ThequestionissoimportantthatIwillrestateit。Ihaveimaginedaworldmadeupofpsychicalphenomena，freedfromthematerialconditionsunderwhichaloneweknowsuchphenomena。Canweadduceanyproofofthepossibilityofsuchaworld？Orifwecannot，doesourfailureraisetheslightestpresumptionthatsuchaworldisimpossible？
　　Thereplytothefirstclauseofthequestionissufficientlyobvious。Wehavenoexperiencewhateverofpsychicalphenomenasaveasmanifestedinconnectionwithmaterialphenomena。WeknowofMindonlyasagroupofactivitieswhichareneverexhibitedtousexceptthroughthemediumofmotionsofmatter。Inallourexperiencewehaveneverencounteredsuchactivitiessaveinconnectionwithcertainverycomplicatedgroupingsofhighlymobilematerialparticlesintoaggregateswhichwecalllivingorganisms。Andwehaveneverfoundthemmanifestedtoaveryconspicuousextentsaveinconnectionwithsomeofthosespeciallyorganizedaggregateswhichhavevertebrateskeletonsandmammaryglands。Nay，more，whenwesurveythenetresultsofourexperienceuptothepresenttime，wefindindisputableevidencethatinthepasthistoryofthevisibleuniversepsychicalphenomenahaveonlybeguntobemanifestedinconnectionwithcertaincomplexaggregatesofmaterialphenomena。
　　Asthesematerialaggregateshaveagebyagebecomemorecomplexinstructure，morecomplexpsychicalphenomenahavebeenexhibited。ThedevelopmentofMindhasfromtheoutsetbeenassociatedwiththedevelopmentofMatter。Andto-day，thoughnoneofushasanyknowledgeoftheendofpsychicalphenomenainhisowncase，yetfromallthemarksbywhichwerecognizesuchphenomenainourfellow-creatures，whetherbruteorhuman，wearetaughtthatwhencertainmaterialprocesseshavebeengraduallyorsuddenlybroughttoanend，psychicalphenomenaarenolongermanifested。Fromfirsttolast，therefore，ourappealtoexperiencegetsbutoneresponse。WehavenotthefaintestshadowofevidencewherewithtomakeitseemprobablethatMindcanexistexceptinconnectionwithamaterialbody。Viewedfromthisstandpointofterrestrialexperience，thereisnomorereasonforsupposingthatconsciousnesssurvivesthedissolutionofthebrainthanforsupposingthatthepungentflavouroftable-saltsurvivesitsdecompositionintometallicsodiumandgaseouschlorine。
　　Ouranswerfromthissideisthusunequivocalenough。Indeed，souniformhasbeentheteachingofexperienceinthisrespectthatevenintheirattemptstodepictalifeafterdeath，menhavealwaysfoundthemselvesobligedtohaverecoursetomaterialisticsymbols。Tothemindofasavagethefutureworldisamerereproductionofthepresent，withitseverlastinghuntingsandfightings。TheearlyChristianslookedforwardtoarenovationoftheearthandthebodilyresurrectionfromSheoloftherighteous。Thepicturesofhellandpurgatory，andevenofparadise，inDante’sgreatpoem，aresointenselymaterialisticastoseemgrotesqueinthismorespiritualage。Butevento-daythepopularconceptionsofheavenarebynomeansfreedfromthenotionofmatter；andpersonsofhighculture，whorealizetheinadequacyofthesepopularconceptions，arewonttoavoidthedifficultybyrefrainingfromputtingtheirhopesandbeliefsintoanydefiniteordescribableform。Notunfrequentlyoneseesasmileraisedattheassumptionofknowledgeorinsightbypreacherswhodescribeineloquenttermsthejoysofafuturestate；yetthesmiledoesnotnecessarilyimplyanyscepticismastotheabstractprobabilityofthesoul’ssurvival。Thescepticismisaimedatthecharacterofthedescriptionratherthanattherealityofthethingdescribed。Itimpliesatacitagreement，amongcultivatedpeople，thattheunseenworldmustbepurelyspiritualinconstitution。Theagreementisnothabituallyexpressedindefiniteformulas，forthereasonthatnomentalimageofapurelyspiritualworldcanbeformed。Muchstressiscommonlylaidupontherecognitionoffriendsinafuturelife；
　　andhoweverdeepameaningmaybegiventothephrase“theloveofGod，“onedoesnoteasilyrealizethataheavenlyexistencecouldbeworththelongingthatisfeltforit，ifitweretoaffordnofurtherscopeforthepureandtenderhouseholdaffectionswhichgivetothepresentlifeitspowerfulthoughindefinablecharm。Yettherecognitionoffriendsinapurelyspiritualworldissomethingofwhichwecanframenoconceptionwhatever。Wemaylookwithunspeakablereverenceonthefeaturesofwifeorchild，lessbecauseoftheirphysicalbeautythanbecauseofthebeautyofsoultowhichtheygiveexpression，buttoimaginetheperceptionofsoulbysoulapartfromthematerialstructureandactivitiesinwhichsoulismanifested，issomethingutterlybeyondourpower。Nay，evenwhenwetrytorepresenttoourselvesthepsychicalactivityofanysinglesoulbyitselfascontinuingwithouttheaidofthephysicalmachineryofsensation，wegetintounmanageabledifficulties。Agreatpartofthecontentsofourmindsconsistsofsensuouschieflyvisualimages，andthoughwemayimaginereflectiontogoonwithoutfurtherimagessuppliedbyvisionorhearing，touchortasteorsmell，yetwecannotwellseehowfreshexperiencescouldbegainedinsuchastate。Thereader，ifherequirefurtherillustrations，caneasilyfollowoutthislineofthought。Enoughhasnodoubtbeensaidtoconvincehimthatourhypothesisofthesurvivalofconsciousactivityapartfrommaterialconditionsisnotonlyutterlyunsupportedbyanyevidencethatcanbegatheredfromtheworldofwhichwehaveexperience，butisutterlyandhopelesslyinconceivable。
　　ItisinconceivableBECAUSEitisentirelywithoutfoundationinexperience。Ourpowersofconceptionarecloselydeterminedbythelimitsofourexperience。Whenaproposition，orcombinationofideas，issuggested，forwhichtherehasneverbeenanyprecedentinhumanexperience，wefindittobeUNTHINKABLE，——theideaswillnotcombine。Thepropositionremainsonewhichwemayutteranddefend，andperhapsvituperateourneighboursfornotaccepting，butitremainsnonethelessanunthinkableproposition。Ittakestermswhichseverallyhavemeaningsandputsthemtogetherintoaphrasewhichhasnomeaning。[11]Nowwhenwetrytocombinetheideaofthecontinuanceofconsciousactivitywiththeideaoftheentirecessationofmaterialconditions，andtherebytoasserttheexistenceofapurelyspiritualworld，wefindthatwehavemadeanunthinkableproposition。Wemaydefendourhypothesisaspassionatelyaswelike，butwhenwestrivecoollytorealizeitinthoughtwefindourselvesbaulkedateverystep。
　　[11]SeemyOutlinesofCosmicPhilosophy，Vol。I。pp。64-67。
　　Butnowwehavetoask，Howmuchdoesthisinconceivabilitysignify？Inmostcases，whenwesaythatastatementisinconceivable，wepracticallydeclareittobeuntrue；whenwesaythatastatementiswithoutwarrantinexperience，weplainlyindicatethatweconsideritunworthyofouracceptance。Thisislegitimateinthemajorityofcaseswithwhichwehavetodealinthecourseoflife，becauseexperience，andthecapacitiesofthoughtcalledoutandlimitedbyexperience，areouronlyguidesintheconductoflife。Buteveryonewilladmitthatourexperienceisnotinfinite，andthatourcapacityofconceptionisnotcoextensivewiththepossibilitiesofexistence。Itisnotonlypossible，butintheveryhighestdegreeprobable，thattherearemanythingsinheaven，ifnotonearth，whichareundreamedofinourphilosophy。Sinceourabilitytoconceiveanythingislimitedbytheextentofourexperience，andsincehumanexperienceisveryfarfrombeinginfinite，itfollowsthattheremaybe，andinallprobabilityis，animmenseregionofexistenceineverywayasrealastheregionwhichweknow，yetconcerningwhichwecannotformthefaintestrudimentofaconception。Anyhypothesisrelatingtosucharegionofexistenceisnotonlynotdisprovedbythetotalfailureofevidenceinitsfavour，butthetotalfailureofevidencedoesnotraiseeventheslightestprimafaciepresumptionagainstitsvalidity。
　　Theseconsiderationsapplywithgreatforcetothehypothesisofanunseenworldinwhichpsychicalphenomenapersistintheabsenceofmaterialconditions。Itistrue，ontheonehand，thatwecanbringupnoscientificevidenceinsupportofsuchanhypothesis。Butontheotherhanditisequallytruethatintheverynatureofthingsnosuchevidencecouldbeexpectedtobeforthcoming:evenweretheresuchevidenceinabundance，itcouldnotbeaccessibletous。Theexistenceofasinglesoul，orcongeriesofpsychicalphenomena，unaccompaniedbyamaterialbody，wouldbeevidencesufficienttodemonstratethehypothesis。
　　Butinthenatureofthings，evenwerethereamillionsuchsoulsroundaboutus，wecouldnotbecomeawareoftheexistenceofoneofthem，forwehavenoorganorfacultyfortheperceptionofsoulapartfromthematerialstructureandactivitiesinwhichithasbeenmanifestedthroughoutthewholecourseofourexperience。Evenourownself-consciousnessinvolvestheconsciousnessofourselvesaspartlymaterialbodies。Theseconsiderationsshowthatourhypothesisisverydifferentfromtheordinaryhypotheseswithwhichsciencedeals。Theentireabsenceoftestimonydoesnotraiseanegativepresumptionexceptincaseswheretestimonyisaccessible。Inthehypotheseswithwhichscientificmenareoccupied，testimonyisalwaysaccessible；andifwedonotfindany，thepresumptionisraisedthatthereisnone。WhenDr。Bastiantellsusthathehasfoundlivingorganismstobegeneratedinsealedflasksfromwhichalllivinggermshadbeenexcluded，wedemandtheevidenceforhisassertion。Thetestimonyoffactsisinthiscasehardtoelicit，andonlyskilfulreasonerscanproperlyestimateitsworth。Butstillitisallaccessible。Withmoreorlesslabouritcanbegotat；andifwefindthatDr。Bastianhasproducednoevidencesavesuchasmayequallywellreceiveadifferentinterpretationfromthatwhichhehasgivenit，werightlyfeelthatastrongpresumptionhasbeenraisedagainsthishypothesis。Itisacaseinwhichweareentitledtoexpecttofindthefavouringfactsifthereareany，andsolongaswedonotfindsuch，wearejustifiedindoubtingtheirexistence。Sowhenourauthorspropoundthehypothesisofanunseenuniverseconsistingofphenomenawhichoccurintheinterstellarether，oreveninsomeprimordialfluidwithwhichtheetherhasphysicalrelations，weareentitledtodemandtheirproofs。Itisnotenoughtotellusthatwecannotdisprovesuchatheory。Theburdenofprooflieswiththem。Theinterstellaretherissomethingconcerningthephysicalpropertiesofwhichwehavesomeknowledge；andsurely，ifallthethingsaregoingonwhichtheysupposeinamediumsocloselyrelatedtoordinarymatter，thereoughttobesometraceableindicationsofthefact。Atleast，untilthecontrarycanbeshown，wemustrefusetobelievethatallthetestimonyinacaselikethisisutterlyinaccessible；andaccordingly，solongasnoneisfound，especiallysolongasnoneisevenalleged，wefeelthatapresumptionisraisedagainsttheirtheory。
　　Theseillustrationswillshow，bysheercontrast，howdifferentitiswiththehypothesisofanunseenworldthatispurelyspiritual。Thetestimonyinsuchacasemust，undertheconditionsofthepresentlife，beforeverinaccessible。Itlieswhollyoutsidetherangeofexperience。Howeverabundantitmaybe，wecannotexpecttomeetwithit。Andaccordinglyourfailuretoproduceitdoesnotraiseeventheslightestpresumptionagainstourtheory。Whenconceivedinthisway，thebeliefinafuturelifeiswithoutscientificsupport；butatthesametimeitisplacedbeyondtheneedofscientificsupportandbeyondtherangeofscientificcriticism。Itisabeliefwhichnoimaginablefutureadvanceinphysicaldiscoverycaninanywayimpugn。Itisabeliefwhichisinnosenseirrational，andwhichmaybelogicallyentertainedwithoutintheleastaffectingourscientifichabitofmindorinfluencingourscientificconclusions。