Modern environmentalism originates with the recognition of ecological connectivity and the negative effects of technological intervention. This paper examines critical concepts developed by the architect Frederick Kiesler and the critic-historian Sigfried Giedion for their relevance to that discourse. Kiesler's principle of Correalism and Giedion's appeal for Equipoise offer both a prehistory to the current mandates about sustainability and cautions about its limitations. The sustainable is ultimately a social condition that cannot be applied therapeutically nor ever wholly institutionalized.