Is sustainability a viable concept for planning?

Sustainability needs to be considered to be dynamic and evolving, a verb and not a noun. The systems which need to be considered must be understood within a time frame which needs a metric much larger than the current “inter‐generational” ruler and one which takes into consideration that, as a species, humans, both biophysically and socio‐culturally, may not be in their optimum, or final, evolutionary manifestation. Sustainability provides the resilience which allows learning through mistakes and evolving visions not tied to a past that never was and a future that never will be. By renorming the time frame, and the concept of history, sustainability mandates that human intelligence not abdicate its responsibilities by attempting to defer to a static, mythic, external force. What is important in a world where a clock “ticks” once a century, or where a diorama in the museum of the future has, as its only artefacts of the 20th century, a suit of chain mail and a can of Diet Coke?