Defining and predicting sustainability

This paper attempts to separate the definition of sustainability (which is argued to be quite straightforward) from related issues concerning: (1) which system, subsystem, or characteristics are to be sustained; (2) for how long they are to be sustained; and (3) when we can assess whether the system has actually been sustained. We argue that because we can only assess sustainability after the fact, it is a prediction problem more than a definition problem. We also propose that in order for evolutionary adaptation to occur, there must be an ordered, hierarchical relationship between the expected (finite) life spans of systems and their space and time scales.