Itdoesnotseemthatanadequateexplanationcanbefoundintheoperationofhabit。Itisnodoubttruethatactionsthroughfrequentuniformrepetitiontendtobecomeautomaticandlosetheirconsciouscounterparts，andhedonicindifferencecertainlyseemsinsomecasestobeastagethroughwhichsuchactionspassonthewaytounconsciousness。Thusevenabusinesswalkinastrangetownisnormallypleasantthroughthenoveltyofthesights:butasimilarwalkinthetownwhereonelivesisordinarilyindifferent，ornearlyso；whileifone’sattentionisstronglyabsorbedbythebusiness，itmaybeperformedtoagreatextentunconsciously。Ontheotherhand，theoperationsofhabitoftenhavetheoppositeeffectofmakingactivitiespleasantwhichwereatfirstindifferentorevendisagreeable:asinthecaseofacquiredtastes，physicalorintellectual。Indeedsuchexperienceshavelongbeen——Ithink，quitelegitimately——usedbymoralistsasanencouragementtoirksomeduties，onthegroundthattheirirksomenesswillbetransient，throughtheoperationofhabit，whilethegainoftheirperformancewillbepermanent。Mr。Spencer，indeed，regardssuchexperiencesassoimportantthatheventurestobaseonthemthepredictionthat``pleasurewilleventuallyaccompanyeverymodeofactiondemandedbysocialconditions’’。This，however，seemsundulyoptimistic，inviewnotonlyofthefirst-mentionedtendencyofhabittohedonicindifference，butalsoofathirdtendencytorenderactions，atfirstindifferentorevenpleasant，graduallymoreirksome。Thusourintellectgraduallyweariesofmonotonousactivities，andtheennuimaysometimesbecomeintense:soagaintherelishofakindofdietatfirstagreeablemayturnthroughmonotonyintodisgust。
　　Somequitedifferentexplanationmustthereforebesoughtforthevaryingdegreesinwhichpleasureaccompaniesnormalactivities。CanwefindthisinasuggestionofMr。Spencer’s，developedbyMr。GrantAllen，thatthepleasurablenessofnormalorganicactivitiesdependsontheirintermittence，andthat``theamountofpleasureisprobably？intheinverseratioofthenaturalfrequencyofexcitation’’
　　ofthenerve-fibresinvolved？Thistheorycertainlyfindssomesupportinthefactthatthesensualpleasuresgenerallyrecognisedasgreatestarethoseattendingtheactivitiesoforganswhicharenormallyleftunexercisedforconsiderableintervals。Still，therearemanyfactsthatitdoesnotexplain——e。g。thegreatdifferencesinthepleasuresobtainableatanygiventimebydifferentstimulationsofthesamesense；thephenomenonexpressedintheproverbialphrase``L’appé；titvientenmangeant’’；
　　andthefactthattheexerciseofthevisualorgansafterapparentlydreamlesssleepdoesnotgiveappreciablykeenerpleasurethanitdoesatordinarytimes。Itwouldseemthatwemustseekforsomespecialcauseofthepleasurableeffectofintermittenceincertaincases。Andthiscannotbemerelythegreaterintensityofthenervousactionthattakesplacewhenlongunexercisedandwell-nourishednerve-centresarestimulated:forwhy，ifthatweretheexplanation，shouldthenormalconsciousnessoffullnervousactivity，graduallyattained——aswhenweareinfullswingofenergeticunweariedworkofaroutinekind——beoftennearlyorquiteindifferent？
　　Amongthevariouscompetinghypothesesofferedatthispointofourinquiry——nooneofwhich，Ibelieve，hasattainedanythinglikegeneralacceptanceascoveringthewholeground——Iselectfordiscussiononethathasspecialethicalinterest。
　　Accordingtothishypothesis，theorganicprocessaccompaniedbypleasureistobeconceivedasa``restorationofequilibrium’’after``disturbance’’:sothattheabsenceofappreciablepleasureinthecaseofcertainnormalactivitiesisexplainedbytheabsenceofantecedentdisturbance。Thisviewisobviouslyapplicabletocertainclassesofpleasureswhich，thoughbynomeansrareareincidentalinanormallife:——thepleasureofreliefafterphysicalpain，orafterthestrainofgreatanxiety，andthepleasureofreposeafterunusualexertions，intellectualormuscular。Butwhenweattempttoapplyittosensationalpleasuresgenerally，theindefinitenessofthenotionof``equilibrium’’，asappliedtotheprocessesofalivingorganism，becomesmanifest。Forourphysicallifeconsistsofaseriesofchanges，forthemostpartperiodicallyrecurrentwithslightmodificationaftershortintervals:anditisdifficulttoseewhyweshouldattachtheideaof``disturbance’’or``restorationofequilibrium’’toanyoneamongthesenormalprocessesratherthananother:e。g。itisdifficulttoseewhytheconditionofhavingexpendedenergyshouldberegardedasadeparturefromequilibriumanymorethantheconditionofhavingjusttakeninnutriment。Infact，torenderthehypothesisweareconsideringatallapplicabletonormalpleasuresofsense，wehavetopassfromthephysiologicaltothepsychologicalpointofview，andtakenoteofthepsychicalstateofdesire，asaconsciouslyunrestfulcondition，ofwhichtheessenceisafeltimpulsetopassoutofthisstatetowardstheattainmentofthedesiredobject。Ourhypothesis，then，maytakethisunrestfulconsciousnessasasignofwhat，fromaphysiologicalpointofview，is``disturbanceofequilibrium’’，andsimilarly，thesatisfactionofdesiremaybetakentobe，physiologically，arestorationofequilibrium。
　　Onthisassumption，thetheorybecomesundeniablyapplicabletothosegratificationsofsensualappetitewhichformthemostprominentelementofthepleasuresofsense，aspopularlyconceived。
　　Nowwehavealreadynotedthatbyawide-spreadconfusionofthought，desirehasoftenbeenregardedasaspeciesofpain。Accordingly，thetheorythatweareconsideringwasoriginallypromptedbytheethicalmotiveofdepreciatingthevulgarlyovervaluedpleasuresofsatisfiedbodilyappetite，bylayingstressontheirinseparableconnexionwithantecedentpain。Thedepreciation，however，failssofarastheappetitewhichisanecessaryantecedentconditionofthepleasureis——thoughanunrestfulstate——notappreciablypainful。
　　Inanycase，admittingthephysicalcounterpartofconsciousdesiretobea`disturbanceofequilibrium’，oraneffectandsignofsuchdisturbance，thetheoryseemsopentoobviousobjections，ifitisextendedtocoverthewholerangeofthepleasuresofsense。Forconsciousdesireiscertainlynotanecessaryconditionofexperiencingthesimplepleasuresofthespecialsenses:normallynosenseofwanthasprecededtheexperienceofpleasantsights，sounds，odours，flavours，orofthemoreimportantpleasures，morecomplexintheirpsychicalconditions，whichwecallæ；sthetic。Nodoubtinspecialcasesantecedentprivationmayproduceaconsciouswantoftheselatterpleasureswhichmayincreasetheirintensitywhentheyareatlengthattained:orevenwithoutanyfeltprivation，theprospectofenjoyingsuchpleasuresmayproduceakeendesirefortheenjoyment，whichmayberegardedasa``disturbanceofequilibrium’’
　　nolessplausiblythanabodilyappetite。Butitwouldbequiteunwarrantablethereforetosupposeasimilardisturbance，thoughunfelt，intheordinarycaseswherepleasuresofthiskindareexperiencedwithoutanyantecedentconsciousnessofdesireorwant。
　　IhaveperhapssaidenoughtosupportmygeneralconclusionthatpsychophysicalspeculationastothecausesofpleasureandpaindoesnotatpresentaffordabasisforadeductivemethodofpracticalHedonism。But，beforepassingfromthistopic，Imayremarkthatthedifficultiesinthewayofanysuchtheoryseemespeciallygreatinthecaseofthecomplexpleasureswhichwedistinguishas``æ；sthetic’’。Allwouldagreethatæ；stheticgratification，whenatallhigh，dependsonasubtleharmonyofdifferentelementsinacomplexstateofconsciousness；
　　andthatthepleasureresultingfromsuchharmoniouscombinationisindefinitelygreaterthanthesumofthesimplerpleasureswhichtheuncombinedelementswouldyield。Buteventhosewhoestimatemosthighlythesuccessthathassofarbeenattainedindiscoveringtheconditionsofthisharmony，inthecaseofanyparticularart，wouldadmitthatmereconformitytotheconditionsthusascertainedcannotsecuretheproductionofæ；stheticpleasureinanyconsiderabledegree。Howeversubtlywestateingeneraltermstheobjectiverelationsofelementsinadelightfulworkofart，onwhichitsdelightseeingtodepend，wemustalwaysfeelthatitwouldbepossibletoproduceoutofsimilarelementsaworkcorrespondingtoourgeneraldescriptionwhichwouldgivenodelightatall；thetouchthatgivesdelightdependsuponaninstinctforwhichnodeductivereasoningcansupplyasubstitute。Thisistrue，evenwithouttakingintoaccountthewidedivergencesthatweactuallyfindinthe，estheticsensibilitiesofindividuals:stillless，therefore，isitneedfultoarguethat，fromthepointofviewofanindividualseekinghisowngreatesthappiness，nonebutamainlyinductiveandempiricalmethodofestimatingæ；stheticpleasurescanbemadeavailable。
　　Inowpasstoconsideratheorywhichmaybedistinguishedfromthosediscussedintheprecedingsectionasbeingbiologicalratherthanpsychophysical:sinceitdirectsattentionnottotheactualpresentcharacteristicsoftheorganicstatesorchangesofwhichpleasuresandpainsaretheconcomitantsorimmediateconsequents，buttotheirrelationstothelifeoftheorganismasawhole。
　　Imeanthetheorythat``painsarethecorrelativesofactionsinjurioustotheorganism，whilepleasuresarethecorrelativesofactsconducivetoitswelfare。’’Mr。Spencer，fromwhomtheabovepropositionsarequoted，subsequentlyexplains``injurious’’and``conducivetowelfare’’tomeanrespectively``tendingtodecreaseorlossoflife’’，and``tendingtocontinuanceorincreaseoflife’’:butinhisdeductionbywhichtheaboveconclusionissummarilyestablished，``injurious’’and``beneficial’’areusedasequivalentsimplyto``destructive’’and``preservative’’oforganiclife:anditwillbemoreconvenienttotakethetermsfirstinthissimplersignification。
　　Mr。Spencer’sargumentisasfollows:
　　``IfwesubstituteforthewordPleasuretheequivalentphrase——afeelingwhichweseektobringintoconsciousnessandretainthere；andifwesubstituteforthewordPaintheequivalentphrase——afeelingwhichweseektogetoutofconsciousnessandtokeepout；weseeatoncethat，ifthestatesofconsciousnesswhichacreatureendeavourstomaintainarethecorrelativesofinjuriousactions，andifthestatesofconsciousnesswhichitendeavourstoexpelarethecorrelativesofbeneficialactions，itmustquicklydisappearthroughpersistenceintheinjuriousandavoidanceofthebeneficial。Inotherwords，thoseracesofbeingonlycanhavesurvivedinwhich，ontheaverage，agreeableordesiredfeelingswentalongwithactivitiesconducivetothemaintenanceoflife，whiledisagreeableandhabitually-avoidedfeelingswentalongwithactivitiesdirectlyorindirectlydestructiveoflife；andtheremusteverhavebeen，otherthingsequal，themostnumerousandlong-continuedsurvivalsamongracesinwhichtheseadjustmentsoffeelingstoactionswerethebest，tendingevertobringaboutperfectadjustment。’’
　　NowIamnotconcernedtodenythevalueofthissummarydeductionforcertainpurposes。Butitcaneasilybeshowntobeinadequatetoaffordabasisforadeductivemethodofseekingmaximumhappinessfortheindividual，bysubstitutingPreservationforPleasureastheenddirectlyaimedat。Inthefirstplace，Mr。Spenceronlyaffirmstheconclusiontobetrue，asherathervaguelysays，``ontheaverage’’:
　　anditisobviousthatthoughthetendencytofindinjuriousactspleasantorpreservativeactspainfulmustbeadisadvantagetoanyspeciesofanimalinthestruggleforexistence，itmay——ifexistingonlytoalimitedextent——beoutweighedbyotheradvantages，sothattheorganisminwhichitexistsmaysurviveinspiteofit。This，Isay，isobviousapriori:andcommonexperience，asMr。Spenceradmits，shows``inmanyconspicuousways’’
　　thatthishasbeenactuallythecasewithcivilisedmanduringthewholeperiodofhistorythatweknow:owingtothechancescausedbythecourseofcivilisation，``therehasarisenandmustlongcontinueadeepandinvolvedderangementofthenaturalconnexionsbetweenpleasuresandbeneficialactionsandbetweenpainsanddetrimentalactions。’’ThisseemstobeinitselfasufficientobjectiontofoundingadeductivemethodofHedonismonMr。Spencer’sgeneralconclusion。Itis，indeed，notoriousthatcivilisedmentakepleasureinvariousformsofunhealthyconductandfindconformitytotherulesofhealthirksome；anditisalsoimportanttonotethattheymaybe，andactuallyare，susceptibleofkeenpleasurefromactsandprocessesthathavenomaterialtendencytopreserve，life。Noristhereanydifficultyinexplainingthisontheevolutionhypothesissincewecannotargueapriorifromthishypothesisthatthedevelopmentofthenervoussysteminhumanbeingsmaynotbringwithitintensesusceptibilitiestopleasurefromnon-preservativeprocesses，ifonlythepreservationoftheindividualsinwhomsuchsusceptibilitiesaredevelopedisotherwiseadequatelyprovidedfor。Nowthislattersuppositionisobviouslyrealisedinthecaseofpersonsofleisureincivilisedsociety；whoseneedsoffood，clothing，shelter，etc。，areabundantlysuppliedthroughthecomplexsocialhabitwhichwecalltheinstitutionofprivateproperty:andIknownoempiricalgroundforsupposingthatacultivatedmantends，inconsequenceofthekeenandvariedpleasurewhichheseeksandenjoys，tolivelongerthanamanwhogoesthroughacomparativelydullroundofmonotonousroutineactivity，interspersedbyslightlypleasurableintervalsofreposeandplay。