This note is a part of my Zettelkasten. What is below might not be complete or accurate. It
is also likely to change often.
A system is Sustainable if it doesn't decline with time and change. But truly, no complex system can resist change and so when we say a system is sustainable, we mean that it changes so gradually in response to the environment that it is not apparent to the observer in real-time. Somewhat of a Ship of thesues scenario.
Culture is one such system, it adds more and more nuances and layers to the system which makes it more and more resilient as it ages. Every cultural change might not be adding to the resilience but due to Natural Selection, changes which boost the survivability and prosperity of a particular group will, over time, make that cultural change more prevalent. Things like Costly Signalling are retained because of this phenomenon and many cultural ideas degrade and are lost over time naturally. Its important to keep in mind that Old will likely outlast new in this regard.
As you zoom out and see more dimensions, the bigger system which contains a lot of smaller, more homogenous systems is more resilient than the ones it contains, put together (I cant prove this mathematically. It feels correct though). This is because diversity creates more possibilities and higher chance of survival through difficult circumstances.
This is not, of course, valid for biological entities. This is more relevant to non-perishable things like ideas, music, technology and systems.
If a book has been in print for forty years, I can expect it to be in print for another forty years. But, and that is the main difference, if it survives another decade, then it will be expected to be in print another fifty years. This, simply, as a rule, tells you why things that have been around for a long time are not "aging" like persons, but "aging" in reverse. Every year that passes without extinction doubles the additional life expectancy. This is an indicator of some robustness. The robustness of an item is proportional to its life! -Nassim Taleb
The longer technologies have survived, the longer they are likely to stay alive. This is called the Lindy effect.
An idea or system that has lasted 1000s of years is likely to outlast an idea that has just sprung up. This is something to think about when considering what is Sustainable and what is not. Something that is old is more likely to be sustainable than something that is new.
This phenomenon is beyond value judgement. Social norms like caste-based discrimination are slow to change and so is adoption of toilets.
Think of a normal curve. We are most likely to be in the middle of the lifecycle of an an idea than its beginning or the end.
Human society has existed for more than 60000 years or longer. In that time, it has evolved continually - discarding and picking up things as times goes on. It has grown and split, grown and split and grown-split again many times to form super diverse, small, somewhat homogenous groups.
These small groups were more or less Sustainable, having marginal interactions with other groups.
Since Old will likely outlast new, it is important to keep in mind that we dont know why a particular system has lasted 1000 years. If there is a slice of the system which will suffice to keep the system afloat for more than that. Society is that system and it has many, many slices. Many slices might be, for all you know, irrelevant to the life of the