IamgratefultoDarrenBradleyLisaCassellKennyEaswaranChrisMeachamRogerWhiteananonymousrefereeandaudiencemembersatAmherstCollegefortheirhelpfulfeedbackandcriticismÕ óJ153149Z132Z149 ID: 847321
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1 TuA§¶u±
TuA§¶u±§DêuIou§uhuJonathanWeisbergUniversityofTorontoAf«±§Zh±.Iarguethattherationalebehindthene-tuningargumentfordesignisself-undermining,refutingtheargument'sownpremisethatne-tuningistobeexpectedgivendesign.In(Weisberg,óþÕþ)Iarguedoninformalgroundsthatthispremiseisunsupported.White(óþÕÕ)counteredthatitcanbederivedfromthreeplausibleassumptions.ButWhite'sthirdassumptionisbasedonafallaciousratio-nale,andisevenobjectionablebythedesigntheorist'sownlights.eargumentthatshowsthis,theargumentfromdivineindierence,simultaneouslyexposesthene-tuningargument'sself-underminingcharacter.esameargumentalsoanswersBradley's(forthcoming)replytomyearlierobjection.Tune-tuningargumentfordesignrestsonarelativelynewdiscoveryincos-mology:thatouruniverse'sconstantsandinitialconditionsareprecariouslybalancedtoallowfortheexistenceofintelligentlife.Outofthewiderangethesevaluescouldhavetaken,onlyasmallsubsetyieldauniversecapableofsupportingintelligentlife.Andyettheactualvaluesdolieinthatsmallsubset.isdiscoveryissurprisingifouruniversewasnotdesigned.But,theargumentalleges,itistobeexpectedifouruniversewascreatedbyadesignerintentoncreatingintelligentlife.usthediscoveryofne-tuningtsbetterwiththedesignhypothesisthanwithitsnegation.LetDbethedesignhypothesisandNthenewdiscoverythatouruniverseisne-tuned.eargumentturnsoncomparingtheprobabilitiesthatDand Deachconferonthenewevidence,N.Accordingtotheargument,pNSDApNS D,soNsupportsDover D.Butinmy(óþÕþ)Iworriedthatthiscomparisonoverlooksanoldpiecebackgroundknowledge,thatlifeexists.LettingObetheoldnewsthatlifeexists,thecorrectstatementofthene-tuningargumentis:pNSD,OApNS D,O.(Õ)eLikelihoodPrinciple:ifpESHApES HthenEsupportsHover H.(ó)SoNsupportsDover D(givenO).(ì) IamgratefultoDarrenBradley,LisaCassell,KennyEaswaran,ChrisMeacham,RogerWhite,ananonymousreferee,andaudiencemembersatAmherstCollegefortheirhelpfulfeedbackandcriticism.Õ óJZ±ZWu«fu§Myobjectionwasthatpremise(Õ)isnotcompelling.Wehaveknownformanyyearsthatouruniversecontainsintelligentlife,andthusthatthecons
2 tantsandinitialcon-ditionshadtobeinthera
tantsandinitialcon-ditionshadtobeintherangenecessarytosupportsuchlife.Whatwedidnotknowwaswhetherthatrangewaswideornarrow.InWhite's(óþÕÕ)helpfulterminology,whatwedidnotknowwaswhetherthelawsofouruniverseareªstringentºorªlaxº.Wehavenewlylearnedthattheyarestringent.But,theobjectiongoes,thisisnotsomethingwehavereasontoexpectatthehandsofadesigner,sinceshecouldhavechosenlaxlawsinstead.FollowingWhite,letSbethefactthatthelawsofouruniversearestringent,i.e.thattheywillonlysupportintelligentlifeonafewsettingsoftheconstantsandinitialconditions.SandNareequivalentgivenO,so(Õ)isequivalentto:pSSD,OApSS D,O.(Õ*)Myobjectionwasthatwehavenoreasontoaccept(Õ*),sincewehavenoreasontothinkthatadesignerwouldchoosestringentlawsasherwayofcreatingintelligentlife.Shecouldeasilyhavechosenlaxlawsasameansofcreatingintelligentlife.Whiterepliesthat(Õ*)canbederivedfromthreeplausibleassumptions.erstisthatstringencyandlife'sexistencearenegativelydependentifwesupposethereisnodesigner:pOSS, D@pOS S, D.(¦)Ifthereisnodesigner,stringentlawsmakelifelesslikely.Second,stringencyandlife'sexistenceareindependentontheassumptionthatthereisadesigner:pOSS,DpOS S,D.(¢)Ifthereisadesigner,shewillcreatelifecomewhatmay.Andthird:pDSSCpDS S.(ä)Insupportof(ä)Whitesays:[...]thefactthatthelawsputstringentconditionsonlifedoesnotbyitselfprovideanyevidenceagainstdesign[...]Ofcourseitispossiblethatadesignerhasapreferenceforlawsthatputstringentconditionsonlife'sexistence,orapreferenceforlaxconditions.Butaswehavenoreasontosuspectsoeitherway,SbyitselfhasnobearingonD.(White,óþÕÕ,p.äß)But(ä)isnotsupportedbythisrationale;indeed,thedesigntheorist'sownreasonsfor(Õ)actuallytellagainst(ä).IwillrstdescribeacasethatunderminesWhite's TuA§¶u±§DêuIou§uhuìrationalefor(ä).enI'llarguethatthedesigntheorist'sownreasoningactuallyrefutes(ä),andeven(Õ).SupposeÕþþprisonersaresentencedtodeath,halfhousedincellblockAandhalfincellblockB.elawrequiresthatexactlyoneprisonerbepardoned,andtheluckyprisonerwillbeselectedeitherbyrandomlotteryorbyajudgewhowillbeappointedtomakethedecision.Ifappointed,thejudgewillpardonsomeon
3 ewhoisinnocent.Wehavenoreasontothinkthej
ewhoisinnocent.Wehavenoreasontothinkthejudgecareswherethepardonedprisonerishoused,butasithappensthereareÉinnocentprisonersincellblockA,andonlyÕincellblockB.Itiskeptsecrethowtheluckypardoneeisselected.NowsupposewelearnthatthepardonedprisonerwashousedincellblockB.isdiscoveryhasanegativebearingonthehypothesisthatthejudgewasappointed.ForshewasÉtimesmorelikelytopardonaprisonerfromcellblockAthanfromcellblockB,whereasitwasa¢þ/¢þshotatthehandsofchance.So,eventhoughwehavenoreasontothinkthejudgehasanypreferenceaboutwherethepardoneeishoused,wherethepardoneewashousedstillbearsonthehypothesisthatthejudgemadethedecision.So,thatwehavenoreasontosuspectadesignerwouldhaveanypreferencebetweenstringentandlaxlawsdoesnotshowthatScannotbearnegativelyonD.isshowsthat(ä)isinadequatelysupported,butitalsosuggeststhat(ä)isfalse.JustasthepardonedprisonerbeingfromcellblockBhasanegativebearingonthehypothesisthatthejudgeissuedthepardon,thesuppositionthatouruniverse'slawsarestringentmayhaveanegativebearingonthehypothesisthatitisdesigned.Foradesignerintentoncreatinglifeismorelikelytochooseoneoftheplentifullaxoptions,justasthejudgeismorelikelytochooseaprisonerfromthecellblockwithmoreinnocentprisoners.isisasurprisingsuggestion,as(ä)lookedplausibleenoughonitsface.Soratherthanrelyonanalogy,Iwillpresentanexplicitargumenttothiseect:bythedesigntheorist'sownlights,both(ä)and(Õ*)arefalse.eargument'smainideacanbeconveyedpictorially.Picturethespaceofpossibleuniversesarrangedinalineaccordingtothestrictnessoftheirlaws,withstrictnessincreasingtothele: «±§h± Zì O Y Y Y Y Y Y Y Y Y Y Y Y edotsrepresentthelife-supportinguniverses,thosewhereOholds.Asthepicturesuggests,thesebecomemorecommonaswemovetotheright;bydenition,laxerlawsyieldalife-supportinguniverseonmoreofthepossiblesettingsoftheconstants ¦JZ±ZWu«fu§andinitialconditions.NowconsiderhowprobabilitiesaredistributedoverthesepossibleuniversessupposingDandsupposing D.Ifthereisnodesigner,itisamatterofªblindchanceºwhichuniverseisactual,resultinginauniformdistributionoverthewholeline;chanceªthrowsadartºattheinterval.Ifthereisadesignerthough,onlythedotsarelivepossibilities,sincethepostulateddesignerisintentoncreatinglife.Andsinceweknownothingmoreaboutheraimsandmethodst
4 hanthis,auniformdistributionoverthedotsr
hanthis,auniformdistributionoverthedotsrepresentsourexpectations.Nowthepunchline:chance'sdartismorelikelytolandtowardstheleendofthespectrumthanthedesigner's.edesignerwillªlandherdartºononeofthedots,sohersismorelikelytolandclosertotherightthantothele.Butifthereisnodesigner,thedartmaylandanywhereintheline,makingitmorelikelythanthedesigner'stolandtowardsthele.Contra(ä)then,strictnessisnegativelyrelevanttodesign.Wecangofurtherandseewhy(Õ*)isfalsetoo.SupposewelearnthatthedartlandedononeoftheO-possibilities.isdoesnotchangethewayprobabilitiesaredistributedsupposingdesign;givendesign,wealreadyknewanO-possibilitywouldbehit.Supposing Dthoughtheprobabilitiesdochange:toexactlythesameprobabilitieswegetsupposingD.Conditionalizingauniformprobabilitydistributionresultsinauniformdistributionovertheremainingpossibilities.Sonow,given D,eachO-possibilityhasequalprobabilityofbeinghit.us,onceweknowO,theprobabilityofselectingapointtowardsthestrictendofthespectrumisthesamegivenDandgiven D,contra(Õ*).Let'snowmaketheargumentrigorous.efollowingthreeassumptionsshouldbeacceptabletotheproponentoftheoriginalne-tuningargument.First:DivineIntent:pOSDÕ.ejusticationhereisthesameasforWhite's(¢):thepostulateddesignerisintentoncreatinglife,and(wemaysuppose)canbecountedontodosocomewhatmay.Second:BlindIndierence:pSO, DisauniformdistributionovertheO-possibilities,wherepSO, DistheprobabilityfunctionobtainedbyconditionalizingponO, D.BlindIndierenceisjustiedbythedesigntheorist'sownrationaleforsayingthatpSS D,Oislowandthusthat(Õ)istrue.Ifthereisnodesigner,itisamatterofªblindchanceºhowtheworldturnsouttobe,sopS Disauniformdistributionoverallpossiblecosmologies.ismakespSO, DauniformdistributionoverthepossiblecosmologieswhereOholds.ethirdpremiseis: TuA§¶u±§DêuIou§uhu¢DivineIndierence:pSO,DisauniformdistributionovertheO-possibilities.DivineIndierenceismotivatedbythethoughtthat,absentanyinformationorstipulationaboutthedesigner,savethatshewillcreateoneoftheO-possibilities,eachO-possibilityshouldberegardedasequallyprobable.Mo
5 reneedstobesaidaboutDivineIndieren
reneedstobesaidaboutDivineIndierenceandwewillreturntothematterinamoment.Firstletusseehowtheseassumptionsrefute(ä)and(Õ*).Together,DivineIndierenceandBlindIndierenceentailthatOªscreensoºD(and D)fromtheO-possibilities.OnceOisgiven,supposingD(or D)hasnoeectonthewayprobabilitiesaredistributedovertheO-possibilities.uswehave:DivineIrrelevance:pXSO,DpXSOforanyXthatisaunionofO-possibilities.Wecanthenderive:pDSSpDpSSD pSbyBayes'eorem(~ä)pDpSSO,D pSbyDivineIntentpDpSSO pSbyDivineIrrelevancepDpOSS pObyprobabilitycalculus@pD.bythedefn.ofSWecanalsoderivedirectlyfromDivineIndierenceandBlindIndierence:pSSD,OpSS D,O.(~Õ*)eseresultsvindicatemyearlierobjectionto(Õ)intworespects:acrucialassumptioninthederivationof(Õ*)isfalse,andsois(Õ*)itself.eseresultsalsoanswerBradley's(forthcoming)replytomyobjection.WhileIthinkSdoesnotsupportD,IdoallowthatOmayoersomesupportforDinitially;it'sjustthatSoersnoadditionalsupport.But,Bradleyobserves,theamountofsupportOlendstoDdependsonwhetherSor Sistrue.Plausibly,thedierencebetweenpOSD,SandpOS D,SissignicantlygreaterthanthatbetweenpOSD, SandpOS D, S,sothatOoerssignicantlygreatersupporttoDgivenSthangiven S.usne-tuningdoessupportdesign,justindirectly,byamplifyingthesupportfromouroldevidenceO.WhileBradleymayberightthatlearningSampliestheevidentialsupportOlendstoD,thisdoesnotmeanthatlearningSinadditiontoOincreasesthenetsupport äJZ±ZWu«fu§forD.ForSmaysimultaneouslybeevidenceagainstD,sothattheamplicationofO'ssupportisdrownedoutbythedisconrmationeectedbyS.Infact,theaboveargumenttellsusthatthisisexactlywhathappens.(~ä)showsthatStellsagainstD.And(~Õ*)tellsusthatthisdisconrmationofDexactlybalancesouttheamplicationofO'ssupport,sincelearningSaerlearningOneitherincreasesnordecreasestheprobabilityofD.Let'snowreturntoDivineIndierencewithamorecriticaleye.Indierence-basedreasoningisnotorious
6 lyproblematic,soit'snaturaltowonderwheth
lyproblematic,soit'snaturaltowonderwhethertheaboveargumentusesitillicitly.ereareseveralworrieshere.OneworryisthattheuniformprobabilitydistributionpositedbyDivineIndier-ence(andBlindIndierence)doesnotexist,sincethespaceofrelevantpossibilitiesisunbounded.erangeofpossiblelaws,constants,andinitialconditionsisnotbounded,soanypositiveuniformdistributionoveritwillbeimproper.Butthisisaproblemfortheproponentofthene-tuningargumenttosolve,sincesheassumesauniformdistributionoverthespaceofpossibleuniversestomotivatepremise(Õ)(Colyvanetal.,óþþ¢).Howevershesolvesit(perhapsbyre-parameterizingthespacetotanitearea,orbyimposinganitepartitionwhereeachcellgetsequalpriorprobability),wecanadopthersolutiontosaythatpSO,DisauniformdistributionoverthesubsetofpossibilitieswhereO.AnotherworryarisesinconnectionwithBertrand'sparadox.Auniformdistribu-tionoveranuncountablesetparameterizedonewaywillnotbeuniformunderallalternativeparameterizationsofthesameset.WhatparameterizationispresupposedbyDivineIndierence?isagainisaproblemfortheproponentofthene-tuningargumenttosolve.Whateverparameterizationsheusestomotivatepremise(Õ)ofherargument,DivineIndierenceistobeinterpretedusingit.Itisimportanttonote,however,thatherparameterizationcannotbethesortusuallypresupposedinstatementsofthene-tuningargument.esestatementsonlyprovideaparameteri-zationofthespaceofpossibleconstantsandinitialconditionsfortheactuallawsofouruniverse.Butweareassessingtheimportofthediscoverythatthesearetheactuallaws.Soweneedaparameterizationofthespaceofallpossiblelaws,notjustofthespaceofpossibleconstantsandinitialconditionsforourlaws.Itisuptothedesigntheoristtoprovidesuchaparameterizationifshewishestohaveanargumentatall,sinceshemustprovidesomereasonforthinking(Õ*)plausible.Presumably,shewillprovidethisreasonbypresentinguswithanaturalparameterizationonwhichStakesupasmallportionofthespaceofpossibilities.BlindIndierencethenjustacceptsthisparameterization,sayingthatpS Disauniformdistributionoverit,andthusthatpSO, DisauniformdistributionovertheO-possibilities. TuA§¶u±§DêuIou§uhußAnalworryisthatthedesigntheoristmightobj
7 ecttoauniformdistributionoverthespaceofp
ecttoauniformdistributionoverthespaceofpossiblelawsgivendesign.Considerthejudge:shemightpickaninnocentprisoneratrandom,butshemightinsteadipacointosettleonacellblockandthenpickaprisoneratrandom(orbysomeothermeans).Inthatcase,wheretheprisonerwashousedhasnobearingonwhetherthejudgewasappointed.Similarly,thedesignermightdealwithherindierenceaboutSvs. SbyippingacoinandthenchoosingfromamongtheSpossibilities(or S,asthecasemaybe).Ofcoursewehavenoreasontosuspectthedesignerwouldusesuchamethod.Butthedesigntheoristmayarguethatindierenceshouldbeappliedtothepossiblemethodsthedesignermightuse,ratherthantothepossibilitiesthesemethodsselectfrom.AndanaturalwaytopartitionandparameterizethesemethodsisbythechanceeachhasofresultinginS,yieldingÕ/óprobabilityforeachofSand S,givenD.iswon'thelpthedesigntheorist'scausethough.edivisionbetweenªstringentºandªlaxºlawswasanarticialsimplicationweadoptedforconvenience.Really,stringencycomesonacontinuum.SothenaturalparameterizationisþBxBÕ,wherexistheportionofthepossiblesettingsoftheconstantsandinitialconditionsthatcansupportintelligentlife.Andauniformdistributionoverthisparameter(or,whatcomestothesamething,auniformaverageofthepossibledistributionsoverit)willyieldthesameuniformdistributionpostulatedbyBlindIndierence.For,ifthedesigntheoristthinksthisparameterizationisreasonablegivenD,itisreasonablegiven Dtoo.Aerall,thestringencyofourlawsisthediscoveryinquestion,soauniformdistributionoverthepossibledegreesofstringencyisnaturalgivennodesigner.Tomakethisresponseworkthen,thedesigntheoristwouldhavetosupplyanddefendasecondparameterizationshewantstoapplyindierencetogiven D.Untilshedoes,herargumentiscollapsingunderitsownweight.Forthenaturalextensionofherownthinkingunderminesherkeypremise,yieldinginsteadourargumentfor(~Õ*),theargumentfromdivineindierence.Ruu§uhu«Bradley,Darren.forthcoming.Weisbergondesign:Whatne-tuning'sgottodowithit.Erkenntnis.Colyvan,Mark,JayL.Gareld&GrahamPriest.óþþ¢.Problemswiththeargumentfromnetuning.SyntheseÕ¦¢(ì):ìó¢±ìì.Weisberg,Jonathan.óþÕþ.Anoteondesign:What'sne-tuninggottodowithit?Analysisßþ(ì):¦ìÕ±.White,Roger.óþÕÕ.Whatne-tuning'sgottodowithit:Replytoweisberg.AnalysisßÕ(¦):äßä±