The degree of advancement is whenever a civilization moves above tribal level and establishees a nation.
I said specific, my little denim diddler. That is vague. Precisely the opposite of specific.
It is specific. You can clearly tell when a nation is established.
Well then, you should have no trouble clearly and unambiguously defining it. What specifically is it that qualifies a society as a nation, without which it is merely a tribe?
A tribe is a smaller group, consisting of a community and based on close blood ties. A nation contains multiple communities under a unified government.
Once again, vague. What does "smaller group" even mean? Are we talking population, land area, town/city density, something else entirely or a combination of all of these things? Whichever it is, specifically how small (and I'm talking numbers, not some vague descriptor) defines tribal?
As for blood ties, do I even have to say it? Remind us all, why exactly is your True Heir the True Heir in the first place? It's certainly not merit.
Finally, feudalism is about as far from a unified government as you can possibly get. It's a constantly shifting web of loose hierarchic alliances between ruling clans. If that's what qualifies as a unified government to you, I'd love to see what you think is a fractured mess.