In this chapter we track the influence of the dominant neoclassical economic model’s mindset and ontological framework, which actively steers focus away from institutional transformation towards strong sustainability. The wide penetration of the neoclassical way of thought in environmental debates and public policy in general ‘naturalises’ its primary assumption, disabling capacities to see alternatives to it. We tackle to central ontological assumptions and challenges of neoclassical economics: the conceptions of ‘scarcity’ and ‘market subjects’. We argue that the economic ontology of strong sustainability should take as starting points an emphasis on the given material condition (as opposed to given preferences), including recognition of limits rather than leaning on the notion of scarcity. This has direct connections to the need to open the category of preferences for normative scrutiny. Optimisation of material use relative to any preferences does not suffice. Rather, limited resources should be used to meet real needs and aim at the creation of use value rather than exchange value, and to focus on the organisation of social life to support common use of goods. This will steer the metatheory away from the incentive systems to a repolitisation of the environmental debate.