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toexistbecauseofsomecognitivelimitationonourpart(McGinn1989)—wearetoostupid(orhavethewrongtypeofintelligence)toappreciatetheexplanatoryconnection.Aproperunderstandingofthephysicalandphenomenalfactswould,inreality,showusthatoneexplainstheother.Idonotbelieveanyofthesethreestrategiesareacceptable.Thefirstsimplyflatlyconflictswiththeevidence.Itsproponentsneedtoproducemuchstrongerargumentsthantheyhaveproducedtomakeitaseriouscontender,andIampessimisticthatsuchargumentsexist.Eachoftheothertwostrategiessuffersfromanotherseriousfault:theyareexercisesinexcusemaking.Theexplanatorygapisaninstanceofexplanatoryfailure.Whenconfrontedwithexplanatoryfailure,standardpracticeinscienceistore-evaluatethetheoryforinaccuracyorincompleteness.Thesemovesattempttoblamethepsychologyorperspectiveofthetheorymakersratherthantheontologyofthetheory,andarecompletelyanomalous.Theystandinthewayoftherealpossibilitythatwecanfindabettertheory.InthischapterIwillpursueafourthstrategybytacklingtheproblemmoredirectly.Iwillshowfaultinthetheories,ratherthanthetheory-makers.Mymethodology,Page35then,ismoretraditionalthanthemethodologyoftheotherstrategies.TheconclusionIreach,however,mayseemmoreradical.Iamgoingtoarguethatphysicalthingsare"twofaced"also.Morefactsthanjustthefactsaboutwhattheydoaretrueofthem,andthesefurtherfactsmayfillthegap.Ifthisconclusioniscorrectthentheformofthetheoriestraditionallyemployedinthesciencesneedstobesupplementedbeforewecancrosstheexplanatorygap.Someonepursuingthisstrategyneedstomeetthreechallenges,whichIwilltrytodo.Thefirstchallengeistoavoidbeing ... theabilitytoreproducewithoutgeneratinganyaprioricontradictions,butgiventheradicalincompletenessofhisconceptsvis-à-visthenaturesofthetwophenomenatowhichheappliedthem,nothingreallyfollowsregardingwhatrelationsoflogical(ormetaphysical)possibilitymightholdbetweenthosephenomenathemselves.AretheconceptsusedbyChalmersandtheneodualistmoreadequatethanthevitalist's?Firstwemustask,"whatspecificconceptsdotheyuse?"Onthementalsidetheyuseaconceptofexperiencederivedfromourfirstpersonawarenessofourownconsciousmentalstatesandprocesses.Thenatureoftheseconceptsderivesfromtheirrepresentationalandregulatoryroleinthemonitoringandcontrolofourconsciousmentallife.Theysurelymeetconditionsofadequacyrelativetothatrole.Butinwhatotherrespectsmighttheybeadequateorinadequate?Fortheneodualist'spurposeshisconceptofconsciousexperience,callitCCE,mustbeadequatetolimntheboundariesofconsciousness;whateversatisfiesCCEinanyworldmustPage19beaninstanceofconsciousnessandwhateverfailstofallunderCCEmustequallyfailtobeaninstanceofconsciousness.TheneodualisttreatshisconceptCCEastheuniversal(Protagorean)standardofconsciousness,butthatassumptionseemslessthanplausibleoratleastproblematic.Whyshouldthatconceptofexperiencederivedfromitsroleinregulatingourspecificformofconsciousnessprovideacharacterizationofconsciousnesssufficientlygeneraltodeterminethelogicallypossibleboundariesofconsciousness.PleasenoteIamnotsayingthattheneodualistassumesthatalllogicallypossibleconsciousexperiencemustinvolvethesamespecificphenomenalpropertiesassociatedwithhumanconsciousness;hemostsurelyandrightlydoesnotsaythat.Butwhathedoesimplicitlyassume,thoughmoremodest,isstilluponreflectionimplausible,namelythattheconceptsofconsciousnessthatwecommandonthebasisoftheirapplicationwithinourownself-awarenesscanprovideuswithageneralmeansofdelimitingthelogicallypossibleboundariesofconsciousness.Moreover,thereisafurtherdimensionofadequacyinwhichtheneodualist'sconceptofconsciousnessisevenlessplausiblyuptothetask,onethatisdirectlyrelevanttohisthoughtexperiment.ThequestioniswhetherorUndertherealistalternativethecausalnexushastwoaspects,itseffectiveanditsreceptivefaces.Thesetwofacesarelogicallyinseparable,asonecannothavereceptivenesswithouteffectiveness,andviceversa .The naturalrelationbetweenthesetwofaceswillconstituteacausalnexus.Sincearealistwishestofindatheoryofthisnexus,atheoryofthecausalnexusmustbeatheoryofthedetailedrelationbetweenthesetwofaces.First,findingthemostgeneraltheoryofthecausalnexusrequiresovercomingonetemptingview.Thisistheviewthatconceivesofthereceptiveandtheeffectivepropertiesofindividualsaseachbeingmonadicpropertiesofthoseindividuals.Inplaceofthiscommonsensepicture,onemustsubstituteapictureofreceptivityasaconnection ... 75Page72—TheObjectionTheobjectionIwishtoconsiderinvolvesatwo-prongedattackontheargument.First,theobjectortakesissuewiththeclaimthatstatementslike(i)aboveareanalytic,orthattheycanberenderedintopic-neutralterms.Second,theobjectorrespondstotheobviousquestionthatarisesasaresultofthefirstprongoftheattack:namely,if(i)isneitheranalyticnortopic-neutral,thenwhyistherenoexplanatorygapinESI,givenitsrelianceonthebridgepremise(5)?Theansweristochallengetheassumptiononwhichthequestionisbased,that(5)itselfrequiresanexplanation.Thedenialofanalyticstatusto(i)ispartofageneralchallengetotheanalytic-syntheticdistinction,whichdatesbacktoQuine(1953).Foronething,noonehaseverproducedaconvincingexampleofaconceptualanalysis,asidefrommarginalcaseslike"bachelor"ormathematicalconcepts.Afterall,whatwouldreallygointotheexpansionof"watery"?Isitreallyanalyticthatwaterfallsfromthesky,orisliquidatroomtemperature ?Of course,onecanalwayssaythatwejusthaven'tfoundtherightanalysis,orthatitisbestunderstoodasaclusterconceptwithnoonenecessaryconditionbutaweightedsumofnecessaryconditions.Atthispointtheburdenshiftstotheadvocateofanalyticitytoshowwhyweshouldbelievethereissuchathingastherightanalysistobefound.Therearealotofmovesandcounter-movestomakeatthispoint,andIcan'tdelveintothemhere.6Butsurelyonereasonforthinkingtherehastobeananalysisfortermslike"water"isthatwithoutonewewouldbeatalosstoexplainidentitieslike(5).Thisbringsustothesecondprongoftheattack,removingoneoftheprincipalreasonsforbelievinginthenecessityofanalysis.Theargumenthereisthatidentities,unlikecorrelations,donotrequireexplanation.Thatsomethingisitselfispreciselythesortofsituationthatweacceptasabrutefact.Whatelsecoulditbe?Whatreallywouldcountasexplaininganobject'sidentitywithitself?Ofcourseitdoesseemasifweoftenaskforexplanationsofidentities.Doesn'titmakesensetoaskwhy,orhowitis,thatwaterisH2O?Butwheneversuchaquestionmakessense,itispossibletoreinterpretitinoneoftwoways:eitherasajustificatoryquestion,orasaquestionaboutthecoinstantiationofdistinctproperties.So,withrespecttoaskingforanexplanationof(5),wemightbeaskingnotwhywaterisH2O,butratherwhyweshouldthinkthatwaterisH2O.Thisisawayofseekingevidenceforitstruth,notanexplanationofitstruth.Ontheotherhand,wemightbeaskingsomethinglikethis:HowisitthatthissubstancemadeoutofH2Omoleculesappearscontinuouslydivisible?Hereweareaskingforanexplanation,butwhatwewantexplainedishowtwodistinctproperties—inthiscase,beingcomposedofH2OmoleculesandappearingcontinuouslyPage8divisible—couldbeinstantiatedinthesamesubstance.Thisisaquiteproperobjectofexplanation,butnoticethatitinvolvesaconnectionbetweentwodistinctproperties.What,goestheargument,youneverhaveis,strictly,whyisthisthesameasthat?Tothisquestion,ifitwereeverasked,theonlypossibleansweris,"becauseitis,that'swhy."Iftheforegoingisright,andIthinkitis,thenthereasonwedon'tfindagapinESIhasnothingtodowiththeavailabilityofananalysisof"water,"andsonothingtodowithourabilitytoexplainthebridgeidentity(5).Thereisnogapbecausebridgeidentitiesdon'tgenerallyrequireexplanations.ButifthereisnogapinESIKunioYasueResearchInstituteforInformaticsandScienceNotreDameSeishinUniversity2-16-9Ifuku-cho,Okayama700-8516,JapanArthurZajoncDepartmentofPhysicsAmherstCollegeAmherst,MA01002PagexixPREFACEWhatisconsciousness?Howandwhydowehaveconsciousexperience,aninnerlifetexturedandcomprisedofthefeelingsandsensationsthatphilosopherscall''qualia"?Asanewmillenniumbeckons,thesequestionshaveemergedfromalongdarknessthatdominatedpsychologyformuchofthelastcentury.Thisinternationalandinterdisciplinaryintrospectionhasstemmedinpartfromanumberofhigh-profilebooksinthearea,inpartfromadevelopmentofnewexperimentaltechniquesforaddressingtheproblem,andinpartsimplyfromasensethatnowisthetimeforthescienceofthemindtoaddressitscentralandmostdifficultproblem.Themostburningissueisthatofwhetherconsciousexperience—feelings,qualia,our"innerlife"—canbeaccommodatedwithinpresent-dayscience.Manyseeconsciousexperienceasjustanotherphysicalprocessinthebrain.Othersseeconsciousexperienceasoutsidescience,orbelievethatsciencemustexpandtoincludeexperience.ThesephilosophicalbattlelineswereoriginallydrawnbetweenSocrates,whobelievedthatthe"cerebrumcreatedconsciousness,"andDemocritus,whoarguedthatmentalprocesseswerefundamentalconstituentsofreality.Ridingandfacilitatingthelatetwentiethcenturywaveofinterestinthenatureofconsciousexperience,threeinterdisciplinaryandinternationalTucsonconferences(TowardaScienceofConsciousness)havebeenheldin1994,1996 ,and1 998(thefourthisscheduledforApril10–15,2000).Theconferenceshavebeenintegrative,attemptingtoassimilateandsynthesizeavarietyofapproachestowardunderstandingtheconsciousmind.Fivemajorareasaredelineated:philosophy,neuroscience,cognitivescience,math/physics/biology,andexperiental/culturalapproaches.Theideafromthebeginninghasbeentobringproponentsandresearchersineachoftheseareasunderonetent,toavoidtunnelvisioninthistrickyandpotentiallyoverwhelmingmystery.ThefirstTucsonconferencein1994wasrelativelysmallandtentative.Couldaninterdisciplinaryconsciousnessconferencework?Wouldproponentsofthevariedapproachesbeabletocommunicate,orwouldthegatheringdegenerateintoamodernTowerofBabel?"TucsonI"succeededbeyondexpectations,andasecond,expandedTucsonIIwasheldin1996,movingfromtheUniversityofArizonacampustothelargerfacilitiesattheTucsonConventionCenterandMusicHall.Manyofthecentralfiguresinthenewlyformingfieldofconsciousnessstudieswereinvitedandparticipated,andtheissueswerefiercelydebatedamid1000attendees,producingnumerousprintandelectronicreports.FollowingTucsonII,morefocusedconferencesonconsciousnesssprangupacrosstheglobe.Consciousnesshadbecomepartoftheconsciousnessofthescientificworld.Wecomethustothesecondandmoregeneralquestionaboutthedualist'sthoughtexperiments.Aretheconceptsthatheusesadequatetothetasktowhichheputsthem?Isourconceptofphenomenalconsciousnessorourconceptofitspossiblephysicalbasiswellenoughdevelopedtoallowustodrawmetaphysicalconclusionsabouttheirrelation?Asnotedabove,Ithinktheyarenot.Considerfirstanothernonmentalexample.Imagineamid-nineteenth-centuryvitalistwhoarguesasfollows:1.Icanconceiveofcreaturesthatarejustlikeactualcreatures(sayactualcats)inallphysicalrespectsbutthathavenoabilitytoreproduce.2.Thereforetheabilitytoreproducedoesnotlogicallysuperveneonacreature'sphysicalstructure.Withthebenefitoflatetwentiethcenturyscienceweknowthevitalist'sconclusionisdeadwrong;theabilitytoreproduce...