmetriesbetweenIOMsandphilosophers’
hallucinationsthatpreventaustererelationistsfromadaptingtheirpreferredanalysisof
hallucinationstoIOMs.Tothisend,Iwillarguethattheepistemicaccountof
hallucinationscannotbeappliedtoIOMs.Attheend,Iwillgeneralizemyconclusionsto
anyattemptatassimilatingIOMstophilosophers’hallucinations.
Theepistemicaccountofhallucinationisaparadigmaticwayofanalyzing
misleadingexperienceswithoutintroducingperceptualcontents.Itseekstoexplain
whatitistohaveahallucinatoryexperienceintermsofacounterfactualcondition.Ifa
subject,S,hasahallucinationofanF,Shasanexperiencethatcouldnotbe
discriminated⎯byreflectionalone⎯fromacorrespondingsuccessfulperceptionofan
F.15Theconceptofindiscriminabilityistobeunderstoodinepistemicterms.The
hallucinationofanFisacaseinwhichitisnotpossibletoknow“thatitisnotoneofthe
[successful]perceptions”ofFs(Martin2006:364).Inotherwords,itisacasethatis
unknowablydistinctfromacorrespondingsuccessfulexperience(Martin2004:77).
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Thisepistemicanalysisenablestheaustererelationisttoaccountforhallucinations
withoutintroducingperceptualcontents.16
Theepistemicconceptionofhallucinationhasbeenstronglycriticized(Hellie
2013;Siegel2008;Sturgeon2008).AlthoughIamsympathetictosomeofthese
objections,Iwillassume—forthesakeoftheargument—thataustererelationistscould
respondtothem.Eveninthishappyscenario,however,theepistemicaccountof
hallucinationcannotbeusedtoaccountforIOMs.
Inhiselaborationoftheepistemicaccount,MichaelMartinwrites:
[T]hedisjunctivistiscommittedtosayingthat,atleastwhenitcomestoamentalcharacterization
ofthehallucinatoryexperience,nothingmorecanbesaidthantherelationalandepistemological
claimthatitisindiscriminablefromtheperception(Martin2004:72).
IftheepistemicanalysiscouldbegeneralizedtoIOMs,itshouldexplainwhy
theseexperiencesseemtopresentoneobjectinmotionjustbyinvokingtheir
indiscriminabilityfromacorrespondingsuccessfulexperience.Unfortunately,thisis
implausible.Theepistemicanalysisexplainsthephenomenalcharacterofhallucination
byabstractingfromanyrelationbetweenthetargethallucinationandtheactualworld.
Thisisinadequateinthepresentcase,however,forthephenomenalcharacterofIOMsis
alsodeterminedbyotherfactors:twomind-independentdotsandtheirproperties,their
respectivelocations,andaspecifictemporalintervalthatmediatestheirpresentation.
Indeed,whenscientistsengineertheirexperiments,theydonotdirectlyactivatethe
visualcortexofsubjects.Instead,theyinterveneonsomedistalitemsintheworld.Ifone
treatedIOMsasphilosophers’hallucinations,onewouldhavetoassumethatsubjects
whoexperiencethemarecompletelyoutoftouchwithreality.Thisisimplausible,
however,forsubjectsdogetanumberofthingsright:theysuccessfullyperceivethe
colors,sizes,andshapesofthedots,theirinitialandfinallocation,andthetemporal
intervals.Thesesuccessfullyperceivedfeaturesworkascuesthatleadtheirperceptual
systemsastray.17Hadsubjectsmisperceivedthem,thephenomenalcharacteroftheir
experienceswouldchangeaccordingly.
Tosumup,theepistemicaccountwasinitiallydesignedtodealwithtotal
hallucinations(Section1).Unfortunately,IOMsarenottotalhallucinations,forthey
involvedistalobjectsandpropertiesthatmakeacontributiontotheirphenomenal
character.Therefore,theepistemicaccountcannotbegeneralizedtoIOMs.
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Defendersoftheepistemicanalysismightwanttoresistthisobjection,though.
Theymightgrantthattheworlddoesmakeacontributiontothephenomenalcharacter
ofIOMsbutmaintainthattheepistemicanalysiscanbeadapted.Tothisend,theymight
exploitanatomisticstrategyhintedatbyMartin:
Togeneralizetheaccount,wewouldneedtofixonthevariousaspectsofastateofperceptual
awareness,thewaysinwhichitmaybethesameordifferentfromothersuchstatesofawareness.
Focusingjustoncasesofveridicalperception,wecansaythattheseaspectswillallinvolvethe
presentationofthatentityasitis.Inturn,asensoryexperienceofthatsortistheoccurrenceofa
situationwhichisindiscriminableinthisparticularrespectfromaperceptionoftheelementin
question(Martin2004:81).
ConsiderIOMs.Ontheonehand,theyaresuccessfulexperiencesofanumberof
features:thecolors,sizes,andshapesofthedots,theirinitialandfinallocation,andtheir
temporalintervals.Ontheotherhand,theyaremisleadingexperiencesasofoneobject
movingfromonelocationtoanother.Onemightthereforetreattheexperienceasa
compositeofsuccessfulperceptionandhallucination.Itshallucinatorydimensioncould
betakenasindiscriminablefromacorrespondingperceptionofoneobjectmovingfrom
onelocationtoanother.
Unfortunately,asMartinhimselfrecognizes,thisapproachremainsseriously
incomplete.Indeed,thedefenderoftheepistemicaccountshouldsaymoreinorderto
“accommodateaspectsofthephenomenalcharacterofexperiencewhicharisefrom
globalpropertiesofthescene,thecombinationofelements,ratherthanjustatomic
elementsofthepresentationofobjectsorcolorpointsinagivenscene”(Martin2004:
81).
Martin’sstrategycanonlybegeneralizedtopartialhallucinationsifonecantreat
theperceptualandhallucinatorycomponentsasindependentvariationdimensionsof
IOMs.Alas,thisisnotaplausibleclaimtomakeinrelationtoIOMsbecausethe
perceptualcomponentofIOMsbearsanexplanatoryrelationtoitshallucinatory
component,andthisexplanatoryrelationisnotcapturedbytheatomisticstrategy.
Indeed,itisbecausesubjectssuccessfullyperceivethefeaturesmentionedabovethat
theyhaveamisleadingexperienceasof—letussay—onereddotbecominggreen.
Hence,thesesuccessfullyperceivedfeaturesarenotseparablefromthemisleading
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characteroftheexperience.Ifsubjectsfailedtosuccessfullyperceiveanyofthese
features,thephenomenalcharacteroftheexperiencewouldchangeaccordingly.
Tosumup,theepistemicanalysisofhallucinationcannotbegeneralizedtoIOMs
becausethelatterarenotplausiblyconstruedastotalhallucinations.Besides,one
cannotadapttheaccountbypursuinganatomisticstrategy,forthephenomenal
characterofIOMsseemstobeinextricablyrelatedtothesuccessfullyperceivedfeatures
inthescene.ThisconclusiongeneralizestoanyotherattemptatassimilatingIOMsto
philosophers’hallucinations.Thesameconsiderationswouldholdevenifonetriedto
replacetheepistemicrelationofindiscriminabilitywithanon-epistemicrelation(Pautz
2010)orheldthathallucinationslackphenomenalcharacter(Fish2009:81,93-ff.).
Iconcludethattheworldmakesanon-eliminableandnon-atomisticcontribution
tothephenomenalcharacterofIOMs.Asaresult,onemightbetemptedtoanalyzethem
onthemodelofphilosophers’illusions.Inthenextsection,Iarguethattheaustere-
relationistaccountofillusionscannotbegeneralizedtoIOMseither.Withsome
additionalassumptions,thisconclusionunderminestheaustere-relationistaccountof
thephenomenalcharacterofperceptualexperiences.18
5. TheEpistemicAccountofIllusions
Inthissection,Iarguethatitisimplausibletoconstruethecontributionofthe
worldtothephenomenalcharacterofIOMsonthemodelofphilosophers’illusions.The
latterrequirethatthesubjectsuccessfullyperceivemind-independentobjects.
Unfortunately,thereisnoplausiblewayofconstruingIOMsasgroundedinobject
perception.IproposetofocusonBrewer’s(2011,forthcoming)view⎯oneofthemost
sophisticatedaustere-relationistaccountsofillusions.Lateron,Igeneralizethe
conclusionstoanyotherattemptatanalyzingIOMsasphilosophers’illusions.
HereisBrewer:
Thecoreofthe[ObjectView]accountoflooksisthatanobjectofacquaintance,o,thinlylooksFiff
ohas,fromthepointofviewandinthecircumstancesofperceptioninquestion,appropriate
visuallyrelevantsimilaritieswithparadigmexemplarsofF.[…]Furthermore,some,butnotall,of
thesethinlookswillbesalienttousinanyparticularcase,forexample,asweswitchbetweenthe
duckandrabbitlooksoftheduck-rabbitfigure.Isaythatanobject,o,thicklylooksFiffothinly
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looksFandthesubjectregistersitsvisuallyrelevantsimilaritieswithparadigmexemplarsofF
(Brewerforthcoming:2).
Letusbracketthecontrastbetweenthinandthicklooksinordertofocusonthe
two-stagestructureofBrewer’sanalysis,whichiscommontomanyotherepistemic
accountsofillusions.19Onthisview,illusionshavetwocomponents:First,subjectsare
perceptuallyrelatedtoobjectsintheworld.Thoseobjectsstandinarelevantsimilarity
relationtoparadigmcasesinwhichaniteminstantiatesarelevantproperty.Second,the
illusionarisesbecausethesubjectcognitivelyreacts(orcanreact)tothatsimilarity.Her
reactionmayconsistintheformationofacorrespondingjudgmentorbelief.20
Consideranexample.IntheMüller-Lyerillusion,thesubjectisfirstperceptually
relatedtothelinesinthediagram.Theselinesstandinarelevantsimilarityrelationto
otherpairsoflines:“onelongerandmoredistantthantheplaneofthediagram,one
shorterandlessdistant”(Brewer2011:102).Becausetheperceiverwasprobably
raisedinacarpenteredworldwherelineswithinward-slantingslashesreliablyindicate
lessdistantplanesthanlineswithoutward-slantingslashes,shemayjudgeorbelieve
thattheformerlinesareshorterthanthelatter.
Therearetwoaspectstothisaccount.First,perceptualrelationstoobjectsfigure
inthefirststage.ThisenablesBrewertopreservetheoriginalclaimthatperceptual
experienceisfundamentallycharacterizedbycitingmind-independentobjects.Second,
theaccountintroducesapost-perceptualstageinwhichthesubjectregistersthe
relevantsimilarity.Itisonlyatthislevelthatrepresentationalcontentsareinvolved.
Sincethosecontentsarepost-perceptual,defendersofthetwo-stageanalysiscanavoid
theintroductionofperceptualcontentstoexplainillusions.
Thetwo-stagemodelrequiresthatonefirstidentifywhatisperceived.Thisis
necessaryinordertodefinethesimilarityrelationtorelevantparadigms.Letuscallthis
the‘perceptualbasis’oftheillusion.Therearetworeasonswhythisperceptualbasis
oughttobecharacterizedbymeansofperceivedobjects.First,thisfollowsfrom
philosophers’definitionofillusionasacaseinwhichaperceivedobjectseemsto
instantiateapropertyitdoesnotinstantiate(Section1).Second,itfollowsfromthe
definitionoftheobjectview,whichconceivesofperceptualrelationstoobjectsas“the
mostfundamentalcharacterizationofourexperience”(Brewer2011:92;seealso:62-3)
(Section3).Thisraisesthequestion:Whatobjectsconstitutetheperceptualbasisof
IOMs?
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Aneasyanswerwouldbe:theillusioninvolvesonenon-existentobjectbesidethe
tworealdots.Onehastheimpressionoftrackingonemovingobjectbecauseanon-
existentobjectfollows(orseemstofollow)aspatiotemporaltrajectory,andthis
trajectoryissufficientlysimilartothetrajectoriesfollowedbyparadigmaticrealobjects
inourworld.Yet,introducingnon-existentobjectswouldbeahighpricetopay.Indeed,
Brewer’sandCampbell’sformulationsofaustererelationismseektoavoidthe
introductionofmysteriousentitieslikenon-existentobjects.Thismakesgoodsensein
thepresentdialecticalcontext.Ifonefindsperceptualcontentsmysterious,oneoughtto
findnon-existentobjectsatleastequallymysterious(Section3).Therefore,theaustere
relationisthasonlythreeremainingoptionsinordertoanalyzeIOMsastraditional
illusions:
(1) Explaintheillusionbymeansofaperceptualrelationtothefirstobject
(e.g.areddotatlocationla).
(2) Explaintheillusionbymeansofaperceptualrelationtothesecond
object(e.g.agreendotatlocationlb).
(3) Explaintheillusionbymeansofaperceptualrelationtobothobjects.
Iproposetoexaminethesethreeoptionsbyfocusingoncasesinvolvingnotonly
apparentmotionbutalsoapparentchange.Supposethatareddotisfollowedbyagreen
dot.Inthiscase,observershaveanexperienceasofareddotchanginglocationand
switchingtogreeninmidcourse.Myclaimisthatoptions1-3donotofferplausible
characterizationsoftheperceptualbasisoftheseIOMs.
Option1holdsthattheperceptualbasisoftheillusionisnothingbutthe
perceptualrelationtothereddot.AsGoodman(1978)andDennett(1991)madeclear,
thissolutionisforlorn.Plausiblyenough,theappearanceoftheseconddotatlocationlb
isnecessarytogeneratetheexperienceasofonemovingdotswitchingtogreen.Thus,
thisapproachwouldonlyworkifthevisualsystemcouldpredictthattherewouldbea
greenobjectatlocationlb.Butthishypothesislackssupport.Ontheonehand,the
experienceofqualitativechangeisequallyrobustwhensubjectsarepresentedwith
IOMsforthefirsttime.Ontheotherhand,therearesomanyvariationsofIOMsthat
thereisnoreasontothinkthatthebrain‘knows’(eitherbyevolutionorpriortraining)
whichpropertieswillbeexemplifiedbytheseconditemandwhereitwillappear.For
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thesereasons,Goodman(1978:83)rejectsapproachesalongtheselinesasinvolving“a
beliefinclairvoyance”(seealsoDennett1991:120andGrush2008:155).
Option2positsarelationtotheseconddotasthesolebasistodefinearelevant
similarityrelationwithaparadigmobject.Butthissolutionisimplausibleaswell.Ifthe
seconddotcontributestotheexperienceasofareddotbecominggreen,itisnoless
truethatthefirstdotplaysanon-eliminableroleaswell.
Apreliminaryconclusionisthatthetwodotsmustbetakenintoaccountinorder
tocharacterizetheperceptualbasisofIOMs.Hence,theaustererelationistcould
developanalternativeproposalalongthefollowinglines.First,thesubjectseesdotAat
la.Second,thevisualsystemunconsciouslyregistersB’sappearanceatlb.Upon
registeringB’sappearanceatlb,thesubjectisledtoexperiencedotAasmovingtolband
switchingtogreeninmidcourse.Theresultingproposalintegratestheintuitionbehind
option1thatonlythefirstdotisconsciouslyperceivedandtheintuitionthatthesecond
dotsomehowcontributestothephenomenalcharacteroftheillusoryexperience.21
Unfortunately,thisproposalraisesanumberofquestions.Whyshouldwetreat
dotsAandBdifferently?WhatcouldjustifytheclaimthatdotAisconsciouslyperceived
whiledotBisjustunconsciouslyregistered?Introspectionalonedoesnotseemtoyield
aclearverdictonthisissue.Inaddition,itwouldbehastytoconcludethatdotAis
consciouslyperceivedjustbecauseitwasflashedfirst.Afterall,thereseemtobecasesin
whichtheappearanceofaseconditempreventsthefirstitemfrombeingconsciously
perceived.Thus,onemightwonderwhetherthisisnotwhatoccursinthepresent
case.22
Supposenowthatthereisasatisfactorywayofrespondingtotheseobjections.
Eveninthiscase,theproposedaccountwouldfaceatleasttwoadditionalproblems:the
iterationproblemandthegapproblem.
Theiterationproblem:Inmanyexperimentalsetups,observersarepresented
withalternatingdotsattwolocations:la,lb,la,lb…(Wertheimer1912)Thus,observers
haveexperiencesasofonedotmovingfromlatolb,thenfromlbtola,andagainfromlato
lb,andsoon.TheseiteratedIOMsunderminetheproposalunderconsideration.By
hypothesis,dotAatlaisconsciouslyperceivedatt1.Byhypothesis,dotBatlbisnot
consciouslyperceivedatt2.Still,observershaveanexperienceasofonedotmoving
fromlbatt2tolaatt3.Thisleadstheaustererelationisttoadilemma:IfdotBisnot
consciouslyperceivedatlb,thentheconsciousperceptionofthefirstdotinagiven
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temporalintervalisnotnecessarytoexplainIOMs.IfdotBisconsciouslyperceivedatlb,
thentheproposalunderconsiderationismistaken.23
Thegapproblem:Thepresentproposalpresupposestheexistenceofasharp
dividebetweentwolevels:theconsciousperceptionofdotAandtheunconscious
registrationofdotB.Thisraisesaproblem:Ifthereisasharpdistinctionbetweenthe
twolevels,whyisthissharpdistinctionnotreflectedinthephenomenologyofthe
experience?Ifobserversareconsciouslyawareofthereddotatlocationlabutmerely
unconsciouslyregisterthegreendotatlocationlb,whyistherenogapbetweentheir
consciousperceptionofastaticreddotatlocationlaandtheunconsciousregistrationof
agreendotatlocationlb?Theabsenceofanysuchgapinconsciousnessstrongly
suggeststhat,ifdotAisconsciouslyperceived,dotBisconsciouslyperceivedtoo.24
Themainlessonfromthepreviousanalysisisthereforethat,iftheaustere
relationistwantstotreatIOMsasphilosophicalillusions,sheshouldnotonlyascribea
causalroletotheseconddotinthegenerationoftheillusion.Sheshouldalsoholdthat
bothdotsreachphenomenalconsciousness.Thisleadsustooption3above.
Accordingtooption3,thesubjectisperceptuallyrelatedtothereddotandthe
greendot.25Inordertoexplaintheillusoryexperience,itisnecessarytodepictthetwo
dotsasstandinginasimilarityrelationtoaparadigm.Whenthetemporalinterval
betweenthetwodotsisfrom10to45milliseconds,subjectsreportanexperienceasof
onemovingdot.Thus,inordertoexperiencethereddotandthegreendotasoneobject,
theremustbeasignificantnumberofobjectsinthesubject’senvironmentthatcovera
similardistanceinanintervalofbetween10and45milliseconds.Inotherwords,the
reddotandthegreendotmustexemplifyaspatiotemporalvariationsimilartothe
spatiotemporalvariationexemplifiedbyparadigmsofpairsofobject-phaseslike
<object-phase1,object-phase2>coveringthesamedistance.26
Unfortunately,thissolutionfacestwomajorproblems:itdepartsfromtheletter
ofaustererelationismandconflictswithsomewell-entrenchedintuitionsonsuccessful
objectperception.Letmeelaborate.
Noticethatitisnotsufficienttobeperceptuallyrelatedtoareddotandagreen
dotinordertohaveanexperienceasofareddotbecominggreen.Itisalsonecessary
thatthetwodotsbeparsedinaspecificorder:thereddotfirstly,thegreendotsecondly.
Afterall,ifonepermutestheorder,oneobtainsadifferentillusion:anexperienceasofa
greendotbecomingred.Atraditionalwayofrepresentingtheorderingrelationbetween
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twoentitiesisbymeansofaset-theoreticalrepresentation.Theobserverisperceptually
relatedtotheorderedpair:<reddot,greendot>.
Moreover,beingperceptuallyrelatedtotheorderedpair<reddot,greendot>is
notsufficientinordertohaveanexperienceasofareddotbecominggreen.Afterall,
pairsofentitiesbythemselvescannotstandinsimilarityrelationstootherpairsof
entities.AsGoodman(1972:473-ff.)madeclear,similarityisrelative,variable,and
highlycontext-dependent.Indeed,inordertocompareapair1withanotherpair2,one
mustspecifyinwhichrespectoneisconsideringtheentitiesinpair1andtheentitiesin
pair2respectively.Inotherwords,itisnecessarytoconsiderthereddotandthegreen
dotinthepair<reddot,greendot>inaspecificrespectbeforeonecancomparethem
withapairofobject-phasesin<object-phase1,object-phase2>.Ifoneabstractsfrom
thespatiotemporalrelationsbetweenthetwodotsintheinitialpair,onewillbeunable
togroundthesimilarityrelationbetweentheperceptualbasisandthetwophasesofa
singleobjectcoveringthesamedistance.Afterall,whatgeneratesIOMsisthe
spatiotemporalrelationbetweenthetwodots,notthepairofdotsitself.
Thiscreatesaproblem,though.Iftheperceptualbasisofthesimilarityrelationis
notthepairofdotsitselfbutthepairofdotsasbeingrelatedinaspecificway,wehave
somethingquitedifferentfromtheobjectslistedintheoriginalcharacterizationof
austererelationism(Section3).Wehaveanorderedpairofdotsthatstandinaspecific
spatiotemporalrelationtoeachother.Wecanrepresentthisentityasfollows:
<<reddot,greendot>,beinginsuchandsuchspatiotemporalrelation>
Unfortunately,thiscomplexisnotoneofthephysicalobjectsBrewerandother
austererelationiststypicallylistasmind-independentphysicalobjects,whichinclude
trees,tables,andstones.Thiscomplexisratherakintoafactorstateofaffairs(Dokic
2000;Fish2009;McDowell1996).
ThepreviousargumentshowsthatanyaccountofIOMswoulddepartfromthe
letterofaustererelationism,foritwouldhavetointroduceentitiesotherthanbare
mind-independentobjectstogroundtheirphenomenalcharacter.Somemightreply,
however,thatfactsorstatesofaffairsarestillcongenialwiththespiritofaustere
relationism,formind-independentobjectsstillplayafundamentalroleinthe
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characterizationofperceptualexperience.Unfortunately,theobjectsthatconstitute
thesefactsorstatesofaffairsarenotsuccessfullyperceivedinIOMs,orsoIshallargue.
Brewer(2011:71)insiststhattheremustbe“limitsonthenatureandextentof
anyerrorsinvolved”inillusion.Onhisview,beyondsomelimits,thesubjectdoesnot
countassuccessfullyperceivingtherelevantobject.Supposeyouarelookingata
square,anditseemstoyouthatthereisanelephantthere.AccordingtoBrewer(2011:
71-3),itwouldbewrongtosaythatyouseethesquareanditlookselephantinetoyou.
Rather,oneshouldsaythatyoudonotseethesquareatall.Thesameholdsifonetries
toaccountforIOMsbymeansoffactsorstatesofaffairs.Inordertoperceivethe
complex<<reddot,greendot>,beinginsuchandsuchspatiotemporalrelation>,itis
necessarytoseethereddotasnumericallydifferentfromthegreendot.Unfortunately,
observersdonotseethereddotasnumericallydifferentfromthegreendot.Therefore,
itisamistaketoholdthattheyperceivethecomplex<<reddot,greendot>,beingin
suchandsuchspatiotemporalrelation>,andthatthiscomplexgroundsthephenomenal
characterofIOMs.
Wecansubstantiatethisconclusionbymeansofanintuitiveconstrainton
successfulobjectperception.Philosophersofallstripeshaveinsistedthatperceptual
differentiationisanecessaryconditionforobjectperception(Campbell2002:7-ff.;
Dretske1969:20-9).Thisplausibleintuitionhasthefollowingconsequence:
Ifavisualscenecontainsobjectsoiandoj,then:Ifasubject,S,seesoiandoj,S
differentiatesoifromoj.
IOMsarecasesinwhichsubjectsfailtodifferentiatethetwoobjectspresentina
scene.Thetwodotsseemtobe‘fused’or‘merged’intoasingle,movingobject.
Therefore,subjectscannotbedescribedassuccessfullyperceivingthetwodots.27
ItisthereforeimplausibletoaccountforthephenomenalcharacterofIOMsby
positingaperceptualrelationtothetwodots,evenifthelatterareconstruedas
constituentsoffactsorstatesofaffairs.Sincephilosophers’illusionsrequiresuccessful
perceptualrelationstoatleastoneobject,thepresentargumentunderminesany
accountofIOMsasphilosophers’illusions.
Letusbringtogethertheresultssofar.Wehavegoodreasonstothinkthatdistal
objectsandtheirpropertiesmakeanon-eliminableandnon-atomisticcontributionto
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thephenomenalcharacterofIOMs(Section4).Thus,IOMsarenotcasesinwhich
subjectsarecompletelyoutoftouchwiththeworld,asthehallucinationaccountwould
predict.Nevertheless,wehavealsogoodreasonstothinkthatthetworelevantobjects
somehowreachconsciousexperiencebutarenotsuccessfullyperceived(Section5).
Hence,ifanaustererelationistwantstoprovideanaccountofthesecases,sheshould
considerthemasacounterexampletoBrewer’sclaimthatphysicalobjectsarethedirect
objectsofperception(Section3).IOMsarecasesinwhichdirectperceptualrelationsto
physicalobjectsdonotprovide,paceBrewer,“themostfundamentalcharacterizationof
ourexperience”(Brewer2011:92).Inthesecases,ourperceptualexperiencereaches
outintoaworldinvolvingexternalobjects,yetthoseobjectsarenotsuccessfully
perceived.
Austererelationistsmightgrantthispointbutholdthatitdoesnotundermine
thespiritoftheirview.Tothisend,theymightreasonasfollows.Althoughphysical
objectsarenotalwaysthedirectobjectsofperception,theyoftenare.Thus,austere
relationistscouldjustbroadentheclassofmind-independententitiesinorderto
accommodateIOMs.Thisisconsistentwithsomeformulationsofnaïverealism,suchas
Sturgeon’s(2008:116):“Good[orsuccessfulphenomenal]characterderivesfrombitsof
thephysicalworldstandinginanexplanatorilybasicrelationtopercipients”.Onthis
view,thelistofmind-independentobjectscaninclude,notonlyparadigmaticobjects
liketrees,tables,andstones,butalsowhateverbitsofthephysicalworldonemightneed
inordertoaccountforIOMsandotherpuzzlingcases.
Alas,thislineofreplyraisesaproblem.Recallthatsubjectsreportanexperience
asofonemovingobjectinIOMs(sections1-2).Inotherwords,theirexperiencesseem
topresentoneobject.Ifonepositsrelationstoentitiesotherthanobjectsinorderto
accountforIOMs,onehastherebyconcededthatperceptualrelationstomind-
independentobjectsneednotbetakenasfundamentalforanaccountofexperiences
thatseemtopresentmind-independentobjects.Afterall,ifonecanexplainIOMsby
introducingperceptualrelationstoentitiesotherthanmind-independentobjects,there
isnoreasonnottogeneralizethisconclusiontoallotherexperiencesasofmind-
independentobjects.
Thereareatleasttwowaysofmotivatingtheproposedgeneralization.First,it
woulddeliveramoreparsimoniousaccountofexperiencesasofmind-independent
objects.Second,theresultingaccountwouldnotbepreytoRobinson’s(1994:154)
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famousargumentagainstnaïverealism.Ifnaïverealistswantedtoprovidedifferent
accountsofthephenomenalcharacterofIOMsandsuccessfulexperiencesofobjects,
theyshouldassumethatthebraincouldmysteriouslyknowwhetherthecaseisoneof
successfulperception(sothatitstandsinaperceptualrelationtoanobject)oronein
whichanentityotherthanamind-independentobjectismistakenforanobject(sothat
theseemingrelationtoanobjectisderivativefromarelationtosomethingelse).
Unfortunately,thereisnogoodreasontothinkthatthebrainhasthismysterious
knowledge.
Theimportanceofthepresentchallengemightbeobscuredbythefactthatnaïve
realistsareratherunclearonwhattheymeanbyobjects.Ifwetakeseriouslytheir
paradigmexamples—i.e.,trees,tables,andstones—,thenmind-independentobjectsare
thesortsofthingsthatpersistovertime.28Giventhedescriptionofferedinsections1-2,
IOMsareplausiblycharacterizedasillusionsofpersistence.Afterall,subjectsreport
experiencesasofoneobjectchangingqualitiesandlocation.Hence,theseillusions
cannotbeexplainedbyinvokingprimitiverelationstomind-independententitieswhose
persistenceisimmediatelyappreciatedbytheobserver.
TherepresentationalistcanthereforeuseIOMstoprovideafundamental
characterizationofperceptualexperiencesthatdoesnotinvokeperceptualrelationsto
objectsconsideredaspersistingentities.Shecanconstrueexperiencesofobjectsas
persistingovertimeasderivativefromperceptualrelationstomoreprimitive,non-
persistingentities.Theseentitiesmightbeshort-livedeventsorobject-phases(see,e.g.,
Smith1996:117-35).
Iexplorethissuggestioninthenextsection.Tothisend,Isketchanaccountof
therepresentationalcontentsrequiredtoexperienceobjectsaspersistingovertime,
andapplythemtoIOMs.
6. Object-DirectedExperiencesandPerceptualContent
Inthissection,Idevelopanaccountofperceptualcontentdesignedtoexplain
IOMsand,moregenerally,experiencesofobjectsaspersistingovertime.Theproposed
accountbuildsontwoideas:Evans’(1981)insightthatperceptualtrackingrequires
dynamicmodesofpresentationandFine’s(2007)relationalsemanticsforidentity.
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6.1. DynamicModesofPresentation
IOMshavetwosalientfeatures:theyinvolveapparentmotionandareillusory.
Hence,inordertousethemtodrawgenerallessonsonthestructureofperceptual
experiences,weshouldgeneralizefromIOMsintwoways.First,weoughttoshowthat
IOMsmayteachussomethingaboutthefundamentalnatureofsuccessfulperceptual
experiencesofobjectsaspersistingovertime.Second,weoughttoshowthatthese
illusionsarerevelatory,notonlyofthenatureofexperiencesasofmovingobjects,but
alsoofexperiencesasofstaticobjects.Iconsidereachgeneralizationinturn.
Firstgeneralization:Imagineasubjectwhoiskeepingtrackofawomanover
time.Barringoccludersormomentarydistraction,visualexperiencecouldputour
subjectinapositiontoformthefollowingseriesofthoughts:
(A) P1 Thatwomanisrunning.
P2 Thatwomanisjumping.
C Therefore,thatwomanisrunningandjumping.
AsCampbell(2002:129)comments:“Recognizingthevalidityoftheinference
requiresthatyourexperienceshouldmakethesamenessoftheobjecttransparentto
you”(seealsoCampbell2014:34-5).FollowingEvans(1981),wecouldsaythatthe
numericalidentityofthewomanistransparenttoyoubecauseitisperceivedunderthe
same‘dynamicmodeofpresentation’.Adynamicmodeofpresentationfixesthe
referencetothewomanandenablestheobservertokeeptrackofthatwomanas
persistingovertime.29
WecangeneralizethisaccounttoIOMsbysayingthatdynamicmodesof
presentationnotonlycapturecasesinwhichnumericalidentityisperceptuallyobvious
butalsocasesinwhichonemerelyseemstobepresentedwithoneobjectaspersisting
overtime.WecanfleshoutthissuggestionbycomparingcasesoftypeAwithIOMs.
CasesoftypeAarescenariosinwhichtheco-referenceofthetwodemonstrativesis
perceptuallymanifesttotheobserver.IOMsarecasesinwhichonehasanexperienceas
ofco-referencebutthisisanerror.
Recallthat,insomeexperimentalsetups,observersarepresentedwith
alternatingdotsattwolocations:la,lb,la,lb,…(Section5)Supposenowthatanobserver
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whoisunfamiliarwiththesetupiswatchingthesealternatingpresentations.Inthis
case,itwouldbenaturalforhertoproducethefollowingseriesofthoughts:
(B) P1 Thatdotwasatlocationla.
P2 Thatdotwasatlocationlb.
C Therefore,thatdot(atla)isthesameasthatdot(atlb).
IncaseB,theobservertakestheoccurrencesof‘thatdot’asco-referential.
Indeed,theexperiencethatseemstojustifythemovefromP1-P2toCseemstopresent
asingleobjectmovingfromonelocationtotheother.Hence,itsharesaphenomenal
featurewithcasesoftypeA.Still,contrarytocasesoftypeA,thetwooccurrencesof
‘thatdot’arenotco-referential.
ItisreasonabletointerpretthesimilaritiesbetweencasesoftypeAandIOMsas
anargumenttointroducearepresentationalistanalysisofourperceptualexperienceof
objectsaspersistingovertime.Indeed,therepresentationalistmightreasonasfollows:
thesubjectiveimpressionthattheoccurrencesof‘thatdot’co-referisgroundedinhow
thingsareperceptuallyrepresented;differentdot-phasesareperceptuallyrepresented
asonemovingdot.ThesimilaritybetweenIOMsandsuccessfultrackingistherefore
explained:bothcasesinvolverepresentationsofdifferentphasesasonemovingobject.
Insuccessfultracking,thephasesrepresentedasphasesofoneobjectareinfactphases
ofoneobject.InIOMs,bycontrast,theyarephasesofnumericallydifferentobjects.30
Secondgeneralization:Oursecondquestionwaswhetherwecouldgeneralizethe
presentanalysistoexperiencesasofstaticobjects.Idothinkso.Indeed,our
understandingofobjectsisparasiticonourunderstandingofthewaytheymove.This
assumptionunderliessomeofthemostsuccessfulstudiesonobjectperceptionin
cognitivescience.Developmentalpsychologistshaveexaminedinfants’perceptionof
objectsbyevaluatingtheirabilitytoparsesomewholesaskeepingtheirpartsbound
togetherwhilefollowingrelativelycontinuoustrajectoriesthroughspace.Anotherreason
whyinfantsarethoughttoperceiveobjectsisthattheycountthesewholesasthesame
evenwhentheyfailtoregisterchangesinqualitieslikesize,shapeorcolor(Carey
2009).
Anumberofphilosophershavemadesimilarpoints.Evans(1981:311)famously
heldthat“thestaticnotionof‘havingholdofanobjectatt’isessentiallyanabstraction
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fromthedynamicnotionof‘keepingtrackofanobjectfromttot’’”.Inaddition,one
mightholdthattheabilitytokeeptrackofobjectsovertimeisconstitutiveoftheability
toperceiveobjectstoutcourtbecausetrackingiswhatenablesustodistinguish
persistentobjectsfromotherentities.Indeed,Burge(2010:80,198-9,444-7,459,469)
haspersuasivelyarguedthatwedistinguishobjectsfromeventsandshapesbecausewe
expecttheformer—butnotthelatter—tokeeptheirboundaryintegrityovertime.One
mightthereforeclaimthatIOMsareincorrectrepresentationsoftwoeventsorshapes
asonepersistingobject.Inwhatfollows,Ipresentaformalanalysisthatcapturesthe
gistofEvans’andBurge’sremarks,avoidssomeproblems,andlocatesthepresent
proposalwithinthewiderfamilyofneo-Fregeanaccountsofperceptualcontent.
6.2. TheCommonContentofObject-DirectedExperiences
Onacommon-factoranalysis,thevisualsystemrepresentssomephasesas
bearingsomespatiotemporalrelationstoeachother.Ceterisparibus,ifthevisualsystem
representsmobject-phasesasstandinginspatiotemporalrelationstoeachotherthat
aresufficientlysimilartotherelationsthatnphasesofoneobjectbeartoeachother
whenitisfollowingarelativelycontinuoustrajectory,theperceptualexperienceisasof
oneobject.Thecontentofthisexperienceiscorrectwhenthemobject-phasesare
appropriatelycausedbymobject-phasesofoneobject.Itisincorrectotherwise.Ifthese
spatiotemporalrelationsaredifferent,theperceptualexperienceisasoftwoobjects.
Thiswilloccurwhentheintervalistoobriefortoolong.Wecanarticulatethisproposal
byintroducingthefollowing,relationalsemanticsforobject-directedexperiences(Fine
2007):
Theperceptualcontentofanobject-directedexperience|E|isthefunctionf(|P1,
P2,…,Pm|)ofthesequence|P1,P2,…,Pm|onthephasesP1,P2,…,Pm.31
Theargumentofthisfunctionisasequenceofphases.Inordertobepartofthis
sequence,thephasesmustbeparsedasstandinginsomespatiotemporalrelationsto
eachother.Onecouldgeneralizethisanalysistoexperiencesasofstaticobjectsby
substitutingstaticobject-partsforobject-phases(Echeverriforthcoming).
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Morecouldbesaidonwhatmakestherelevantcausalrelationappropriate.Since
appropriatecausalrelationsareinvokedbyanyrepresentationalisttheory,Iproposeto
focusonthemaintheoreticalinnovationofthepresentanalysis.Thiswillenableusto
seehowthepresentproposalaccommodatesEvans’andBurge’sremarks,howitavoids
someproblems,andhowitrelatestothewiderfamilyofneo-Fregeanaccountsof
perceptualcontent.
Therelationalfunctionhasa‘relationalsemantics’:theargumentsarenotthe
phasestakenindividuallybutsequencesofphases.ThisaccommodatesEvans’(1981:
311)ideathat“thestaticnotionof‘havingholdofanobjectatt’isessentiallyan
abstractionfromthedynamicnotionof‘keepingtrackofanobjectfromttot’’”.32Inhis
developmentofsemanticrelationism,Fine(2007)interpretseachelementofthe
sequenceasstandingforoneobject.However,thiswouldnotenableustopreserve
Burge’s(2010)insightthatasubject’sperceptualappreciationofsomethingasanobject
persistingovertimemaybederivativefrom—notpriorto—atemporallyextended
trackingepisode(Section6.1).Forthisreason,IproposetodepartfromFineand
interprettheargumentsofthefunctioninamoreaustereway.33Onmyview,thevisual
systeminitiallyrepresentsvariousphasesinaneutralwayastowhethertheyare
phasesofoneobject.Itisthevalueoftherelationalfunctionthatyieldsacommittal
representation,i.e.arepresentationofthesephasesasphasesofoneobject.This
representationmightbeconstruedasanobjectfile,i.e.amentalrepresentationthathas
thefunctionofrepresentingobjectsasnumericallyidenticalovertime(Carey2009;
Echeverriforthcoming).Thecommittalrepresentationistokenedonlyifthevarious
phasesstandinsomespatiotemporalrelationstoeachother.34
Fine’sinterpretationwouldalsohavetwoundesirableconsequences.First,itwas
alreadypointedoutthatsubjectsfailtodifferentiatethetwodotsinIOMs(Section5).
Thus,thetwodot-phasesshouldnotappearasdifferentiatedintheargumentsofthe
function.Second,Fine’saccountwouldleadustointroduceanimpossiblecontentinto
thephenomenologyoftheexperience.Acontentcisimpossiblejustincasethereisno
possibleworldinwhichcistrue.Onastandardview,contradictorycontentsare
impossibleinthissense.Now,ifnumericallydifferentobjectsoiandojfigureas
argumentsoftherelationalfunction,thereisasenseinwhichtheexperiencerepresents
animpossiblecontent:thedotsarerepresentedastwointheargumentofthefunction
andasoneinthevalueofthefunction.ThetroublehereisthatIOMsdonotseemto
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presentanimpossiblestateofaffairs,contrarytowhatoccursinotherwell-knowncases
likethewaterfallillusion,inwhichastationaryobjectseemstomoveandstandstillat
thesametime(Pautz2010:274).
Theseproblemsshouldnotariseifwecarefullydistinguishthewaythedotsare
givenintheargumentofthefunctionfromthewaytheyarerepresentedinthevalueof
thefunction.Thetwodotsarenotrepresentedasdifferentiatedintheargumentofthe
function.Instead,theyfigureaselementsofasequencethatisindiscriminablefromthe
sequencesformedbyobject-phasesofoneobject.Thisexplainswhyitistemptingto
holdthatthetwodotsappeartobe‘fused’or‘merged’intoasingle,movingobject
(Section5).ThisapproachalsoenablesustodistinguishIOMsfromillusionsthatseem
topresentimpossiblestatesofaffairs.Thesubjectcanexperiencetwonumerically
differentdotsasphasesofonemovingdotwithoutbeingawareoftheimpossible
characterofthatstateofaffairsbecausethetwodot-phasesfallunderthesamedynamic
modeofpresentation.Thisdynamicmodeofpresentationmaskstheimpossibilityfrom
thesubject’sperspective.Inanutshell:eventhoughitismetaphysicallyimpossiblethat
twonumericallydifferentobjectsbeoneobject,thismetaphysicalimpossibilitydoesnot
reachphenomenalconsciousnessbecausethetwodotsaregivenasmeredot-phases
andthesedot-phasesfallunderthesamedynamicmodeofpresentation.
Theaboveanalysisshouldalsomakeclearwhytherelationalfunctiondiffers
fromtwootherFregeanaccountsofcontent:dedictoandderemodesofpresentation.
Dedictomodesofpresentationimposesomeconditionsthattheobjectof
perceptualexperiencemustsatisfyinordertobethereferentofthatexperience.The
relationalfunction,bycontrast,imposessomeconditionsthatphasesmustsatisfyin
ordertobeexperiencedasphasesofthesameobject(seeEcheverriforthcoming,for
discussion).
“[D]eremodesofpresentationareinherentlyrelationalinthatwhatobjector
propertyinstancethesubjectisrelatedtomakesaconstitutivedifferencetothenature
oftheensuingcontent”(Schellenberg2013:303;seealsoPeacocke1981).Inthis
framework,eitherthemodeofpresentationis‘filled’byoneobjectoritisgappy.The
relationalfunctiondiffersfromderemodesofpresentationbecauseitmakesroomfora
thirdpossibility.Therearecasesofreferentialfailurethatdonotarisefromtheabsence
ofobjects—asinthehallucinatorycase—butfromthepresenceofdifferentobjects
withinaspatiotemporalrangethatisnormallyfilledbyphasesofasingleobject.Hence,
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thosearecasesinwhichtherelationalfunctionis‘filled’byphasesofnumerically
differentobjects,theexperienceinvolvesoneobjectfile,butthatobjectfilefailstorefer
tooneobject.
7. ConcludingRemarks
Ithasoftenbeenclaimedthat,whereasrepresentationalismtreatsperceptual
experiencesasobject-independent,naïverealismtakesmind-independentobjectsas
constituentsofexperiences.Theargumentsfromthispapersuggestthattheseclaims
areambiguous.Sincethecontentsofobject-directedexperiencesmaybedefinedover
object-phases,theyneednotbeconstruedasobject-independent.Nevertheless,there
arereasonstotreatperceptualexperiencesasindependentfromobjectsconsideredas
persistingovertime.Afterall,wemayneedtopositperceptualcontentsinorderto
accountforthephenomenalcharacterofmisleadingexperiencesasofpersistingobjects.
Considernowthenaïve-realistclaimthatobjectsfigureasconstituentsofexperiences.If
wereaditastheclaimthatourperceptualappreciationofobjectpersistenceis
fundamental,itisanunwarrantedclaim.Afterall,onecanintroducedynamicmodesof
presentationrangingovermoreprimitiveentitiesinordertoelucidateourappreciation
ofobjectsaspersistingovertime.
Theseremarksaredirectlyrelevanttoaseriesofrecentattemptsatreconciling
representationalismwithnaïverealism(see,e.g.,Hellie2013;Kennedy2013;McDowell
2013;Schellenberg2014;Siegel2010;Soteriou2010).Beforeonetriestobuildrelations
tomind-independentobjectsintoperceptualcontents,oneoughttobeclearonwhatit
meansforperceptualexperiencestohaveobjectsasconstituents.
IOMscertainlyraisemanyotherinterestingissues.Myaiminthispaperwasto
examinetheprospectsofaustererelationismtoaccountfortheseintriguingcasesandto
formulateanalternative,representationalistaccount.Ihopeaustererelationistswill
takethischallengeasanopportunitytorespondtomyobjections.Ifthearguments
presentedherearecorrect,IOMscompelustogetridoftheprocrusteandichotomyof
hallucinationandillusion.Besides,theycastdoubtontheprioritygiventomind-
independentobjectsinthecharacterizationofthephenomenalcharacterofperceptual
experiences.35
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DépartementdePhilosophieUniversitédeGenève
NOTES
1Ihaveborrowedthephrase‘austererelationism’fromSchellenberg(2014).Therearealsocompatibilistaccountsthatcombinerelationismandrepresentationalism(e.g.,Hellie2013;Kennedy2013;McDowell2013;Schellenberg2014;Siegel2010;Soteriou2010).Imakesomeremarksoncompatibilisminfootnote13andSection7.So-calledsensedatumtheories(e.g.,Robinson1994;Russell1912)donotfallintothisdichotomy,fortheyneitheranalyzeperceptualexperiencesasinvolvingrelationstomind-independentobjects,norpositperceptualcontents.Iwillnotexaminethesetheorieshere.2Ishalluse‘misleadingexperiences’todenoteillusoryandhallucinatoryperceptualexperiencesand‘successfulexperiences’todenotenon-illusory,non-hallucinatoryperceptualexperiences.Thus,Iwillnotexamineso-called‘veridical’illusionsandhallucinations.Thesephrasesarealsomeanttobeneutralonwhetherperceptualexperiencesfundamentallyinvolverepresentationalcontents.3Foranon-linedemonstration,see:http://www.michaelbach.de/ot/col-colorPhi/index.html.Thereissomeconfusiononwhatismeantbytheϕphenomenon.ItisoftentakentorefertowhatIamcalling‘optimalmotion’.Othersuseittoreferto“perceivedmotionwithoutobjectsbeingperceivedasmoving”(Wagemansetal.2012:1206).Forausefuldiscussion,seeHoerl(2015).4Inwhatfollows,IonlyofferprimafacieconsiderationsfortheclaimthatIOMsdonotclearlyfitintothephilosophicaldichotomyofhallucinationsandillusions.Isubstantiatetheseconsiderationsinsections4and5.5SeealsoBrewer(2011:64),Fish(2009:80),Martin(2006:394),andPautz(2010:280),amongothers.6SeealsoFish(2009:45,146-7)andSmith(2002:23),amongothers.7IwillcomebacktothispointinSection5.Someaustererelationistshavecriticizedrepresentationalaccountsofillusionsbyarguingthatmanyordinaryillusionsandhallucinationsdonotfitintothetraditionaldichotomy(Campbell2014;Genone2014;Kalderon2011).Isharethespiritofthecriticismbutnottheanti-representationalistconclusion.Myviewisthatadescriptivelycorrectaccountofillusionsmayleadustoreviseourviewsontherepresentationalstructureofperceptualexperiencesbutnottorejectperceptualrepresentationsaltogether.8Forsomerelevantstudies,seeKolers(1972),KolersandvonGrünau(1976),Palmer(1999:Chapter10),andSekuler(2012).9Genone(2014:359)mentionstheϕphenomenonasapotentialcounterexampletothetraditionaldichotomyofhallucinationsandillusionsbutdoesnotofferananti-representationalistaccountthereof.Hoerl(2015)offersananalysisofillusionsofpuremotionwithinaustererelationism.Bythishemeansasub-classofillusionsofimperfectmotioninwhichthesubjecthastheimpressionthatthereismovement,withoutanyawarenessofasinglebearerofthatmovement.Unfortunately,Hoerldoesnotaccountforeitherexperiencesofdualmotion,orexperiencesofoptimalmotion.10Burge(2010)arguesthatperceptualconstancyissufficientforobjectivity.11SeeCarey(2009:72-ff.),Pylyshyn(1999:356),SigmanandRock(1974),Wertheimer(1912),amongothers.Therearealsomanyphilosopherswhograntthedescriptionintermsofnumericalidentity.SeeBurge(2010:463),Genone(2014:359),Goodman(1978),andMatthen(2012:55-6).12SeealsoShepardandZare(1983)andSigmanandRock(1974).13Therearedifferentcharacterizationsofnaïverealismintheliterature.Somerelyontheconceptofessence,othersontheconceptoffundamentality,andstillothersontheconceptofconstituency.Whilesomeofthemwillleadtotheconclusionthatnaïverealismisanti-representationalist,otherswillmakeroomforcompatibilistaccounts.Byqualifyingperceptualexperiencesasfundamentallyinvolvingrelationsbetweensubjectsandmind-independententitiesImeantoremainneutralonwhetherthenaïverealistmayintroducerepresentationalcontentstoaccountforsomeaspectsofperceptualexperiences.
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Fortunately,takingsidesonthisissueisnotdecisiveforthemaingoalofthispaper,whichconcernstheroleofperceptualcontentsinaphilosophicalaccountofthestructureofperceptualexperience.14Mostversionsofnaïverealismalsointroducerelationstomind-independentproperty-instancesortropesintheirfundamentalcharacterizationofperceptualexperiences.Icomebacktotheroleofproperty-instancesinSection5.15Foreaseofexposition,Iwillignorethequalification‘byreflectionalone’.16AlthoughMartinhascriticizedsomeargumentsinfavorofperceptualcontent,itisnotentirelyclearwhetherheisanaustererelationist.Inhis(2004:71),heleavesopenthepossibilityofaccountingforimperfecthallucinationsintermsofrepresentationalcontentsorsensedata.Nevertheless,inthesamepaper,healsosuggeststhathisepistemicaccountofhallucinationcouldbegeneralizedtoothermisleadingexperiences(2004:81-ff.).Bethatasitmay,theepistemicanalysishasbeeninvokedtoaccountformisleadingexperienceswithinanaustere-relationistframework.SeeBrewer(2011:101-ff.).17Iamusingtheword‘feature’inatheory-neutralwaytodenoteanybitoftheworldthatmaycontributetothephenomenalcharacterofIOMs.18Itisworthstressingthatsomenaïverealistsrejecttheepistemicanalysisofhallucination.SeeCampbell(2014:92-ff.)andJohnston(2014).19SeealsoAnthony(2011:40),Campbell(2014:85-90),Fish(2009:172-7),Genone(2014),andTravis(2004).Althoughtheseviewsdifferinimportantrespects,theproblemsIshallformulategeneralizetoanyanalysisofillusionsthatpositsasimilartwo-stagestructure.20Itisnotalwaysclearwhetherthecognitivereactionisconstitutiveoftheillusoryexperience.Althoughthispointisphilosophicallyimportant,itwillnotaffecttheargumentstofollow.21Iowethissuggestiontoarefereeofthisjournal.22Ihaveinmindthephenomenonofmetacontrast(Breimayer1984).Supposethatthefirststimulusisadiscandthesecondonearingthatfitscloselyoutsidethespacewherethediscwasdisplayed.Inthiscase,observersreportthattheydidnotseethediscbutonlythering.Thisphenomenonisstandardlyinterpretedasacaseinwhichthediscwas‘masked’bythering(DennettandKinsbourne1992:193-ff.).23Tobesure,defendersofaustererelationismcouldtrytotreatsimpleanditeratedIOMsdifferently.Butthiswouldyieldanadhocandextremelycomplexaccount.24Idonotmeantoimplythatunconsciousperceptualprocessingcannothavebehavioralandcognitiveeffectsonus.Indeed,primingeffectsareexamplesoftheeffectsofunconsciousperceptualprocessing.Thetroublehereisthattheeffectsrequiredtovindicatetheapproachunderconsiderationseemverydifferentfromotherwell-knowneffectsofunconsciousprocessing.WhenoneexperiencesanIOM,itisnotasifonecouldguess(asinaforcedchoiceparadigm)thatthereddotwasfollowedbyagreendot.Instead,itappearstobecomegreenjustinthemidpointthatseparateslocationslaandlb.25Soteriou(2010:234)arguesthatrelationistscanpositacquaintancewithoccurrenceswithtemporalextension.26AlthoughIamusingtheword‘phase’todescribethesecases,Iamneutralonanytheoryofpersistence.Thereaderisinvitedtosubstitutetherelevantexpressionswithherpreferredones.27Somereadersmightinsistthatthesubjectdoesseethetwodotsasnumericallydifferentbutisunabletoreportthemasnumericallydifferent.Unfortunately,thisreplywouldbeself-defeating.Ifverbalreportsarenottakenasreliablemeanstodeterminewhatisperceived,naïverealistsarenotentitledtorelyontheirownverbalreportstomotivatetheclaimthatmind-independentobjectsareconstituentsoftheirsuccessfulexperiences.28ThatobjectsareexperiencedaspersistingovertimeplaysacentralroleinBrewer’s(2011:69-70)argumentsagainstrepresentationalism.ItalsoplaysadecisiveroleinCampbell’s(2002,2009)workofperceptualtracking.29SinceCampbellisananti-representationalist,hecannotintroducedynamicmodesofpresentation.Instead,heintroduces‘mannersofpresentation’thatdonotfixthereferencetotheobjectbutonlycapturethetransparencyoftheco-referenceofthetwooccurrencesof‘thatwoman’.Aswillbecomeclear
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later,Campbell(2002:79,129;2014:46-7)iswrongtothinkthatrepresentationalistscannotaccountfortrackingovertime.30Pautz(2010:284)hasarguedthatacommon-factoranalysisofphenomenologydoesnotentailacommonfactoranalysisofperceptualreference(seealsoKennedy2013).Thepreviousconsiderationssuggestthatphenomenologyisnotorthogonaltoperceptualreference.Indeed,acommon-factoranalysisofsomespecificformsofphenomenologyseemstogohandinhandwithafactorizationofperceptualsuccess.ThephenomenologicalcommonalitiesbetweencasesoftypeAandcasesoftypeBsuggestthatperceptualreferencetoobjectsconsideredaspersistingovertimeisnotprimitive.InIOMs,thereisaperceptualmisrepresentationoftwodot-phasesasphasesofonedot.ItisnaturaltoholdthatthismisrepresentationisabyproductofareferentialmechanismthatworkswellincasesoftypeA.31Thisfunctiononlyconsiderstheobjectsideofperceptualcontent.Thus,itshouldbesupplementedwithanaccountofperceptualattributionofcolor,shape,size,andsoon.SeeEcheverri(forthcoming),fordiscussion.32Itmightturnoutthatsomeoftheargumentsofthefunctionconsistofphasesthataremerelyanticipatedbythevisualsystem(Burge2010).33ThisisnotintendedasacriticismofFine’sframework,whichwasdesignedtoaccountforco-referenceinlanguageandthought.Mypointisthattheframeworkshouldberevisedinordertoaccountforourexperienceofobjectsaspersistingovertime.34Therelationalfunctionshouldnotbeconstruedasasufficientconditionfortheexperienceofvariousphasesasphasesofoneobject.Afterall,IOMscanbecancelledbybackgroundevents,suchastheappearanceofvirtualoccluders(SigmanandRock1974).Thus,amoredetailedanalysisshouldmakeroomforcontextualmodulationsoftherelationalfunction.Iwillexaminethisissueinfuturework.35Ipresentedearlierversionsofthispaperatthe21stMeetingoftheEuropeanSocietyforPhilosophyandPsychology(9-12July2013),the5thGraduateSummerSchoolinCognitiveSciencesandSemantics:Perception(19-29July2013),theXVIIInter-AmericanCongressofPhilosophy(7-11October2013),theWorkshop:AbilitiesinPerception(29-30November2013),andtheColombo-BrazilianMeetingofAnalyticPhilosophy(5-6December2013).Iamgratefultotheaudiencesfortheircomments,especiallytoTomCrowther,PascalEngel,MichaelMartin,BenceNanay,andBarryC.Smith.IamalsoindebtedtoFabriceTeroniandtwoanonymousrefereesfortheirwrittencommentsonearlierdraftsofthispaper.IwouldalsoliketothankJamesGenoneforafruitfulemailexchangeonthetopicsofthispaper.ThisworkwasfundedbytheSwissNationalScienceFoundation(researchgrantNo.100012-150265/1).
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