搜索
1CHAPTER2THEPOSTULATESOFTHECLASSICALECONOMICS第二章古典经济学的假定条件MOSTtreatisesonthetheoryofValueandProductionareprimarilyconcernedwiththedistributionofagivenvolumeofemployedresourcesbetweendifferentusesandwiththeconditionswhich,assumingtheemploymentofthisquantityofresources,determinetheirrelativerewardsandtherelativevaluesoftheirproducts1.大多数关于价值论和生产论的著述均主要既关注既定量的已用资源在不同用途之间如何配置，也关注在使用这一既定量资源的前提下，各种资源的相对报酬及其产品的相对价值如何决定2。Thequestion,also,ofthevolumeoftheavailableresources,inthesenseofthesizeoftheemployablepopulation,theextentofnaturalwealthandtheaccumulatedcapitalequipment,hasoftenbeentreateddescriptively.Butthepuretheoryofwhatdeterminestheactualemploymentoftheavailableresourceshasseldombeenexaminedingreatdetail.Tosaythatithasnotbeenexaminedatallwould,ofcourse,beabsurd.Foreverydiscussionconcerningfluctuationsofemployment,ofwhichtherehavebeenmany,hasbeenconcernedwithit.Imean,notthatthetopichasbeenoverlooked,butthatthefundamentaltheoryunderlyingithas1ThisisintheRicardiantradition.ForRicardoexpresslyrepudiatedanyinterestintheamountofthenationaldividend,asdistinctfromitsdistribution.Inthishewasassessingcorrectlythecharacterofhisowntheory.Buthissuccessors,lessclear-sighted,haveusedtheclassicaltheoryindiscussionsconcerningthecausesofwealth.VideRicardo'slettertoMalthusofOctober9,1820:PoliticalEconomyyouthinkisanenquiryintothenatureandcausesofwealth--Ithinkitshouldbecalledanenquiryintothelawswhichdeterminethedivisionoftheproduceofindustryamongsttheclasseswhoconcurinitsformation.Nolawcanbelaiddownrespectingquantity,butatolerablycorrectonecanbelaiddownrespectingproportions.EverydayIammoresatisfiedthattheformerenquiryisvainanddelusive,andthelatteronlythetrueobjectsofthescience.2这符合李嘉图的传统。因为李嘉图明确表示对国民收入的总量不感兴趣，他关注的是国民收入的分配。在更关注分配这一点上，李嘉图正确地评价了其理论的特色之处。他的后继者，由于眼光不够清晰，却将古典理论运用于对财富来源问题的讨论。李嘉图于1820年10月9日致马尔萨斯的信中写道：“你认为政治经济学是对财富性质和来源的探究—而我认为它应该探究社会各阶层依据何种法则分配他们共同生产的社会产品。关于国民收入的总量并无法则可言，但关于国民收入的分配比例还是存在一个大致正确的法则。我每一天都更确信前者的探究是徒然和虚妄的，而后者才是科学研究的真正目标所在。”2beendeemedsosimpleandobviousthatithasreceived,atthemost,abaremention1.同样，对于可用资源数量的问题，例如可就业人口的规模，自然财富的丰瘠以及累积的资本设备的多寡，一向采用描述的方法予以处理。但是，关于何种力量决定可用资源实际使用数量的纯理论在很多细节上并未得到检验。当然，要说这种理论全然未得到检验未免荒谬，因为讨论资源使用量的波动的论述为数甚多，而每种论述都涉及到前述纯理论。我并不是说这个主题被忽视了，而是要指出这一主题所依托的基本理论一向被认为如此简单和明显，以致最多只需稍作提及2。ITheclassicaltheoryofemployment—supposedlysimpleandobvious--hasbeenbased,Ithink,ontwofundamentalpostulates,thoughpracticallywithoutdiscussionnamely:我认为，尽管实际上并未加以讨论，但被视作简单和明了的古典就业理论奠基于两个基本假定之上，即：I.Thewageisequaltothemarginalproductoflabour.Ⅰ.工资等于劳动的边际产品1Forexample,Prof.PigouintheEconomicsofWelfare(4thed.p.127)writes(myitalics):Throughoutthisdiscussion,exceptwhenthecontraryisexpresslystated,thefactthatsomeresourcesaregenerallyunemployedagainstthewilloftheownersisignored.Thisdoesnotaffectthesubstanceoftheargument,whileitsimplifiesitsexposition.Thu-,whilstRicardoexpresslydisclaimedanyattempttodealwiththeamountofthenationaldividendasawhole,Prof.Pigou.,inabookwhichisspecificallydirectedtotheproblemofthenationaldividend,maintainsthatthesametheoryholdsgoodwhenthereissomeinvoluntaryunemploymentasinthecaseoffullemployment.2例如，庇古教授在《福利经济学》（第四版，第127页）中写道（着重号是我加的）：“在整个讨论中，除了明确指出的例外情形，我们忽略通常存在的某些资源愿意但并未得到使用的事实。这非但不影响论证的实质，反而可以简化对论点的阐释。”两相对照，李嘉图总是明确放弃将国民所得总量作为一个整体予以研究的任何企图，而庇古教授在一本研究国民所得问题的专著中主张同一理论既适用于存在某些非自愿失业的情形，也适用于充分就业的情形。3Thatistosay,thewageofanemployedpersonisequaltothevaluewhichwouldbelostifemploymentweretobereducedbyoneunit(afterdeductinganyothercostswhichthisreductionofoutputwouldavoid);subject,however,tothequalificationthattheequalitymaybedisturbed,inaccordancewithcertainprinciples,ifcompetitionandmarketsareimperfect.这就是说，一位就业人员的工资等于就业量减少一单位所损失的产值（在扣除由于产出下降而减少的其他成本之后）；然而，如果竞争和市场表现出不完全性，依据有关原理，二者相等所必须服从的限制条件便不再得到满足。II.Theutilityofthewagewhenagivenvolumeoflabourisemployedisequaltothemarginaldisutilityofthatamountofemployment.Ⅱ.对于给定的就业人数，工资的效用等于该就业量的边际负效用。Thatistosay,therealwageofanemployedpersonisthatwhichisjustsufficient(intheestimationoftheemployedpersonsthemselves)toinducethevolumeoflabouractuallyemployedtobeforthcoming;subjecttothequalificationthattheequalityforeachindividualunitoflabourmaybedisturbedbycombinationbetweenemployableunitsanalogoustotheimperfectionsofcompetitionwhichqualifythefirstpostulate.Disutilitymustbehereunderstoodtocovereverykindofreasonwhichmightleadaman,orabodyofmen,towithholdtheirlabourratherthanacceptawagewhichhadtothemautilitybelowacertainminimum.这就是说，每一位就业者的实际工资（根据就业人员自己的估计）正好足以吸引实际被雇佣的劳动力继续维持原有就业量，类似于竞争的不完全性会破坏第一个假定所遵循的限制条件，第二个假定所要求的单个劳动者地位对等的限制条件会由于劳动者结成工会而不再被满足。负效用的理解应该涵盖各种原因，它们可能导致一个人或一群人宁愿失业也不愿意接受对他们来说其效用低于某一最低限度的工资。Thispostulateiscompatiblewithwhatmaybecalledfrictionalunemployment.Forarealisticinterpretationofitlegitimatelyallowsforvariousinexactnessesofadjustmentwhichstandinthewayofcontinuousfullemployment:forexample,unemploymentduetoatemporarywantofbalancebetweentherelativequantitiesofspecialisedresourcesasaresultofmiscalculationorintermittentdemand;ortotime-lagsconsequentonunforeseenchanges;ortothefactthatthechange-overfrom4oneemploymenttoanothercannotbeeffectedwithoutacertainde