The nation state is. The state is not. The state is ancient.
> But even without official, stated administrative organization, 'borders' still exist as the demarcation point between groups.
But they’re not borders as such. Without administration, they shift constantly, and frequently are not clear at the edges.
> Start with the point that most 'states' (or administrative regions) in history, have been ethnocentric. From Egypt through Minoan, Greek, Roman etc..
Sure, but the phenomenon of the nation state is the part that you’re missing here. You can argue that historically, humans have grouped themselves ethnically. What you can’t argue is that this somehow makes ethnocentrism in the political environment of a nation state “natural,” as the concept of the nation and the state have been aligned for hundreds of years now.
> Some more so than others. The US, no, Sweden, mostly.
But this distinction basically proves this is not intrinsic to how humans function. The existence of variation is a pretty good argument against historical determinism.