David Reich

They probably are, but maybe you could argue they knew about each other somehow.

Or the Papuan one, maybe you could argue they somehow knew about what was going on in other parts of the world, but probably didn't.

But certainly the Americas one was isolated.

And suddenly, for the first time, you have these independent evolutions of full-blown agriculture at the same time in many places in the world after the Ice Age.

This makes you think that it's somehow deterministic, that somehow some kind of setup of characteristics at this time causes this to happen.

And why doesn't it happen at the previous period of stable climate before the last ice age?

Some people say, well, maybe it was actually not as good as the last 10,000 years.

But...

I find that confusing as a statement.

It seems that somehow some set of characteristics, it's tempting to think that some sort of cultural or biological, but more likely cultural characteristics are in place and seated already at the time of the last ice age, such as when the reemergence happens, this happens in multiple places simultaneously.

That culture is very old in the Americas.

Yeah, it's tempting to think that.

So I'm very confused about this personally.

People say that the last 10,000 years are very unique on a scale of millions of years.

If that's true, maybe we're in a very special time.

That is somehow a period of warmth and stability of climate that's unprecedented for two million years.

Maybe that's true.

But the other way people often say it is that we're in these cyclical periods of a few tens of thousands of years.

And the Holocene, the last 12,000 years or so, is a period of warming.

And then there's a period of a couple of tens of thousands of years, which is the last ice age.