This note is a part of my Zettelkasten. What is below might not be complete or accurate. It is also likely to change often.
The definition of Sustainable is "able to continue over a period of time". In other words, for something to be sustainable, it has to be resilient, at least.
Anything which cannot be broken down into smaller things is un-changing, regardless of what goes on in its super-environment. Such a thing cannot be called as sustainable - it cannot change, it simply is.
When we talk about sustainability, we talk about something which has the capacity to change. A complex system, called Sankaara in Buddhist philosophy, is one which is always changing.
Can we assign an objective value to a such a system? Assuming we can, there are types of systems which respond differently to change: