autobiography and selected essays-第24节

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asleep　as　when　you　are　awake。



Well；　now；　you　cannot　at　the　moment　answer　that　kind　of　reasoning。

You　feel　that　your　worthy　friend　has　you　somewhat　at　a

disadvantage。　　You　will　feel　perfectly　convinced　in　your　own　mind；

however；　that　you　are　quite　right；　and　you　say　to　him；　〃My　good

friend；　I　can　only　be　guided　by　the　natural　probabilities　of　the

case；　and　if　you　will　be　kind　enough　to　stand　aside　and　permit　me

to　pass；　I　will　go　and　fetch　the　police。〃　　Well；　we　will　suppose

that　your　journey　is　successful；　and　that　by　good　luck　you　meet

with　a　policeman；　that　eventually　the　burglar　is　found　with　your

property　on　his　person；　and　the　marks　correspond　to　his　hand　and　to

his　boots。　　Probably　any　jury　would　consider　those　facts　a　very

good　experimental　verification　of　your　hypothesis；　touching　the

cause　of　the　abnormal　phenomena　observed　in　your　parlor；　and　would

act　accordingly。



Now；　in　this　supposititious　case；　I　have　taken　phenomena　of　a　very

common　kind；　in　order　that　you　might　see　what　are　the　different

steps　in　an　ordinary　process　of　reasoning；　if　you　will　only　take

the　trouble　to　analyse　it　carefully。　　All　the　operations　I　have

described；　you　will　see；　are　involved　in　the　mind　of　any　man　of

sense　in　leading　him　to　a　conclusion　as　to　the　course　he　should

take　in　order　to　make　good　a　robbery　and　punish　the　offender。　　I

say　that　you　are　led；　in　that　case；　to　your　conclusion　by　exactly

the　same　train　of　reasoning　as　that　which　a　man　of　science　pursues

when　he　is　endeavouring　to　discover　the　origin　and　laws　of　the　most

occult　phenomena。　　The　process　is；　and　always　must　be；　the　same；

and　precisely　the　same　mode　of　reasoning　was　employed　by　Newton　＇90＇

and　Laplace　＇91＇　in　their　endeavours　to　discover　and　define　the　causes

of　the　movements　of　the　heavenly　bodies；　as　you；　with　your　own　common

sense；　would　employ　to　detect　a　burglar。　　The　only　difference　is；

that　the　nature　of　the　inquiry　being　more　abstruse；　every　step　has

to　be　most　carefully　watched；　so　that　there　may　not　be　a　single

crack　or　flaw　in　your　hypothesis。　　A　flaw　or　crack　in　many　of　the

hypotheses　of　daily　life　may　be　of　little　or　no　moment　as　affecting

the　general　correctness　of　the　conclusions　at　which　we　may　arrive；

but；　in　a　scientific　inquiry；　a　fallacy；　great　or　small；　is　always

of　importance；　and　is　sure　to　be　in　the　long　run　constantly

productive　of　mischievous　if　not　fatal　results。



Do　not　allow　yourselves　to　be　misled　by　the　common　notion　that　an

hypothesis　is　untrustworthy　simply　because　it　is　an　hypothesis。　　It

is　often　urged；　in　respect　to　some　scientific　conclusion；　that；

after　all；　it　is　only　an　hypothesis。　　But　what　more　have　we　to

guide　us　in　nine…tenths　of　the　most　important　affairs　of　daily　life

than　hypotheses；　and　often　very　ill…based　ones？　　So　that　in

science；　where　the　evidence　of　an　hypothesis　is　subjected　to　the

most　rigid　examination；　we　may　rightly　pursue　the　same　course。　　You

may　have　hypotheses；　and　hypotheses。　　A　man　may　say；　if　he　likes；

that　the　moon　is　made　of　green　cheese：　that　is　an　hypothesis。　　But

another　man；　who　has　devoted　a　great　deal　of　time　and　attention　to

the　subject；　and　availed　himself　of　the　most　powerful　telescopes

and　the　results　of　the　observations　of　others；　declares　that　in　his

opinion　it　is　probably　composed　of　materials　very　similar　to　those

of　which　our　own　earth　is　made　up：　and　that　is　also　only　an

hypothesis。　　But　I　need　not　tell　you　that　there　is　an　enormous

difference　in　the　value　of　the　two　hypotheses。　　That　one　which　is

based　on　sound　scientific　knowledge　is　sure　to　have　a　corresponding

value；　and　that　which　is　a　mere　hasty　random　guess　is　likely　to

have　but　little　value。　　Every　great　step　in　our　progress　in

discovering　causes　has　been　made　in　exactly　the　same　way　as　that

which　I　have　detailed　to　you。　　A　person　observing　the　occurrence　of

certain　facts　and　phenomena　asks；　naturally　enough；　what　process；

what　kind　of　operation　known　to　occur　in　Nature　applied　to　the

particular　case；　will　unravel　and　explain　the　mystery？　　Hence　you

have　the　scientific　hypothesis；　and　its　value　will　be　proportionate

to　the　care　and　completeness　with　which　its　basis　had　been　tested

and　verified。　　It　is　in　these　matters　as　in　the　commonest　affairs

of　practical　life：　the　guess　of　the　fool　will　be　folly；　while　the

guess　of　the　wise　man　will　contain　wisdom。　　In　all　cases；　you　see

that　the　value　of　the　result　depends　on　the　patience　and

faithfulness　with　which　the　investigator　applies　to　his　hypothesis

every　possible　kind　of　verification。







ON　THE　PHYSICAL　BASIS　OF　LIFE　＇92＇





In　order　to　make　the　title　of　this　discourse　generally

intelligible；　I　have　translated　the　term　〃Protoplasm；〃　which　is　the

scientific　name　of　the　substance　of　which　I　am　about　to　speak；　by

the　words　〃the　physical　basis　of　life。〃　　I　suppose　that；　to　many；

the　idea　that　there　is　such　a　thing　as　a　physical　basis；　or　matter；

of　life　may　be　novelso　widely　spread　is　the　conception　of　life　as

a　something　which　works　through　matter；　but　is　independent　of　it；

and　even　those　who　are　aware　that　matter　and　life　are　inseparably

connected；　may　not　be　prepared　for　the　conclusion　plainly　suggested

by　the　phrase；　〃THE　physical　basis　or　matter　of　life；〃　that　there

is　some　one　kind　of　matter　which　is　common　to　all　living　beings；

and　that　their　endless　diversities　are　bound　together　by　a

physical；　as　well　as　an　ideal；　unity。　　In　fact；　when　first

apprehended；　such　a　doctrine　as　this　appears　almost　shocking　to

common　sense。



What；　truly；　can　seem　to　be　more　obviously　different　from　one

another；　in　faculty；　in　form；　and　in　substance；　than　the　various

kinds　of　living　beings？　　What　community　of　faculty　can　there　be

between　the　bright…coloured　lichen；　which　so　nearly　resembles　a

mere　mineral　incrustation　of　the　bare　rock　on　which　it　grows；　and

the　painter；　to　whom　it　is　instinct　with　beauty；　or　the　botanist；

whom　it　feeds　with　knowledge？



Again；　think　of　the　microscopic　fungusa　mere　infinitesimal　ovoid

particle；　which　finds　space　and　duration　enough　to　multiply　into

countless　millions　in　the　body　of　a　living　fly；　and　then　of　the

wealth　of　foliage；　the　luxuriance　of　flower　and　fruit；　which　lies

between　this　bald　sketch　of　a　plant　and　the　giant　pine　of

California；　towering　to　the　dimensions　of　a　cathedral　spire；　or　the

Indian　fig；　which　covers　acres　with　its　profound　shadow；　and

endures　while　nations　and　empires　come　and　go　around　its　vast

circumference。　　Or；　turning　to　the　other　half　of　the　world　of　life；

picture　to　yourselves　the　great　Finner　whale；＇93＇　hugest　of　beasts

that　live；　or　have　lived；　disporting　his　eighty　or　ninety　feet　of　bone；

muscle　and　blubber；　with　easy　roll；　among　waves　in　which　the

stoutest　ship　that　ever　left　dockyard　would　flounder　hopelessly；

and　contrast　him　with　the　invisible　animalculesmere　gelatinous

specks；　multitudes　of　which　could；　in　fact；　dance　upon　the　point　of

a　needle　with　the　same　ease　as　the　angels　of　the　Schoolmen　could；

in　imagination。　　With　these　images　before　your　minds；　you　may　well

ask；　what　community　of　form；　or　structure；　is　there　between　the

animalcule　and　the　whale；　or　between　the　fungus　and　the　fig…tree？

And；　a　fortiori；＇94＇　between　all　four？



Finally；　if　we　regard　substance；　or　material　composition；　what

hidden　bond　can　connect　the　flower　which　a　girl　wears　in　her　hair

and　the　blood　which　courses　through　her　youthful　veins；　or；　what　is

there　in　common　between　the　dense　and　resisting　mass　of　the　oak；　or

the　strong　fabric　of　the　tortoise；　and　those　broad　disks　of　glassy

jelly　which　may　be　seen　pulsating　through　the　waters　of　a　calm　sea；

but　which　drain　away　to　mere　films　in　the　hand　which　raises　them

out　of　their　element？



Such　objections　as　these　must；　I　think；　arise　in　the　mind　of　every

one　who　ponders；　for　the　first　time；　upon　the　conception　of　a

single　physical　basis　of　life　underlying　all　the　diversities　of

vital　existence；　but　I　propose　to　demonstrate　to　you　that；

notwithstanding　these　apparent　difficulties；　a　threefold　unity

namely；　a　unity　of　power　or　faculty；　a　unity　of　form；　and　a　unity

of　substantial　compositiondoes　pervade　the　whole　living　world。





No　very　abstruse　argumentation　is　needed；　in　the　first　place　to

prove　that　the　powers；　or　faculties；　of　all　kinds　of　living　matter；

diverse　as　they　may　be　in　degree；　are　substantially　similar　in

kind。



Goethe　has　condensed　a　survey　of　all　powers　of　mankind　into　the

well…known　epigram：＇95＇



〃Warum　treibt　sich　das　Volk　so　und　schreit？　　Es　will　sich　ernahren

Kinder　zeugen；　und　die　nahren　so　gut　es　vermag。

。　　　　。　　　　。　　　　。　　　　。　　　　。　　　　。　　　　。　　　　。　　　　。　　　　。　　　　。　　　　。

Weiter　bringt　es　kein　Mensch；　stell'　er　sich　wie　er　auch　will。〃





In　physiological　language　this　means；　that　all　the　multifarious　and

complicated　activities　of　man　are　comprehensible　under　three

categories。　　Either　they　are　immediately　directed　towards　the

mainten