【Cowboyorspaceman？Adilemmaforachildren'sparty，perhaps．Butalsoaquestionforeconomists，arguedKennethBoulding，aBritisheconomist，inanessaypublishedin1966．Wehaverunoureconomies，hewarned，likecowboysontheopengr】

　　Cowboyorspaceman？Adilemmaforachildren'sparty，perhaps．Butalsoaquestionforeconomists，arguedKennethBoulding，aBritisheconomist，inanessaypublishedin1966．Wehaverunoureconomies，hewarned，likecowboysontheopengrassland：takingandusingtheworld'sresources，confidentthatmoreliesoverthehorizon．ButtheEarthislessagrasslandthanaspaceship-aclosedsystem，aloneinspace，carryinglimitedsupplies．Weneed，saidBoulding，aneconomicsthattakesseriouslytheideaofenvironmentallimits．Inthehalfcenturysincehisessay，anewmovementhasrespondedtohischallenge．"Ecologicaleconomists"，astheycallthemselves，wanttorevolutioniseitsaimsandassumptions．Whatdotheysay-andwilltheirideasachievelift-off？

　　Toitsadvocators，ecologicaleconomicsisneitherecologynoreconomics，butamixofboth．Theirstartingpointistorecognisethatthehumaneconomyispartofthenaturalworld．Ourenvironment，theynote，isbothasourceofresourcesandasinkforwastes．Butitisignoredinconventionaltextbooks，whereneatdiagramstracetheflowsbetweenfirms，householdsandthegovernmentasthoughnaturedidnotexist．Thatisamistake，sayecologicaleconomists．

　　Therearetwowaysoureconomiescangrow，ecologicaleconomistspointout：throughtechnologicalchange，orthroughmoreintensiveuseofresources．Onlytheformer，theysay，isworthhaving．TheyaresuspiciousofGDP，acrudemeasurewhichdoesnottakeaccountofresourceexhaustion，unpaidwork，andcountlessotherfactors．Initsplacetheyadvocatemoreholistic（全面的）approaches，suchastheGenuineProgressIndicator（GPI），acompositeindex（复合指标）thatincludesthingslikethecostofpollution，deforestationandcaraccidents．WhileGDPhaskeptgrowing，globalGPIperpersonpeakedin1978：bydestroyingourenvironmentwearemakingourselvespoorer，notricher．Thesolution，saysHermanDaly，aformerWorldBankeconomistandeco-guru，isa"steady-state"economy，wheretheuseofmaterialsandenergyisheldconstant．

　　Mainstreameconomistsareunimpressed．TheGPI，theypointout，isasubjectivemeasure．AndtalkoflimitstogrowthhashadabadpresssincethedaysofThomasMalthus，agloomy18thcenturyclericwhopredicted，wrongly，thato