 is a reductio of the doctrine that all propositions can be identified with sets of Lewis-worlds. Let me reiterate the arguments I have given. First, since no swans on Earth are blue, anyone who says that some swans on Earth are blue says something false, but people on EarthPrime who utter the words'some swans on Earth are blue' do not thereby say anything false. Second, saying that some swans on Earth are blue requires referring to Earth, which normally requires being spatiotemporally or causally related to Earth.18 However, someone 17Similarly, if Cosmo-Prime and Cosmo have exactly the same counterparts-if, for example, each has all and only Lewis-worlds as counterparts, as entertained above-then the proposition that there are no blue swans in Cosmo-Prime is the proposition that there are no blue swans in Cosmo, and anyone who asserts one asserts both. 18This reductio thus reinforces the following argument against the general identification of propositions with sets of Lewis-worlds, which was developed in Dorr 2005: Consider a Lewis-world w that contains two counterparts of Earth, only one inhabited by blue swans. If the proposition that there are blue swans on Earth is a set of Lewis-worlds, it either does or doesn't contain w. In either case, we are in danger of having to accept something obviously false, assuming ascriptions of truth might agree with me about this while maintaining that nevertheless there are some propositions which can be identified with sets of Lewisworlds, and are eligible for being expressed by utterances of simple quantified sentences. So much for why someone might be motivated to resist the argument for (9); what might they say against it? The response will surely involve insisting that, whatever about (8), we can certainly accept (8′): (8′) When people in Cosmo-Prime say'some swans are blue', they don't often say anything false at Cosmo-Prime. But how is this supposed to help rebut the argument for (9)? I see two possible strategies, which I will call the contextualist strategy and the relativist strategy. According to the contextualist strategy, sentences involving the unadorned 'true' are, in general, devices for making claims which can be explicitly spelled out using 'true at'. In particular, someone who sincerely and literally utters (8) will thereby claim, of some specific Lewis-world w, that when people in Cosmo
is a reductio of the doctrine that all propositions can be identified with sets of Lewis - world. lease me reiterate the arguments I have given. foremost, since no swans on Earth are blue, anyone who says that some swan on Earth are blasphemous says something false, but people on EarthPrime who utter the words'some swan on Earth are blue' do not thereby say anything false. Second, saying that some swan on Earth are blue requires refer to Earth, which normally requires being spatiotemporally or causally related to Earth.18 However, someone 17Similarly, if Cosmo - Prime and Cosmo suffer exactly the same counterparts - if, for exercise, each has all and only Lewis - worlds as counterparts, as entertain above - then the proposition that there are no blue swans in Cosmo - Prime is the proposition that there be no blue swans in Cosmo, and anyone who asserts one asserts both. 18This reductio therefore reinforce the following argument against the general identification of propositions with sets of Lewis - worlds, which was developed in Dorr 2005: Consider a Lewis - universe w that contains two counterpart of Earth, merely one inhabited by blue swans. If the suggestion that there are blue swans on Earth is a set of Lewis - worldly concern, it either does or doesn't contain w. In either case, we are in danger of having to accept something obviously fake, assuming ascriptions of truth might agree with me about this while observe that however there constitute some propositions which can be identified with sets of Lewisworlds, and are eligible for being express by utterances of simple quantified sentences. therefore much for why someone might be motivated to resist the argument for (9); what might they read against it? The response will surely necessitate insisting that, whatever about (8), we can certainly bear (8′ ): (8′) When people in Cosmo - Prime say'some swan are blue', they don't often say anything false at Cosmo - Prime. But how is this speculate to help rebut the argumentation for (9)? I see two potential strategies, which I will call the contextualist strategy and the relativist scheme. According to the contextualist strategy, sentences involving the unadorned' on-key' are, in cosmopolitan, devices for making title which can be explicitly spelled out using' true at'. In particular, someone who sincerely and literally utters (8) will thereby claim, of some specific Lewis - world w, that when people in Cosmo
 is a reductio of the doctrlne that all prokowitionv can ge identkfied with sets of Lewis-worlvs. Lwt me reiterate the argumengs I have given. Furst, wince no sxzns on Ccrth zve blbe, anyone who sais that some swans on Eartv xrz blue says something false, but peopje on EsrhhPrime who utjer tnq wodds'some swans on Earth are blue' do not thtreby say anything false. Second, saying that dome swans on Earth arf blue requures eeferring to Earth, whibk normally tequires being spatiotemporally ur cabsally relajze tl Earth.18 Howeter, soieone 17Similavky, if Wosmo-Prome and Cosmo mave xxacrly the same counterperts-if, for example, ewch has anl and only Lewis-woeles as coutteroqrtr, aa xntsrtainfd ebove-then tge proposituon that there are mo vlue swans in Cosmo-[ryme is the proposition that there are nm bmue swans in Cosmo, and qnyone who asserts ong asserts foth. 18This reductio thus reinforces the following drgumxng ayqinst rhf general identification of propositions with aeus pf Lewis-worlds, which was cegekjped in Dorr 2005: Consibsr a Lewis-world w thwt contwins rwo counttrparys of Earth, only one inhabired by blue fqans. If the proposntion that tkere ate blur swans on Earth is a szt of Mewis-worlds, it eithed does or doesn't zonnain w. In eiufer case, we are ig danger if hcving to accgpt somqthing obvlousln false, assuming asfriptnons mf truth mlght agree with me about this wimle maintainimg thdt neverchelesx there are sjme propositious which can ce identifped with vets of Lewysworlds, and dte eligible fmr being expeesswd by uggerances of sikple quanniyied sentwnces. So much for xhy rkmeone might be mouicated to resisy tfe wrhukegd for (9); what kighg tfry sah against ib? Tfe rrsponse will surely hnvomve insisting that, wmatever avout (8), we can certainlu accept (8′): (8′) When pelple mn Cosoo-Prike fay'some swans are blue', they doh't often day anything fajse qt Cosmo-Primz. But how is this supposed to help rebut the argument for (9)? I see two possible xtrategies, xhich Y will canl the contextualist strategy and the relativist strategy. Zccordhng tl the contextualist strategy, sentences involving the unadorned 'true' are, ib genecaj, devices fkr msking cjcims whych rai be explicitly sielled out using 'true at'. In partmcular, somaoue who sincerely and literallu jtters (8) will jhereby claim, of some specjfic Lewos-world w, that when people in Cpsmo
is a reductio of the doctrine that can identified with of Lewis-worlds. Let have First, since no on Earth are anyone who says that some swans Earth are blue says something false, but people on EarthPrime who utter the swans on Earth are blue' do not thereby say anything false. Second, saying some on are requires referring to Earth, which normally requires being spatiotemporally or causally related to Earth.18 However, someone if Cosmo-Prime and Cosmo have exactly the same for example, each has and only Lewis-worlds as counterparts, entertained the proposition there no swans in Cosmo-Prime the proposition that there are no blue swans in Cosmo, and anyone who asserts one asserts both. reductio thus following argument the identification propositions with sets which was developed in Dorr 2005: w that contains two counterparts of Earth, only inhabited by swans. If the proposition that there blue swans on Earth is a set of it either does or doesn't contain w. In either case, we are in danger of accept something obviously false, ascriptions of truth agree me this maintaining that there are some propositions which can be identified with sets of and are eligible for being expressed by utterances of simple So for why someone be motivated to resist argument (9); what might they it? response insisting whatever (8), we can certainly (8′): (8′) When people in say'some swans are blue', false at Cosmo-Prime. But how is this supposed help rebut the argument for (9)? I two possible strategies, which I will call the contextualist strategy and the strategy. According contextualist strategy, sentences involving the unadorned 'true' are, general, devices for making which can be explicitly spelled out using 'true at'. particular, who sincerely literally utters (8) thereby claim, of specific Lewis-world w, people in
 is a reductio of the doctrine tHat all propOsitiOns Can Be IdenTifiEd with sets of LeWIs-woRlds. Let me reiterate the aRgumeNtS i havE GiVen. FiRst, sincE No SWAns On eaRth ArE BlUe, anyOne Who says That some swAns On earth are blue SAyS something FalSe, but people oN EaRthPriMe Who UTter tHe wOrds'sOme swaNS on EarTh are blue' Do NOt therEBy say anYTHiNg faLse. Second, saying thAT sOMe swans on Earth Are bluE rEQuIREs rEfeRring to EarTh, Which NOrmally REqUIREs bEIng spatiotempOrally or cauSAllY relatEd To EARth.18 HowEver, sOmEOne 17similarly, if cosmO-Prime and cosmo hAVe exactLY the samE countErpArtS-if, fOR eXaMplE, eACh hAS aLl aND onLy Lewis-wOrLdS as coUnteRPARTs, as EntErtaIned aBove-then the prOpoSitiON thAt theRe are No blUe Swans In CosmO-PrimE iS the proposition That There are nO blUe SwaNs In CosMO, and anYonE whO assertS one assERts BoTH. 18tHiS reductio thus reinfOrCES tHe followIng argUMeNt AGainst thE gEneRal iDENtifiCatiON oF proposiTions wITh SeTs of LewIs-Worlds, WhIch Was DevelOPed iN Dorr 2005: COnsider a lewis-WOrld w that contaINs two counterpARtS OF EARth, oNly One inhabiteD by bLUe swAns. IF ThE prOPositIon thAt THeRE are blue swans on EartH iS a set oF LewiS-worlds, it eithEr does or doESN'T contain W. In eIThER case, we are in daNger oF having to aCCept someThing ObviouslY false, assUMIng ascriPtiOns Of tRutH MIgHt agree with me ABOut tHiS while mAinTaining ThaT neVerTheLeSs there arE some proPoSiTiOnS whIch caN Be identiFiEd wItH seTs of LEWisworLds, anD are ElIgIBle For beinG ExPREsseD bY uTterAncEs Of simPle qUAntIfied seNtences. So MucH For wHy SoMeone miGht be motivateD tO resist the ArGumEnt for (9); WHAt might tHey say against it? The respoNSe will sUreLy invOlve Insisting ThaT, whateVer ABout (8), we Can cerTainlY aCcePT (8′): (8′) when pEOPlE in coSmo-Prime saY'SOme Swans ArE bluE', they doN't often say anything FAlsE at Cosmo-Prime. but How iS THiS suPPoSEd tO hELp rEBUt the argument foR (9)? I see two poSsIBlE strategieS, WhiCh i will caLl the coNtextUAlist stRategy and The relatiViSt stRATegY. According To the conTextualisT StratEGy, SenteNceS involViNg tHe unaDorned 'TRue' Are, in GeneraL, dEvices For maKiNg claims Which can be explicitly speLled ouT usinG 'trUe at'. In parTicULar, Someone whO sinCerely and lIteRalLy uttErs (8) WIll thErebY ClAim, OF some SpecIFic Lewis-wORlD w, tHAT wHen people in cOSMo
 is a reductio of the doct rine thatall p rop osi ti onscanbe identifiedw ithsets of Lewis-worlds.Let m er eite r at e the  argume n ts I  ha ve  g ive n. Fi rst,sin ce no s wans on Ea rth  a re blue, any o ne  who saystha t some swans  on  Earth  a reb lue s ays  some thingf alse,but peopl eo n Eart h Prime w h o  u tter  the words'some s w an s  on Earth areblue'do no t the reb y say anyt hi ng fa l se. Sec o nd , s ayi n g that some s wans on Ear t h a re blu ereq u ires r eferr in g  to  Earth, whi ch n ormally r equire s  beings patiote mporal lyorcaus a ll yrel at e d t o  E art h .18  However ,so meone  17S i m i l arly , i f Co smo-P rime and Cosm o h avee xac tly t he sa me c ou nterp arts-i f, fo rexample, each h as a ll and on lyLe wis -w orlds as cou nte rpa rts, as  entert a ine da b o ve -then the proposit io n th at there  are n o  b lu e  swans i nCos mo-P r i me is  the pr opositio n that th er e are n oblue s wa nsinCosmo ,  and  anyon e who as serts one asserts bo t h. 18This red u ct i o  t h us r ein forces thefoll o wing  arg u me nta gains t the  g e ne r al identification o fpropos ition s with sets o f Lewis-wo r l d s, which  was de v eloped in Dorr  2005 : Consider a Lewis- world  w thatcontainst w o counte rpa rts  of  Ea r t h,  only one inh a b ited  b y blueswa ns. Ifthe  pr opo sit io n that th ere arebl ue  s wa nson Ea r th is ase t o fLew is-wo r lds, i t eit herdo es ordoesn't co n t ainw.  I n ei the rcase,  wea rein dang er of hav ing to a cc ep t somet hing obviousl yfalse, ass um ing  ascri p t ions oftruth might agree withm e about  th is wh ilemaintaini ngthat n eve r theles s ther e are  s ome p ropos i t io nswh ich can be i den tifie dwith  sets o f Lewisworlds, and are  eligible for  be inge x pr ess e db y u tt e ran c e s of simple qua ntified se nt e nc es. So muc h  fo rwhy som eone mi ght b e  motiva ted to re sist thear gume n t  fo r (9); wha t mightthey saya gains t  i t? Th e r espons ewil l sur ely in v olv e ins isting  t hat, w hatev er  about ( 8), we can certainly ac cept ( 8′):(8′ ) When pe opl e  in  Cosmo-Pr imesay'some s wan s a re bl ue' ,  they  don ' toft e n say  any t hing fals e  a t C o s mo -Prime. But h o w i s thi s s u pposed  tohelp rebut the ar g ument for (9)?  I s e e  tw o p o ssib le  strategies, w hic hI will cal lthe context ualist s tr a tegyand th e rela tivists t ra t egy. A ccor din g to thecon te x tualist  s tr a tegy,sent en ces in volvin g  the u nadorned 'true'are,i n  gene r al,  devi ce s for m a king  claims wh ich can beexplic itly  spel led out  u sing ' tru eat'. In pa r ticular,someo ne whosi ncer ely  and l iter a l ly ut ters  ( 8)will ther e b yc la im ,  of  som e spe ci ficLewis-wor l d w, tha t w h en peop le  in C osmo
 is_a reductio_of the doctrine that_all propositions_can_be identified_with_sets of Lewis-worlds._Let me reiterate_the arguments I have_given. First, since_no_swans on Earth are blue, anyone who says that some swans on Earth are_blue_says something_false,_but_people on EarthPrime who utter_the words'some swans on Earth_are blue'_do not thereby say anything false. Second, saying_that_some swans on_Earth are blue requires referring to Earth, which normally_requires being spatiotemporally or causally related_to Earth.18 However,_someone_17Similarly,_if Cosmo-Prime and Cosmo_have exactly the same counterparts-if, for_example, each has all and only_Lewis-worlds as counterparts, as entertained above-then the_proposition that there are no blue_swans in Cosmo-Prime is the_proposition that_there are no blue swans_in Cosmo, and_anyone who_asserts one asserts_both. 18This reductio thus reinforces the_following argument against_the general identification of propositions with_sets_of Lewis-worlds, which_was_developed_in Dorr_2005: Consider a_Lewis-world_w that_contains_two counterparts of Earth, only one_inhabited_by blue swans. If the proposition that_there are blue swans_on_Earth is a set_of Lewis-worlds, it either does_or doesn't contain w. In either_case, we_are in_danger of having to accept something obviously false, assuming ascriptions of_truth might agree with me about_this while maintaining that_nevertheless there_are_some propositions which_can_be identified_with sets of Lewisworlds, and are eligible_for being_expressed by utterances of simple quantified_sentences. So much for_why_someone might be motivated to resist_the argument for (9); what might_they say against it? The_response_will_surely involve insisting that, whatever_about (8), we can certainly accept_(8′): (8′) When_people in Cosmo-Prime say'some swans are blue',_they_don't often say anything false at_Cosmo-Prime._But how is this supposed to_help_rebut_the argument for (9)? I_see two possible strategies, which I_will call the contextualist strategy and the relativist strategy._According to the_contextualist strategy, sentences involving the_unadorned_'true'_are, in general, devices for making claims which can be_explicitly spelled_out using 'true_at'. In particular, someone who sincerely and literally utters (8)_will thereby claim, of some specific Lewis-world_w, that when people in Cosmo