A Designer UniverseWord文档格式.docx
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A Designer UniverseWord文档格式.docx
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tseehowit'
spossibletotalkaboutthiswithouthavingatleastsomevagueideaofwhatadesignerwouldbelike.Anypossibleuniversecouldbeexplainedastheworkofsomesortofdesigner.Evenauniversethatiscompletelychaotic,withoutanylawsorregularitiesatall,couldbesupposedtohavebeendesignedbyanidiot.
Thequestionthatseemstometobeworthanswering,andperhapsnotimpossibletoanswer,iswhethertheuniverseshowssignsofhavingbeendesignedbyadeitymoreorlesslikethoseoftraditionalmonotheisticreligionsâ
€”notnecessarilyafigurefromtheceilingoftheSistineChapel,butatleastsomesortofpersonality,someintelligence,whocreatedtheuniverseandhassomespecialconcernwithlife,inparticularwithhumanlife.Iexpectthatthisisnottheideaofadesignerheldbymanyhere.Youmaytellmethatyouarethinkingofsomethingmuchmoreabstract,somecosmicspiritoforderandharmony,asEinsteindid.Youarecertainlyfreetothinkthatway,butthenIdon'
tknowwhyyouusewordslike'
designer'
or'
God,'
exceptperhapsasaformofprotectivecoloration.
Itusedtobeobviousthattheworldwasdesignedbysomesortofintelligence.Whatelsecouldaccountforfireandrainandlightningandearthquakes?
Aboveall,thewonderfulabilitiesoflivingthingsseemedtopointtoacreatorwhohadaspecialinterestinlife.Todayweunderstandmostofthesethingsintermsofphysicalforcesactingunderimpersonallaws.Wedon'
tyetknowthemostfundamentallaws,andwecan'
tworkoutalltheconsequencesofthelawswedoknow.Thehumanmindremainsextraordinarilydifficulttounderstand,butsoistheweather.Wecan'
tpredictwhetheritwillrainonemonthfromtoday,butwedoknowtherulesthatgoverntherain,eventhoughwecan'
talwayscalculatetheirconsequences.Iseenothingaboutthehumanmindanymorethanabouttheweatherthatstandsoutasbeyondthehopeofunderstandingasaconsequenceofimpersonallawsactingoverbillionsofyears.
Theredonotseemtobeanyexceptionstothisnaturalorder,anymiracles.Ihavetheimpressionthatthesedaysmosttheologiansareembarrassedbytalkofmiracles,butthegreatmonotheisticfaithsarefoundedonmiraclestoriesâ
€”theburningbush,theemptytomb,anangeldictatingtheKorantoMohammedâ
€”andsomeofthesefaithsteachthatmiraclescontinueatthepresentday.Theevidenceforallthesemiraclesseemstometobeconsiderablyweakerthantheevidenceforcoldfusion,andIdon'
tbelieveincoldfusion.Aboveall,todayweunderstandthatevenhumanbeingsaretheresultofnaturalselectionactingovermillionsofyearsofbreedingandeating.
I'
dguessthatifweweretoseethehandofthedesigneranywhere,itwouldbeinthefundamentalprinciples,thefinallawsofnature,thebookofrulesthatgovernallnaturalphenomena.Wedon'
tknowthefinallawsyet,butasfaraswehavebeenabletosee,theyareutterlyimpersonalandquitewithoutanyspecialroleforlife.Thereisnolifeforce.AsRichardFeynmanhassaid,whenyoulookattheuniverseandunderstanditslaws,'
thetheorythatitisallarrangedasastageforGodtowatchman'
sstruggleforgoodandevilseemsinadequate.'
True,whenquantummechanicswasnew,somephysiciststhoughtthatitputhumansbackintothepicture,becausetheprinciplesofquantummechanicstellushowtocalculatetheprobabilitiesofvariousresultsthatmightbefoundbyahumanobserver.But,startingwiththeworkofHughEverettfortyyearsago,thetendencyofphysicistswhothinkdeeplyaboutthesethingshasbeentoreformulatequantummechanicsinanentirelyobjectiveway,withobserverstreatedjustlikeeverythingelse.Idon'
tknowifthisprogramhasbeencompletelysuccessfulyet,butIthinkitwillbe.
Ihavetoadmitthat,evenwhenphysicistswillhavegoneasfarastheycango,whenwehaveafinaltheory,wewillnothaveacompletelysatisfyingpictureoftheworld,becausewewillstillbeleftwiththequestion'
why?
'
Whythistheory,ratherthansomeothertheory?
Forexample,whyistheworlddescribedbyquantummechanics?
Quantummechanicsistheonepartofourpresentphysicsthatislikelytosurviveintactinanyfuturetheory,butthereisnothinglogicallyinevitableaboutquantummechanics;
IcanimagineauniversegovernedbyNewtonianmechanicsinstead.Sothereseemstobeanirreduciblemysterythatsciencewillnoteliminate.
Butreligioustheoriesofdesignhavethesameproblem.EitheryoumeansomethingdefinitebyaGod,adesigner,oryoudon'
t.Ifyoudon'
t,thenwhatarewetalkingabout?
Ifyoudomeansomethingdefiniteby'
God'
design,'
ifforinstanceyoubelieveinaGodwhoisjealous,orloving,orintelligent,orwhimsical,thenyoustillmustconfrontthequestion'
AreligionmayassertthattheuniverseisgovernedbythatsortofGod,ratherthansomeothersortofGod,anditmayofferevidenceforthisbelief,butitcannotexplainwhythisshouldbeso.
Inthisrespect,itseemstomethatphysicsisinabetterpositiontogiveusapartlysatisfyingexplanationoftheworldthanreligioncaneverbe,becausealthoughphysicistswon'
tbeabletoexplainwhythelawsofnaturearewhattheyareandnotsomethingcompletelydifferent,atleastwemaybeabletoexplainwhytheyarenotslightlydifferent.Forinstance,noonehasbeenabletothinkofalogicallyconsistentalternativetoquantummechanicsthatisonlyslightlydifferent.Onceyoustarttryingtomakesmallchangesinquantummechanics,yougetintotheorieswithnegativeprobabilitiesorotherlogicalabsurdities.Whenyoucombinequantummechanicswithrelativityyouincreaseitslogicalfragility.Youfindthatunlessyouarrangethetheoryinjusttherightwayyougetnonsense,likeeffectsprecedingcauses,orinfiniteprobabilities.Religioustheories,ontheotherhand,seemtobeinfinitelyflexible,withnothingtopreventtheinventionofdeitiesofanyconceivablesort.
Now,itdoesn'
tsettlethematterformetosaythatwecannotseethehandofadesignerinwhatweknowaboutthefundamentalprinciplesofscience.Itmightbethat,althoughtheseprinciplesdonotreferexplicitlytolife,muchlesshumanlife,theyareneverthelesscraftilydesignedtobringitabout.
Somephysicistshavearguedthatcertainconstantsofnaturehavevaluesthatseemtohavebeenmysteriouslyfine-tunedtojustthevaluesthatallowforthepossibilityoflife,inawaythatcouldonlybeexplainedbytheinterventionofadesignerwithsomespecialconcernforlife.Iamnotimpressedwiththesesupposedinstancesoffine-tuning.Forinstance,oneofthemostfrequentlyquotedexamplesoffine-tuninghastodowithapropertyofthenucleusofthecarbonatom.Thematterleftoverfromthefirstfewminutesoftheuniversewasalmostentirelyhydrogenandhelium,withvirtuallynoneoftheheavierelementslikecarbon,nitrogen,andoxygenthatseemtobenecessaryforlife.Theheavyelementsthatwefindonearthwerebuiltuphundredsofmillionsofyearslaterinafirstgenerationofstars,andthenspewedoutintotheinterstellargasoutofwhichoursolarsystemeventuallyformed.
Thefirststepinthesequenceofnuclearreactionsthatcreatedtheheavyelementsinearlystarsisusuallytheformationofacarbonnucleusoutofthreeheliumnuclei.Thereisanegligiblechanceofproducingacarbonnucleusinitsnormalstate(thestateoflowestenergy)incollisionsofthreeheliumnuclei,butitwouldbepossibletoproduceappreciableamountsofcarboninstarsifthecarbonnucleuscouldexistinaradioactivestatewithanenergyroughly7millionelectronvolts(MeV)abovetheenergyofthenormalstate,matchingtheenergyofthreeheliumnuclei,but(forreasonsI'
llcometopresently)notmorethan7.7MeVabovethenormalstate.
Thisradioactivestateofacarbonnucleuscouldbeeasilyformedinstarsfromthreeheliumnuclei.Afterthat,therewouldbenoprobleminproducingordinarycarbon;
thecarbonnucleusinitsradioactivestatewouldspontaneouslyemitlightandturnintocarboninitsnormalnonradioactivestate,thestatefoundonearth.Thecriticalpointinproducingcarbonistheexistenceofaradioactivestatethatcanbeproducedincollisionsofthreeheliumnuclei.
Infact,thecarbonnucleusisknownexperimentallytohavejustsucharadioactivestate,withanenergy7.65MeVabovethenormalstate.Atfirstsightthismayseemlikeaprettyclosecall;
theenergyofthisradioactivestateofcarbonmissesbeingtoohightoallowtheformationofcarbon(andhenceofus)byonly0.05MeV,whichislessthanonepercentof7.65MeV.Itmayappearthattheconstantsofnatureonwhichthepropertiesofallnucleidependhavebeencarefullyfine-tunedtomakelifepossible.
Lookedatmoreclosely,thefine-tuningoftheconstantsofnatureheredoesnotseemsofine.Wehavetoconsiderthereasonwhytheformationofcarboninstarsrequirestheexistenceofaradioactivestateofcarbonwithanenergynotmorethan7.7MeVabovetheenergyofthenormalstate.Thereasonisthatthecarbonnucleiinthisstateareactuallyformedinatwo-stepprocess:
first,twoheliumnucleicombinetoformtheunstablenucleusofaberylliumisotope,beryllium8,whichoccasionally,beforeitfallsapart,capturesanotherheliumnucleus,formingacarbonnucleusinitsradioactivestate,whichthendecaysintonormalcarbon.Thetotalenergyoftheberyllium8nucleusandaheli
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