Withorwithouttheaccompanimentofthathypothesisofnebularcondensation
　　whenceitnaturallyfollows，thedoctrinethattheSunisgraduallylosing
　　hisheat，hasnowgainedgeneralacceptance;andcalculationshavebeenmade，
　　bothrespectingtheamountofheatandlightalreadyradiated，ascompared
　　withtheamountthatremains，andrespectingtheperiodduringwhichactive
　　radiationwillcontinue。Prof。Helmholtzestimatesthatsincethetimewhen，
　　accordingtothenebularhypothesis，themattercomposingtheSolarSystem
　　extendedtotheOrbitofNeptune，therehasbeenevolvedbythearrestof
　　sensiblemotion，anamountofheat454timesasgreatasthatwhichtheSun
　　stillhastogiveout。Healsomakesanapproximateestimateoftherate
　　atwhichthisremaining1/464thisbeingdiffused:showingthatdecrease
　　oftheSun'sdiametertotheextentof1/10，000wouldproduceheat，atthe
　　presentrate，formorethan2000years;orinotherwords，thatacontraction
　　of1/20，000，000ofhisdiameter，sufficestogeneratethelightandheat
　　annuallyemitted;andthatthusatthepresentrateofexpenditure，theSun's
　　diameterwilldiminishbysomethinglike1/20inthelapseofthenextmillion
　　years。*Ofcourse
　　theseconclusionsarebutrudeapproximationstothetruth。Untilquiterecently，
　　wehavebeentotallyignorantoftheSun'schemicalcomposition，andeven
　　nowhaveobtainedbutasuperficialknowledgeofit。Weknownothingofhis
　　internalstructure;anditisquitepossiblethattheassumptionsrespectingcentraldensity，madeintheforegoingestimates，arewrong。Butnouncertaintyinthedataonwhichthesecalculationsproceed，and
　　noconsequenterrorintheinferredrateatwhichtheSunisexpendinghis
　　reserveenergy，militatesagainstthegeneralpropositionthatthisreserveofenergyisbeingexpended，andmustintimebeexhausted。ThuswhiletheSolarSystem，ifevolvedfromdiffusedmatter，hasillustrated
　　thelawofequilibrationintheestablishmentofamovingequilibrium;and
　　while，asatpresentconstituted，itillustratesthelawofequilibration
　　intheperpetualbalancingofallitsmovements;italsoillustratesthis
　　lawintheseprocesseswhichastronomersandphysicistsinferarestillgoing
　　on。ThatmotionofmassesproducedduringEvolution，isbeingslowlyrediffused
　　inmolecularmotionoftheetherealmedium;boththroughtheprogressive
　　integrationofeachmass，andtheresistancetoitsmotionthroughspace。
　　Infinitelyremoteasmaybethestatewhenalltherelativemotionsofits
　　massesshallbetransformedintomolecularmotion，andallthemolecular
　　motiondissipated;yetsuchastateofcompleteintegrationandcomplete
　　equilibration，isthattowardswhichthechangesnowgoingonthroughouttheSolarSysteminevitablytend。§172。Asphericalfigureistheonewhichcanaloneequilibratethe
　　forcesofmutually—gravitatingmolecules。Ifanaggregateofsuchmolecules
　　rotates，theformofequilibriumbecomesaspheroidofgreaterorlessoblateness，
　　accordingtotherateofrotation;andithasbeenascertainedthattheEarth
　　isanoblatespheroid，divergingjustasmuchfromsphericityasisrequisite
　　tocounterbalancethecentrifugalforceconsequentonitsvelocityround
　　itsaxis。Thatistosay，duringtheevolutionoftheEarth，therehasbeen
　　reachedanequilibriumofthoseforceswhichaffectitsgeneraloutline。
　　TheonlyotherequilibrationwhichtheEarthasawholecanexhibit，isthe
　　lossofitsrotation;andthatanysuchlossisgoingonwehavenodirect
　　evidence。Ithasbeencontended，however，byProf。Helmholtzandothers，
　　thatinappreciableasmaybeitseffectwithinknownperiodsoftime，the
　　frictionofthetidalwavemustbediminishingtheEarth'smotionroundits
　　axis，andmusteventuallydestroyit。Nowthoughitseemsanoversightto
　　saythattheaxialmotioncanthusbedestroyed，sincetheextremeeffect，
　　tobereachedonlyininfinitetime，wouldbeanextensionoftheEarth's
　　daytothelengthoflunation;yetitseemsclearthatthisfrictionofthe
　　tidalwaveisarealcauseofdecreasingrotation。Slowasitsactionis，
　　wemustrecognizeitsretardingeffectasexemplifying，underanotherform，
　　theuniversalprogresstowardsequilibrium。（*）ItisneedlesstoshowindetailhowthosemovementswhichtheSun'srays
　　generateintheairandwaterontheEarth'ssurface，andthroughthemin
　　theEarth'ssolidsubstance，（*）one
　　andallteachthesamegeneraltruth。Evidentlythewindsandwavesandstreams，
　　aswellasthedenudationsanddepositionstheyeffect，illustrateonagrand
　　scale，andinendlessmodes，thatgradualdissipationofmotionsdescribed
　　inthefirstsection，andtheconsequenttendencytowardsabalanceddistribution
　　offorces。Eachofthesesensiblemotions，produceddirectlyorindirectly
　　byintegrationofthoseinsensiblemotionscommunicatedfromtheSun，becomes
　　dividedandsubdividedintomotionslessandlesssensible;untilbygradual
　　orsuddenarrestofeach，andproductionofitsequivalentinmolecularmotion，
　　thereisanescapeofitintospaceintheshapeofthermalundulations。
　　Intheirtotality，thesecomplexmotionsconstituteadependentmovingequilibrium。
　　Aswebeforesawthereistraceablethroughoutthemaninvolvedcombination
　　ofrhythms。Theunceasingcirculationofwaterfromtheoceantotheland
　　andfromthelandbacktotheocean，isatypeofthesevariouscompensating
　　actionswhich，inthemidstofalltheirregularitiesproducedbytheirmutual
　　interferences，maintainanaverage。Andinthis，asinotherequilibrations
　　ofthethirdorder，weseethattheenergyeverincourseofdissipation，
　　iseverrenewedfromwithout:therisesandfallsinthesupplybeingbalanced
　　byrisesandfallsintheexpenditure;aswitnessthevariationsofmeteorologic
　　activityinnorthernzonescausedbychangesoftheseasons。Butthefact
　　itchieflyconcertsustonoteisthatthisprocessmustgoonbringingthings
　　evernearertocompleterest。Thesemechanicalmovements，meteorologicand
　　geologic，whicharecontinuallybeingequilibrated，bothtemporarybycounter—movements
　　andpermanentlybythedissipationofsuchmovementsandcounter—movements，
　　willslowlydiminishasthequantityofforcereceivedfromtheSundiminishes。
　　Astheinsensiblemotionspropagatedtousfromthecentreofoursystem
　　becomefeebler，thesensiblemotionshereproducedbythemmustdecrease;
　　andatthatremoteperiodwhenthesolarheathasceasedtobeappreciable，
　　therewillnolongerbeanyappreciablere—distributionsofmatteronthesurfaceofourplanet。Thus，allterrestrialchangesareincidentsinthecourseofcosmical
　　equilibration。Itwasbeforepointedout（§69），thatoftheincessant
　　alterationswhichtheEarth'scrustandatmosphereundergo，thosewhichare
　　notduetotheactionofthemoonandtothestill—progressingmotionof
　　theEarth'ssubstancetowardsitscentreofgravity，areduetothestill—progressing
　　motionoftheSun'ssubstancetowardsitscentreofgravity。Hereitisto
　　beremarkedthatthiscontinuanceofintegrationintheEarthandinthe
　　Sun，isacontinuanceofthattransformationofsensiblemotionintoinsensible
　　motionwhichwehaveseenendsinequilibrium;andthatthearrivalineach
　　caseattheextremeofintegration，isthearrivalatastateinwhichno
　　moresensiblemotionremainstobetransformedintoinsensiblemotion——
　　astateinwhichtheforcesproducingintegrationandtheforcesopposingintegrationhavebecomeequal。§173。Everylivingbodyexhibits，inafour—foldform，theprocess
　　wearetracingout——exhibitsitfrommomenttomomentinthebalancing
　　ofmechanicalforces;fromhourtohourinthebalancingoffunctions;from
　　yeartoyearinthechangesofstatethatcompensatechangesofconditions;
　　andfinallyinthearrestofvitalmovementsatdeath。Letusconsiderthefactsundertheseheads。Thesensiblemotionconstitutingeachvisibleactionofananimal，is
　　soonbroughttoaclosebysomeopposingforcewithinorwithouttheanimal。
　　Whenaman'sarmisraised，themotiongiventoitisantagonizedpartly
　　bygravityandpartlybytheinternalresistancesconsequentonstructure;
　　anditsmotion，thussufferingcontinualdeduction，endswhenthearmhas
　　reachedapositionatwhichtheforcesareequilibrated。Thelimitsofeach
　　systoleanddiastoleoftheheart，severallyshowusamomentaryequilibrium
　　betweenmuscularstrainsthatproduceoppositemovements;andeachgushof
　　bloodhastobeimmediatelyfollowedbyanotherbecausetherapiddissipation
　　ofitsmomentumwouldotherwisesoonbringthecirculatingmasstoastand。
　　Asmuchintheactionsandreactionsgoingonamongtheinternalorgans，
　　asinthemechanicalbalancingofthewholebodythereisateveryinstant
　　aprogressiveequilibrationofthemotionsateveryinstantproduced。Viewed
　　intheiraggregate，andasformingaseries，theorganicfunctionsconstitute
　　adependentmovingequilibrium，amovingequilibriumofwhichthemotive
　　poweriseverbeingdissipatedthroughthespecialequilibrationsjustexemplified，
　　andiseverbeingrenewedbythetakinginofadditionalmotivepower。The
　　forcestoredupinfoodcontinuallyaddstothemomentumofthevitalactions，
　　asmuchasiscontinuallydeductedfromthembytheforcesovercome。All
　　thefunctionalmovementsthusmaintainedarerhythmical（§85）;bytheir
　　unioncompoundrhythmsofvariouslengthsandcomplexitiesareproduced;
　　andinthesesimpleandcompoundrhythms，theprocessofequilibration，besides
　　beingexemplifiedateachextremeofeveryrhythm，isseeninthehabitual
　　preservationofaconstantmean，andinthere—establishmentofthatmean
　　whenaccidentalcauseshaveproduceddivergence。fromit。When，forinstance，
　　thereisagreatexpenditureofmuscularenergy，therearisesareactive
　　demandonthosestoresofenergywhicharelaidupintheformofconsumable
　　matterthroughoutthetissues:increasedrespirationandincreasedcirculation
　　aidanextragenesisofforce，thatcounterbalancestheextradissipation
　　offorce。Thisunusualtransformationofmolecularmotionintosensiblemotion，
　　ispresentlyfollowedbyanunusualabsorptionoffood——thesourceofmolecular
　　motion;andtheprolongeddraftonthesparecapitalinthetissues，isfollowed
　　byaprolongedrest，duringwhichtheabstractedcapitalisreplaced。If
　　thedeviationfromtheordinarycourseofthefunctionshasbeensogreat
　　astoderangethem，aswhenviolentexertionproduceslossofappetiteand
　　lossofsleep，anequilibrationisstilleventuallyeffected。Providingthe
　　disturbanceisnotsuchastodestroylife（inwhichcasecompleteequilibration
　　issuddenlyeffected），theordinarybalanceisby—and—byre—established:
　　thereturningappetiteiskeeninproportionasthewastehasbeenlarge;
　　whilesleep，soundandprolonged，makesupforpreviouswakefulness。Not
　　evenwhensomeextremeexcesshaswroughtaderangementthatisneverwholly
　　rectified，isthereanexceptiontothegenerallaw;forinsuchcasesthe
　　cycleofthefunctionsis，afteratime，equilibratedaboutanewmeanstate，
　　whichthenceforthbecomesthenormalstateoftheindividual。Andthisprocess
　　exemplifiesinalargewaywhatphysicianscallthevismedicatrixnaturae。
　　Thethirdformofequilibrationdisplayedbyorganicbodies，isasequence
　　ofthatjustillustrated。When，throughachangeofhabitorcircumstance，
　　anorganismispermanentlysubjecttosomenewinfluence，ordifferentamount
　　ofanoldinfluence，therearises，aftermoreorlessdisturbanceofthe
　　organicrhythms，abalancingofthemaroundthenewaverageconditionproduced
　　bythisadditionalinfluence。ifthequantityofmotiontobehabitually
　　generatedbyamusclebecomesgreaterthanbefore，itsnutritionbecomes
　　greaterthanbefore。iftheexpenditureofthemusclebearstoitsnutrition，
　　agreaterratiothanexpenditurebearstonutritioninotherpartsofthe
　　system，theexcessofnutritionbecomessuchthatthemusclegrows。Andthe
　　cessationofitsgrowthistheestablishmentofabalancebetweenthedaily
　　wasteandthedailyrepair。Thelikeismanifestlythecasewithallorganic
　　modificationsconsequentonchangesofclimateorfood。Ifweseethata
　　differentmodeoflifeisfollowed，afteraperiodofderangement，bysome
　　alteredconditionofthesystem——ifweseethatthisalteredcondition，
　　becomingby—and—byestablished，continueswithoutfurtherchange;wehave
　　noalternativebuttosaythatthenewforcesbroughttobearonthesystem，
　　havebeencompensatedbytheopposingforcestheyhaveevoked。Andthisis
　　theinterpretationoftheprocesscalledadaptation。Finally，eachorganism
　　illustratesthelawintheensembleofitslife。Attheoutsetitdailyabsorbs
　　undertheformoffood，anamountofforcegreaterthanitdailyexpends;
　　andthesurplusisdailyequilibratedbygrowth。Asmaturityisapproached
　　thissurplusdiminishes;andintheperfectorganismtheday'sabsorption
　　oflatentenergybalancestheday'sexpenditureofactualenergy。Thatis
　　tosay，duringadultlifethereiscontinuouslyexhibitedanequilibrium
　　ofthethirdorder。Eventually，thedailylossbeginstooutbalancethedaily
　　gain，andthereresultsadiminishingamountoffunctionalaction;theorganic
　　rhythmsextendlessandlesswidelyoneachsideofthemediumstate;andtherefinallycomesthatcompleteequilibriumwecalldeath。Theultimatestructuralstateaccompanyingthatultimatefunctionalstate
　　towardswhichanorganismtends，maybededucedfromoneofthepropositions
　　setdownintheopeningsectionofthischapter。Wesawthatthelimitof
　　heterogeneityisreachedwhentheequilibrationofanyaggregatebecomes
　　complete——thatthere—distributionofmattercancontinuesolongonly
　　astherecontinuessomemotionunbalanced。Whatistheimplicationinthe
　　caseoforganicaggregates？Wehaveseenthattomaintainthemovingequilibrium
　　ofone，requiresthehabitualgenesisofinternalforcescorrespondingin
　　number，directions，andamountstotheexternalincidentforces——asmany
　　innerfunctions，singleorcombined，astherearesingleorcombinedouter
　　actionstobemet。Butfunctionsarethecorrelativesoforgans;amounts
　　offunctionsare，otherthingsequal，thecorrelativesofsizesoforgans;
　　andcombinationsoffunctionsthecorrelativesofconnexionsoforgans。Hence
　　thestructuralcomplexityaccompanyingfunctionalequilibrium，isdefinable
　　asoneinwhichthereareasmanyspecializedpartsasarecapable，separately
　　andjointly，ofcounteractingtheseparateandjointforcesamidwhichthe
　　organismexists。Andthisisthelimitoforganicheterogeneity。towhichManhasapproachedmorenearlythananyothercreature。Groupsoforganismsdisplaythisuniversaltendencytowardsabalance
　　veryobviously。in§85，everyspeciesofplantandanimalwasshown
　　tobeperpetuallyundergoingarhythmicalvariationinnumber——nowfrom
　　abundanceoffoodorabsenceofenemiesrisingaboveitsaverage;andthen，
　　byaconsequentscarcityoffoodorabundanceofenemies，beingdepressed
　　belowitsaverage。Andherewehavetoobservethatthereisthusmaintained
　　anequilibriumbetweenthesumofthoseforceswhichresultintheincrease
　　ofeachrace，andthesumofthoseforceswhichresultinitsdecrease。Either
　　limitofvariationisapointatwhichtheonesetofforces，beforeinexcess
　　oftheother，iscounterbalancedbyit。Andamidtheseoscillationsproduced
　　bytheirconflict，liesthataveragenumberofthespeciesatwhichitsexpansive
　　tendencyisinequilibriumwithsurroundingrepressivetendencies。Norcan
　　itbequestionedthatthisbalancingofthepreservativeanddestructive
　　forceswhichweseegoingonineveryrace，mustnecessarilygoon。Increase
　　ofnumbercannotbutcontinueuntilincreaseofmortalitystopsit;anddecrease
　　ofnumbercannotbutcontinueuntilitiseitherarrestedbyfertilityorextinguishestheraceentirely。§174。Theequilibrationsofthosenervousactionswhichconstitute
　　theobversefaceofmentallife，maybeclassifiedinlikemannerwiththose
　　whichconstitutewhatwedistinguishasbodilylife。Wemaydealwiththeminthesameorder。Eachpulseofnerveforcefrommomenttomomentgenerated，（anditwas
　　explainedin§86thatnervecurrentsarenotcontinuousbutrhythmical，）
　　ismetbycounteractingforces，inovercomingwhichitisdispersedandequilibrated。
　　Suchpartofitasdoesnotworkmentalchangesworksbodilychanges——contractions
　　oftheinvoluntarymuscles，thevoluntarymuscles，orboth;asalsosome
　　stimulationofsecretingorgans。Thatthemovementsthusinitiatedareever
　　beingbroughttoaclosebytheopposingforcestheyevoke，wehavejust
　　seen;andhereitistobeobservedthatthelikeholdswiththecerebral
　　changesthusinitiated。Thearousingofathoughtorfeeling，involvesthe
　　overcomingofacertainresistance:instancethefactthatwheretheassociation
　　ofmentalstateshasnotbeenfrequent，asensibleeffortisneededtocall
　　uptheoneaftertheother;instancethefactthatduringnervousprostration
　　thereisacomparativeinabilitytothink——theideaswillnotfollowone
　　anotherwiththeordinaryrapidity;instancetheconversefactthatattimes
　　ofunusualenergy，naturalorartificial，thinkingiseasy，andmorenumerous，
　　moreremote，ormoredifficultconnexionsofideasareformed。Thatisto
　　say，thewaveofnervousenergyeachinstantgenerated，propagatesitself
　　throughoutbodyandbrain，alongthosechannelswhichthepassingconditions
　　renderlinesofleastresistance;andspreadingwidelyinproportiontoits
　　amount，endsonlywhenitisequilibratedbytheresistancesiteverywhere
　　meets。Ifwecontemplatementalactionsasextendingoverhoursanddays，
　　wediscoverequilibrationsanalogoustothosehourlyanddailyestablished
　　amongthebodilyfunctions。Thisisseeninthedailyalternationofmental
　　activityandmentalrest——theforcesexpendedduringtheonebeingcompensated
　　bytheforcesacquiredduringtheother。Itisalsoseenintherecurring
　　riseandfallofeachdesire。Eachdesirereachingacertainintensity，is
　　equilibratedeitherbyexpenditureoftheenergyitembodiesinthedesired
　　actions，or，lesscompletely，intheimaginationofsuchactions:theprocess
　　endinginthatsatietyorthatcomparativequiescence，formingtheopposite
　　limitoftherhythm。Anditisfurthermanifestunderatwo—foldformon
　　occasionsofintensejoyorgrief。Eachparoxysm，expressingitselfinviolent
　　actionsandloudsounds，presentlyreachesanextremewhencethecounteracting
　　forcesproducereturntoaconditionofmoderateexcitement;andthesuccessive
　　paroxysms，finallydiminishinginintensity，endinamentalequilibrium
　　eitherlikethatbeforeexisting，orhavingapartiallydifferentmedium
　　state。Butthekindofmentalequilibrationtobeespeciallynoted，isthat
　　shownintheestablishmentofacorrespondencebetweenrelationsamongour
　　ideasandrelationsintheexternalworld。Eachouterconnexionofphenomena
　　whichwearecapableofperceiving，generates，throughaccumulatedexperiences，
　　aninnerconnexionofmentalstates;andtheresulttowardswhichthisprocess
　　tends，istheformationofamentalconnexionhavingarelativestrength
　　thatanswerstotherelativeconstancyofthephysicalconnexionrepresented。
　　Inconformitywiththegenerallawthatmotionpursuesthelineofleast
　　resistance，andthat，otherthingsequal，alineoncetakenbymotionis
　　madealinewhichwillbemorereadilytakenbyfuturemotion，wehaveseen
　　thattheeasewithwhichnervousimpressionsfollowoneanotheris，other
　　thingsequal，greatinproportiontothenumberoftimestheyhavebeenrepeated
　　togetherinexperience。Hence，correspondingtosuchaninvariablerelation
　　asthatbetweentheresistanceofanobjectandsomeextensionpossessed
　　byit，therearisesanindissolubleconnexioninconsciousness;andthis
　　connexion，beingasabsoluteinternallyastheansweringoneisexternally，
　　undergoesnofurtherchange——theinnerrelationisinperfectequilibrium
　　withtheouterrelation。Conversely，ithappensthat，answeringtosuchuncertain
　　relationsofphenomenaasthatbetweencloudsandrain，thereariserelations
　　ofideasoflikeuncertainty;andif，undergivenaspectsofthesky，the
　　tendenciestoinferfairorfoulweather，correspondstothefrequencies
　　withwhichfairorfoulweatherfollowssuchaspects，theaccumulationof
　　experienceshasbalancedthementalsequencesandthephysicalsequences。
　　Whenitisrememberedthatbetweentheseextremestherearecountlessorders
　　ofexternalassociationshavingdifferentdegreesofconstancy，andthat
　　duringtheevolutionofintelligencethereariseansweringeternalassociations
　　havingdifferentdegreesofcohesion;itwillbeseenthatthereisaprogress
　　towardsequilibriumbetweentherelationsofthoughtandtherelationsof
　　things。Thelikegeneraltruthsareexhibitedintheprocessofmoraladaptation，
　　whichisacontinualapproachtoequilibriumbetweentheemotionsandthe
　　kindsofconductrequiredbysurroundingconditions。Justasrepeatingthe
　　associationoftwoideasfacilitatestheexcitementoftheonebytheother，
　　sodoeseachdischargeoffeelingintoactionrenderthesubsequentdischarge
　　ofsuchfeelingintosuchactionmoreeasy。Thusithappensthatifanindividual
　　isplacedpermanentlyinconditionswhichdemandmoreactionofaspecial
　　kindthanhasbeforebeenrequisite，orthanisnaturaltohim——ifbyevery
　　morefrequentormorelengthenedperformanceofitundersuchpressure，the
　　resistanceissomewhatdiminished;then，dearly，thereisanadvancetowards
　　abalancebetweenthedemandforthiskindofactionandthesupplyofit。
　　Eitherinhimself，orinhisdescendantscontinuingtoliveundertheseconditions，
　　enforcedrepetitionmustatlengthbringaboutastateinwhichthismode
　　ofdirectingtheenergieswillbenomorerepugnantthantheothermodes
　　previouslynaturaltotherace。Hencethelimittowardswhichemotionalmodification
　　perpetuallytends，isacombinationofdesirethatcorrespondtothevarious
　　ordersofactivitywhichthecircumstancesoflifecallfor。Inacquired
　　habits，andinthemoraldifferencesofracesandnationsthatareproduced
　　byhabitsmaintainedthroughsuccessivegenerations，wehaveillustrations
　　ofthisprogressiveadaptation，whichcanceaseonlywiththeestablishmentofequilibriumbetweenconstitutionandconditions。###第40章§175。Eachsocietydisplaystheprocessofequilibrationinthecontinuous
　　adjustmentofitspopulationtoitsmeansofsubsistence。Atribeofmen
　　livingonwildanimalsandfruits，ismanifestly，likeeverytribeofinferior
　　creatures，alwaysoscillatingfromsidetosideofthataveragenumberwhich
　　thelocalitycansupport。Though，byartificialproductionunceasinglyimproved，
　　asuperiorracecontinuallyaltersthelimitwhichexternalconditionsput
　　topopulation;yetthereiseveracheckingofpopulationatthetemporary
　　limitreached。Itistruethatwherethelimitisbeingrapidlychanged，
　　asamongourselves，thereisnoactualstoppage:thereisonlyarhythmical
　　variationintherateofincrease。Butinnotingthecausesofthisrhythmical
　　variation——inwatchinghow，duringperiodsofabundance，theproportion
　　ofmarriagesincreases，andhowitdecreasesduringperiodsofscarcity，
　　itwillbeseenthattheexpansiveforceproducesunusualadvancewhenever
　　therepressiveforcediminishes，andviceversa;andthusthereisasnearabalancingofthetwoasthechangingconditionspermit。Theinternalactionsconstitutingsocialfunctions，exemplifythegeneral
　　principlenolessclearly。Supplyanddemandarecontinuallybeingadjusted
　　throughoutallindustrialprocesses;andthisequilibrationisinterpretable
　　inthesamewayasprecedingones。Theproductionanddistributionofacommodity
　　implyacertainaggregateofforcescausingspecialkindsandamountsof
　　motion。Thepriceofthiscommodity，isthemeasureofacertainotheraggregate
　　offorcesexpendedinotherkindsandamountsofmotionbythelabourerwho
　　purchasesit。Andthevariationsofpricerepresentarhythmicalbalancing
　　oftheseforces。Everyriseorfallinthevalueofaparticularsecurity，
　　impliesaconflictofforcesinwhichsome，becomingtemporarilypredominant，
　　causeamovementthatis。presentlyarrested，orequilibrated，bytheincreased
　　opposingforces;andamidthesedailyandhourlyoscillationsliesamore
　　slowly—varyingmedium，intowhichthevalueevertendstosettle，andwould
　　settlebutfortheconstantadditionofnewinfluences。Asintheindividual
　　organismsointhesocialorganism，functionalequilibrationsgeneratestructural
　　equilibrations。Whenontheworkersinanytradetherecomesanincreased
　　demand，andwheninreturnfortheincreasedsupplytheyreceiveanamount
　　ofothercommoditieslargerthanbefore——when，consequently，theresistances
　　overcomebytheminsustaininglifearelessthantheresistancesovercome
　　byotherworkers;thereresultsaflowofotherworkersintothistrade。
　　Thisflowcontinuesuntiltheextrademandismet，andthewagessofarfall
　　thatthetotalresistanceovercomeinobtainingalivelihood，isasgreat
　　inthisnewly—adoptedoccupationasintheoccupationswhenceitdrewrecruits。
　　Theoccurrenceofmotionalonglinesofleastresistance，wasbeforeshown
　　tonecessitatethegrowthofpopulationinthoseplaceswherethelabour
　　requiredforself—maintenanceisthesmallest;andherewefurtherseethat
　　thoseengagedinanysuchadvantageouslocality，mustmultiplytillthere
　　arisesanapproximatebalancebetweenitspopulationandthatofothersavailablebythesamecitizens。Thesevariousindustrialactionsandreactionsconstituteadependent
　　movingequilibriumlikethatmaintainedamongthefunctionsofanindividual
　　organism，andlikeittendsevertobecomemorecomplete。Duringearlystages
　　ofsocialevolution，whiletheresourcesofthelocalityinhabitedareunexplored
　　andtheartsofproductionundeveloped，thereisneveranythingmorethan
　　atemporaryandpartialbalancingofsuchactions。Butwhenasocietyapproaches
　　thematurityofthattypeonwhichitisorganized，thevariousindustrial
　　activitiessettledownintoacomparativelyconstantstate。Moreover，advance
　　inorganization，aswellasadvanceingrowth，isconducivetoabetterequilibrium
　　ofindustrialfunctions。Whilethediffusionofmercantileinformationis
　　slowandthemeansoftransportdeficient，theadjustmentofsupplytodemand
　　isveryimperfect。Greatover—productionofacommodityisfollowedbygreat
　　under—production，andthereresultsarhythmhavingextremesthatdepart
　　widelyfromthemeanstateinwhichdemandandsupplyareequilibrated。But
　　whengoodroadsaremadeandthereisarapiddiffusionofprintedorwritten
　　intelligence，andstillmorewhenrailwaysandtelegraphscomeintoexistence
　　——whentheperiodicalfairsofearlydaysgrowintoweeklymarkets，and
　　theseintodailymarkets，thereisgraduallyproducedabetterbalanceof
　　productionandconsumption:therapidoscillationsofpricewithinnarrow
　　limitsoneithersideofacomparativelyuniformmean，indicateanearapproach
　　toequilibrium。Evidentlythisindustrialprogresshasforitslimit，that
　　whichMr。Millhascalled"thestationarystate。"Whenpopulation
　　shallhavebecomedenseoverallhabitablepartsoftheglobe;whentheresources
　　ofeveryregionhavebeenfullyexplored;andwhentheproductiveartsadmit
　　ofnofurtherimprovements;theremustresultanalmostcompletebalance，
　　bothbetweenthefertilityandmortalityineachsociety，andbetweenits
　　producingandconsumingactivities。Eachsocietywillexhibitonlyminor
　　deviationsfromitsaveragenumber，andtherhythmofitsindustrialfunctions
　　willgoonfromdaytodayandyeartoyearwithcomparativelyinsignificantperturbations。Oneotherkindofsocialequilibrationhasstilltobeconsidered:——
　　thatwhichresultsintheestablishmentofgovernmentalinstitutions，and
　　whichbecomescompleteastheseinstitutionsfallintoharmonywiththedesires
　　ofthepeople。Thoseaggressiveimpulsesinheritedfromthepre—socialstate
　　——thosetendenciestoseekself—satisfactionregardlessofinjurytoother
　　beings，whichareessentialtoapredatorylife，constituteananti—social
　　forcetendingevertocauseconflictandseparation。Contrariwise，those
　　desireswhichcanbefulfilledonlybyco—operationandthosewhichfind
　　satisfactionthroughintercoursewithfellow—men，aswellasthoseresulting
　　inwhatwecallloyalty，areforcestendingtokeeptheunitsofasociety
　　together。Ontheonehand，thereisineachmanmoreorlessofresistance
　　againstrestraintsimposedonhisactionsbyothermen——aresistancewhich，
　　tendingevertowideneachman'ssphereofaction，andreciprocallytolimit
　　thespheresofactionofothermen，constitutesarepulsiveforcemutually
　　exercisedbythemembersofasocialaggregate。Ontheotherhand，thegeneral
　　sympathyofmanformanandthemorespecialsympathyofeachvarietyof
　　manforothersofthesamevariety，togetherwithalliedfeelingswhichthe
　　socialstategratifies，actasanattractiveforce，tendingevertokeep
　　unitedthosewhohaveacommonancestry。Andsincetheresistancestobe
　　overcomeinsatisfyingthetotalityoftheirdesireswhenlivingseparately，
　　aregreaterthantheresistancestobeovercomeinsatisfyingthetotality
　　oftheirdesireswhenlivingtogether，thereisaresiduaryforcethatprevents
　　separation。Likeotheropposingforces，thoseexertedbycitizensonone
　　anotherproducealternatingmovementswhich，atfirstextreme，undergogradual
　　diminutiononthewaytoultimateequilibrium。Insmall，undevelopedsocieties，
　　markedrhythmsresultfromtheseconflictingtendencies。Atribethathas
　　maintaineditsunityforagenerationortwo，reachesasizeatwhichit
　　willnolongerholdtogether;and，ontheoccurrenceofsomeeventcausing
　　unusualantagonismamongitsmembers，divides。Eachprimitivenationexhibits
　　wideoscillationsbetweenanextremeinwhichthesubjectsareunderrigid
　　restraint，andanextremeinwhichtherestraintfailstopreventrebellion
　　anddisintegration。Inmoreadvancednationsofliketype，wealwaysfind
　　violentactionsandreactionsofthesameessentialnature:"despotism
　　temperedbyassassination，"characterizingapoliticalstateinwhich
　　unbearablerepressionfromtimetotimebringsaboutaburstingofbonds。
　　AmongourselvestheconflictsbetweenConservatism（whichstandsforthe
　　restraintsofsocietyovertheindividual）andReform（whichstandsforthe
　　libertyoftheindividualagainstsociety），fallwithinslowlyapproximating
　　limits。sothatthetemporarypredominanceofeitherproducesalessmarkeddeviationfromthemediumstate——asmallerdisturbanceofthemovingequilibrium。Ofcourseinthiscase，asinprecedingcases，thereisinvolvedalimit
　　totheincreaseofheterogeneity。Afewpagesback，itwasshownthatan
　　advanceinmentalevolutionistheestablishmentofsomefurtherinternal
　　actioncorrespondingtosomefurtherexternalaction。Weinferredthateach
　　suchnewfunction，involvingsomenewmodificationofstructure，implies
　　anincreaseofheterogeneity;andthatthus，increaseofheterogeneitymust
　　goonwhilethereremainanyouterrelationsaffectingtheorganismwhich
　　areunbalancedbyinnerrelations。Evidentlythelikemustsimultaneously
　　takeplacewithsociety。Eachincrementofheterogeneityintheindividual
　　implies，ascauseorconsequence，someincrementofheterogeneityinthe
　　arrangementsoftheaggregateofindividuals。Andthelimittosocialcomplexity
　　canbereachedonlywiththeestablishmentoftheequilibrium，justdescribed，betweensocialandindividualforces。§176。Herepresentsitselfafinalquestion，whichhasprobablybeen
　　takingshapeinthemindsofmanywhilereadingthischapter。"IfEvolution
　　ofeverykindisanincreaseincomplexityofstructureandfunctionthat
　　isincidentaltotheuniversalprocessofequilibration，andifequilibration
　　mustendincompleterest，whatisthefatetowardswhichallthingstend？
　　IftheSolarSystemisslowlydissipatingitsenergies——iftheSunislosing
　　hisheatataratewhichwilltellinmillionsofyears——ifwithdecrease
　　oftheSun'sradiationstheremustgoonadecreaseintheactivityofgeologic
　　andmeteorologicprocessesaswellasinthequantityofvegetableandanimal
　　life——ifManandSocietyaresimilarlydependentonthissupplyofenergy
　　whichisgraduallycomingtoanend;arewenotmanifestlyprocessingtowardsomnipresentdeath？"Thatsuchastatemustbetheoutcomeofthechangeseverywheregoing
　　on，seemsbeyonddoubt。Whetheranyulteriorprocessmayreversetheseprocesses
　　andinitiateanewlife，isaquestiontobeconsideredhereafter。Forthe
　　presentitmustsufficethattheendofallthetransformationswehavetraced，
　　isquiescence。Thisadmitsofaprioriproof。Thelawofequilibration，not
　　lessthantheprecedinggenerallaws，isdeduciblefromtheultimatedatumofconsciousness。Theforcesofattractionandrepulsionbeing，asshownin§74，universally
　　co—existent，itfollowsthatallmotionismotionunderresistance:either
　　thatexercisedonthemovingbodybyotherbodies，orthatexercisedbythe
　　mediumtraversed。Therearetwocorollaries。Thefirstisthatdeductions
　　perpetuallymadebythecommunicationofmotiontothatwhichresists，cannot
　　butbringthemotionofthebodytoanendinalongerorshortertime。The
　　secondisthatthemotionofthebodycannotceaseuntilthesedeductions
　　destroyit。Inotherwords，movementmustcontinuewhileequilibrationis
　　incomplete，andequilibrationmusteventuallybecomecomplete。Boththese
　　aremanifestdeductionsfromthepersistenceofforce。Hencethisprimordial
　　truthisourwarrantfortheconclusionsthatthechangeswhichEvolution
　　presentscannotenduntilequilibriumisreached，andthatequilibriummustatlastbereached。Atthesametimeitfollowsthatineveryaggregatehavingcompoundmotions，
　　thereresultsacomparativelyearlydissipationofthemotionswhichare
　　smallerandmuchresisted，followedbylong—continuanceofthelargerand
　　lessresistedmotions;andthatsotherearisemovingequilibria。Hence，
　　also，maybeinferredthetendencytoconservationofsuchmovingequilibria。
　　Foranynewmotiongiventothepartsofamovingequilibriumbyadisturbing
　　force，musteitherbesuchthatitcannotbedissipatedbeforethepre—existing
　　motions，inwhichcaseitbringsthemovingequilibriumtoanend。orelse
　　itmustbesuchthatitcanbedissipatedbeforethepre—existingmotions，inwhichcasethemovingequilibriumisre—established。Thusfromthepersistenceofforcefollow，notonlythevariousdirect
　　andindirectequilibrationsgoingonaround，togetherwiththatcosmical
　　equilibrationwhichbringsEvolutionunderallitsformstoaclose，but
　　alsothoselessmanifestequilibrationsshowninthereadjustmentsofmoving
　　equilibriathathavebeendisturbed。Bythisultimateprincipleisprovable
　　thetendencyofeveryorganism，disorderedbysomeunusualinfluence，to
　　returntoabalancedstate。Toitalsomaybetracedthecapacity，possessed
　　inaslightdegreebyindividualsandinagreaterdegreebyspecies，of
　　becomingadaptedtonewcircumstances。Andnotlessdoesitaffordabasis
　　fortheinferencethatthereisagradualadvancetowardsharmonybetween
　　man'smentalnatureandtheconditionsofhisexistence。
　　Chapter23Dissolution§177。When，inChapter22，weglancedatthecycleofchangesthrough
　　whicheveryexistencepasses，inashorttimeorinatimealmostinfinitely
　　long——whentheoppositere—distributionsofmatterandmotionimpliedwere
　　severallydistinguishedasEvolutionandDissolution。thenaturesofthe
　　two，andtheconditionsunderwhichtheyrespectivelyoccur，werespecified
　　ingeneralterms。Sincethen，wehavecontemplatedthephenomenaofEvolution
　　indetail，andhavefollowedthemouttothosestatesofequilibriuminwhich
　　theyallend。Tocompletetheargumentwemustnowcontemplate，somewhat
　　moreindetailthanbefore，thecomplementaryphenomenaofDissolution。Not，
　　indeed，thatweneeddwelllongonDissolution，whichhasnoneofthosevarious
　　andinterestingaspectswhichEvolutionpresents;butsomethingmoremustbesaidthanhasyetbeensaid。Itwasshownthatneitherofthesetwoantagonistprocessesgoesonunqualified
　　bytheother，andthatamovementtowardseitherisadifferentialresult
　　oftheconflictbetweenthem。Anevolvingaggregate，whileontheaverage
　　losingmotionandintegrating，isalways，inonewayorother，receiving
　　somemotionandtothatextentdisintegrating;andaftertheintegrative
　　changeshaveceasedtopredominate，thereceptionofmotion，thoughperpetually
　　checkedbyitsdissipation，constantlytendstoproduceareversetransformation，
　　andeventuallydoesproduceit。WhenEvolutionhasrunitscourse——when
　　anaggregatehasreachedthatequilibriuminwhichitschangesend，itthereafter
　　remainssubjecttoallactionsinitsenvironmentwhichmayincreasethe
　　quantityofmotionitcontains，andwhichincourseoftimearesure，either
　　slowlyorsuddenly，togiveitspartssuchexcessofmotionaswillcause
　　disintegration。Accordingasitssize，itsnature，anditsconditionsdetermine，
　　itsdissolutionmaycomequicklyormaybeindefinitelydelayed——mayoccur
　　inafewdaysormaybepostponedforbillionsofyears。Butexposedasit
　　istothecontingenciesnotsimplyofitsimmediateneighbourhoodbutof
　　aUniverseeverywhereinmotion，thetimemustatlastcomewhen，eitheraloneorincompanywithsurroundingaggregates，ithasitspartsdispersed。Theprocessofdissolutionsocausedwehaveheretolookatasittakes
　　placeinaggregatesofdifferentorders。Thecourseofchangebeingthereverse
　　ofthathithertotraced，wemayproperlytaketheillustrationsofitin
　　thereverseorder——beginningwiththemostcomplexandendingwiththemostsimple。§178。Regardingtheevolutionofasocietyasatonceanincrease
　　inthenumberofindividualsintegratedintoacorporatebody，anincrease
　　inthemassesandvarietiesofthepartsintowhichthiscorporatebodydivides，
　　aswellasoftheactionscalledtheirfunctions，andanincreaseinthe
　　degreeofcombinationamongthesemassesandtheirfunctions;weshallsee
　　thatsocialdissolutionconformstothegenerallawinbeing，materially
　　considered，adisintegration，and，dynamicallyconsidered，adecreasein
　　themovementsofwholesandanincreasethemovementsofparts;whileit
　　furtherconformstothegenerallawinbeing，causedbyanexcessofmotioninsomewayorotherreceivedfromwithout。Itisobviousthatthesocialdissolutionwhichfollowstheaggression
　　ofmothernation，andwhich，ashistoryshowsus，isapttooccurwhensocial
　　evolutionhasendedanddecayhasbegun，is，underitsbroadest，aspect，
　　thereceptionofanewexternalmotion;andwhen，assometimeshappens，the
　　conqueredsocietyisdispersed，orwhenitscomponentdivisionsfallapart，
　　itsdissolutionisliterallyacessationofthosecorporatemovementswhich
　　thesociety，bothinitsarmyandinitsindustrialbodies，presented，andalapseintoindividualoruncombinedmovements。Again，socialdisorder，howevercaused，entailsadecreaseofintegrated
　　movementsandanincreaseofdisintegratedmovements。Asthedisorderprogresses
　　thepoliticalactionspreviouslycombinedbecomeuncombined:therearise
　　theantagonisticactionsofriotorrevolt。Simultaneously，theindustrial
　　andcommercialprocessesthatwereco—ordinatedthroughoutthebodypolitic，
　　arebrokenup;andonlythelocal，orsmall，tradingtransactionscontinue。
　　Andeachfurtherdisorganizingchangediminishesthejointoperationsby
　　whichmensatisfytheirwants，andleavesthemtosatisfytheirwants，as
　　besttheycan，byseparateoperations。Ofthewayinwhichsuchdistintegrations
　　aresetupinasocietythathasevolvedtothelimitofitstype，andreached
　　astateofmovingequilibrium，agoodillustrationisfurnishedbyJapan。
　　Thefinishedfabricintowhichitspeoplehaveorganizedthemselves，maintained
　　analmostconstantstatesolongasitwaspreservedfromfreshexternal
　　forces。ButassoonasitreceivedanimpactfromEuropeancivilization，
　　partlybyarmedaggression，partlybycommercialimpulse，partlybytheinfluence
　　ofideas，thisfabricbegantofalltopieces。Thereisnowinprogressa
　　politicaldissolution。*Probablyapolitical
　　reorganizationwillfollow;but，bethisasitmay，thechangethusfarproduced
　　byanouteractionisachangetowardsdissolution——achangefromintegratedmotionstodisintegratedmotions。Evenwhereasocietythathasdevelopedintothehighestformpermitted
　　bythecharactersofitsunits，beginstodwindleanddecay，theprogressive
　　dissolutionisstillessentiallyofthesamenature。Declineofnumbersis，
　　insuchcase，broughtaboutpartlybyemigration;forasocietyhavingthe
　　fixedstructureinwhichevolutionends，isonethatwillnotyieldandmodify
　　underpressureofpopulation:solongasitsstructureisplasticitisstill
　　evolving。Hencethesurpluspopulationiscontinuallydispersed:theinfluences
　　broughttobearonthecitizensbyothersocietiescausetheirdetachment，
　　andthereisanincreaseoftheuncombinedmotionsofunitsinsteadofan
　　increaseofcombinedmotions。Graduallyasthesocietybecomesstillless
　　capableofchangingintotheformrequiredforsuccessfulcompetitionwith
　　moreplasticsocieties，thenumberofcitizenswhocanlivewithinitsunyielding
　　frameworkbecomespositivelysmaller。Henceitdwindlesboththroughcontinued
　　emigrationandthroughthediminishedmultiplicationthatfollowsinnutrition。
　　Andthisfurtherdwindlingissimilarlyadecreaseinthetotalquantity
　　ofcombinedmotionandanincreaseinthequantityofuncombinedmotion——asweshallpresentlyseewhenwecometodealwithindividualdissolution。Considering，then，thatsocialaggregatesdiffersomuchfromaggregates
　　ofotherkinds，formed，astheyare，ofunitsheldtogetherlooselyandindirectly，
　　insuchvariablewaysbysuchcomplexforces，theprocessesofdissolutionamongthemconformstothegenerallawquiteasclearlyascouldbeexpected。§179。Whenfromthesesuper—organicaggregateswedescendtoorganic
　　aggregates，thetruththatDissolutionisadisintegrationofmattercaused
　　bythereceptionofadditionalmotionfromwithout，becomeseasilydemonstrable。Wewilllookfirstatthetransformationandafterwardsatitscause。Death，orthatfinalequilibrationwhichprecedesdissolution，isthe
　　bringingtoacloseallthosemanyconspicuousintegratedmotionsthatarose
　　duringevolution。Theimpulsionsofthebodyfromplacetoplacefirstcease;
　　presentlythelimbscannotbestirred;laterstilltherespiratoryactions
　　stop;finallytheheartbecomesstationaryand，withit，thecirculating
　　fluids。Thatis，thetransformationofmolecularmotionintothemotionof
　　masses，comestoanend。Theprocessofdecayinvolvesanincreaseofinsensible
　　movements;sincethesearefargreaterinthegasesgeneratedthantheyare
　　inthefluid—solidmattersoutofwhichthegasesarise。Eachofthecomplex
　　chemicalunitscomposinganorganicbody，possessesarhythmicmotionin
　　whichitsmanycomponentunitsjointlypartake。Whendecompositionbreaks
　　upthesecomplexmolecules，andtheirconstituentsassumegaseousforms，
　　thereis，besidesthatincreaseofmotionimpliedbydiffusion，aresolution
　　ofsuchmotionsasthecomplexmoleculespossessed，intomotionsoftheir
　　constituentmolecules。Sothatinorganicdissolutionwehave，first，an
　　endputtothattransformationofthemotionsofunitsintothemotionsof
　　aggregates，whichconstitutesevolution，dynamicallyconsidered;andwehave
　　afterwards，thoughinasubtlersense，atransformationofthemotionsof
　　aggregatesintothemotionsofunits。Stillitisnotthusshownthatorganic
　　dissolutionanswerstothegeneraldefinitionofdissolution——theabsorption
　　ofmotionandconcomitantdisintegrationofmatter。Thedisintegrationof
　　matteris，indeed，conspicuousenough;buttheabsorptionofmotionisnot
　　conspicuous。True，thefactthatmotionhasbeenabsorbedmaybeinferred
　　fromthefactthatparticlespreviouslyintegratedintoasolidmass，occupying
　　asmallspace，havemostofthemmovedawayfromoneanotherandnowoccupy
　　agreatspace;forthemotionimpliedbythisexpansionmusthavebeenobtained
　　fromsomewhere。Butitssourceisnotobvious。Alittlesearch，however，willbringustoitsderivation。Atatemperaturebelowthefreezingpointofwater，decompositionoforganic
　　matterdoesnottakeplace。Deadbodieskeptatthistemperatureareprevented
　　fromdecomposingforanindefinitelylongperiod:witnessthefrozencarcases
　　ofmammoths（elephantsofaspecieslongagoextinct）thatarefoundimbedded
　　intheiceatthemouthsofSiberianrivers;andwhich，thoughtheyhave
　　beenthereformanythousandsofyears，havefleshsofreshthatwhenat
　　lengthexposeditisdevouredbywolves。What，now，isthemeaningofsuch
　　exceptionalpreservations？Abodykeptbelowfreezingpoint，isabodywhich
　　receivesverylittleheatbyradiationorconduction;andthereceptionof
　　butlittleheatisthereceptionofbutlittlemolecularmotion。Thatis
　　tosay，inanenvironmentwhichdoesnotfurnishitwithmolecularmotion
　　passingacertainamount，anorganicbodydoesnotundergodissolution。Confirmatory
　　evidenceisyieldedbythevariationsinrateofdissolutionwhichaccompany
　　variationsoftemperature。Allknowthatincoolweathertheorganicsubstances
　　usedinourhouseholdskeeplonger，aswesay，thaninhotweather。