While the definition of sustainability remains open for all to contribute to and participate in, there do seem to be some notions it has come to embody that should not be neglected as the definition coalesces. Among these are the ethical and social dimensions of sustainability. Whether or not it is appropriate, required, or even desirable, concepts like social equity, human rights, ethical sharing of commons, etc. have increasingly come under the umbrella of the sustainability discourse. Even if “sustainability” as a bare word doesn’t imply those things, the concept of sustainable development certainly has taken on those dimensions. That sustainability might be redefined or re-scoped to be a purely environmental or a rigidly scientific endeavor, is not an immediate concern of this paper, though if that were to occur (whether for the sake of simplicity or pragmatics), it should be done explicitly so the ethical sub-discourse can be maintained (indeed, sustained) by some other movement.

This paper proposes a mechanism by which such a migration in terms can be prevented. First, in reviewing the work of Denis Goulet, it shows the solid basis for including an ethical aspect in the sustainability discourse. Second, it points out that Karl-Henrik Robèrt’s highly-lauded and broadly-employed sustainability framework, The Natural Step, is deficient in this area. This deficiency provides the impetus for, finally, proposing a mechanism by which The Natural Step can be extended to include the important social and ethical dimensions of sustainability. This mechanism is based on the capabilities approaches that, in many respects, evolved out of Goulet’s early work. Augmented accordingly, TNS can continue to be used without fear of overlooking the social and ethical aspects of the sustainability discourse.

In his writings over the past decade, Brad Allenby has proposed (at least) 16 principles of sustainable engineering (see references) that are collectively known as the Earth Systems Engineering and Management (ESEM) principles. These principles have merit and applicability in many disciplines and domains of discourse, but are sometimes awkward to use due to the quantity of words required to accurately express their meaning. In light of this, it has become necessary to formulate a simplified list of “abbreviated tags” for ease of reference in conversation and concise writing. This list of tags also makes the principles immediately accessible to those who may want to pursue the more thorough definitions offered by Allenby. The following tags have been proposed for use when a concise phrasing is required. The citation provided after the tag is, in my opinion, the most complete expression of Allenby’s thought on this principle. It can be used when citing the principle in written assignments or publications.