Brain expansion (Evolution)

by dhw, Saturday, August 01, 2020, 10:34 (84 days ago) @ David Turell

dhw: No sudden leap from nowhere. As regards stasis, please explain why, in your own theory, your God stepped in one night 315,000 years ago to give some Moroccans bigger brains (with unnecessary 150 cc), skulls and pelvises, only for them and their descendants to do nothing with them for the next 270,000 years.

DAVID: God gave us the big brain, from which stasis shows we took time to learn how to use it.

dhw: According to you, there were no advances for 270,000 years! How do you know we were learning to use it if we didn't produce anything new?

DAVID: I'm sure there were minor advances, but the major advances were in the past 50-70,000 years, with resulting shrinkage starting 35,000 years ago.

I agree. So how do you know we were learning to use our big brain during the preceding 270,000 years? Clearly we didn’t start to use it until we had our new “big ideas”, and then complexification proved to be so efficient that the extra cells were redundant. You still haven’t explained why you think your God gave them to us that dark night in Morocco.

dhw: NOBODY knows what caused the expansion, but new artefacts might have been a factor.

DAVID: We do not know the length of time the Moroccan sapiens had been around, when the artifacts were made of or thought of. I agree artifacts are a factor.

dhw: So your reference [...] to the Moroccans does not in any way contradict my theory.

DAVID: It is neutral, not support.

Precisely. So there is no point in harping on about the Moroccans as if somehow their story contradicted my theory.

David’s second post deals with more finds relating to tools, which further confuses the issue of who did what when.

DAVID: I expected you to be confused. It was clear in that post that advanced stone tools predated Moroccan sapiens. The true confusion is no homo fossils to tell us who thought of it. No support for your theory a bright idea drives expansion to a new brain, which is why you have perfunctorily sloughed off the post.

I didn’t slough it off! On the contrary I presented it because it squashed your effort to use the Moroccans as evidence against my theory! Once more: NOBODY knows why the brain expanded. None of these articles provide the slightest support for your theory that one night God stepped in and dabbled with the brains, skulls and pelvises of a few Moroccans! Does that lead you to reject it?

DAVID: We can agree that bigger brains are consistent with better made tools. What caused the bigger brains is our dispute. I'll stick with God running evolution.

dhw: My theory does not exclude God, but if he exists, I propose that his involvement lay in creating the mechanism which “ran” evolution, including brain expansion: instead of every detail being preprogrammed or dabbled, the cells of which all organisms are made were given the intelligence to do their own designing, including brain expansion.

DAVID: As usual your theory lessens God.

What do you mean by “lessens” God? Why is a God who creates autonomous organisms “less” than a God who directs every move? You never complain about a lesser God giving humans free will!

Thank you for all of today’s natural wonders, which do not require any comment from me, and also for the highly technical articles on the brain. I can only comment briefly on your own comments:

DAVID: (on “Our unusual cerebellum”): This adds more to the amazing expansion of the sapiens brain. Unfortunately we cannot study pre-sapiens cerabellums to understand the evolution, but its ties to the expanded cerebrum could be newly arrived to aide in cognition and abstractions.

I’d be happy with “newly expanded cerebrum” rather than “expanded cerebrum newly arrived”. A dualist, in my view, would have to argue that all the complexifications and expansions were in RESPONSE to the soul’s new ideas. A materialist would argue that they caused the new ideas. In my THEORY OF INTELLIGENCE (beginning April 2018) I tried to develop a compromise between the two theories.

DAVID: (on “Astrocytes drove enlargements): Our big brain is astroglial driven. "Due to an exaptation". Wow!: exaptations are unexpected changes in function of that which previously existed with a different function. As if God stepped in and added His design. It certainly was 'punctuated equilibrium', although not in the true Gouldian sense. One senses the appearance of a surprising evolutionary event.

Since there was a long period of stasis before, presumably, different parts of the brain changed their functions, and there were also long periods of stasis between earlier expansions, I reckon “punctuated equilibrium” is a good description. I don’t know why your God would have had to step in, since you have already agreed that complexification is an autonomous process. I would suggest that once major expansion had been discounted for anatomical reasons – part of my theory - intelligent cells (we shouldn’t forget that astrocytes are cells) cooperated in adapting themselves to perform whatever functions were required of them.


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