Whatislife生命是什么by薛定谔.docx

Whatislife生命是什么by薛定谔.docx

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Whatislife生命是什么by薛定谔

What-is-life-（生命是什么）-by-薛定谔

WHATISLIFE?

ERWINSCHRODINGER

Firstpublished1944

Whatislife?

ThePhysicalAspectoftheLiving

Cell.

Basedonlecturesdeliveredundertheauspicesof

theDublinInstituteforAdvancedStudiesat

TrinityCollege,Dublin,inFebruary1943.

TothememoryofMyParents

Preface

Ascientistissupposedtohaveacompleteand

thoroughIofknowledge,atfirsthand,ofsome

subjectsand,therefore,isusuallyexpectednotto

writeonanytopicofwhichheisnotalife,

master.Thisisregardedasamatterofnoblesse

oblige.ForthepresentpurposeIbegtorenounce

thenoblesse,ifany,andtobethefreedofthe

ensuingobligation.Myexcuseisasfollows:

We

haveinheritedfromourforefathersthekeen

longingforunified,all-embracingknowledge.

Theverynamegiventothehighestinstitutions

oflearningremindsus,thatfromantiquitytoand

throughoutmanycenturiestheuniversalaspect

hasbeentheonlyonetobe

TheClassicalPhysicist'sApproachtotheSubject

Thislittlebookarosefromacourseofpublic

lectures,deliveredbyatheoreticalphysicisttoan

audienceofaboutfourhundredwhichdidnot

substantiallydwindle,thoughwarnedatthe

outsetthatthesubject-matterwasadifficultone

andthatthelecturescouldnotbetermedpopular,

eventhoughthephysicist’smostdreaded

weapon,mathematicaldeduction,wouldhardly

beutilized.Thereasonforthiswasnotthatthe

subjectwassimpleenoughtobeexplained

withoutmathematics,butratherthatitwasmuch

tooinvolvedtobefullyaccessibleto

mathematics.Anotherfeaturewhichatleast

inducedasemblanceofpopularitywasthe

lecturer'sintentiontomakeclearthefundamental

idea,whichhoversbetweenbiologyandphysics,

toboththephysicistandthebiologist.For

actually,inspiteofthevarietyoftopicsinvolved,

thewholeenterpriseisintendedtoconveyone

ideaonly-onesmallcommentonalargeand

importantquestion.Inordernottoloseourway,

itmaybeusefultooutlinetheplanverybriefly

inadvance.Thelargeandimportantandvery

muchdiscussedquestionis:

Howcantheevents

inspaceandtimewhichtakeplacewithinthe

spatialboundaryofalivingorganismbe

accountedforbyphysicsandchemistry?

The

preliminaryanswerwhichthislittlebookwill

endeavortoexpoundandestablishcanbe

summarizedasfollows:

Theobviousinabilityof

present-dayphysicsandchemistrytoaccountfor

sucheventsisnoreasonatallfordoubtingthat

theycanbeaccountedforbythosesciences.

STATISTICALPHYSICS.THE

FUNDAMENTALWDIFFERENCEIN

STRUCTURE

Thatwouldbeaverytrivialremarkifitwere

meantonlytostimulatethehopeofachievinginthefuturewhathasnotbeenachievedinthepast.

Butthemeaningisverymuchmorepositive,viz.

thattheinability,uptothepresentmoment,is

amplyaccountedfor.Today,thankstothe

ingeniousworkofbiologists,mainlyof

geneticists,duringthelastthirtyorfortyyears,

enoughisknownabouttheactualmaterial

structureoforganismsandabouttheir

functioningtostatethat,andtotellprecisely

whypresent-dayphysicsandchemistrycouldnot

possiblyaccountforwhathappensinspaceand

timewithinalivingorganism.Thearrangements

oftheatomsinthemostvitalpartsofan

organismandtheinterplayofthesearrangements

differinafundamentalwayfromallthose

arrangementsofatomswhichphysicistsand

chemistshavehithertomadetheobjectoftheir

experimentalandtheoreticalresearch.Yetthe

differencewhichIhavejusttermedfundamental

isofsuchakindthatitmighteasilyappearslight

toanyoneexceptaphysicistwhoisthoroughly

imbuedwiththeknowledgethatthelawsof

physicsandchemistryarestatisticalthroughout.

Foritisinrelationtothestatisticalpointofview

thatthestructureofthevitalpartsofliving

organismsdifferssoentirelyfromthatofany

pieceofmatterthatwephysicistsandchemists

haveeverhandledphysicallyinourlaboratories

ormentallyatourwritingdesks.Itiswell-nigh

unthinkablethatthelawsandregularitiesthus

discoveredshouldhappentoapplyimmediately

tothebehaviourofsystemswhichdonotexhibit

thestructureonwhichthoselawsandregularities

arebased.Thenon-physicistcannotbeexpected

eventograspletalonetoappreciatethe

relevanceofthedifferencein‘statistical

structure’statedintermssoabstractasIhave

justused.Togivethestatementlifeandcolour,

letmeanticipatewhatwillbeexplainedinmuch

moredetaillater,namely,thatthemostessential

partofalivingcell-thechromosomefibremay

suitablybecalledanaperiodiccrystal.Inphysics

wehavedealthithertoonlywithperiodiccrystals.

Toahumblephysicist'smind,thesearevery

interestingandcomplicatedobjects;they

constituteoneofthemostfascinating

andcomplexmaterialstructuresbywhich

inanimatenaturepuzzleshiswits.Yet,compared

withtheaperiodiccrystal,theyareratherplain

anddull.Thedifferenceinstructureisofthe

samekindasthatbetweenanordinarywallpaper

inwhichthesamepatternisrepeatedagainand

againinregularperiodicityandamasterpieceof

embroidery,sayaRaphaeltapestry,whichshows

nodullrepetition,butanelaborate,coherent,

meaningfuldesigntracedbythegreatmaster.In

callingtheperiodiccrystaloneofthemost

complexobjectsofhisresearch,Ihadinmind

thephysicistproper.Organicchemistry,indeed,

ininvestigatingmoreandmorecomplicated

molecules,hascomeverymuchnearertothat

'aperiodiccrystal'which,inmyopinion,isthe

materialcarrieroflife.Andthereforeitissmall

wonderthattheorganicchemisthasalready

madelargeandimportantcontributionstothe

problemoflife,whereasthephysicisthasmade

nexttonone.

THENAIVEPHYSICIST'SAPPROACHTO

THESUBJECT

Afterhavingthusindicatedverybrieflythe

generalidea-orrathertheultimatescope-ofour

investigation,letmedescribethelineofattack.I

proposetodevelopfirstwhatyoumightcall'a

naivephysicist'sideasaboutorganisms',thatis,

theideaswhichmightariseinthemindofa

physicistwho,afterhavinglearnthisphysicsand,

moreespecially,thestatisticalfoundationofhis

science,beginstothinkaboutorganismsand

aboutthewaytheybehaveandfunctionandwho

comestoaskhimselfconscientiouslywhetherhe,

fromwhathehaslearnt,fromthepointofview

ofhiscomparativelysimpleandclearand

humblescience,canmakeanyrelevant

contributionstothequestion.Itwillturnoutthat

hecan.Thenextstepmustbetofcomparehis

theoreticalanticipationswiththebiologicalfacts.

Itwillthenturnoutthat-thoughonthewholehis

ideasseemquitesensible-theyneedtobe

appreciablyamended.Inthiswayweshall

graduallyapproachthecorrectview-or,toputit

moremodestly,theonethatIproposeasthe

correctone.EvenifIshouldberightinthis,Ido

notknowwhethermywayofapproachisreally

thebestandsimplest.But,inshort,itwasmine.

The'naivephysicist'wasmyself.AndIcouldnot

findanybetterorclearerwaytowardsthegoal

thanmyowncrookedone.

WHYARETHEATOMSSOSMALL?

Agoodmethodofdeveloping'thenaive

physicist'sideas'istostartfromtheodd,almost

ludicrous,question:

Whyareatomssosmall?

To

beginwith,theyareverysmallindeed.Every

littlepieceofmatterhandledineverydaylife

containsanenormousnumberofthem.Many

exampleshavebeendevisedtobringthisfact

hometoanaudience,noneofthemmore

impressivethantheoneusedbyLordKelvin:

Supposethatyoucouldmarkthemoleculesina

glassofwater;thenpourthecontentsoftheglass

intotheoceanandstirthelatterthoroughlysoastodistributethemarkedmoleculesuniformly

throughoutthesevenseas;ifthenyoutooka

glassofwateranywhereoutoftheocean,you

wouldfindinitaboutahundredofyourmarked

molecules.Theactualsizesofatomsliebetween

about1/5000and1/2000thewave-lengthof

yellowlight.Thecomparisonissignificant,

becausethewave-lengthroughlyindicatesthe

dimensionsofthesmallestgrainstill

recognizableinthemicroscope.Thusitwillbe

seenthatsuchagrainstillcontainsthousandsof

millionsofatoms.Now,whyareatomsso

small?

Clearly,thequestionisanevasion.Forit

isnotreallyaimedatthesizeoftheatoms.Itis

concernedwiththesizeoforganisms,more

particularlywiththesizeofourowncorporeal

selves.Indeed,theatomissmall,whenreferred

toourcivicunitoflength,saytheyardorthe

metre.Inatomicphysicsoneisaccustomedto

usetheso-calledAngstrom（abbr.A）,whichis

the10lOthpartofametre,orindecimalnotation

0.0000000001metre.Atomicdiametersrange

between1and2A.Nowthosecivicunits（in

relationtowhichtheatomsaresosmall）are

closelyrelatedtothesizeofourbodies.Thereis

astorytracingtheyardbacktothehumourofan

Englishkingwhomhiscouncillorsaskedwhat

unittoadopt-andhestretchedouthisarm

sidewaysandsaid:

'Takethedistancefromthe

middleofmychesttomyfingertips,thatwilldo

allright.'Trueornot,thestoryissignificantfor

ourpurpose.ThekingwouldnaturallyIindicate

alengthcomparablewiththatofhisownbody,

knowingthatanythingelsewouldbevery

inconvenient.Withallhispredilectionforthe

Angstromunit,thephysicistpreferstobetold

thathisnewsuitwillrequiresixandahalfyards

of