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1.2.Paretoturn-economicsandpsychology
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Theprimarypurposeofrevealedpreferenceswastoremoveoperationalterms
fromeconomictheory(Hands,2014).Weneedtohaveobservableandmeasurable
datatobuildatheory.Itisimpossibletoobservepreferences.Thus,wecanonly
lookattheactofchoice,andonthisassumptionSamuelsonbasedhistheory.
Thebasicideaofrevealedpreferenceisasfollows.Ifonechoosesoptionx
insteadofoptiony,thenoptionxisrevealedtobepreferredtooptiony.Choices
areconsistentiftheysatisfythelweakaxiomofrevealedpreference’(WARP),
whichmeansthat,ifxisrevealedtobepreferredtoy,thenymustnotberevealed
tobepreferredtox.Ifchoicessatisfytheconsistencyconditions,thenwecan
constructacomplete,transitiveandcontinuousrevealed-preferenceordering
fromthem(Sen,1971,1973).
Fromtheperspectiveofthisbook,themostcrucialfeatureofrevealedpreferences
theoryistheperceptionofrationality.Inthistheoryagentsarerationalwhen
theyactbytheweakaxiomofrevealedpreferences(WARP).Therefore,
rationalityistreatedinstrumentally,becauseeconomistsdonotknowanddo
notwanttoknowaboutthemotivationsofpeople.Neoclassicaleconomistsare
onlyinterestedintheresultsbutnotinthecausesofbehaviour.Theeconomists
stoppedbeinginterestedinhumanmotivesandtheyassumedapriorithat
peoplearealwaysrationalandthattheyalwaysmaximizetheirutility.However,
itisessentialtounderstandthatutilityhereisentirelydifferentfromBentham’s
utilityandutilityusedbymarginalists.Nowadays,wheneconomistssaythat
individualsmaximizeutility,theyareonlysayingthatpeopledonotrankany
feasibleoptionabovetheoptiontheychoose.Sometimeseconomistsspeak
aboutindividualswhoareaimingtomaximizeutilityorseekingmoreutility.
However,itdoesnotmeanthatutilityisanobjectofchoiceoritisperceivedas
anultimately(orabsolutely)goodthing.Utilityisonlyanindexofpreferences.
Utilitymaximizeronlydoeswhatsheprefers.Tosaythatagentsmaximize
theirutilitysaynothingaboutthenatureoftheirpreferences.Theonlything
itdoesistoconnectpreferenceandchoice.Rationalindividualsrankavailable
alternativesandchoosewhattheypreferthemost(Hausman,1992,p.18).
Intheend,however,itmustbestatedthatSamuelsonhasnotachievedwhathe
wanted.In1938hetriedtobaseconsumerchoicetheoryonstrictlyobservable
foundationswhichwoulddifferentiatehistheoryfrombothcardinalandordinal
approaches.Inthepaperfrom1938,hedidnotintroducethetermlrevealed
preferences’(Samuelson,1938).Hestartedtousethistermin1948(Samuelson,
1948).Thischangeisimportant,becauseifwell-orderedpreferencesexist,then
theycanberepresentedbyanordinalutilityfunction.Itmeansthatutilityis
stillintheinterestofeconomics(Hands,2009).In1938Samuelsonperceived
revealedpreferencetheoryasanalternativetoutilitytheory.In1950,however,
itwasobviousthatthistheorywasnothingdifferentfromtheordinalapproach
AsWong(2006,pp.73,74)summeditup:
