the darwinian hypothesis-第2章

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Hemisphere　as　its　own　autochthones；　but　are　in　many　cases　absolutely
better　adapted；　and　so　overrun　and　extirpate　the　aborigines。　　Clearly；
therefore；　the　species　which　naturally　inhabit　a　country　are　not
necessarily　the　best　adapted　to　its　climate　and　other　conditions。　　The
inhabitants　of　islands　are　often　distinct　from　any　other　known　species
of　animal　or　plants　（witness　our　recent　examples　from　the　work　of　Sir
Emerson　Tennent；　on　Ceylon）；　and　yet　they　have　almost　always　a　sort　of
general　family　resemblance　to　the　animals　and　plants　of　the　nearest
mainland。　　On　the　other　hand；　there　is　hardly　a　species　of　fish；　shell；
or　crab　common　to　the　opposite　sides　of　the　narrow　isthmus　of　Panama。
Wherever　we　look；　then；　living　nature　offers　us　riddles　of　difficult
solution；　if　we　suppose　that　what　we　see　is　all　that　can　be　known　of　it。

But　our　knowledge　of　life　is　not　confined　to　the　existing　world。
Whatever　their　minor　differences；　geologists　are　agreed　as　to　the　vast
thickness　of　the　accumulated　strata　which　compose　the　visible　part　of
our　earth；　and　the　inconceivable　immensity　of　the　time　of　whose　lapse
they　are　the　imperfect；　but　the　only　accessible　witnesses。　　Now；
throughout　the　greater　part　of　this　long　series　of　stratified　rocks　are
scattered；　sometimes　very　abundantly；　multitudes　of　organic　remains；
the　fossilized　exuviae　of　animals　and　plants　which　lived　and　died　while
the　mud　of　which　the　rocks　are　formed　was　yet　soft　ooze；　and　could
receive　and　bury　them。　　It　would　be　a　great　error　to　suppose　that　these
organic　remains　were　fragmentary　relics。　　Our　museums　exhibit　fossil
shells　of　immeasurable　antiquity；　as　perfect　as　the　day　they　were
formed；　whole　skeletons　without　a　limb　disturbednay；　the　changed
flesh；　the　developing　embryos；　and　even　the　very　footsteps　of　primieval
organisms。　　Thus　the　naturalist　finds　in　the　bowels　of　the　earth
species　as　well　defined　as；　and　in　some　groups　of　animals　more　numerous
than；　those　that　breathe　the　upper　air。　　But；　singularly　enough；　the
majority　of　these　entombed　species　are　wholly　distinct　from　those　that
now　live。　　Nor　is　this　unlikeness　without　its　rule　and　order。　　As　a
broad　fact；　the　further　we　go　back　in　time　the　less　the　buried　species
are　like　existing　forms；　and　the　further　apart　the　sets　of　extinct
creatures　are　the　less　they　are　like　one　another。　　In　other　words；
there　has　been　a　regular　succession　of　living　beings；　each　younger　set
being　in　a　very　broad　and　general　sense　somewhat　more　like　those　which
now　live。

It　was　once　supposed　that　this　succession　had　been　the　result　of　vast
successive　catastrophes；　destructions；　and　re…creations　'en　masse'；　but
catastrophes　are　now　almost　eliminated　from　geological；　or　at　least
palaeontological　speculation；　and　it　is　admitted　on　all　hands　that　the
seeming　breaks　in　the　chain　of　being　are　not　absolute；　but　only　relative
to　our　imperfect　knowledge；　that　species　have　replaced　species；　not　in
assemblages；　but　one　by　one；　and　that；　if　it　were　possible　to　have　all
the　phenomena　of　the　past　presented　to　us；　the　convenient　epochs　and
formations　of　the　geologist；　though　having　a　certain　distinctness；　would
fade　into　one　another　with　limits　as　undefinable　as　those　of　the
distinct　and　yet　separable　colours　of　the　solar　spectrum。

Such　is　a　brief　summary　of　the　main　truths　which　have　been　established
concerning　species。　Are　these　truths　ultimate　and　irresolvable　facts；
or　are　their　complexities　and　perplexities　the　mere　expressions　of　a
higher　law？

A　large　number　of　persons　practically　assume　the　former　position　to　be
correct。　　They　believe　that　the　writer　of　the　Pentateuch　was　empowered
and　commissioned　to　teach　us　scientific　as　well　as　other　truth；　that
the　account　we　find　there　of　the　creation　of　living　things　is　simply
and　literally　correct；　and　that　anything　which　seems　to　contradict　it
is；　by　the　nature　of　the　case；　false。　　All　the　phenomena　which　have
been　detailed　are；　on　this　view；　the　immediate　product　of　a　creative
fiat　and　consequently　are　out　of　the　domain　of　science　altogether。

Whether　this　view　prove　ultimately　to　be　true　or　false；　it　is；　at　any
rate；　not　at　present　supported　by　what　is　commonly　regarded　as　logical
proof；　even　if　it　be　capable　of　discussion　by　reason；　and　hence　we
consider　ourselves　at　liberty　to　pass　it　by；　and　to　turn　to　those　views
which　profess　to　rest　on　a　scientific　basis　only；　and　therefore　admit　of
being　argued　to　their　consequences。　　And　we　do　this　with　the　less
hesitation　as　it　so　happens　that　those　persons　who　are　practically
conversant　with　the　facts　of　the　case　（plainly　a　considerable　advantage）
have　always　thought　fit　to　range　themselves　under　the　latter　category。

The　majority　of　these　competent　persons　have　up　to　the　present　time
maintained　two　positions；the　first；　that　every　species　is；　within
certain　defined　or　definable　limits；　fixed　and　incapable　of
modification；　the　second；　that　every　species　was　originally　produced　by
a　distinct　creative　act。　　The　second　position　is　obviously　incapable　of
proof　or　disproof；　the　direct　operations　of　the　Creator　not　being
subjects　of　science；　and　it　must　therefore　be　regarded　as　a　corollary
from　the　first；　the　truth　or　falsehood　of　which　is　a　matter　of　evidence。
Most　persons　imagine　that　the　arguments　in　favour　of　it　are
overwhelming；　but　to　some　few　minds；　and　these；　it　must　be　confessed；
intellects　of　no　small　power　and　grasp　of　knowledge；　they　have　not
brought　conviction。　　Among　these　minds；　that　of　the　famous　naturalist
Lamarck；　who　possessed　a　greater　acquaintance　with　the　lower　forms　of
life　than　any　man　of　his　day；　Cuvier　not　excepted；　and　was　a　good
botanist　to　boot；　occupies　a　prominent　place。

Two　facts　appear　to　have　strongly　affected　the　course　of　thought　of　this
remarkable　manthe　one；　that　finer　or　stronger　links　of　affinity
connect　all　living　beings　with　one　another；　and　that　thus　the　highest
creature　grades　by　multitudinous　steps　into　the　lowest；　the　other；　that
an　organ　may　be　developed　in　particular　directions　by　exerting　itself
in　particular　ways；　and　that　modifications　once　induced　may　be
transmitted　and　become　hereditary。　　Putting　these　facts　together；
Lamarck　endeavoured　to　account　for　the　first　by　the　operation　of　the
second。　　Place　an　animal　in　new　circumstances；　says　he；　and　its　needs
will　be　altered；　the　new　needs　will　create　new　desires；　and　the　attempt
to　gratify　such　desires　will　result　in　an　appropriate　modification　of
the　organs　exerted。　　Make　a　man　a　blacksmith；　and　his　brachial　muscles
will　develop　in　accordance　with　the　demands　made　upon　them；　and　in　like
manner；　says　Lamarck；　〃the　efforts　of　some　short…necked　bird　to　catch
fish　without　wetting　himself　have；　with　time　and　perseverance；　given
rise　to　all　our　herons　and　long…necked　waders。〃

The　Lamarckian　hypothesis　has　long　since　been　justly　condemned；　and　it
is　the　established　practice　for　every　tyro　to　raise　his　heel　against
the　carcass　of　the　dead　lion。　　But　it　is　rarely　either　wise　or
instructive　to　treat　even　the　errors　of　a　really　great　man　with　mere
ridicule；　and　in　the　present　case　the　logical　form　of　the　doctrine
stands　on　a　very　different　footing　from　its　substance。

If　species　have　really　arisen　by　the　operation　of　natural　conditions；　we
ought　to　be　able　to　find　those　conditions　now　at　work；　we　ought　to　be
able　to　discover　in　nature　some　power　adequate　to　modify　any　given　kind
of　animal　or　plant　in　such　a　manner　as　to　give　rise　to　another　kind；
which　would　be　admitted　by　naturalists　as　a　distinct　species。　　Lamarck
imagined　that　he　had　discovered　this　'vera　causa'　in　the　admitted　facts
that　some　organs　may　be　modified　by　exercise；　and　that　modifications；
once　produced；　are　capable　of　hereditary　transmission。　　It　does　not
seem　to　have　occurred　to　him　to　inquire　whether　there　is　any　reason　to
believe　that　there　are　any　limits　to　the　amount　of　modification
producible；　or　to　ask　how　long　an　animal　is　likely　to　endeavour　to
gratify　an　impossible　desire。　　The　bird；　in　our　example；　would　surely
have　renounced　fish　dinners　long　before　it　had　produced　the　least　effect
on　leg　or　neck。

Since　Lamarck's　time；　almost　all　competent　naturalists　have　left
speculations　on　the　origin　of　species　to　such　dreamers　as　the　author　of
the　'Vestiges'；　by　whose　well…intentioned　efforts　the　Lamarckian　theory
received　its　final　condemnation　in　the　minds　of　all　sound　thinkers。
Notwithstanding　this　silence；　however；　the　transmutation　theory；　as　it
has　been　called；　has　been　a　〃skeleton　in　the　closet〃　to　many　an　honest
zoologist　and　botanist　who　had　a　soul　above　the　mere　naming　of　dried
plants　and　skins。　　Surely；　has　such　an　one　thought；　nature　is　a　mighty
and　consistent　whole；　and　the　providential　order　established　in　the
world　of　life　must；　if　we　could　only　see　it　rightly；　be　consistent　with
that　dominant　over　the　multiform　shapes　of　brute　matter。　　But　what　is
the　history　of　astronomy；　of　all　the　branches　of　physics；　of　chemistry；
of　medicine；　but　a　narration　of　the　steps　by　which　the　human　mind　has
been　compelled；　often　sorely　against　its　will；　to　recognize　the
operation　of　secondary　causes　in　events　where　ignorance　beheld　an
immediate　intervention　of　a　higher　power？　　And　when　we　know　that　living
things　are　formed　of　the　same　elements　as　the　inorganic　world；　that　they
act　and　react　upon　it；　bound　by　a　thousand　ties　of　natural　piety；　is　it
probable；　nay　is　it　possible；　that　they；　and　they　alone；　should　have　no
order　in　their　seeming　disorder；　no　unity　in　their　seeming
multiplicity；　should　suffer　no　explanation　by　the　discovery　of　some
central　and　sublime　law　of　mutual　connexion？

Questions　of　this　kind　have　assuredly　often　arisen；　but　it　might　have
been　long　before　they　received　such　expression　as　would　have　commanded
the　respect　and　attention　of　the　scientific　world；　had　it　not　been　for
the　publication　of　the　work　which　prompted　this　article。　　Its　author；
Mr。　Darwin；　inheritor　of　a　once　celebrated　name；　won　his　spurs　in
science　when　most　of　those　now　distinguished　were　young　men；　and　has
for　the　last　20　years　held　a　place　in　the　front　ranks　of　British
philosophers。　　After　a　circumnavigatory　voyage；　undertaken　solely　for
the　love　of　his　science；　Mr。　Darwin　published　a　series　of　researches
which　at　once　arrested　the　attention　of　naturalists　and　geologists；　his
generalizations　have　since　received　ample　confirmation；　and　now　command
universal　assent；　nor　is　it　questionable　that　they　have　had　the　most
important　influence　on　the　progress　of　science。　　More　recently　Mr。
Darwin；　with　a　versatility　which　is　among　the　rarest　of　gifts；　turned
his　attention　to　a　most　difficult　question　of　zoology　and　minute
anatomy；　and　no　living　naturalist　and　anatomist　has　published　a　better
monograph　than　that　which　resulted　from　his　labours。　　Such　a　man；　at
all　events；　has　not　entered　the　sanctuary　with　unwashed　hands；　and　when
he　lays　before　us　the　results　of　20　years'　investigation　and　reflection
we　must　listen　even　though　we　be　disposed　to　strike。　　But；　in　reading
his　work　it　must　be　confessed　that　the　attention　which　might　at　first
be　dutifully；　soon　becomes　willingly；　given；　so　clear　is　the　author's
thought；　so　outspoken　his　conviction；　so　honest　and　fair　the　candid