As a practical matter, "sustainable" development may be an oxymoron. Requests for pragmatic definition or functional examples most often are met with thunderous silence. However, the ideal generally assumes a socio-economic and ecological system in balance: inputs matching outputs. Negative feedback mechanisms are both implicit and explicit. It may be negentropic. The system elements are economic, social and ecological. Each needs definition in ways which clarify assumptions and deal with intended as well as unintended consequences of application.
Basis of economics:
Resource conversion, in which "resource" and "conversion" need clarification.
General Economic formula:
"(Sustainable) conversion of local resources by local people first for local use in such ways as to create economic surplus available for local reinvestment."
Definitions needed for:
"Sustainable" within the context applied (which assumes description of the context);
"Conversion": describes the processes involved from raw material to finished good;
"Local" deals with community and locality;
"People" deals with community members, all sentience involved;
"Priority of local use" deals with tangible rewards and intimate relationships with the compound and complex outputs of work ;
"Ways" involve such matters as meaningful work in the definition of the workers at all levels of enterprise and relationship to enterprise as well as the physical processes;
"Surplus" Outcome of a system registering an excess of revenue, broadly defined, over expense also broadly defined;
"reinvestment" deals with the creation of sustainabilty built into the overall system.
Reinvestment operates as negative feedback. May be thought of as a possibly negentropic product.