revelationinsomniac

Synthese(2020)197:2039–2050https://doi.
org/10.
1007/s11229-018-1781-0Self-ascriptionandthedeseJamesOpenshaw1Received:24August2017/Accepted:3April2018/Publishedonline:18April2018TheAuthor(s)2018AbstractThispaperdefendsLewis'(PhilosRev88:513–543,1979a)inuentialtreat-mentofdeseattitudesfromrecentcriticismtotheeffectthatakeyexplanatorynotion—self-ascription—goesunexplained(CappelenandDeverinTheinessentialindexical,OxfordUniversityPress,Oxford,2013;Holton,in:Loewer,Schaffer(eds)TheBlackwellcompaniontoDavidLewis,Blackwell,Oxford,pp.
399–410,2015).
ItisshownthatLewis'treatmentcanbereconstructedinawaywhichprovidesclearresponses.
ThisshedslightontheexplanatoryambitionsofthoseengagedinLewis'project.
KeywordsDese·Self-ascription·DavidLewis·Centeredworlds·Properties1IntroductionRatherthantakingthecontentsofattitudestobesetsofpossibleworlds(Hintikka1962)—waysaworldmightbe—Lewis(1979a)proposedthatwetakethemtobeproperties—waysanindividualmightbe.
AstrikingfeatureofLewis'discussionisitsbrevity.
Atfacevalue,quickreectiononsomebasicthoughtexperimentsrevealsthatpossibleworldscontentscannotbetherightobjectsofpropositionalattitudesafterall.
RecentwritershavearguedthattheaccountLewis(1979a)givesofdeseattitudessuffersfromalacuna:SpecialthankstoJohnHawthorne,TimWilliamson,andanonymousrefereesforthisjournalfortheircomments.
IamalsogratefultotheArtsandHumanitiesResearchCouncilandtheRoyalInstituteofPhilosophyfortheirnancialsupportduringthisperiodofresearch.
BJamesOpenshawjames.
openshaw@philosophy.
ox.
ac.
uk1St.
EdmundHall,UniversityofOxford,Queen'sLane,OxfordOX14AR,UK1232040Synthese(2020)197:2039–2050…itisnottherevisionarytheoryofcontentthatdoesthesolving,buttheunex-plainednotionofself-ascriptionofaproperty…(CappelenandDever2013:p.
103).
[…]Theroleofself-ascriptionislittleemphasizedeitherbyLewisorinthesubsequentliterature.
Buttheworkofsolvingtheinformationalpuzzle[s]restsentirelyon[…]self-ascription(2013:p.
108).
Thesecondpart[ofLewis'account],whichismuchlesstotheforeinLewis'spresentationandinthesubsequentdiscussion,involvestreatingourattitudetothesepropertiesasthatofself-ascription(Holton2015:p.
400).
Takingself-ascriptionasprimitiveiscrucialtoLewis'saccount(Holton2015:p.
403)Itistruethatitisnotjusttherevisionarytheoryofcontentthatdoesthesolving.
Butitisfalsethatself-ascriptionisitselfaprimitiverelation,incapableofbeingilluminated.
Inthispaper,IprovidetheemphasiswhichCappelenandDever(2013)andHolton(2015)askfor.
WhatthosewhoendorseLewis'inuentialmoveincharacterizingdeseattitudesneedtakeasprimitiveisnotsomeadhocattitude.
Infact,whetherornotLewis'accountofthedeseiscorrect,1ifitisproblematicforthereasonstowhichrecentcriticshaveappealed,thentheoristswhoattributepossibleworlds(orcenteredworlds)contentstothinkers,andtheoristswhoattributecontentswhichcanonlybeevaluatedfortruthatacontext,facethesameconcern.
Thecomplaintsthat"[t]akingself-ascriptionasprimitiveiscrucialtoLewis'saccount"(Holton2015:p.
403)andthatthis"unexplainednotion"iswhatdoestheexplanatorywork(CappelenandDever2013:p.
103)thereforemisstheirmark.
MuchmorewouldneedtobesaidinordertoundermineLewis'(1979a)characterizationofdeseattitudes.
IbegininSect.
2byoutliningLewis'(1979a)classictreatmentofdeseattitudesandclarifyingthenecessarydetails.
Section3thenreturnstothematterofexplainingthenotionofself-ascriptioninawaywhichdisarmsthecomplaintsoftheabovecritics.
Section4closeswithabriefsummaryandconclusion.
2Lewis,Lingens,andFregeAccordingtotheframeworkinLewis(1974),ourfolk-psychologicaltalkandattitude-reportingpracticesarepartofa'generaltheoryofpersons',theunderlyingprinciplesofwhichsetout"howbeliefsanddesiresandmeaningsarenormallyrelatedtooneanother,tobehavioraloutput,andtosensoryinput"(1974:p.
334).
Thistacit,generaltheoryofpersonsmaybesystematizedintoasetofplatitudesaboutbeliefanddesire,andputthiswayitprovidesanimplicitdenitionoftheattitudes:theyarewhateverstatesplaytherightcausalroles.
Thussetout,Lewisthought,weareledtoaprogramaccordingtowhichcontentsareassigned"tocharacterizestatesofthehead;tospecifytheircausalroleswithrespecttobehavior,stimuli,andoneanother"(1979a:p.
526).
ThepropositionsLewis(1974)hadinmindwerepossibleworldscontents.
Butthatconceptionoftheobjectsofpropositionalattitudeswasrevisedinhis(1979a)inwhich1ForapresentationofotherconsiderabledifcultiesfacingLewis'(1979a)accountofmentalcontent,seeMagidor(2015).
Iwillnotbedefendingtheaccountagainsttheseobjections.
NeitherwillIbeaddressingscepticismastowhetherthereisanydistinctivekindofdeserepresentation(interalia,CappelenandDever2013).
123Synthese(2020)197:2039–20502041hecitesseveralarguments-by-thought-experimentfortheclaimthatanadequatetheoryofintentionalitymustrecogniseanirreduciblekindofindexicality:thephenomenonofdeseattitudes.
AsLewislatersummarized:Thecontentfulunityistheentiresystemofbeliefsanddesires[…].
Itscontentisdened,insofarasitisdenedatall,byconstitutiverationalityonthebasisofitstypicalcausalrole.
Thecontentisintherstinstancenarrowanddese(1999:p.
324).
2ConsidertheplightofRudolfLingens,anamnesiaclostinMainlibrary,Stanford.
Inanattempttodiscoverwhoandwhereheis,hereadsmanybooks,includingonewhichisinfactabiographyofhisownlifeandanotherwhichisinfactadescriptionofMainlibrary.
UnfortunatelyforLingens,whilehemaylearnthatMainlibraryisnexttoHoovertower,[h]estillwon'tknowwhoheis,andwhereheis,nomatterhowmuchknowl-edgehepilesup,untilthatmomentwhenheisreadytosay,'Thisplaceisaisleve,oorsix,ofMainLibrary,Stanford.
IamRudolfLingens.
'(Perry1977:p.
492).
Theconclusiondrawnisthatnotallknowledgeispropositionalknowledge,wherepropositionsarestipulatedtobesetsofpossibleworlds.
Lingensmighthaveallofthatsortofknowledgeandyetstillfailtoknowwhoandwhereheis.
Lingensneedsmoreinformationthanisgivenbyapartitioningofthesetofworlds.
CallthedistinctivesortofknowledgelackedbyLingensdeseknowledge.
Amorene-grainedsortofcontentisrequiredtocapturethedesestateexpressedbythesentence'IamRudolfLingens'.
Thekindofcontentwemustseekwillpartitionnotonlypossibleworldsbuttheindividualsatthoseworlds.
3Lewis(1979a)proposedthatweconvenientlytaketheobjectsofdesestatestobeproperties.
Apossibleworldscontentdeterminesasetofworlds:thoseatwhichthecontentistrue.
Andforanysetofworldswemaytalkofthecorrespondingworldsetproperty:thepropertyofbeingataworldinthatset.
Thissufcestoestablishthatpropertiesareatleastasne-grainedaspossibleworldscontents.
However,proper-tiesalsogofurther:ifxinstantiatespropertyFwhilesomeworldmateydoesnot,Fcannotcorrespondtoaproposition.
AccordingtoLewis(1979a),wecanthensaythatwhatLingensneedstodo,inordertondoutwhoandwhereheis,isnottobelievesomepossibleworldscontentbuttoself-ascribesomeproperty:to'locate'himselfnotonlyamongworldsbutwithinthem.
Inparticular,Lewis'(1979a)conclusionisthatLingens'revelationinvolvessomethingmorethanjusttheself-ascriptionofaworldsetproperty.
Afterall,learningthatMainlibraryisnexttoHoovertowerdidnothelpLingensndoutwhereheis.
Lingens'revelationmustinvolvetheself-2SeealsoLewis(1986:p.
36).
3Perry's(1977)ownproposalwastoinsteadsuggestthatthebeliefrelationistertiary:wehavetheagent,thecontentbelieved,andtheagent'sbeliefstate.
1232042Synthese(2020)197:2039–2050ascriptionofamorene-grainedproperty,onewhichcutsacrosstheindividualsatworlds.
4Thenotionofself-ascriptionisintroducedcasuallybyLewis(1979a:p.
518)astherelationasubjectmustbeartoapropertyinordertocountasentertainingadesebelief.
5WemayalsofollowLewis(1979a)intranslatingtalkofproperty-contentsintoananalogueofwhatQuine(1968)calledcenteredworldscontents,tradinginapropertyforasetoforderedpairsofaworldandanindividualatthatworld.
AsLewissuggests,"[a]classofcenteredworldscorrespondstoaproperty"(1979a:p.
532).
6Theideaisthatbothkindsofcontentareeligibletoplaythetheoreticalroleofaccommodatingthedese:"centeredworlds[also]amounttopresentationsofpossibleindividuals"(1983a:p.
25,n.
18).
ThattheseareintendedbyLewisastwowaysofsayingthesamethingdespitethelatterinvolvingnotalkofself-ascriptionmightraiseprimafaciesuspicionsabouttheallegedessentialityofthatnotionforLewis'(1979a)account.
Grantingtheassumptionthatpropertiescaningeneralbematchedupone–onewithsetsofcenteredworlds,theresults,forLewis,arethefollowingtwoequivalentcharacterisationsofdesebelief.
Beliefdese:Sbelievesdese(atw)thatsheisFiff(i)everycenteredworldinthesetofcenteredworldscompatiblewithS'sbeliefs(atw)issuchthatsisFatw.
Or,equivalently,(ii)Sself-ascribes(atw)λx·xisFatw.
7Sincepropertiesself-ascribedareatleastasne-grainedaspossibleworldscontentsbelieved,itshouldbepossibletoreduceallbelieftodesebelief.
Notoriously,thisiswhatLewis(1979a)proposes.
Tobelievethepropositionthatcyanoacrylategluedissolvesinacetoneistoself-ascribethepropertyofbeinglocatedwithinthesetof4AsHolton(2015:p.
402)observes,whatLingensreallyneedstondoutwhoandwhereheisis'break-throughknowledge':deseknowledgewhichconnectsupwiththededictoknowledgehegainsinthelibrary.
Whatkindsofpropertiesisitpossibletoself-ascribeInshort,anywayanindividualcouldbe.
Ifyouweretobelieveyouwereapoachedegg,youwouldtherebyself-ascribeλx·xisapoachedegg.
SeeLewis(1979a:p.
530).
5Notethatself-ascribingaproperty-contentislocaltothecharacterisationofbelief.
Perhapsinthecaseofdesiringdesethatoneeatpastawecouldspeakofself-prescribingthecontentλx·xiseatingpasta.
Oncounterfactualattitudessuchasimaginingthat,andtheproblemstheyraiseforLewis'(1979a)account,seeNinan(2013).
6Onwhetheraone–onecorrespondencebetweenpropertiesandcenteredworldsholds,seeHolton(2015:pp.
403–405).
Thereisalsoaclusterofworriesherefamiliartounstructuredviewsofmentalcontent.
Ifpropertiesareonlyasne-grainedascenteredworlds,willSally'signorancethatbeingapodiatrististhesamepropertyasbeingafootdoctorresultinusconstruingherashavingirrationalbeliefsAndwillshecomeoutastriviallybelieving'logicaltruths'like'Iexist'(Kaplan1989)Isetthesekindsofworriesasideinthispaper.
7Iuselambdacalculusinthespecicationsofpropertiesforlucidity.
Holton(2015)observesthatwewillsometimeshavetoberesourcefulwiththepropertieschosentobecontentsofattitudes.
Forexample,thebeliefthat"Ichosemyselftoassessmyself[…]seemstoinvolveself-ascribingthepropertyofself-self-assessing-choosing"(2015:p.
408).
ThefollowingspecicationmakesLewis'proposalmuchmoretractable,however:λx·xchosextoassessx.
123Synthese(2020)197:2039–20502043worldsatwhichcyanoacrylategluedissolvesinacetone:thatis,λx·xinhabitssomew∈wwhere{w:cyanoacrylategluedissolvesinacetoneatw}(1979a:p.
518).
Ingeneral,tohaveadedictobeliefistoself-ascribewhatIearliercalledaworldsetproperty.
WhiletherearedifferencesbetweenthecaseofLingensandotherswhichLewis(1979a)considers(themadHeimson,thetwogods,theinsomniac…),theunderlyingargumentisthesame.
Inspiteofthefactthatthesubjectknowsalloftherelevantpropositions,thereissomeinformationshelacks.
ItistemptingtodrawananalogybetweenthissortofignoranceandtheignorancedisplayedinstandardFregecases.
Indeed,onemightworrythattotheextentthatthereisapuzzleaboutpropositionalattitudesraisedbycaseslikethatofLingenstheamnesiac,itisreducibletofamiliarpuzzlesofcognitivesignicance.
Thecase[…]givesusnoreasontoacceptarevisionarytheoryofcontent—itis,atbest,justanotherinstanceofFrege'spuzzle,[and]willbesolvedbywhateverourgeneraltheoryofopacityis…(CappelenandDever2013:p.
103).
AccordingtotheFregean[…]Lingenshas[not]learntallthe(relevant)truepropositions:thepropositionthatisexpressed(intherelevantcontext)usingthesentence'YouareintheStanfordlibrary'isnotthesamepropositionastheoneexpressedby['LingensisintheStanfordlibrary'][…].
TheLingenscasethusposesnospecialpuzzle(Magidor2015:pp.
254–255).
Incombinationwiththeconcernsastowhetherthenotionofself-ascriptionisingoodstanding,thislineofobjectionformsatwo-prongedattack.
Inresponse,thosewhoendorseLewis'abovecharacterizationofdeseattitudesmustdotwothings:(a)explainwhyweshouldtreatthetwosuperciallysimilarinformationalpuzzlesdifferently;(b)explainthe'unexplained'notionofself-ascription.
Inwhatremainsofthepresentsection,Iprovideabriefexplanationoftherstkind,clarifyingimportantdetailsofLewis'(1979a)picturealongtheway.
Section3addresses(b).
Thetransitiontotheproperty-contentframeworkaboveallowsauniedsolutiontobothPerry-andFrege-puzzles.
NotonlydidLewisreducethededictotothedese,hereducedthe(so-called)deretothedese.
OnLewis'(1979a,1983a)accountsubjectsentertainderethoughtsonlywithrespecttoarelationofacquaintance,whereSandoareacquaintedjustincasethereexistsan"extensivecausaldependenceof[S's]statesupon[o's];andthiscausaldependenceisofasortaptforthereliabletransmissionofinformation"(1979a:p.
542).
Considerthefollowingexample.
BatheBabylonianisfamiliarwiththeplanetVenusundertwodifferentguises.
HeknowsitasPhosphorus,themorningstar,andalsoasHesperus,theeveningstar.
HeisunawarethatthetwoareidenticalandbelievesthatPhosphorusisayoungstarwhileHesperusisold.
BabearsboththeP-relationandtheH-relationtoVenus,wherePistherelationxbearstoyiffyistheuniqueobjectwhichxseesshiningbrightlyinthemorningsky,andHistherelationxbearstoyiffyistheuniqueobjectwhichxseesshiningbrightlyintheeveningsky.
ThecontentsofBa'sbeliefsarethepropertiesλx·xbearsPuniquelytoayoungstarandλx·xbearsHuniquelytoanoldstar.
Bycharacterisingthecontentsofsubjects'beliefstatesinthisway,wecapturethedifferencesincognitivesignicanceanddispositionstobehaviourbetweenBa'sbeliefthatHesperusisvisible1232044Synthese(2020)197:2039–2050(λx·xbearsHuniquelytosomethingwhichisvisible)andhisbeliefthatPhosphorusisvisible(λx·xbearsPuniquelytosomethingwhichisvisible).
Ingeneral,then,wehavethefollowingcharacterisationofderebelief(Lewis1979a,1983a).
Beliefdere:Sbelievesdere(atw)thatxisFiff:(a)thereissomeacquaintancerelationRsuchthatSbearsRtoxuniquely(atw)(b)everycenteredworldinthesetofcenteredworldscompatiblewithS'sbeliefs(atw)issuchthatthethingtowhichsbearsRatwisFatw.
Or,equivalently(to(b)),(c)"…thesubjectself-ascribes[(atw)]thepropertyofbearingrelation[R]uniquelytosomethingwhichhasproperty[F(atw)]"(Lewis1979a:p.
539).
SothewayinwhichtheLewisianresolvestotreattheFregepuzzles,incontrastwiththedesepuzzles,isjustiedbythefactthatweultimatelyachieveauniedaccountofbothphenomena.
8Theburdenofexplainingtheelusivenotionofself-ascriptionremains,however.
3Self-ascription…evenifoneacceptsthatthereisaspecialproblemtobesolved[i.
e.
beyondthegeneralproblemofopacity],itisnottherevisionarytheoryofcontentthatdoesthesolving,buttheunexplainednotionofself-ascriptionofaproperty…(CappelenandDever2013:p.
103).
Ifthecharacterizationsin(i)and(b)wereavailabletoLewis,whydidheintroduce(ii)and(c)alongwiththeelusivenotionofself-ascriptionIsself-ascriptiondispensableafterallThissectionclariestheexplanatoryprojectinwhichLewiswasengagedandusesthisclaricationtoresolvetheseandothercriticalquestionsraisedattheoutsetofthepaper.
WhatthosewhoendorseeitherofLewis'characterizationsofbeliefdesemusttakeasprimitiveisnotsomeadhocattitude.
Lewis(1983b:p.
230)observesthatitispossibletorepresentthesemanticnotionofacontextofuseasanorderedpairofaworldandaspeakeratthatworld.
9Everythingelse,including'standardsofpermissibility'(Lewis1979b:pp.
340–341),'rankingsofcomparativesalience'(ibid.
348–50),'standardsofprecision'(ibid.
351–4),inter8WhileCappelenandDever(2013:pp.
103–108)andMagidor(2015)mentionthisresponse,theytakeittobeunsuccessfulbecauseitfailstoprovideanswerstofurtherproblems.
CappelenandDever'scomplaintsarethesubjectofSect.
3.
Magidor(2015:pp.
266–271)worriesthatthedescriptivistelementsofLewis'treatmentofdereattitudesareproblematic(seealsoHolton(2015:pp.
405–406)).
Ifocusononlytheformercomplainthere,sincemyaimistoshowthatLewis'(1979a)storycanbereconstructedasabonadetreatmentofthedese,evenifhisbroaderpictureofsingularthoughtsuffersdefects.
9Purelyforconvenienceofpresentationhere,Iassumethatagentsare(necessarily)time-slicesofindivid-uals.
Therearealternatives,ofcourse,dependingonone'smetaphysicalviews.
Ifagentsare(necessarily)world-boundthentheworldelementhereisredundant:acontextorcenteredworldissimplyanindividual'ssingletonset.
Ontheotherhand,ifwedenythatagentsare(necessarily)time-slicesofindividuals,wewillneedatimeelement.
Theimportantpointisthatcontextsandcenteredworldshavethesamestructure,whateverstructurethatis.
123Synthese(2020)197:2039–20502045alia,mayberecoveredfromtheseminimalcoordinates.
AccordingtoLewis(1980),theinputtocompositionalsemanticsforlanguageselicitingcontext-sensitivitywillbeapairofasentence-typeSandacontextofusec.
Theoutputwillbeanassignmentofatruth-valuetothesemanticvalueofSateveryindex(everyorderedpairofaworldandspeaker).
Atthispointwefaceachallenge.
Ifwhatgetsevaluatedfortruthisasententialsemanticvaluewithrespecttoeachindex,whatdoessuchanotion—truthatanindex—havetodowithanysortoftruthwhichmightplausiblynormlinguisticpracticeWhatwewantisforthesemanticvaluesofnaturallanguagesentencestoreceivetruth-valueswhich,bydefault,tellussomethingaboutourdefactoutterancesituations.
Ontheorthodoxwayofresolvingthischallenge,wechoosetosetorinitializetheindexparametervalues,bydefault,tothosecorrespondingtothegivenutterancesituation.
10AsLewisputsit,…wemustdistinguishtwosortsofindices:Originalindices,inwhichtheshiftablefeaturesareasdeterminedbythecontext[…];andshiftedindices,inwhichthatisnotso.
Truthinacontextistruthatanoriginalindex,andthisisthesemanticnotionthatisdirectlyrelevanttotruthfulspeech(Lewis1983b:p.
231).
Byaccessingthecontextofuse,wecanextractanotionoftruthwithcommunicativeimport—truthatacontextofuse—fromthenotionoftruthatanindex.
Specically:forallsentencesS,SistrueatciffthesemanticvalueofSistrueat.
Nowwhatdoesallthishavetodowithself-ascriptionInafootnotetothe(1983b)postscriptto'GeneralSemantics',Lewisremarks:Itwillnotescapethereaderof'AttitudesDeDictoandDeSe'[…]thatthese'contexts'arethesameasthe'subjects'thatself-ascribeproperties,andthatsetsofthemaretheself-ascribedproperties(1983b:p.
230,n.
2).
11Thistellingremarksuggeststhefollowingpicture.
Contextsarecenteredworlds.
Andsetsofcenteredworlds,orindeedofcontexts,areequivalenttoproperty-contents.
Asubject'stotalbeliefstate,thecontentofwhichisnarrowanddeseaccordingtoLewis,determinesasetofcenteredworlds(equivalently,acollectionofproperty-contents).
Forexample,thecontentexpressedbythebeliefthatcyanoacrylategluedissolvesinacetoneisasetofcenteredworlds(equivalently,thepropertyλx·xinhabitssomew∈Wwhere{W:cyanoacrylategluedissolvesinacetoneatW}).
Noticethatnoneofthesecontents,centeredworldsorproperties,canbeevaluatedfortruthsimpliciter.
Ifproperty-contents,forinstance,aretobetruth-evaluableatall,weneedaspecicationofanobjectwhichservestodeterminethetruth-valueoftheproperty-content.
Byanalogy,whatwoulditbeforustoevaluatethesentence-type'Itisraining',independentofanyspecicationoftimeorplaceThisiswherethesemanticresourcesaboveenterin.
Itistheprocessofinitialization—ofdeningtruthatacontextofuseviatruthatanindex—whichforcesourhandtoevaluatebelief10SeealsoHeimandKratzer(1998:p.
243),Kaplan(1989:p.
547)andMacFarlane(2014:p.
53).
11ThisremarkagainindicatesLewis'intendedequivalencebetweenpropertiesandsetsofcenteredworlds.
1232046Synthese(2020)197:2039–2050contentsinawaywhichprivilegestheworldandagentofthecontextofthebeliefoverthecoordinatesofsomearbitraryindex.
RecallthatLewisintroducedthenotionofself-ascriptioncasuallyjusttodenotetherelationasubjectmustbeartoapropertyinordertocountashavingadesebelief(1979a:p.
518).
Inlightoftheproposalsuggestedbythis(1983b)remark,itisthisprocessofinitializationwhichsecurestherightrelationbetweensubjectandsetofcenteredworlds(orproperty-content)believed.
12Talkofself-ascriptionisthenjustanintuitiveglossonworkperformedbythestipulativeprocessofinitialization.
ThisisourrstinsightintothecharacterofLewis'(1979a)proposal.
Self-ascriptionisnotsomeadhocattitude.
Itisaphraseusedtoexpresstherelationthatabeliever,S,bearstoaproperty-contentwhichistrueatcwhereSisthesubjectofc.
13IntheremainderofthissectionIprovideresponsestothreeworries.
EachoftheseresponseswillservetoclarifythereconstructionofLewis'(1979a)accountofdesebeliefIhavebeguntosuggest.
Thethirdworry,inparticular,willclarifywhatnotionsLewis'characterisationdoestakeasprimitive.
First,thereconstructionabovedrawsonremarksLewismadeaboutlanguage.
Inspiteoftheencouragementinthequoteabove(1983b:p.
230,n.
2),conclusionsaboutthenatureofthoughtdrawnfromconclusionsaboutthenatureoflanguagerequireseriousscrutiny.
Specically,indicesaredevicesusedbylinguisticsemanticiststocapturethedisplacementofsentencesacrossparameterssuchastimeandlocation.
Itisarguablyanecessaryconditiononpositinganindex-parameterinasemantictheoryforalanguagethattherebeasententialoperatorwhichshiftsthatparameter.
Doesthatmeanthatwehavetonotonlymakesenseofbutposit'Mentalese'index-shiftingoperatorstosupportLewis'claimsabouttheindex-relativityofbeliefNo.
Toseewhy,letusconsiderthedistinctionLewis(1980)emphasisesbetweensententialsemanticvalueandcontent.
14First,supposewechosenottorecogniseanysuchdistinction,afrmingthatthesemanticvaluesofsentencesarecontents(àlaKaplan(1989)).
Inthatcase,itwouldnotbeaplausiblenecessaryconditiononpositinganindex-parameterthattherebeasententialoperatorwhichshiftsthatparameter.
Fornotallconstraintsonthenatureofcontentcomefromsemantictheorising.
Lewis'(1979a)pointwaspreciselythatthoughtexperimentslikePerry's(1977)giveusgood,andgoodenough,reasontothinkofmentalcontentasanagent-relativeentity.
Ontheotherhand,supposeweweretorecogniseadistinctionbetweenthesemanticvaluesofsentencesandcontents.
Inthatcase,despiteLewis'(1983b)useoftheterm'indices'intheremarkquotedabove,itisclearthatLewis'intentwouldbetotalkaboutpointsofevaluation:sequencesofparametersagainstwhichcontentsaretobe12Specically,whenisthecontentofabeliefofsatworldw—whichistosayatcontextc,wherecis—thiscenteredworldscontentisevaluatedfortruthatc.
Itistrueatcjustincaseisamemberof.
13Arefereeforthisjournalhasnotedthatsimilarsuggestionsabouttheroleofself-ascriptioninLewis'(1979a)accountappearinRecanati(2007)andPagin(2016,especiallyp.
277):"[w]heneverarepresentationistokenedinthesubject'smind,thecontentoftherepresentationisevaluatedwithrespecttoasituationinvolvingthesubjectandthetimeandplaceofthetokening.
Inotherwords,thecontentisconstruedasapropertywhichisascribedtothecontextinwhichtherepresentationistokened"(Recanati2007:p.
269).
14Lewisappreciatesthepossibilityoftheorizingaboutthenatureofmentalcontentindependentof'psy-cholinguistic'theorizinganditswould-besemanticvaluesat(1980:p.
83).
123Synthese(2020)197:2039–20502047evaluated.
15Thenotionsofindexandpointofevaluationwerenotyetdistinguishedatthetimeofthe(1970)paperwhichhis(1983b)postscriptconcerns.
ButLewisdidlateremphasiseadistinctionbetweenthesetwonotions.
16Oncethatdistinctionisinplace,weopenthepossibilitytoevaluatingcontentswithrespecttoaparameter—forexam-ple,anagentorpossibleworld—forreasonssomewhatindependentofcompositionalsemantics.
Andoncethatpossibilityopensup,itbecomespossibletotheoriseaboutthenatureofmentalcontentsomewhatindependentof'psycholinguistic'semantictheorising.
17Here,again,Lewis'(1979a)pointwasthatthoughtexperimentslikePerry's(1977)giveusgood,andgoodenough,reasontothinkofmentalcontentasanagent-relativeentity.
Asecondworryconcernstherelationshipbetweenbelieverandcontentbelieved.
Ifproperty-contentsaretobetruth-evaluable,weneedaspecicationofanobject.
SinceLewis(1979a)claimsthatallthoughtisdesethought,weneedthepropertytobeevaluatedfortruthwithrespecttothebelieveratthecontextofthebeliefinquestion.
WhatdeterminesthatitisthebelieverLikewise,onthecenteredworldscharacterizationofmentalcontent,invirtueofwhatdoesthecentreofacenteredworldrepresentthebelieverIsaidabovethatinitialization—theprocessofdeningtruthatacontextofuseviatruthatanindex(orpointofevaluation)—iswhatenablesustoevaluatecontentsinawaywhichprivileges,bydefault,theworldandsubjectofthecontextofuse.
AsNinan(2008)haspointedout,thereissomethingmerelystipulativeabouttheanswertothissecondworry:"[thereis]animplicitstipulationthat,whenweconsideracenteredworldasacandidatedoxasticalternativeforsomeagentx,thecentreofthatcenteredworldrepresentsx"(59).
Truthatanindex,ortruthatapointofevaluation,bearslittlefamiliaritywiththenotionoftruthwhichnormslinguisticpracticeandinquiry.
Optingtodenetruthatacontextiswhatallowsustorecapturethefamiliarnotionoftruth.
InLewis'words:"Truthatacontextistruthatanoriginalindex[orcontext-initializedpointofevaluation],andthisisthesemanticnotionthatisdirectlyrelevanttotruthfulspeech"(1983b:p.
231).
Sothefactthatthecentreofacenteredworldcontentrepresentsthebelieverisnocoincidence.
Thisisexplicitlystipulatedintheintentionaltheory.
Moreover,becauseLewis(1979a:p.
518)introducesself-ascriptionjusttodenotetherelationasubjectmustbeartoapropertyinordertocountashavingadesebelief,andbecauseallbeliefisdesebelief,whatitisforStoself-ascribeproperty-contentP,itturnsout,isfortheprocessofinitializationforPtodeterminethatSisthebelieveratthecontextatwhichPistobeevaluatedfortruth.
Athirdandnalworry.
Evenifthisstoryelucidatesthemechanicsofself-ascription,howdoesitgetusbeyondatreatmentofmere'x-ascriptionbyx',asetofattitudesofwhichthedeseisapropersubset18Foritispossibletoascribeapropertytooneself15TouseKaplan's(1989)distinction,Lewis(1983b)isnottalkingaboutcontent-generatingparametersbutcontent-evaluatingparameters.
16OnLewis'distinctionbetweensententialsemanticvalueandcontent,seehis(1980)andRabern(2017).
17AsRabern(2012)putsit:"Theoristsworkingonthenatureofassertoriccontent(ormentalcontentandinformation)shouldwelcomethisdistinction,asitallowsthemtotheorizeaboutthenatureofcontent,somewhatliberatedfromtheconnesofthestrictcompositionalityprinciple"(94–5).
18Thisobjection,anditsphrasing,isduetoCappelenandDever(2013).
1232048Synthese(2020)197:2039–2050withoutself-ascribingthatproperty.
ConsiderKaplan's(1989:p.
533)exampleofascribingthepropertyofbeingonretothatman,wherethemaninquestionis,unbeknownsttoKaplan,himself.
Itwillserveuswelltorememberhowthingsworkontheclassicalpossibleworldssemanticsforbelief(Hintikka1962).
Asubject'sbeliefstateistakentodetermineasetofpossibleworlds:thoseworldswhicharecompatiblewithwhatthesubjectbelieves.
Thisnotionofcompatibilitywithwhatasubjectbelievesistakenasprimitive.
Thegoal,inshort,istocharacterizethesubject'sbeliefstateinawaywhichmakesvariousdoxasticandlogicalrelationsexplicit.
ForLewis(1979a),ofcourse,beliefsimpliciterwillnotdo.
ThisispreciselythepointoftheinformationalpuzzlesaboutLingensandothercharacters,recalledinSection2.
WhatLewis'(1979a)decisionamountstoistotakeasprimitivethenotionofasetofcenteredworlds(or,equivalently,aproperty-content)beingcompatiblewithwhatasubjectbelievesdese.
Inotherwords,Lewis'(1979a)primitivejustisdesebelief.
19ThebiconditionalsinBeliefdese,above,donothavethestatusofreductiveanalysesofdesebelief.
Lewis(1979a)simplydoesnotpursueanysuchanalysis.
Thetargetnotionisinfactimplicitlyappealedtoontherightsideofthebiconditionals.
Aswemightsaymoreexplicitly:Beliefdese(explicit):Sbelievesdese(atw)thatsheisFiff:(i)everycenteredworldinthesetofcenteredworldscompatiblewithS'sdesebeliefs(atw)issuchthatsisFatwOr,equivalently,(ii'*)Sbelievesdese(atw)λx·xisFatwForLewis,allbeliefisdesebelief.
Andallbeliefexpressesacontentwhichistobeevaluatedfortruthatacontext.
ThisistheimportoftheirreduciblesortofindexicalityneededtotreatthepuzzleaboutLingens.
ThedeseisnotanalysedbuttakenasafundamentalcomponentofLewis'intentionaltheory.
Theaimistoprovideanon-reductivecharacterizationofbeliefdese,analogoustoHintikka's(1962)non-reductivecharacterizationofbelief'perse'.
This,accordingtoLewis(1979a)iswhatweneedifweare'tocharacterizethestatesofLingens'head;tospecifytheircausalroleswithrespecttobehavior,stimuli,andoneanother'.
204ConclusionTosummarise,whicheverwayyousliceit—(i*)or(ii*)—whatissoughtisanon-reductivecharacterisationofbeliefdese.
Lewisachievesthischaracterisationbystipulating(inthewayofapossibleworldssemanticistwithbeliefsimpliciter)thatthephenomenonofbeliefdesebetrackedbythespecicationofacertainsortofcontent.
Suchcontentcanonlybeevaluatedfortruthatacontext;acontextprovid-ingabeliever.
Self-ascribingisnotsomethingthesubjectdoes.
Itisaphraseusedto19Weber(2016:p.
257)makesasimilarobservationaboutthestatusofLewis'proposalasagainstHintikka's(1962).
20Lewis(1979a:p.
526).
123Synthese(2020)197:2039–20502049expresstherelationbornebyStoaproperty-contentwhichistrueatc,whereSisthebelieveratc;anarrangementstipulatedtotrackS'sdesebeliefs.
CappelenandDever(2013)arerightthatamereshiftintheso-calledobjectsofbeliefisnotwhatsolvesthethoughtexperimentstowhichLewis(1979a)appealedasmotivation,andHolton(2015)isrightthatanewprimitiveisintroducedinordertosupportthesolutionheprovided.
Butthatprimitiveiscompatibilitywithasubject'sbeliefsdese,replacingtheprimitiveoftheclassicalpossibleworldsaccount,compatibilitywithasubject'sbeliefsperse.
Thisismadeexplicitin(i*)and(ii*),above.
WhetherornotLewis'characterizationofdesebeliefiscorrect,then,ifitisproblematicforthereasonstowhichrecentcriticshaveappealed,thentheoristswhoattributeevenpossibleworldscontentstothinkers,andtheoristswhoingen-eralattributecontentswhichcanonlybeevaluatedfortruthatacontext,facethesameproblems.
Thisisnot,ofcourse,tosaythatsuchcriticswouldbewrongtohavegripeswithsuchprimitives,orwiththeexplanatoryinterestoftheresultingprojects.
Insofarastheseconstitutetheirgripes,however,theyapplyfarwiderthantoLewis'(1979a)characterizationofdesebelief.
Correctlyunderstood,then,Lewis'(1979a)characterizationofdesebeliefisresistanttomuchofthecriticismithasfacedintherecentliterature.
OpenAccessThisarticleisdistributedunderthetermsoftheCreativeCommonsAttribution4.
0Interna-tionalLicense(http://creativecommons.
org/licenses/by/4.
0/),whichpermitsunrestricteduse,distribution,andreproductioninanymedium,providedyougiveappropriatecredittotheoriginalauthor(s)andthesource,providealinktotheCreativeCommonslicense,andindicateifchangesweremade.
ReferencesCappelen,H.
,&Dever,J.
(2013).
Theinessentialindexical.
Oxford:OxfordUniversityPress.
Heim,I.
,&Kratzer,A.
(1998).
Semanticsingenerativegrammar.
Oxford:Blackwell.
Hintikka,J.
(1962).
Knowledgeandbelief:Anintroductiontothelogicofthetwonotions.
Ithaca,NewYork:CornellUniversityPress.
Holton,R.
(2015).
Primitiveself-ascription:Lewisonthedese.
InB.
Loewer&J.
Schaffer(Eds.
),TheBlackwellcompaniontoDavidLewis(pp.
399–410).
Oxford:Blackwell.
Kaplan,D.
(1989).
Demonstratives.
InJ.
Almog,J.
Perry,&H.
Wettstein(Eds.
),ThemesfromKaplan(pp.
481–563).
Oxford:OxfordUniversityPress.
Lewis,D.
(1970).
Generalsemantics.
Synthese,22(1),18–67.
Lewis,D.
(1974).
Radicalinterpretation.
Synthese,27,331–344.
Lewis,D.
(1979a).
Attitudesdedictoanddese.
PhilosophicalReview,88,513–543.
Lewis,D.
(1979b).
Scorekeepinginalanguagegame.
JournalofPhilosophicalLogic,8,339–359.
Lewis,D.
(1980).
Index,context,andcontent.
InS.
Kanger&S.
hman(Eds.
),Philosophyandgrammar(pp.
79–100).
Dordrecht:Reidel.
Lewis,D.
(1983a).
Individuationbyacquaintanceandbystipulation.
PhilosophicalReview,92,3–32.
Lewis,D.
(1983b).
Postscriptsto'Generalsemantics'.
Inhisphilosophicalpapers(Vol.
1,pp.
230–232).
Oxford:OxfordUniversityPress.
Lewis,D.
(1986).
Onthepluralityofworlds.
Oxford:Blackwell.
Lewis,D.
(1999).
Reductionofmind.
Inhispapersinmetaphysicsandepistemology(pp.
291–324).
Cam-bridge:CambridgeUniversityPress.
MacFarlane,J.
(2014).
Assessmentsensitivity:Relativetruthanditsapplications.
Oxford:OxfordUniversityPress.
Magidor,O.
(2015).
Themythofthedese.
PhilosophicalPerspectives,29,249–283.
Ninan,D.
(2008).
Imagination,content,andtheself.
Ph.
D.
thesissubmittedtotheMassachusettsInstituteofTechnology.
1232050Synthese(2020)197:2039–2050Ninan,D.
(2013).
Self-locationandother-location.
PhilosophyandPhenomenologicalResearch,87(2),301–331.
Pagin,P.
(2016).
Desecommunication.
InM.
García-Carpintero&S.
Torre(Eds.
),Aboutoneself:Desethoughtandcommunication(pp.
272–306).
Oxford:OxfordUniversityPress.
Perry,J.
(1977).
Fregeondemonstratives.
PhilosophicalReview,86,474–497.
Quine,W.
V.
O.
(1968).
Propositionalobjects.
Crítica:RevistaHispanoamericanade.
Filosofía,2,3–29.
Rabern,B.
(2012).
Againsttheidenticationofassertoriccontentwithcompositionalvalue.
Synthese,189(1),75–96.
Rabern,B.
(2017).
Abridgefromsemanticvaluetocontent.
PhilosophicalTopics,45(2),181–207.
Recanati,F.
(2007).
Perspectivalthought.
Oxford:OxfordUniversityPress.
Weber,C.
(2016).
Beingatthecentre:Self-locationinthoughtandlanguage.
InM.
García-Carpintero&S.
Torre(Eds.
),Aboutoneself:Desethoughtandcommunication(pp.
246–271).
Oxford:OxfordUniversityPress.
123