Allen, Tainter, and Hoekstra (2003) assert that, “the biophysical aspects of sustainability are central. Without a material system capable of functioning for a long time, there is nothing to sustain” (p.29). This is, of course, the literal and pragmatic conceptualization of “sustainability” that is most often associated with environmental sustainability. It addresses whether actions taken by humanity are degrading the Earth’s carrying capacity to the point where the planet will no longer be able to sustain its biodiversity. The broader and, arguably, more existential (yet just as vital) aspects to sustainability, however, lie in the less quantifiable dimensions of humanity’s capacity for embodying what sustainability at all levels, ideally, should be – namely, relationships that emulate balance, equity, justice, health, and connectivity for all constituents. When “sustainability” is framed/defined primarily within the context of the other-than-human environment, our subsequent understanding of it is reified as not pertaining to human relationships, as well. Such reification is hardly value-neutral, either. As Sprague (1993) notes, “[much of Habermas’] work is directed toward exposing the way language constitutes, sustains, and often conceals various social arrangements…[and] Habermas rejects any notion of language as a transparent code that merely transmits meanings” (p.5). Thus, by our omission of sociological dimensions and human relationships in the definition of sustainability, we divert our focus from a more holistic understanding or potential actualization.
Unquestionably, human civilization has survived for centuries, while perpetrating horrific acts of injustice and violence against itself, and it could probably survive (maybe even for a few more centuries), while still enacting the oppression, hegemony, and exploitation that currently exist. My argument, however, is that these ways of being are inherently unsustainable because they allow us to be the least of ourselves, the basest, most unethical, and least critically conscious pieces of what humanity is capable. Further, I believe the longer we allow ourselves to excuse the exploitation and degradation of any living being, and continue pardoning Lord of the Flies’ (Golding, 1999) communication and behavior within our human relations, the more our capacities for apathy and callousness will drive destructive and unsustainable actions toward all beings. These behaviors and belief systems are a regression in evolutionary consciousness, rather than a progression, and as Lincoln proclaimed in his first inaugural address, we must strive to realize “the better angels of our nature” (1861, ¶.28). I assert the need for humanity’s embracing, understanding, and honoring the interconnectivity of all living systems. We must recognize that the ways in which we communicate (and each of our correlative actions) have endless repercussions. Thus, my definition of sustainability is multi-dimensional (integrative, ethical, active), as it is only with an inclusive perspective that humanity’s consciousness, communication, and actions at any level will begin to be transformed.
Allen, T.F.H., Tainter, J.A., & Hoekstra, T.W. (2003). Supply-Side Sustainability. New York: Columbia University.
Golding, W. (1999). The Lord of the Flies. New York: Penguin. (orig. pub. 1954 by Faber & Faber)
Lincoln, A. (1861). First inaugural address. Retrieved December 1, 2009 from http://www.bartleby.com/268/9/25.html 
Sprague, J. (1993). Habermas on pedagogy: Guidelines for the ideal speech classroom. Paper presented at the annual convention of Western States Communication Association. Albuquerque, NM.