博士研究生英语精读-翻译及原文(中科院).doc

博士研究生英语精读-翻译及原文(中科院).doc

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第1课知识的悖论TheParadoxofKnowledge

Thegreatestachievementofhumankindinitslongevolutionfromancienthominoidancestorstoitspresentstatusistheacquisitionandaccumulationofavastbodyofknowledgeaboutitself,theworld,andtheuniverse.Theproductsofthisknowledgeareallthosethingsthat,intheaggregate,wecall"civilization,"includinglanguage,science,literature,art,allthephysicalmechanisms,instruments,andstructuresweuse,andthephysicalinfrastructuresonwhichsocietyrelies.Mostofusassumethatinmodernsocietyknowledgeofallkindsiscontinuallyincreasingandtheaggregationofnewinformationintothecorpusofoursocialorcollectiveknowledgeissteadilyreducingtheareaofignoranceaboutourselves,theworld,andtheuniverse.Butcontinuingremindersofthenumerousareasofourpresentignoranceinviteacriticalanalysisofthisassumption.

Inthepopularview,intellectualevolutionissimilarto,althoughmuchmorerapidthan,somaticevolution.Biologicalevolutionisoftendescribedbythestatementthat"ontogenyrecapitulatesphylogeny"--meaningthattheindividualembryo,initsdevelopmentfromafertilizedovumintoahumanbaby,passesthroughsuccessivestagesinwhichitresemblesancestralformsofthehumanspecies.Thepopularviewisthathumankindhasprogressedfromastateofinnocentignorance,comparabletothatofaninfant,andgraduallyhasacquiredmoreandmoreknowledge,muchasachildlearnsinpassingthroughtheseveralgradesoftheeducationalsystem.Implicitinthisviewisanassumptionthatphylogenyresemblesontogeny,sothattherewillultimatelybeastageinwhichtheaccumulationofknowledgeisessentiallycomplete,atleastinspecificfields,asifsocietyhadgraduatedwithalltheadvanceddegreesthatsignifymasteryofimportantsubjects.

Suchviewshave,infact,beenexpressedbysomeeminentscientists.In1894thegreatAmericanphysicistAlbertMichelsonsaidinatalkattheUniversityofChicago:

WhileitisneversafetoaffirmthatthefutureofPhysicalSciencehasnomarvelsinstoreevenmoreastonishingthanthoseofthepast,itseemsprobablethatmostofthegrandunderlyingprincipleshavebeenfirmlyestablishedandthatfurtheradvancesaretobesoughtchieflyintherigorousapplicationoftheseprinciplestoallthephenomenawhichcomeunderournotice....ThefuturetruthsofPhysicalScienceatetobelookedforinthesixthplaceofdecimals.

InthecenturysinceMichelson'stalk,scientistshavediscoveredmuchmorethantherefinementofmeasurementsinthesixthdecimalplace,andnoneiswillingtomakeasimilarstatementtoday.However,manystillclingtothenotionthatsuchastateofknowledgeremainsapossibilitytobeattainedsoonerorlater.StephenHawking,thegreatEnglishscientist,inhisimmenselypopularbookABriefHistoryofTime（1988）,concludeswiththespeculationthatwemay"discoveracompletetheory"that"wouldbetheultimatetriumphofhumanreason--forthenwewouldknowthemindofGod."PaulDavies,anAustralianphysicist,echoesthatviewbysuggestingthatthehumanmindmaybeabletograspsomeofthesecretsencompassedbythetitleofhisbookTheMindofGod（1992）.Othercontemporaryscientistswriteof"theoriesofeverything,"meaningtheoriesthatexplainallobservablephysicalphenomena,andNobelLaureateStevenWeinberg,oneofthefoundersofthecurrentstandardmodelofphysicaltheory,writesofhisDreamsofaFinalTheory（1992）.

Despitetheeminenceandobviousyearningoftheseandmanyothercontemporaryscientists,thereisnothinginthehistoryofsciencetosuggestthatanyadditionofdataortheoriestothebodyofscientificknowledgewilleverprovideanswerstoallquestionsinanyfield.Onthecontrary,thehistoryofscienceindicatesthatincreasingknowledgebringsawarenessofnewareasofignoranceandofnewquestionstobeanswered.

Astronomyisthemostancientofthesciences,anditsdevelopmentisamodelofotherfieldsofknowledge.Peoplehavebeenobservingthestarsandothercelestialbodiessincethedawnofrecordedhistory.Asearlyas3000B.C.theBabyloniansrecognizedanumberoftheconstellations.InthesixthcenturyB.C.,PythagorasproposedthenotionofasphericalEarthandofauniversewithobjectsinitchatmovedinaccordancewithnaturallaws.LaterGreekphilosopherstaughtthattheskywasahollowglobesurroundingtheEarth,thatitwassupportedonanaxisrunningthroughtheEarth,andchatstarswereinlaidonitsinnersurface,whichrotatedwestwarddaily.InthesecondcenturyA.D.,Ptolemypropoundedatheoryofageocentric（Earth-centered）universeinwhichthesun,planets,andstarsmovedincircularorbitsofcyclesandepicyclesaroundtheEarth,althoughtheEarthwasnotattheprecisecenteroftheseorbits.Whilesomewhatawkward,thePtolemaicsystemcouldproducereasonablyreliablepredictionsofplanetarypositions,whichwere,however,goodforonlyafewyearsandwhichdevelopedsubstantialdiscrepanciesfromactualobservationsoveralongperiodoftime.Nevertheless,sincetherewasnoevidencethenapparenttoastronomersthattheEarthitselfmoves,thePtolemaicsystemremainedunchallengedformorethan13centuries.

InthesixteenthcenturyNocolausCopernicus,whoissaidtohavemasteredalltheknowledgeofhisdayinmathematics,astronomy,medicine,andtheology,becamedissatisfiedwiththePtolemaicsystem.Hefoundthataheliocentricsystemwasbothmathematicallypossibleandaestheticallymorepleasing,andwroteafullexpositionofhishypothesis,whichwasnotpublisheduntil1543,shortlyafterhisdeath.Earlyintheseventeenthcentury,JohannesKeplerbecameimperialmathematicianoftheHolyRomanEmpireuponthedeathofTychoBrahe,andheacquiredacollectionofmeticulousnaked-eyeobservationsofthepositionsofcelestialbodieschathadbeenmadebyBrahe.Onthebasisofthesedata,KeplercalculatedthatbothPtolemyandCopernicuswereinerrorinassumingchatplanetstraveledincircularorbits,andin1609hepublishedabookdemonstratingmathematicallychattheplanetstravelaroundthesuninellipticalorbits.Kepler'slawsofplanetarymotionarestillregardedasbasicallyvalid.

InthefirstdecadeoftheseventeenthcenturyGalileoGalileilearnedoftheinventionofthetelescopeandbegantobuildsuchinstruments,becomingthefirstpersontouseatelescopeforastronomicalobservations,andthusdiscoveringcratersonthemoon,phasesofVenus,andthesatellitesofJupiter.HisobservationsconvincedhimofthevalidityoftheCopernicansystemandresultedinthewell-knownconflictbetweenGalileoandchurchauthorities.InJanuary1642Galileodied,andinDecemberofchatyearIsaacNewtonwasborn.Modernsciencederiveslargelyfromtheworkofthesetwomen.

Newton'scontributionstosciencearenumerous.Helaidthefoundationsformodemphysicaloptics,formulatedthebasiclawsofmotionandthelawofuniversalgravitation,anddevisedtheinfinitesimalcalculus.Newton'slawsofmotionandgravitationarestillusedforcalculationsofsuchmattersastrajectoriesofspacecraftandsatellitesandorbitsofplanets.In1846,relyingonsuchcalculationsasaguidetoobservation,astronomersdiscoveredtheplanetNeptune.

WhilecalculationsbasedonNewton'slawsareaccurate,theyaredismayinglycomplexwhenthreeormorebodiesareinvolved.In1915,Einsteinannouncedhistheoryofgeneralrelativity,whichledtoasetofdifferentialequationsforplanetaryorbitsidenticaltothosebasedonNewtoniancalculations,exceptforthoserelatingtotheplanetMercury.TheellipticalorbitofMercuryrotatesthroughtheyears,butsoslowlythatthechangeofpositionislessthanoneminuteofarceachcentury.Theequationsofgeneralrelativitypreciselyaccountedforthisprecession;Newtonianequationsdidnot.

Einstein'sequationsalsoexplainedtheredshiftinthelightfromdistantstarsandthedeflectionofstarlightasitpassednearthesun.However,Einsteinassumedchattheuniversewasstatic,and,inordertopermitameaningfulsolutiontotheequationsofrelativity,in1917headdedanotherterm,calleda"cosmologicalconstant,"totheequations.Althoughtheexistenceandsignificanceofacosmologicalconstantisstillbeingdebated,Einsteinlaterdeclaredchatthiswasamajormistake,asEdwinHubbleestablishedinthe1920schattheuniverseisexpandingandgalaxiesarerecedingfromoneanotherataspeedproportionatetotheirdistance.

AnotherimportantdevelopmentinastronomygrewoutofNewton'sexperimentationinoptics,beginningwithhisdemonstrationchatsunlightcouldbebrokenupbyaprismintoaspectrumofdifferentcolors,whichledtothescienceofspectroscopy.Inthetwentiethcentury,spectroscopywasappliedtoastronomytoguninformationaboutthechemicalandphysicalconditionofcelestialbodieschatwasnotdisclosedbyvisualobservation.Inthe1920s,precisephotographicphotometrywasintroducedtoastronomyandquantitativespectrochemicalanalysisbecamecommon.Alsoduringthe1920s,scientistslikeHeisenberg,deBroglie,Schrodinger,andDiracdevelopedquantummechanics,abranchofphysicsdealingwithsubatomicparticlesofmatterandquantaofenergy.Astronomersbegantorecognizethatthepropertiesofcelestialbodies,includingplanets,couldbewellunderstoodonlyintermsofphysics,andthefieldbegantobereferredtoas"astrophysics."

Thesedevelopmentscreatedanexplosiveexpansioninourknowledgeofastronomy.Duringthefirstfivethousandyearsormoreofobservingtheheavens,observationwasconfinedtothenarrowbandofvisiblelight.Inthelasthalfofthiscentur