第24章 《佃農理論》英語原著 (18)

Whenthecultivatorhastogivetohislandlordhalfofthereturnstoeachdoseofcapitalandlaborthatheappliestotheland,itwillnotbetohisinteresttoapplyanydosesthetotalreturntowhichislessthantwiceenoughtorewardhim.If,then,heisfreetocultivateashechooses,hewillcultivatefarlessintensivelythanontheEnglishplan[fixedrent]；hewillapplyonlysomuchcapitalandlaboraswillgivehimreturnsmorethantwiceenoughtorepayhimself:sothathislandlordwillgetasmallershareevenofthosereturnsthanhewouldhaveontheplanofafixedpayment.[4]

WhatisimportanthereisthatMarshallsawthataccordingtothisanalysisthesharetenantwillbegettingaresidualreturnandthelandlordwillbegettingasmallerrentalinethanunderfixedrent.WhatisstrangeisthatMarshalldidnotquestionwhythelandlorddoesnotchooseinsteadafixedrentcontractorsellinghislandownershiptothetenantoutright.[5]AndwhatisnaturalisthatMarshallwasreluctanttoletthetenant'sresidualearningremainunexplained:

Ifthetenanthasnofixityoftenure,thelandlordcandeliberatelyandfreelyarrangetheamountofcapitalandlaborsuppliedbythetenantandtheamountofcapitalsuppliedbyhimselftosuittheexigenciesofeachspecialcase.[6]

Marshall'sviewwasthatthemetayertenant"haspracticalfixityoftenure,"[7]andhereferredtoanarticlebyHenryHiggs.[8]Higgsnotedthattherentalsharesdodiffer,andthat"rigidasmetayermayatfirstsightseemtobe,itissusceptibleofconsiderableelasticity."[9]Henonethelesssharedthe"custom"ideawithSismondiandMill.HiggsbasedhisjudgmentonanempiricalsurveyhehadconductedinFrance,whichunfortunatelyinvolvedasampleofonlyasinglefarm.[10]Itisthenotionof"fixityoftenure,"perhaps,thatledMarshalltomentionthepossibilityofadjustmentsonlyinafootnote:

Ifthelandlordcontrolstheamount[ofcapital]freelyandinhisowninterest,andcanbargainwithhistenantastotheamountoflaborheapplies,itcanbeprovedgeometricallythathewillsoadjustitastoforcethetenanttocultivatethelandjustasintensivelyashewouldundertheEnglishtenure[fixedrent]；andhissharewillthenbethesameasunderit.[11]

Marshallprovidednogeometricproof,anditisaninterestingconjecturewhetherhewouldhavealteredthisfootnotehadhedoneso.Thisconjectureisinterestingbecausetheresultsheconceivedarecorrectonlyincertainspecialcases,butasamatterofgeneralitytheyareincorrect.TheyareincorrectbecauseMarshalldidnotallowtherentalpercentagetovary.[12]Letmeexplain.FollowingMarshall,supposethehorizontalaxisoffigure4measuresnotonlylaborbutnonlandinputsingeneral（andassumeawaytheassociatedsubstitutionproblem）.Supposealsotheinitialamountofnonlandinputsisattx.Givenacertain（notany）rentalpercentage,andgiventhatthelandlordhasbeenprovidingasufficientlylargeamountofnonland"capital"input,thenhemayadjustthenonlandinputsprovidedbyeithercontractingpartysothat（a）therentalineundersharerentisthesameasunderfixedrentand（b）thetenant'sresidualearningisexhausted-withoutvaryingthegivenrentalpercentage.Assuch,Marshalliscorrect.Butsupposethatthetenantistopro-videallthenonlandinputs,orthatthelandlordhasbeenprovid-ingapartofthenonlandinputsbuttheamountistoosmall;then,exceptbyaccident,therentalpercentagemustbevaried（inadditiontoadjustingnonlandinputsoverland）toobtaintheresultsMarshallvisualized.Toviewtheproblemfromanotherangle:giventheratioofnonlandinputstolandthatisconsistentwithwealthmaximization,andgiventhattherelativesharesofnonlandinputscontributedbythecontractingpartiesarestipulated,thereexistsoneandonlyonerentalpercentagewhichisconsistentwithequilibrium.[13]Thisdifficultparagraphwillbeeclearerwhenweetothenextsection.

ItshouldbenotedthatMarshall,likeSmith,Jones,andMillbeforehim,attemptedto"rank"variouslandtenurearrangementsaccordingtosomenotionofeconomicefficiency.[14]Theydidnottackletheissuebyidentifyingaspecificsetofpropertyrightconstraintssubjecttowhichseveralformsoflandtenurearrangementsmayimplythesameresourceuse.Intheirdiscussionsofsharetenancy,thefreelyalienablerightsimplicitintheiranalysessuggestthattheconstraintofprivatepropertyrightswasassumed.[15]ButwhereasSmithandJonesviewedasharelease,thoughwasteful,astransitional.MillandMarshalllaidtheblameon"custom."Smith'spredictionthatfixedrentswouldreplacesharerentshadfailedtoetrue;and,asnotedearlier,thetermsofasharecontractmightyieldtheimpressionofbeingcustomarilyfixed.

Amongcontemporarywriterswhoperformedsimilar"rank-ings"andalsoreliedonthenotionof"custom"areRainerSchic-kele[16]andEarlO.Heady.[17]SchickeleandHeadyfurtheredthetaxapproachintheiranalysesofasharelease,butinawaysomewhatdifferentfromMarshall.Usingadiagramidenticaltofigure4,theyconcludedthatequilibriumisatpoints,wherethemarginaltenantcostequalsthemarginaltenantreceipt;thatis,

=

（1-r）.Theamountoftenantinputmittedwillbet1.AccordingtoSchickele,iftenantinputisincreasedfromt1tot2,thenareaABCrepresentsa"present"fromthetenanttothelandowner[18]—sincetheaddedtenantreceipt（areat1ACt2）islessthantheaddedtenantcost（areat1ABt2）bythisamount.Schickeledidnot,however,proceedwiththeparadox:iftenantinputisatt1,thenareaMEA（tenant'sresidualearning）representsa"present"fromthelandownertothetenant.Itfollowsfromthislineofreasoningthatiftenantinputissomewherebetweent1andt2,bothpartieswillbeoffering"presents"toeachother!