normativegoalofsustainabilityeconomicsoralternativelysomeotherlegitimate societal goal. As there may be trade-offs and opportunitycosts in basically these three ways,“efficiency”means that no scarceresources should be wasted in these respects. While economics hasdeveloped a clear, differentiated and operational idea of how tomeasure efficiency with respect to the satisfaction of the needs andwants of many individuals, it remains to be clarified what“waste”or“non-wasteful”means with respect to the achievement of justic