第34章

Thishowever，thoughaverballyintelligiblesupposition，isonethatcannot

berepresentedinthought;sinceunlimitedspaceisinconceivable。Butall

finiteformsofthehomogeneous——allformsofitwhichwecanknoworconceive，

mustinevitablylapseintoheterogeneity;andthelessheterogeneousmust

lapseintothemoreheterogeneous。Inthreeseveralwaysdoesthepersistence

offorcenecessitatethis。Settingexternalagenciesaside，eachunitof

ahomogeneouswholemustbedifferentlyaffectedfromanyoftherestby

theaggregateactionoftherestuponit。Theresultantforceexercisedby

theaggregateoneachunit，beinginnotwocasesalikeinbothamountand

direction，andusuallynotineither，anyincidentforce，evenifuniform

inamountanddirection，cannotproducelikeeffectsontheunits。Andas

thevariouspositionsofthepartsinrelationtoanyincidentforce，prevents

themfromreceivingitinuniformamountsanddirections，afurtherdifferenceintheeffectswroughtontheminevitablyarises。Onefurtherremarkisneeded。Theconclusionthatthechangeswithwhich

Evolutioncommences，arethusnecessitated，hastobesupplementedbythe

conclusionthatthesechangesmustcontinue。Theabsolutelyhomogeneous（supposing

ittoexist）mustloseitsequilibrium;andtherelativelyhomogeneousmust

lapseintotherelativelylesshomogeneous。Thatwhichistrueofanytotal

mass，istrueofthepartsintowhichitsegregates。Theuniformityofeach

suchpartmustasinevitablybelostinmultiformity，aswasthatofthe

originalwhole;andforlikereasons。Andthusthecontinuedchangescharacterizing

Evolution，insofarastheyareconstitutedbythelapseofthehomogeneous

intotheheterogeneous，andofthelessheterogeneousintothemoreheterogeneous，arenecessaryconsequencesofthepersistenceofforce。[AsmallchangeinthedefinitionofEvolutionindicatedinanoteat

theendofChapterXVIIofthispart，mustberecalledasinvolvingacorrelative

changeinthischapter。Here，asbefore，therequiredchange，thoughalready

implied（page367），hasnotbeensufficientlyemphasized，andlackofthe

emphasisinvitesmisinterpretation。Forreasonslikethosebeforegiven，

therequisiteexplanationscannotbemadeinthisplace。ThereaderwillfindtheminAppendixA。Repliestocertaincriticismsonthegeneraldoctrinesetforthinthis

chapterwillbefoundinAppendixC。]

Chapter20TheMultiplicationofEffects§156。Tothecauseofincreasingcomplexitysetforthinthelast

chapter，wehaveinthischaptertoaddanother。Thoughsecondaryinorder

oftime，itisscarcelysecondaryinorderofimportance。Evenintheabsence

ofthecausealreadyassigned，itwouldnecessitateachangefromthehomogeneous

totheheterogeneous;andjoinedwithit，itmakesthischangebothmore

rapidandmoreinvolved。Tocomeinsightofitwehavebuttopursueastep

furtherthatconflictbetweenforceandmatteralreadydelineated。Letusdothis。Asalreadyshown，whenthecomponentsofauniformaggregatearesubject

toauniformforce，theybeingdifferentlyconditioned，aredifferentlymodified。

Butwhilewehavecontemplatedthevariouspartsoftheaggregateasundergoing

unlikechanges，wehavenotyetcontemplatedtheunlikechangessimultaneously

producedonthevariouspartsoftheincidentforce。Thesemustbeasnumerous

astheothers。Indifferentiatingthepartsonwhichitfallsinunlikeways，

theincidentforcemustitselfbecorrespondinglydifferentiated。Instead

ofbeingasbefore，auniformforce，itmustthereafterbeamultiformforce

——agroupofdissimilarforces。Afewillustrationswillmakethistruthmanifest。Inthecase，latelycited，ofabodyshatteredbyviolentcollision，besides

thechangeofthehomogeneousmassintoaheterogeneousgroupofscattered

fragments，thereisachangeofthehomogeneousmomentumintoagroupof

momenta，heterogeneousinbothamountsanddirections。Similarlywiththe

forcesweknowaslightandheat。Afterthedispersionofthesebyaradiating

bodytowardsallpoints，theyarere—dispersedtowardsallpointsbythe

bodiesonwhichtheyfall。OftheSun\'srays，issuingfromhimoneveryside，

somefewstriketheMoon。ReflectedatallanglesfromtheMoon\'ssurface，

somefewofthesestriketheEarth。Byalikeprocessthefewwhichreach

theEarthareagaindiffused:someintospace，somefromobjecttoobject。

Andoneachoccasion，suchportionsoftheraysasaretransmittedinstead

ofreflected，undergorefractionsorotherchangeswhichequallydestroy

theiruniformity。Morethanthisistrue。Byconflictwithmatterauniform

forceisinpartchangedintoforcesdifferingintheirkinds。Whenonebody

isstruckagainstanother，thatwhichweusuallyregardastheeffect，is

achangeofpositionormotioninoneorbothbodies。Butthisisavery

incompleteviewofthematter。Besidesthevisiblemechanicalresult，sound

isproduced——avibrationinoneorbothbodiesandinthesurroundingair;

andundersomecircumstanceswecallthistheeffect。Moreover，theairhas

notsimplybeenmadetovibrate;ithashadcurrentsraisedinitbythe

transitofthebodies。Further，ifthereisnotthatgreatstructuralchange

whichwecallfracture，thereisadisarrangementoftheparticlesofthe

twobodiesaroundtheirpointofcollision;amountinginsomecasestoa

visiblecondensation。Yetmore，thiscondensationisaccompaniedbygenesis

ofheat。Insomecasesaspark——thatis，light——resultsfromtheincandescence

ofaportionstruckoff。Thusbytheoriginalmechanicalforceexpendedin

thecollision，atleastfivekindsofforceshavebeenproduced。Take，again，

thelightingofacandle。Primarily，thisisachemicalchangeconsequent

onariseoftemperature。Theprocessofcombinationhavingoncebeenset

goingbyextraneousheat，thereisacontinuedformationofcarbondioxide，

water，etc。Alongwiththisprocessofcombinationthereisaproduction

ofheat;thereisaproductionoflight;thereisanattendingcolumnof

hotgasesgenerated;therearecurrentscausedinthesurroundingair。Nor

doesthedecompositionofoneforceintomanyforcesendhere。Eachofthe

severalchangesworkedbecomestheparentoffurtherchanges。Thecarbon

dioxideformedwilleventuallycombinewithsomebase;orundertheinfluence

ofsunshinegiveupitscarbontotheleafofaplant。Thewaterwillmodify

thehygrometricstateoftheairaround;or，ifthecurrentofhotgases

containingitcomesagainstacoldbody，willbecondensed:alteringthe

temperature，andperhapsthechemicalstate，ofthesurfaceitcovers。The

heatgivenoutmeltsthesubjacenttallowandexpandswhateverelseitwarms。

Thelight，fallingonvarioussubstances，callsforthfromthemreactions

bywhichitisdecomposed，anddiverscoloursarethusproduced。Similarly

withthesesecondaryactions，whichmaybetracedoutintoever—multiplying

ramifications，untiltheybecometoominutetobeappreciated。Universally，

then，theeffectismorecomplexthanthecause。Whethertheaggregateon

whichitfallsbehomogeneousorotherwise，anincidentforceistransformed

bytheconflictintoanumberofforcesthatdifferintheiramounts，or

directions，orkinds;orinalltheserespects。Andofthisgroupofvariously—modifiedforces，eachultimatelyundergoesaliketransformation。Letusnowmarkhowtheprocessofevolutionisfurtheredbythismultiplication

ofeffects。Anincidentforcedecomposedbythereactionsofabodyinto

agroupofunlikeforces，becomesthecauseofasecondaryincreaseofmultiformity

inthebodywhichdecomposesit。Bythereactionsofthevariousparts，differently

modifiedaswehaveseentheymustbe，theincidentforceitselfmustbe

dividedintodifferentlymodifiedparts。Eachdifferentiateddivisionof

theaggregatethusbecomesacentrefromwhichadifferentiateddivision

oftheoriginalforceisagaindiffused。Andsinceunlikeforcesmustproduce

unlikeresults，eachofthesedifferentiatedforcesmustproduce，throughout

theaggregate，afurtherseriesofdifferentiations。Thissecondarycause

ofthechangefromhomogeneitytoheterogeneity，obviouslybecomesmorepotent

inproportionastheheterogeneityincreases。Whenthepartsintowhichany

evolvingwholehassegregateditself，havedivergedwidelyinnature，they

willnecessarilyreactverydiverselyonanyincidentforce——theywill

divideanincidentforceintosomanystronglycontrastedgroupsofforces。

Andeachofthembecomingthecentreofaquitedistinctsetofinfluences，

mustaddtothenumberofdistinctsecondarychangeswroughtthroughoutthe

aggregate。Yetanothercorollarymustbeadded。Thenumberofunlikeparts

ofwhichanaggregateconsists，isanimportantfactorintheprocess。Every

additionalspecializeddivisionisanadditionalcentreofspecializedforces，

andmustbeafurthersourceofcomplicationamongtheforcesatworkthroughout

themass——afurthersourceofheterogeneity。Themultiplicationofeffectsmustproceedingeometricalprogression。§157。Thescatteredpartsofanirregularnebulaincourseofbeing

drawntogetherorintegrated，cannotdisplayinadefinitemannerthesecondary

traitsofevolution:thesepresupposeanaggregatealreadyformed。Wecan

sayonlythatthehalf—independentcomponents，eachattractedbyalland

allbyeach，exhibitintheirvariousmomenta，differentintheiramounts

anddirections，amultiplicationofeffectsproducedbyasinglegravitativeforce。Butassumingthattheintegrativeprocesshasatlengthgeneratedasingle

massofnebulousmatter，thenthesimultaneouscondensationandrotation

showushowtwoeffectsoftheaggregativeforce，atfirstbutslightlydivergent，

becomeatlastwidelydifferentiated。Anincreaseofoblatenessinthisspheroid

musttakeplacethroughthejointactionofthesetwoforces，asthebulk

diminishesandtherotationgrowsmorerapid;andthiswemaysetdownas

athirdeffect。Thegenesisofheat，accompanyingaugmentationofdensity，

isaconsequenceofyetanotherorder——aconsequencebynomeanssimple;

sincethevariouspartsofthemass，beingvariouslycondensed，mustbevariously

heated。Actingthroughoutagaseousspheroid，ofwhichthepartsareunlike

intheirtemperatures，theforcesofaggregationandrotationmustworka

furtherseriesofchanges:theymustsetupcirculatingcurrents，bothgeneral

andlocal。Atalaterstagelightaswellasheatwillbegenerated。Thus

withoutdwellingonthelikelihoodofchemicalcombinationsandelectric

disturbances，itismanifestthat，supposingmattertohaveoriginallyexisted

inadiffusedstate，theonceuniformforcewhichcauseditsaggregation，

musthavebecomegraduallydividedintodifferentforces;andthateachfurther

stageofcomplicationintheresultingaggregate，musthaveinitiatedfurther

subdivisionsofthisforce——afurthermultiplicationofeffects，increasingthepreviousheterogeneity。Thissectionoftheargumentmayhoweverbeadequatelysustainedwithout

havingrecoursetoanysuchhypotheticalillustrationsastheforegoing。

TheastronomicalattributesoftheEarthwill，evenbythemselves，suffice

forourpurpose。Considerfirsttheeffectsofitsrotation。Thereisthe

oblatenessofitsform;thereisthealternationofdayandnight;there

arecertainconstantmarinecurrents;andtherearecertainconstantaerial

currents。Considernextthesecondaryseriesofconsequencesduetothedivergence

oftheEarth\'splaneofrotationfromtheplaneofitsorbit。Themanyvariations

oftheseasons，bothsimultaneousandsuccessive，whichpervadeitssurface，

arethuscaused。ExternalattractionoftheMoonandSunactingontheequatorial

protuberanceofthisrotatingspheroidwithinclinedaxis，producesthemotion

callednutation，andthatslowerandlargeronefromwhichfollowstheprecession

oftheequinoxes，withitsseveralsequences。Andthen，bythissameforce，aregeneratedthetides，aqueousandatmospheric。Perhaps，however，thesimplestwayofshowingthemultiplicationofeffects

amongphenomenaofthisorder，willbetosetdowntheinfluencesofany

memberoftheSolarSystemontherest。Aplanetdirectlyproducesinneighbouring

planetscertainappreciableperturbations，complicatingthoseotherwiseproduced

inthem;andintheremoterplanetsitdirectlyproducescertainlessvisible

perturbations。Hereisafirstseriesofeffects。Buteachoftheperturbed

planetsisitselfasourceofperturbations——eachdirectlyaffectsall

theothers。Hence，planetAhavingdrawnplanetBoutofthepositionit

wouldhaveoccupiedinA\'sabsence，theperturbationswhichBcausesare

differentfromwhattheywouldelsehavebeen;andsimilarlywithC，D，E，

etc。Herethenisasecondaryseriesofeffects;farmorenumerousthough

farsmallerintheiramounts。Astheseindirectperturbationsmusttosome

extentmodifythemovementsofeachplanet，thereresultsfromthematertiary

series;andsooninevermultiplyinganddiminishingwavesthroughouttheentiresystem。§158。IftheEarthwasformedbytheconcentrationofdiffusedmatter，

itmustatfirsthavebeenincandescent;andwhetherthenebularhypothesis

beacceptedornot，thisoriginalincandescenceoftheEarthmaynowberegarded

asinductivelyestablished——or，ifnotestablished，atleastrenderedso

probablethatitisagenerallyadmittedgeologicaldoctrine。Severalresults

ofthegradualcoolingoftheEarth——astheformationofacrust，thesolidification

ofsublimedelements，theprecipitationofwater，etc。——havebeenalready

noticed，andIagainrefertothemmerelytopointoutthattheyaresimultaneous

effectsoftheonecause，diminishingheat。Letusnow，however，observe

themultipliedchangesafterwardsarisingfromthecontinuanceofthisone

cause。TheEarth，fallingintemperature，mustcontract。Hencethesolid

crustatanytimeexistingispresentlytoolargefortheshrinkingnucleus，

and，beingunabletosupportitself，inevitablyfollowsthenucleus。But

aspheroidalenvelopecannotsinkdownintocontactwithasmallerinternal

spheroid，withoutdisruption:itwillrunintowrinklesastherindofan

appledoeswhenthebulkofitsinteriordecreasesfromevaporation。Asthe

coolingprogressesandtheenvelopethickens，theridgesconsequentonthese

contractionsmustbecomegreater，risingultimatelyintohillsandmountains;

andthelatersystemsofmountainsthusproducedmustnotonlybehigher，

aswefindthemtobe，butmustbelonger，aswealsofindthemtobe。Thus，

leavingoutofviewothermodifyingforces，weseewhatimmenseheterogeneity

ofsurfacearisesfromtheonecause，lossofheat——aheterogeneitywhich

thetelescopeshowsustobeparalleledontheMoon，whereaqueousandatmospheric

agencieshavebeenabsent。Butwehaveyettonoticeanotherkindofheterogeneity

ofsurface，simultaneouslycaused。WhiletheEarth\'scrustwasthin，the

ridgesproducedbyitscontractionsmustnotonlyhavebeensmallinheight

andlength，butthetractsbetweenthemmusthaverestedwithcomparative

smoothnessonthesubjacentliquidspheroid;andthewaterinthosearctic

andantarcticregionswhereitfirstcondensed，musthavebeenevenlydistributed。

Butasfastasthecrustgrewthickerandgainedcorrespondingstrength，

thelinesoffracturefromtimetotimecausedinit，occurredatgreater

distancesapart;theintermediatesurfacesfollowedthecontractingnucleus

withlessuniformity;andthereconsequentlyresultedlargerareasofland

andwater。Ifanyone，afterwrappinganorangeintissuepaperandobserving

bothhowsmallarethewrinklesand，howevenlytheinterveningspaceslie

onthesurfaceoftheorange，willthenwrapitinthickcartridge—paper，

andnoteboththegreaterheightoftheridgesandthelargerspacesthroughout

whichthepaperdoesnottouchtheorange，hewillseethatastheEarth\'s

solidenvelopethickened，theareasofelevationanddepressionbecamegreater。

Inplaceofislandsmoreorlesshomogeneouslyscatteredthroughoutanall—embracing

sea，theremusthavegraduallyarisenheterogeneousarrangementsofcontinent

andocean，suchaswenowknow。Thesesimultaneouschangesintheextent

andintheelevationofthelands，involvedyetanotherspeciesofheterogeneity

——thatofcoast—line。Atolerablyevensurfaceraisedoutoftheoceanwill

haveasimple，regularsea—margin;butasurfacevariedbytable—landsand

intersectedbymountain—chains，will，whenraisedoutoftheocean，have

anoutlineextremelyirregular，alikeinitsleadingfeaturesandinits

details。Thusendlessistheaccumulationofgeologicalandgeographical

resultsbroughtaboutbythisonecause——escapeoftheEarth\'sprimitiveheat。Whenwepassfromtheagencywhichgeologiststermigneous，toaqueous

andatmosphericagencies，weseealikeever—growingcomplicationofeffects。

Thedenudingactionsofairandwaterhave，fromthebeginning，beenmodifying

everyexposedsurface:everywhereworkingmanydifferentchanges。Asalready

said（§69）theoriginalsourceofthosegaseousandfluidmotionswhich

effectdenudation，isthesolarheat。Thetransformationofthisintovarious

modesofenergy，accordingtothenatureandconditionsofthematteron

whichitfalls，isthefirststageofcomplication。TheSun\'srays，striking

atallanglesaspherethatfrommomenttomomentpresentedandwithdrew

differentpartsofitssurface，andeachofthemforadifferenttimedaily

throughouttheyear，wouldproduceaconsiderablevarietyofchangeseven

werethesphereuniform。Butfallingastheydoonaspheresurroundedby

anatmospherecontainingwideareasofcloud，butwhichhereunveilsvast

tractsofsea，thereoflevelland，thereofmountains，thereofsnowand

ice，theycauseinitcountlessdifferentmovements。Currentsofairofall

sizes，directions，velocities，andtemperatures，aresetup;asarealso

marinecurrentssimilarlycontrastedintheircharacters。Inthisregion

thesurfaceisgivingoffvapour;inthat，dewisbeingprecipitated;and

inanother，rainisdescending——unlikenesseswhicharisefromthechanging

ratiobetweentheabsorptionandradiationofheatineachplace。Atone

hourarapidfallintemperatureleadstotheformationofice，withanaccompanying

expansionthroughoutthemoistbodiesfrozen;whileatanotherathawunlocks

thedislocatedfragmentsofthesebodies。Andthen，passingtoasecondstage

ofcomplication，weseethatthemanykindsofmotiondirectlyorindirectly

causedbytheSun\'srays，severallyproduceresultswhichvarywiththeconditions。

Oxidation，drought，wind，frost，rain，glaciers，rivers，waves，andother

denudingagentseffectdisintegrationsthataredeterminedintheiramounts

andqualitiesbylocalcircumstances。Actingonatractofgranite，such

agentshereworkscarcelyanappreciableeffect;therecauseexfoliations

ofthesurfaceandaresultingheapofdebrisandboulders;andelsewhere，

afterdecomposingthefeldsparintoawhiteclay，carryawaythiswiththe

accompanyingquartzandmica，anddeposittheminseparatebeds，fluviatile

ormarine。Whentheexposedlandconsistsofseveralunlikeformations，sedimentary

andigneous，changesproportionatelymoreheterogeneousarewrought。The

formationsbeingdisintegrableindifferentdegrees，therefollowsanincreased

irregularityofsurface。Theareasdrainedbyadjacentriversbeingdifferently

constituted，theseriverscarrydowntotheseaunlikecombinationsofingredients;

andsosundrynewstrataofdistinctcompositionsarise。Andhere，indeed，

wemayseeveryclearlyhowtheheterogeneityoftheeffectsincreasesin

ageometricalprogressionwiththeheterogeneityoftheobjectactedupon。

Letus，forthefullerelucidationofthistruthinrelationtotheinorganic

world，considerwhatwouldfollowfromanextensivecosmicalcatastrophe

——sayagreatsubsidencethroughoutCentralAmerica。Theimmediateresults

wouldthemselvesbesufficientlycomplex。Besidesthenumberlessdislocations

ofstrata，theejectionsofigneousmatter，thepropagationofearthquake

vibrationsmanythousandsofmilesaround，theloudexplosions，andtheescape

ofgases，therewouldbeaninrushoftheAtlanticandPacificOceans，a

subsequentrecoilofenormouswaves，whichwouldtraverseboththeseoceans

andproducemyriadsofchangesalongtheirshores，andcorrespondingatmospheric

wavescomplicatedbythecurrentssurroundingeachvolcanicvent，aswell

aselectricaldischargeswithwhicheruptionsareaccompanied。Butthese

temporaryeffectswouldbeinsignificantcomparedwiththepermanentones。

ThecomplexcurrentsoftheAtlanticandPacificwouldbealteredintheir

directionsandamounts。Thedistributionofheatachievedbythesecurrents

wouldbedifferentfromwhatitis。Thearrangementoftheisothermallines，

notonlyontheneighbouringcontinentsbuteventhroughoutEurope，would

bechanged。Thetideswouldflowdifferentlyfromwhattheydonow。There

wouldbemoreorlessmodificationofthewindsintheirperiods，strengths，

directions，qualities;andrainwouldfallscarcelyanywhereatthesame

timesandinthesamequantitiesasatpresent。Inthesemanychanges，each

includingcountlessminorones，maybeseentheimmenseheterogeneityof

theresultswroughtoutbyoneforce，whenthatforceexpendsitselfona

previouslycomplicatedarea:theimplicationbeingthatfromthebeginningthecomplicationhasadvancedatanincreasingrate。§159。Wehavenexttotracethroughoutorganicevolution，thissame

all—pervadingprinciple。Andhere，wherethetransformationofthehomogeneous

intotheheterogeneouswasfirstobserved，theproductionofmanychanges

byonecauseisleasteasytodemonstrateinadirectway。Hereditycomplicateseverything。Nevertheless，byindirectevidencewemayestablishourproposition。Bywayofpreparationobservehownumerousarethechangeswhichanymarked

stimulusworksonanadultorganism——ahumanbeingforinstance。Analarming

soundorsight，besidesimpressionsontheorgansofsenseandthenerves，

mayproduceastart，ascream，adistortionoftheface，atremblingconsequent

ongeneralmuscularrelaxation，aburstofperspiration，andperhapsanarrest

oftheheartfollowedbysyncope;andifthesystembefeeble，anillness

withitslongtrainofcomplicatedsymptommaysetin。Similarlyincases

ofdisease。Aminuteportionofthesmall—poxvirustakenintothesystem

will，inaseverecase，cause，duringthefirststage，rigors，heatofskin，

acceleratedpulse，furredtongue，lossofappetite，thirst，epigastricuneasiness，

vomiting，headache，patsinthebackandlimbs，muscularweakness，convulsions，

delirium，etc。;inthesecondstage，cutaneouseruption，itching，tingling，

sorethroat，swelledfauces，salivation，cough，hoarseness，dyspnoea，etc。;

andinthethirdstage，oedematousinflammations，pneumonia，pleurisy，diarrhoea，

inflammationofthebrain，ophthalmia，erysipelas，etc。:eachofwhichenumerated

symptomsisitselfmoreorlesscomplex。Nowitneedsonlytoconsiderthat

thisworkingofmanychangesbyoneforceonanadultorganism，mustbepartially

paralleledinanembryo—organism，tounderstandthatinittootheremust

beamultiplicationofeffects，evertendingtoproduceincreasingheterogeneity。