第24章

AlthoughMill’sworkuponpurepoliticaleconomy，liesmainlybeyondmyprovince，itillustratesoneimportantpoint。Millspeaksasoneexpoundinganestablishedsystem。Thespeedwithwhichthebookwaswrittenshowsthatitdidnotimplyanyrevisionoffirstprinciples。MillisworkingingeneraluponRicardo’slines，inwhose’immortalPrinciples，’forexample，hefindsthefirstphilosophicalaccountofinternationaltrade。(2*)

Heassumestooeasilythatameremodificationofolddoctrinesisneeded，wherelaterwritershavedemandedathoroughgoingreconstruction。Hehasincurredsomeridicule，forexample，byanutterancecharacteristicofhisposition。Hesays，(3*)that’thereisnothinginthelawsofValuewhichremainsforthepresentoranyfuturewritertoclearup；thetheoryofthesubjectiscomplete。’Thephrasewasrash。Apparentlyunassailabletheorieshaveanuncomfortabletrickofsuddenlyexploding。Latereconomistsoftentakethisforacaseinpoint。

Theyhave，theythink，madeaspeciallysuccessfulbreachinthispartofMill’sdoctrine，andhisconfidencewassingularlyinfelicitous。Mill’slucklessboastwassuggestedbyhisrectificationofanambiguityintheterminologyofthescience。

How，heasked，couldtherebea’proportion’betweentwodisparatethings，a’quantity’(supply)anda’desire’

(demand)？(4*)Heproceedstoremovetheambiguitybyanaccountofthe’equation’betweendemandandsupply，explainingtheprocessbywhichvaluesadjustthemselvessothatthequantitysuppliedatthecurrentpricewillbeequaltothequantitydemandedatthatprice。Itakeitthathisaccountofthefactsissubstantiallycorrect，andthat，byremovingcertaininconsistenciesoflanguage，hehadpurifiedthetheoryfromoneatoffallacies。Buthehimselfseemstoregardtheimprovementasmerelyoneofterminology。Hethinksthathispredecessorsmeanttostatethesamefacts，and，indeed，thattheymusthaveseenthetruth，thoughhecouldnotfindinthemanexpressstatement。WemayaskwhetherlaterimprovementsofMillhimselfamounttoasubstantialchangeinthetheory，ormerelytoabettermodeofexpression。Idonotdoubtthatmoderneconomistshavemuchimprovedthelanguageinwhichthetheoryisexpressed。

Nor，again，canitbedoubtedthatthelogicisrectifiedbyrectifyingthelanguage。Theonlyquestioncanbeastotheimportanceoftheimprovement。Whatstrikesthescepticisthat，afterall，whenweapproachanypracticalapplicationofthetheory，theoldandthenewtheoristsseemtobeguidedbyprettymuchthesamereasoning。Theimprovementineleganceandconsistencyofthelanguagedoesnotbringwithitacorrespondingimprovementinthetreatmentofactualproblems。

Theobviousreasonisthatpoliticaleconomyhasnotreached，ifiteverwillreach，thestageatwhichtheapplicationofarefinedlogicalmethodispossibleorfruitful。Thepowerofusingdelicatescientificinstrumentspresupposesapreliminaryprocess。Wemusthavesettleddistinctlywhatarethedatatobeobservedandmeasured；andtheuseofmathematicalformulaeisprematureandillusorytillweknowpreciselywhatwehavetocountandhowtocountit。Thedataandthepsychologicalassumptionsofeconomistsarestillfartoovagueanddisputabletoadmitofsuchmethods，exceptbywayofillustration。

Meanwhileroughandeveninaccuratestatementsmaybeadequatetoconveytheknowledgewhichwecanreallyapply。Wearereallymakinguseoffactsadmittedonallhands，andknownwithsufficientaccuracy，thoughtheprinciplesuponwhichtheydependhavenotbeenclearlydefined。

II。CONTEMPORARYMOVEMENTS

ToappreciateMill’sposition，itisnecessarybrieflytonoticetheprejudiceswhichhehadtoencounterandthesympathiesuponwhichhecouldreckon。PoliticaleconomyhadbeenexultantinthedaysofJamesMill。Heandhisallieswereenteringthepromisedland。TheytookthesciencetobeinthesamestageasastronomyjustafterthepublicationofNewton’sPrincipia。Themaintruthswereestablished，thoughprejudiceandsentimentstillblindedtheoutsideworldtotheclearestd