Basically it comes down to lack of archeological evidence. We have lots of cave paintings (and many other things) from 50-100k years ago and they depict a caveman lifestyle not civilization.
We also find tons of tools and fossils such dating back to 200k years ago and there's no evidence of civilization there too. Rather the evidence is pretty clear on how primitive those people were.
Note that advanced, wide-ranging social relationships (i.e. civilisation) do not leave obvious archaeological traces.
We only think it does because we conflate civilisation with technologies of violence and bureaucracy, and those indeed leave clear archaeological traces.
They leave genetic traces, and we’re fairly sure about the migration patterns of all people currently alive on Earth through those.
All of us are very closely related as far as species go, so there must have been a serious population bottleneck at one point. We’re all more similar to each other than two chimpanzees.
> All of us are very closely related as far as species go, so there must have been a serious population bottleneck at one point. We’re all more similar to each other than two chimpanzees.
Is this true of Africans as well? I would expect there to be much more variety in humanity's original homeland than in the rest of the world.
It's true of Africans as well, but you can divide humans by the little variation we have, and it turns out there are a dozen or so groups in sub-Saharan Africa, and one group pretty much everywhere else.
Humans haven’t been around long enough for that to happen. The most divergent groups outside Africa are that way because we met our distant relatives like Neanderthals, but it seems in our case they were just incompatible enough it didn’t add that much.
Africans esp the San have much more diversity than everyone else but IIRC it’s still remarkably low for our current population size.
"Primitive" is relative, we have evidence of tools and tool manufacturing industries more sophisticated than what any other animal uses dating back a whopping 2 600 000 years ago :
Oldowan, also : ~first (non-sapiens) Homo, ~beginning of the current Ice Age (~50 interglacials so far),
and maybe even 3 300 000 years ago (Lomekwian) - also note that even going that far back, Australopithecus *still* doesn't have other remaining descendants than us.
> "Primitive" is relative, we have evidence of tools and tool manufacturing industries more sophisticated than what any other animal uses dating back a whopping 2 600 000 years ago :
That's kind of the point though with regard to early humans and proto-humans and civilization, isn't it? We've found plenty of evidence of basic stone tool manufacture and use of fire and intentional burials from much earlier eras.
But we haven't found evidence of what we call civilization - and traces of iron tools and irrigation works and cities and monuments ought to be easier to discern than small cut flint if early humans flourished with them over those periods - until the last 10-15k of human existence.
We also find tons of tools and fossils such dating back to 200k years ago and there's no evidence of civilization there too. Rather the evidence is pretty clear on how primitive those people were.