¡¶essays on life, art and science¡·

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essays on life, art and science- µÚ32²¿·Ö


°´¼üÅÌÉÏ·½Ïò¼ü ¡û »ò ¡ú ¿É¿ìËÙÉÏÏ·­Ò³£¬°´¼üÅÌÉ쵀 Enter ¼ü¿É»Øµ½±¾ÊéĿ¼ҳ£¬°´¼üÅÌÉÏ·½Ïò¼ü ¡ü ¿É»Øµ½±¾Ò³¶¥²¿£¡
result¡¡of¡¡the¡¡theory¡¡is¡¡the¡¡impossibility¡¡of¡¡the¡¡transmission¡¡of
acquired¡¡characters£»¡¡since¡¡the¡¡molecular¡¡structure¡¡of¡¡the¡¡germ¡­plasm
is¡¡already¡¡determined¡¡within¡¡the¡¡embryo£»¡¡and¡¡Weismann¡¡holds¡¡that
there¡¡are¡¡no¡¡facts¡¡which¡¡really¡¡prove¡¡that¡¡acquired¡¡characters¡¡can
be¡¡inherited£»¡¡although¡¡their¡¡inheritance¡¡has£»¡¡by¡¡most¡¡writers£»¡¡been
considered¡¡so¡¡probable¡¡as¡¡hardly¡¡to¡¡stand¡¡in¡¡need¡¡of¡¡direct¡¡proof¡£

¡¨We¡¡have¡¡already¡¡seen¡¡in¡¡the¡¡earlier¡¡part¡¡of¡¡this¡¡chapter¡¡that¡¡many
instances¡¡of¡¡change£»¡¡imputed¡¡to¡¡the¡¡inheritance¡¡of¡¡acquired
variations£»¡¡are¡¡really¡¡cases¡¡of¡¡selection¡£¡¨

And¡¡the¡¡rest¡¡of¡¡the¡¡remarks¡¡tend¡¡to¡¡convey¡¡the¡¡impression¡¡that¡¡Mr¡£
Wallace¡¡adopts¡¡Professor¡¡Weismann's¡¡view£»¡¡but£»¡¡curiously¡¡enough£»
though¡¡I¡¡have¡¡gone¡¡through¡¡Mr¡£¡¡Wallace's¡¡book¡¡with¡¡a¡¡special¡¡view¡¡to
this¡¡particular¡¡point£»¡¡I¡¡have¡¡not¡¡been¡¡able¡¡to¡¡find¡¡him¡¡definitely
committing¡¡himself¡¡either¡¡to¡¡the¡¡assertion¡¡that¡¡acquired
modifications¡¡never¡¡are¡¡inherited£»¡¡or¡¡that¡¡they¡¡sometimes¡¡are¡¡so¡£
It¡¡is¡¡abundantly¡¡laid¡¡down¡¡that¡¡Mr¡£¡¡Darwin¡¡laid¡¡too¡¡much¡¡stress¡¡on
use¡¡and¡¡disuse£»¡¡and¡¡a¡¡residuary¡¡impression¡¡is¡¡left¡¡that¡¡Mr¡£¡¡Wallace
is¡¡endorsing¡¡Professor¡¡Weismann's¡¡view£»¡¡but¡¡I¡¡have¡¡found¡¡it
impossible¡¡to¡¡collect¡¡anything¡¡that¡¡enables¡¡me¡¡to¡¡define¡¡his
position¡¡confidently¡¡in¡¡this¡¡respect¡£

This¡¡is¡¡natural¡¡enough£»¡¡for¡¡Mr¡£¡¡Wallace¡¡has¡¡entitled¡¡his¡¡book
¡¨Darwinism£»¡¨¡¡and¡¡a¡¡work¡¡denying¡¡that¡¡use¡¡and¡¡disuse¡¡produced¡¡any
effect¡¡could¡¡not¡¡conceivably¡¡be¡¡called¡¡Darwinism¡£¡¡¡¡Mr¡£¡¡Herbert
Spencer¡¡has¡¡recently¡¡collected¡¡many¡¡passages¡¡from¡¡¡¨The¡¡Origin¡¡of
Species¡¨¡¡and¡¡from¡¡¡¨Animals¡¡and¡¡Plants¡¡under¡¡Domestication£»¡¨¡¡£û26£ý
which¡¡show¡¡how¡¡largely£»¡¡after¡¡all£»¡¡use¡¡and¡¡disuse¡¡entered¡¡into¡¡Mr¡£
Darwin's¡¡system£»¡¡and¡¡we¡¡know¡¡that¡¡in¡¡his¡¡later¡¡years¡¡he¡¡attached
still¡¡more¡¡importance¡¡to¡¡them¡£¡¡¡¡It¡¡was¡¡out¡¡of¡¡the¡¡question£»
therefore£»¡¡that¡¡Mr¡£¡¡Wallace¡¡should¡¡categorically¡¡deny¡¡that¡¡their
effects¡¡were¡¡inheritable¡£¡¡¡¡On¡¡the¡¡other¡¡hand£»¡¡the¡¡temptation¡¡to
adopt¡¡Professor¡¡Weismann's¡¡view¡¡must¡¡have¡¡been¡¡overwhelming¡¡to¡¡one
who¡¡had¡¡been¡¡already¡¡inclined¡¡to¡¡minimise¡¡the¡¡effects¡¡of¡¡use¡¡and
disuse¡£¡¡¡¡On¡¡the¡¡whole£»¡¡one¡¡does¡¡not¡¡see¡¡what¡¡Mr¡£¡¡Wallace¡¡could¡¡do£»
other¡¡than¡¡what¡¡he¡¡has¡¡doneunless£»¡¡of¡¡course£»¡¡he¡¡changed¡¡his
title£»¡¡or¡¡had¡¡been¡¡no¡¡longer¡¡Mr¡£¡¡Wallace¡£

Besides£»¡¡thanks¡¡to¡¡the¡¡works¡¡of¡¡Mr¡£¡¡Spencer£»¡¡Professor¡¡Mivart£»
Professor¡¡Semper£»¡¡and¡¡very¡¡many¡¡others£»¡¡there¡¡has¡¡for¡¡some¡¡time¡¡been
a¡¡growing¡¡perception¡¡that¡¡the¡¡Darwinism¡¡of¡¡Charles¡¡Darwin¡¡was
doomed¡£¡¡¡¡Use¡¡and¡¡disuse¡¡must¡¡either¡¡do¡¡even¡¡more¡¡than¡¡is¡¡officially
recognised¡¡in¡¡Mr¡£¡¡Darwin's¡¡later¡¡concessions£»¡¡or¡¡they¡¡must¡¡do¡¡a
great¡¡deal¡¡less¡£¡¡¡¡If¡¡they¡¡can¡¡do¡¡as¡¡much¡¡as¡¡Mr¡£¡¡Darwin¡¡himself¡¡said
they¡¡did£»¡¡why¡¡should¡¡they¡¡not¡¡do¡¡more£¿¡¡¡¡Why¡¡stop¡¡where¡¡Mr¡£¡¡Darwin
did£¿¡¡¡¡And¡¡again£»¡¡where¡¡in¡¡the¡¡name¡¡of¡¡all¡¡that¡¡is¡¡reasonable¡¡did¡¡he
really¡¡stop£¿¡¡¡¡He¡¡drew¡¡no¡¡line£»¡¡and¡¡on¡¡what¡¡principle¡¡can¡¡we¡¡say¡¡that
so¡¡much¡¡is¡¡possible¡¡as¡¡effect¡¡of¡¡use¡¡and¡¡disuse£»¡¡but¡¡so¡¡much¡¡more
impossible£¿¡¡¡¡If£»¡¡as¡¡Mr¡£¡¡Darwin¡¡contended£»¡¡disuse¡¡can¡¡so¡¡far¡¡reduce
an¡¡organ¡¡as¡¡to¡¡render¡¡it¡¡rudimentary£»¡¡and¡¡in¡¡many¡¡cases¡¡get¡¡rid¡¡of
it¡¡altogether£»¡¡why¡¡cannot¡¡use¡¡create¡¡as¡¡much¡¡as¡¡disuse¡¡can¡¡destroy£»
provided¡¡it¡¡has¡¡anything£»¡¡no¡¡matter¡¡how¡¡low¡¡in¡¡structure£»¡¡to¡¡begin
with£¿¡¡¡¡Let¡¡us¡¡know¡¡where¡¡we¡¡stand¡£¡¡¡¡If¡¡it¡¡is¡¡admitted¡¡that¡¡use¡¡and
disuse¡¡can¡¡do¡¡a¡¡good¡¡deal£»¡¡what¡¡does¡¡a¡¡good¡¡deal¡¡mean£¿¡¡¡¡And¡¡what¡¡is
the¡¡proportion¡¡between¡¡the¡¡shares¡¡attributable¡¡to¡¡use¡¡and¡¡disuse¡¡and
to¡¡natural¡¡selection¡¡respectively£¿¡¡¡¡If¡¡we¡¡cannot¡¡be¡¡told¡¡with
absolute¡¡precision£»¡¡let¡¡us¡¡at¡¡any¡¡rate¡¡have¡¡something¡¡more¡¡definite
than¡¡the¡¡statement¡¡that¡¡natural¡¡selection¡¡is¡¡¡¨the¡¡most¡¡important
means¡¡of¡¡modification¡£¡¨

Mr¡£¡¡Darwin¡¡gave¡¡us¡¡no¡¡help¡¡in¡¡this¡¡respect£»¡¡and¡¡worse¡¡than¡¡this£»¡¡he
contradicted¡¡himself¡¡so¡¡flatly¡¡as¡¡to¡¡show¡¡that¡¡he¡¡had¡¡very¡¡little
definite¡¡idea¡¡upon¡¡the¡¡subject¡¡at¡¡all¡£¡¡¡¡Thus¡¡in¡¡respect¡¡to¡¡the
winglessness¡¡of¡¡the¡¡Madeira¡¡beetles¡¡he¡¡wrote£º¡­

¡¨In¡¡some¡¡cases¡¡we¡¡might¡¡easily¡¡put¡¡down¡¡to¡¡disuse¡¡modifications¡¡of
structure£»¡¡which¡¡are¡¡wholly¡¡or¡¡mainly¡¡due¡¡to¡¡natural¡¡selection¡£¡¡¡¡Mr¡£
Wollaston¡¡has¡¡discovered¡¡the¡¡remarkable¡¡fact¡¡that¡¡200¡¡beetles£»¡¡out
of¡¡the¡¡550¡¡species¡¡£¨but¡¡more¡¡are¡¡now¡¡known£©¡¡inhabiting¡¡Madeira£»¡¡are
so¡¡far¡¡deficient¡¡in¡¡wings¡¡that¡¡they¡¡cannot¡¡fly£»¡¡and¡¡that¡¡of¡¡the¡¡29
endemic¡¡genera¡¡no¡¡less¡¡than¡¡23¡¡have¡¡all¡¡their¡¡species¡¡in¡¡this
condition£¡¡¡¡¡Several¡¡facts£»namely£»¡¡that¡¡beetles¡¡in¡¡many¡¡parts¡¡of
the¡¡world¡¡are¡¡frequently¡¡blown¡¡out¡¡to¡¡sea¡¡and¡¡perish£»¡¡that¡¡the
beetles¡¡in¡¡Madeira£»¡¡as¡¡observed¡¡by¡¡Mr¡£¡¡Wollaston£»¡¡lie¡¡much¡¡concealed
until¡¡the¡¡wind¡¡lulls¡¡and¡¡the¡¡sun¡¡shines£»¡¡that¡¡the¡¡proportion¡¡of
wingless¡¡beetles¡¡is¡¡larger¡¡on¡¡the¡¡exposed¡¡Desertas¡¡than¡¡in¡¡Madeira
itself£»¡¡and¡¡especially¡¡the¡¡extraordinary¡¡fact£»¡¡so¡¡strongly¡¡insisted
on¡¡by¡¡Mr¡£¡¡Wollaston£»¡¡that¡¡certain¡¡large¡¡groups¡¡of¡¡beetles£»¡¡elsewhere
excessively¡¡numerous£»¡¡which¡¡absolutely¡¡require¡¡the¡¡use¡¡of¡¡their
wings¡¡are¡¡here¡¡almost¡¡entirely¡¡absent£»these¡¡several¡¡considerations
make¡¡me¡¡believe¡¡that¡¡the¡¡wingless¡¡condition¡¡of¡¡so¡¡many¡¡Madeira
beetles¡¡is¡¡mainly¡¡due¡¡to¡¡the¡¡action¡¡of¡¡natural¡¡selection£»¡¡COMBINED
PROBABLY¡¡WITH¡¡DISUSE¡¡£§italics¡¡mine£§¡£¡¡¡¡For¡¡during¡¡many¡¡successive
generations¡¡each¡¡individual¡¡beetle¡¡which¡¡flew¡¡least£»¡¡either¡¡from¡¡its
wings¡¡having¡¡been¡¡ever¡¡so¡¡little¡¡less¡¡perfectly¡¡developed¡¡or¡¡from
indolent¡¡habit£»¡¡will¡¡have¡¡had¡¡the¡¡best¡¡chance¡¡of¡¡surviving£»¡¡from¡¡not
being¡¡blown¡¡out¡¡to¡¡sea£»¡¡and£»¡¡on¡¡the¡¡other¡¡hand£»¡¡those¡¡beetles¡¡which
most¡¡readily¡¡took¡¡to¡¡flight¡¡would¡¡oftenest¡¡have¡¡been¡¡blown¡¡to¡¡sea£»
and¡¡thus¡¡destroyed¡£¡¨¡¡£û27£ý

We¡¡should¡¡like¡¡to¡¡know£»¡¡first£»¡¡somewhere¡¡about¡¡how¡¡much¡¡disuse¡¡was
able¡¡to¡¡do¡¡after¡¡all£»¡¡and¡¡moreover¡¡why£»¡¡if¡¡it¡¡can¡¡do¡¡anything¡¡at
all£»¡¡it¡¡should¡¡not¡¡be¡¡able¡¡to¡¡do¡¡all¡£¡¡¡¡Mr¡£¡¡Darwin¡¡says£º¡¡¡¡¡¨Any¡¡change
in¡¡structure¡¡and¡¡function¡¡which¡¡can¡¡be¡¡effected¡¡by¡¡small¡¡stages¡¡is
within¡¡the¡¡power¡¡of¡¡natural¡¡selection¡£¡¨¡¡¡¡¡¨And¡¡why¡¡not£»¡¨¡¡we¡¡ask£»
¡¨within¡¡the¡¡power¡¡of¡¡use¡¡and¡¡disuse£¿¡¨¡¡¡¡Moreover£»¡¡on¡¡a¡¡later¡¡page¡¡we
find¡¡Mr¡£¡¡Darwin¡¡saying£º¡­

¡¨IT¡¡APPEARS¡¡PROBABLE¡¡THAT¡¡DISUSE¡¡HAS¡¡BEEN¡¡THE¡¡MAIN¡¡AGENT¡¡IN
RENDERING¡¡ORGANS¡¡RUDIMENTARY¡¡£§italics¡¡mine£§¡£¡¡¡¡It¡¡would¡¡at¡¡first¡¡lead
by¡¡slow¡¡steps¡¡to¡¡the¡¡more¡¡and¡¡more¡¡complete¡¡reduction¡¡of¡¡a¡¡part£»
until¡¡at¡¡last¡¡it¡¡has¡¡become¡¡rudimentaryas¡¡in¡¡the¡¡case¡¡of¡¡the¡¡eyes
of¡¡animals¡¡inhabiting¡¡dark¡¡caverns£»¡¡and¡¡of¡¡the¡¡wings¡¡of¡¡birds
inhabiting¡¡oceanic¡¡islands£»¡¡which¡¡have¡¡seldom¡¡been¡¡forced¡¡by¡¡beasts
of¡¡prey¡¡to¡¡take¡¡flight£»¡¡and¡¡have¡¡ultimately¡¡lost¡¡the¡¡power¡¡of
flying¡£¡¡¡¡Again£»¡¡an¡¡organ£»¡¡useful¡¡under¡¡certain¡¡conditions£»¡¡might
become¡¡injurious¡¡under¡¡others£»¡¡AS¡¡WITH¡¡THE¡¡WINGS¡¡OF¡¡BEETLES¡¡LIVING
ON¡¡SMALL¡¡AND¡¡EXPOSED¡¡ISLANDS£»¡¡and¡¡in¡¡this¡¡case¡¡natural¡¡selection
will¡¡have¡¡aided¡¡in¡¡reducing¡¡the¡¡organ£»¡¡until¡¡it¡¡was¡¡rendered
harmless¡¡and¡¡rudimentary¡¡£§italics¡¡mine£§¡£¡¨¡¡£û28£ý

So¡¡that¡¡just¡¡as¡¡an¡¡undefined¡¡amount¡¡of¡¡use¡¡and¡¡disuse¡¡was¡¡introduced
on¡¡the¡¡earlier¡¡page¡¡to¡¡supplement¡¡the¡¡effects¡¡of¡¡natural¡¡selection
in¡¡respect¡¡of¡¡the¡¡wings¡¡of¡¡beetles¡¡on¡¡small¡¡and¡¡exposed¡¡islands£»¡¡we
have¡¡here¡¡an¡¡undefined¡¡amount¡¡of¡¡natural¡¡selection¡¡introduced¡¡to
supplement¡¡the¡¡effects¡¡of¡¡use¡¡and¡¡disuse¡¡in¡¡respect¡¡of¡¡the¡¡identical
phenomena¡£¡¡¡¡In¡¡the¡¡one¡¡passage¡¡we¡¡find¡¡that¡¡natural¡¡selection¡¡has
been¡¡the¡¡main¡¡agent¡¡in¡¡reducing¡¡the¡¡wings£»¡¡though¡¡use¡¡and¡¡disuse
have¡¡had¡¡an¡¡appreciable¡¡share¡¡in¡¡the¡¡result£»¡¡in¡¡the¡¡other£»¡¡it¡¡is¡¡use
and¡¡disuse¡¡that¡¡have¡¡been¡¡the¡¡main¡¡agents£»¡¡though¡¡an¡¡appreciable
share¡¡in¡¡the¡¡result¡¡must¡¡be¡¡ascribed¡¡to¡¡natural¡¡selection¡£

Besides£»¡¡who¡¡has¡¡seen¡¡the¡¡uncles¡¡and¡¡aunts¡¡going¡¡away¡¡with¡¡the
uniformity¡¡that¡¡is¡¡necessary¡¡for¡¡Mr¡£¡¡Darwin's¡¡contention£¿¡¡¡¡We¡¡know
that¡¡birds¡¡and¡¡insects¡¡do¡¡often¡¡get¡¡blown¡¡out¡¡to¡¡sea¡¡and¡¡perish£»¡¡but
in¡¡order¡¡to¡¡establish¡¡Mr¡£¡¡Darwin's¡¡position¡¡we¡¡want¡¡the¡¡evidence¡¡of
those¡¡who¡¡watched¡¡the¡¡reduction¡¡of¡¡the¡¡wings¡¡during¡¡the¡¡many
generations¡¡in¡¡the¡¡course¡¡of¡¡which¡¡it¡¡was¡¡being¡¡effected£»¡¡and¡¡who
can¡¡testify¡¡that¡¡all£»¡¡or¡¡the¡¡overwhelming¡¡majority£»¡¡of¡¡the¡¡beetles
born¡¡with¡¡fairly¡¡well¡­developed¡¡wings¡¡got¡¡blown¡¡out¡¡to¡¡sea£»¡¡while
those¡¡alone¡¡survived¡¡whose¡¡wings¡¡were¡¡congenitally¡¡degenerate¡£¡¡¡¡Who
saw¡¡them¡¡go£»¡¡or¡¡can¡¡point¡¡to¡¡analogous¡¡cases¡¡so¡¡conclusive¡¡as¡¡to
compel¡¡assent¡¡from¡¡any¡¡equitable¡¡thinker£¿

Darwinians¡¡of¡¡the¡¡stamp¡¡of¡¡Mr¡£¡¡Thiselton¡¡Dyer£»¡¡Professor¡¡Ray
Lankester£»¡¡or¡¡Mr¡£¡¡Romanes£»¡¡insist¡¡on¡¡their¡¡pound¡¡of¡¡flesh¡¡in¡¡the
matter¡¡of¡¡irrefragable¡¡demonstration¡£¡¡¡¡They¡¡complain¡¡of¡¡us¡¡for¡¡not
bringing¡¡forward¡¡some¡¡one¡¡who¡¡has¡¡been¡¡able¡¡to¡¡detect¡¡the¡¡movement
of¡¡the¡¡hour¡­hand¡¡of¡¡a¡¡watch¡¡during¡¡a¡¡second¡¡of¡¡time£»¡¡and¡¡when¡¡we
fail¡¡to¡¡do¡¡so£»¡¡declare¡¡triumphantly¡¡that¡¡we¡¡have¡¡no¡¡evidence¡¡that
there¡¡is¡¡any¡¡connection¡¡between¡¡the¡¡beating¡¡of¡¡a¡¡second¡¡and¡¡the
movement¡¡of¡¡the¡¡hour¡­hand¡£¡¡¡¡When¡¡we¡¡say¡¡that¡¡rain¡¡comes¡¡from¡¡the
condensation¡¡of¡¡moisture¡¡in¡¡the¡¡atmosphere£»¡¡they¡¡demand¡¡of¡¡us¡¡a
rain¡­drop¡¡from¡¡moisture¡¡not¡¡yet¡¡condensed¡£¡¡¡¡If¡¡they¡¡stickle¡¡for
proof¡¡and¡¡cavil¡¡on¡¡the¡¡ninth¡¡part¡¡of¡¡a¡¡hair£»¡¡as¡¡they¡¡do¡¡when¡¡we
bring¡¡forward¡¡what¡¡we¡¡deem¡¡excellent¡¡instances¡¡of¡¡the¡¡transmission
of¡¡an¡¡acquired¡¡characteristic£»¡¡why¡¡may¡¡not¡¡we£»¡¡too£»¡¡demand¡¡at¡¡any
rate¡¡some¡¡evidence¡¡that¡¡the¡¡unmodified¡¡beetles¡¡actually¡¡did¡¡always£»
or¡¡nearly¡¡always£»¡¡get¡¡blown¡¡out¡¡to¡¡sea£»¡¡during¡¡the¡¡reduction¡¡above
referred¡¡to£»¡¡and¡¡that¡¡it¡¡is¡¡to¡¡this¡¡fact£»¡¡and¡¡not¡¡to¡¡the¡¡masterly
inactivity¡¡of¡¡their¡¡fathers¡¡and¡¡mothers£»¡¡that¡¡the¡¡Madeira¡¡beetles
owe¡¡their¡¡winglessness£¿¡¡¡¡If¡¡we¡¡began¡¡stickling¡¡for¡¡proof¡¡in¡¡this
way£»¡¡our¡¡opponents¡¡would¡¡not¡¡be¡¡long¡¡in¡¡letting¡¡us¡¡know¡¡that
absolute¡¡pro
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