David_Gerard comments on Harry Potter and the Methods of Rationality discussion thread, part 16, chapter 85 - Less Wrong

9 Post author: FAWS 18 April 2012 02:30AM

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Comment author: David_Gerard 18 April 2012 07:17:49AM *  7 points [-]

In the 40,000 years since anatomically modern humans had migrated to Australia from Asia

BTW - this was the accepted figure as of 1991, but molecular evidence suggests 62,000-75,000 years. Which makes Harry's point even more strongly: it took a long time for humans as we know them to invent what we think of as basic stuff.

Comment author: FAWS 18 April 2012 07:28:29AM *  7 points [-]

At a cursory glace the date you cite seems to be for the time the population they are descended from split from African populations, not for when they arrived in Australia. Genetic evidence cannot show where your ancestors lived, only how they were related to other populations (which might imply things about where they lived provided you already know that for the other populations)

Comment author: Nornagest 18 April 2012 09:08:05AM 3 points [-]

Genetic evidence can't show where your ancestors lived, but it can gesture furtively in one direction while mouthing "look over there". Even in hunter-gatherer populations, there's enough mobility that it shouldn't take anywhere near 22,000 years for African genes to make their way to Australia (or to wherever the proto-Australians were living at the time).

Comment author: Alsadius 18 April 2012 12:27:46PM 2 points [-]

There's a big difference between a few people making their way over and genes achieving fixation.

Comment author: Normal_Anomaly 18 April 2012 08:10:56PM 4 points [-]

I approve of your stealth xkcd reference.

Comment author: David_Gerard 18 April 2012 08:50:02AM 3 points [-]

Yes, you're right - this piece gives 50,000 years ago for the arrival.

But the point stands as to the minimum time humans were anatomically and cognitively modern.