This，however，isnonethelessahypothesistrulyscientificinconception，andinthespeculationstowhichitleadsuswearestillsureofdealingwithviewsthatadmitatleastofdefiniteexpressionandtreatment。Inotherwords，thoughourstudyofthevisibleuniversehasledustotherecognitionofakindofunseenworldunderlyingtheworldofthingsthatareseen，yetconcerningtheeconomyofthisunseenworldwehavenotbeenledtoentertainanyhypothesisthathasnotitspossiblejustificationinourexperiencesofvisiblephenomena。
Wearenowcalledupon，followinginthewakeofouresteemedauthors，toventureonadifferentsortofexploration，inwhichwemustcutloosealtogetherfromourmooringsintheworldofwhichwehavedefiniteexperience。Weareinvitedtoentertainsuggestionsconcerningthepeculiareconomyoftheinvisibleportionoftheuniversewhichwehavenomeansofsubjectingtoanysortoftestofprobability，eitherexperimentalordeductive。Thesesuggestionsare，therefore，nottoberegardedasproperlyscientific；but，withthiswordofcaution，wemayproceedtoshowwhattheyare。
Comparedwiththelifeanddeathofcosmicalsystemswhichwehaveheretoforecontemplated，thelifeanddeathofindividualsofthehumanracemayperhapsseemasmallmatter；yetbecauseweareourselvesthemenwholiveanddie，thesmalleventisofvastlygreaterinteresttousthanthegrandseriesofeventsofwhichitispartandparcel。Itisnaturalthatweshouldbemoreinterestedintheultimatefateofhumanitythaninthefateofaworldwhichisofnoaccounttoussaveasourpresentdwelling-place。Whetherthehumansoulistocometoanendornotistousamoreimportantquestionthanwhetherthevisibleuniverse，withitsmatterandenergy，istobeabsorbedinaninvisibleether。Itisindeedonlybecauseweareinterestedintheformerquestionthatwearesocuriousaboutthelatter。Ifwecoulddissociateourselvesfromthematerialuniverse，ourhabitat，weshouldprobablyspeculatemuchlessaboutitspastandfuture。Wecareverylittlewhatbecomesoftheblackballoftheearth，afteralllifehasvanishedfromitssurface；or，ifwecareatallaboutit，itisonlybecauseourthoughtsaboutthecareeroftheeartharenecessarilymixedupwithourthoughtsaboutlife。Henceinconsideringtheprobableultimatedestinyofthephysicaluniverse，ourinnermostpurposemustbetoknowwhatistobecomeofallthisrichandwonderfullifeofwhichthephysicaluniverseisthetheatre。Hasitallbeendeveloped，apparentlyatalmostinfinitewasteofeffort，onlytobeabolishedagainbeforeithasattainedtocompleteness，ordoesitcontainorsheltersomeindestructibleelementwhichhavingdrawnsustenanceforawhilefromthesenselessturmoilofphysicalphenomenashallstillsurvivetheirfinaldecay？Thisquestioniscloselyconnectedwiththetime-honouredquestionofthemeaning，purpose，ortendencyoftheworld。Inthecareeroftheworldislifeanend，orameanstowardanend，oronlyanincidentalphenomenoninwhichwecandiscovernomeaning？
Contemporarytheologiansseemgenerallytobelievethatonenecessaryresultofmodernscientificinquirymustbethedestructionofthebeliefinimmortallife，sinceagainsteverythoroughgoingexpounderofscientificknowledgetheyseektohurlthechargeof“materialism。“Theirdoubts，however，arenotsharedbyourauthors，thoroughmenofscienceastheyare，thoughtheirmodeofdealingwiththequestionmaynotbesuchaswecanwelladopt。Whileupholdingthedoctrineofevolution，andalltheso-called“materialistic“viewsofmodernscience，theynotonlyregardthehypothesisofafuturelifeasadmissible，buttheyevengosofarastopropoundaphysicaltheoryastothenatureofexistenceafterdeath。Letusseewhatthisphysicaltheoryis。
Asfarasthevisibleuniverseisconcerned，wedonotfindinitanyevidenceofimmortalityorofpermanenceofanysort，unlessitbeinthesumofpotentialandkineticenergiesonthepersistencyofwhichdependsourprincipleofcontinuity。Inordinarylanguage“thestarsintheircourses“serveassymbolsofpermanence，yetwehavefoundreasontoregardthemasbuttemporaryphenomena。So，inthelanguageofourauthors，“ifwetaketheindividualman，wefindthatheliveshisshorttaleofyears，andthatthenthevisiblemachinerywhichconnectshimwiththepast，aswellasthatwhichenableshimtoactinthepresent，fallsintoruinandisbroughttoanend。Ifanygermorpotentialityremains，itiscertainlynotconnectedwiththevisibleorderofthings。“Inlikemannerourraceisprettysuretocometoanendlongbeforethedestructionoftheplanetfromwhichitnowgetsitssustenance。Andinourauthorsopinioneventheuniversewillbyandbybecome“oldandeffete，nolesstrulythantheindividual:itisagloriousgarmentthisvisibleuniverse，butnotanimmortalone；wemustlookelsewhereifwearetobeclothedwithimmortalityaswithagarment。“