Martins (2011) links the capability approach to the study of ontology and concludes that sustainability economics and the capability approach are complementary. The capability approach, to Martins (2011), “is however an incomplete framework, in the sense that it does not possess a theory of socio-economic processes” (p. 4). The capability approach provides answers to the question of what human well-being is, but does not respond to “substantive issues within economic theory” (Martins, 2011, p. 4).