essays on life, art and science-第33章

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Spencer；　who；　in　his　〃Principles　of　Biology；〃　published　in　1865；
showed　how　impossible　it　was　that　accidental　variations　should
accumulate　at　all。　　I　am　not　sure　how　far　Mr。　Spencer　would　consent
to　being　called　a　Lamarckian　pure　and　simple；　nor　yet　how　far　it　is
strictly　accurate　to　call　him　one；　nevertheless；　I　can　see　no
important　difference　in　the　main　positions　taken　by　him　and　by
Lamarck。

The　question　at　issue　between　the　Lamarckians；　supported　by　Mr。
Spencer　and　a　growing　band　of　those　who　have　risen　in　rebellion
against　the　Charles…Darwinian　system　on　the　one　hand；　and　Messrs。
Darwin　and　Wallace　with　the　greater　number　of　our　more　prominent
biologists　on　the　other；　involves　the　very　existence　of　evolution　as
a　workable　theory。　　For　it　is　plain　that　what　Nature　can　be　supposed
able　to　do　by　way　of　choice　must　depend　on　the　supply　of　the
variations　from　which　she　is　supposed　to　choose。　　She　cannot　take
what　is　not　offered　to　her；　and　so　again　she　cannot　be　supposed　able
to　accumulate　unless　what　is　gained　in　one　direction　in　one
generation；　or　series　of　generations；　is　little　likely　to　be　lost　in
those　that　presently　succeed。　　Now　variations　ascribed　mainly　to　use
and　disuse　can　be　supposed　capable　of　being　accumulated；　for　use　and
disuse　are　fairly　constant　for　long　periods　among　the　individuals　of
the　same　species；　and　often　over　large　areas；　moreover；　conditions
of　existence　involving　changes　of　habit；　and　thus　of　organisation；
come　for　the　most　part　gradually；　so　that　time　is　given　during　which
the　organism　can　endeavour　to　adapt　itself　in　the　requisite
respects；　instead　of　being　shocked　out　of　existence　by　too　sudden
change。　　Variations；　on　the　other　hand；　that　are　ascribed　to　mere
chance　cannot　be　supposed　as　likely　to　be　accumulated；　for　chance　is
notoriously　inconstant；　and　would　not　purvey　the　variations　in
sufficiently　unbroken　succession；　or　in　a　sufficient　number　of
individuals；　modified　similarly　in　all　the　necessary　correlations　at
the　same　time　and　place　to　admit　of　their　being　accumulated。　　It　is
vital　therefore　to　the　theory　of　evolution；　as　was　early　pointed　out
by　the　late　Professor　Fleeming　Jenkin　and　by　Mr。　Herbert　Spencer；
that　variations　should　be　supposed　to　have　a　definite　and　persistent
principle　underlying　them；　which　shall　tend　to　engender　similar　and
simultaneous　modification；　however　small；　in　the　vast　majority　of
individuals　composing　any　species。　　The　existence　of　such　a
principle　and　its　permanence　is　the　only　thing　that　can　be　supposed
capable　of　acting　as　rudder　and　compass　to　the　accumulation　of
variations；　and　of　making　it　hold　steadily　on　one　course　for　each
species；　till　eventually　many　havens；　far　remote　from　one　another；
are　safely　reached。

It　is　obvious　that　the　having　fatally　impaired　the　theory　of　his
predecessors　could　not　warrant　Mr。　Darwin　in　claiming；　as　he　most
fatuously　did；　the　theory　of　evolution。　　That　he　is　still　generally
believed　to　have　been　the　originator　of　this　theory　is　due　to　the
fact　that　he　claimed　it；　and　that　a　powerful　literary　backing　at
once　came　forward　to　support　him。　　It　seems　at　first　sight
improbable　that　those　who　too　zealously　urged　his　claims　were
unaware　that　so　much　had　been　written　on　the　subject；　but　when　we
find　even　Mr。　Wallace　himself　as　profoundly　ignorant　on　this　subject
as　he　still　either　is；　or　affects　to　be；　there　is　no　limit
assignable　to　the　ignorance　or　affected　ignorance　of　the　kind　of
biologists　who　would　write　reviews　in　leading　journals　thirty　years
ago。　　Mr。　Wallace　writes：…

〃A　few　great　naturalists；　struck　by　the　very　slight　difference
between　many　of　these　species；　and　the　numerous　links　that　exist
between　the　most　different　forms　of　animals　and　plants；　and　also
observing　that　a　great　many　species　do　vary　considerably　in　their
forms；　colours　and　habits；　conceived　the　idea　that　they　might　be　all
produced　one　from　the　other。　　The　most　eminent　of　these　writers　was
a　great　French　naturalist；　Lamarck；　who　published　an　elaborate　work；
the　Philosophie　Zoologique；　in　which　he　endeavoured　to　prove　that
all　animals　whatever　are　descended　from　other　species　of　animals。
He　attributed　the　change　of　species　chiefly　to　the　effect　of　changes
in　the　conditions　of　lifesuch　as　climate；　food；　&c。；　and
especially　to　the　desires　and　efforts　of　the　animals　themselves　to
improve　their　condition；　leading　to　a　modification　of　form　or　size
in　certain　parts；　owing　to　the　well…known　physiological　law　that　all
organs　are　strengthened　by　constant　use；　while　they　are　weakened　or
even　completely　lost　by　disuse　。　。　。

〃The　only　other　important　work　dealing　with　the　question　was　the
celebrated　'Vestiges　of　Creation；'　published　anonymously；　but　now
acknowledged　to　have　been　written　by　the　late　Robert　Chambers。〃

None　are　so　blind　as　those　who　will　not　see；　and　it　would　be　waste
of　time　to　argue　with　the　invincible　ignorance　of　one　who　thinks
Lamarck　and　Buffon　conceived　that　all　species　were　produced　from　one
another；　more　especially　as　I　have　already　dealt　at　some　length　with
the　early　evolutionists　in　my　work；　〃Evolution；　Old　and　New；〃　first
published　ten　years　ago；　and　not；　so　far　as　I　am　aware；　detected　in
serious　error　or　omission。　　If；　however；　Mr。　Wallace　still　thinks　it
safe　to　presume　so　far　on　the　ignorance　of　his　readers　as　to　say
that　the　only　two　important　works　on　evolution　before　Mr。　Darwin's
were　Lamarck's　Philosophie　Zoologique　and　the　〃Vestiges　of
Creation；〃　how　fathomable　is　the　ignorance　of　the　average　reviewer
likely　to　have　been　thirty　years　ago；　when　the　〃Origin　of　Species〃
was　first　published？　　Mr。　Darwin　claimed　evolution　as　his　own
theory。　　Of　course；　he　would　not　claim　it　if　he　had　no　right　to　it。
Then　by　all　means　give　him　the　credit　of　it。　　This　was　the　most
natural　view　to　take；　and　it　was　generally　taken。　　It　was　not；
moreover；　surprising　that　people　failed　to　appreciate　all　the
niceties　of　Mr。　Darwin's　〃distinctive　feature〃　which；　whether
distinctive　or　no；　was　assuredly　not　distinct；　and　was　never　frankly
contrasted　with　the　older　view；　as　it　would　have　been　by　one　who
wished　it　to　be　understood　and　judge　upon　its　merits。　　It　was　in
consequence　of　this　omission　that　people　failed　to　note　how　fast　and
loose　Mr。　Darwin　played　with　his　distinctive　feature；　and　how
readily　he　dropped　it　on　occasion。

It　may　be　said　that　the　question　of　what　was　thought　by　the
predecessors　of　Mr。　Darwin　is；　after　all；　personal；　and　of　no
interest　to　the　general　public；　comparable　to　that　of　the　main
issuewhether　we　are　to　accept　evolution　or　not。　　Granted　that
Buffon；　Erasmus　Darwin；　and　Lamarck　bore　the　burden　and　heat　of　the
day　before　Mr。　Charles　Darwin　was　born；　they　did　not　bring　people
round　to　their　opinion；　whereas　Mr。　Darwin　and　Mr。　Wallace　did；　and
the　public　cannot　be　expected　to　look　beyond　this　broad　and
indisputable　fact。

The　answer　to　this　is；　that　the　theory　which　Messrs。　Darwin　and
Wallace　have　persuaded　the　public　to　accept　is　demonstrably　false；
and　that　the　opponents　of　evolution　are　certain　in　the　end　to
triumph　over　it。　　Paley；　in　his　〃Natural　Theology；〃　long　since
brought　forward　far　too　much　evidence　of　design　in　animal
organisation　to　allow　of　our　setting　down　its　marvels　to　the
accumulations　of　fortunate　accident；　undirected　by　will；　effort　and
intelligence。　　Those　who　examine　the　main　facts　of　animal　and
vegetable　organisation　without　bias　will；　no　doubt；　ere　long
conclude　that　all　animals　and　vegetables　are　derived　ultimately　from
unicellular　organisms；　but　they　will　not　less　readily　perceive　that
the　evolution　of　species　without　the　concomitance　and　direction　of
mind　and　effort　is　as　inconceivable　as　is　the　independent　creation
of　every　individual　species。　　The　two　facts；　evolution　and　design；
are　equally　patent　to　plain　people。　　There　is　no　escaping　from
either。　　According　to　Messrs。　Darwin　and　Wallace；　we　may　have
evolution；　but　are　on　no　account　to　have　it　as　mainly　due　to
intelligent　effort；　guided　by　ever　higher　and　higher　range　of
sensations；　perceptions；　and　ideas。　　We　are　to　set　it　down　to　the
shuffling　of　cards；　or　the　throwing　of　dice　without　the　play；　and
this　will　never　stand。