johnlawrenceaspden comments on Counterfactual resiliency test for non-causal models - Less Wrong

21 Post author: Stuart_Armstrong 30 August 2012 05:30PM

You are viewing a comment permalink. View the original post to see all comments and the full post content.

Article Navigation

Comments (78)
Tags: ai predictions models assumptions resilience

Comments (78)

You are viewing a single comment's thread. Show more comments above.

Comment author: taw 30 August 2012 06:54:29PM 11 points [-]

It seems rather easy to mess with the inputs T. Weather conditions or continental drifts could confine pre-agricultural humans to hunting essentially indefinitely

This is sort of amazing, but after a couple million years of hunting and gathering humans developed agriculture independently within a few thousand years in multiple locations (the count is at least 7, possibly more).

This really doesn't have a good explanation, it's too ridiculous to be a coincidence, and there's nothing remotely like a plausible common cause.

Comment author: johnlawrenceaspden 03 September 2012 03:27:56PM *  0 points [-]

Hmm, apparently 'behavioural modernity', 'most recent common ancestor' and 'out of Africa' are all around 50 000 years ago.

Until about 10 000 years ago a great deal of the world was under thick ice sheets, and probably a lot of the rest was cold, so there probably weren't that many humans alive.

If you give each living person a tiny chance of 'inventing agriculture', then "multiple recent inventions thousands of years apart" sounds about right to me.

I realize that that's a completely implausible model, but I'm not sure why a more realistic one would make it 'too ridiculous to be a coincidence', and if you require plant evolution as part of the scheme, that will push the expected dates later.

Comment author: taw 04 September 2012 01:47:16AM 1 point [-]

Some counterpoints:

  • "Behavioural modernity" is a hypothesis which is very far from being universally accepted. Many features supposedly of behavioural modernity have some reasonable evidence of existence far earlier.
  • Any hypothesis linking behavioral modernity with language (the only plausible common cause) is on extremely shaky grounds since as far as we know Neanderthals had language just as well, and that pushes language to nearly 1mya.

  • Behavioural modernity without common cause like language, and without any definite characteristics that weren't present earlier in some form is far less plausible, and pretty much falls apart.

  • Migration out of Africa is dated at anywhere between 125kya and 60kya, not 50kya.

  • Even starting count at 60kya, agriculture being invested 10kya multiple times independently is still extremely surprising.

  • Even disregarding admixtures with Neanderthals, Denisovans etc. most recent common ancestor is more like 140kya-200kya by mitochondrial and Y chromosome dating. Dating anything here is very dubious, so you can find a number that fits your hypothesis whatever your hypothesis might be.

  • At each point of history vast majority of humans lived in places very far from those covered by ice, or particularly cold. Agriculture was invented only in places far from ice. These are still climatic effects like rainfall that depend on glaciations, but these are much more tenuous links.

  • Modern attempts at domesticating plants and animals show it takes a few decades, not tens of thousands of years. Now these are done with benefit of modern science and technology, but still it doesn't imply tens of thousands of years.

  • Agriculture developed in some places very soon after human settlement, like maize and potato agriculture, so that's another argument against requiring thousands of years of plant evolution.
  • If it took plants and animals tens of thousands of years on average, then surely there would be a huge spread in time of domestication. Instead we have an extremely quick succession of domestication events even more ridiculous than the original coincidence (since now number of events is not 7+, it's 100+).
Powered by Reddit Powered by Reddit