Evolution and humans: big brain size uses energy (Evolution)

by dhw, Friday, November 03, 2017, 14:10 (660 days ago) @ David Turell

DAVID: That comment agrees with my concept. Of course they used the trees and ground at first with their changed bodies.
dhw: There is no agreement. My concept is that they descended from the trees, which led to their upright posture, though they retained their long arms. Yours has God preprogramming or dabbling the changes before they descend. The concepts are directly opposed.
DAVID: No self-respecting ape type leaves the trees without a reason. There is evidence of upright posture alterations in the spine 23 million years ago, in preparation for the descent. If they came out of the trees as you propose, there should be more fossil evidence of the pelvic alterations required. There are none. The speciation gap exists.

Why do you assume there was no reason? Local conditions may have made it advantageous to spend more time on the ground than before. What on earth would be God’s reason for altering the spine 23 million years ago if there was nothing for the ape to do on the ground? “Just hang around in the trees, buddy, and in 23 million years’ time, you’ll understand why I fiddled with your spine.” And why should there be more fossils of pelvic alterations after descent than there are of pelvic alterations in anticipation of descent?

DAVID: […] the only event we know of in intense use of a brain is shrinkage. You are extrapolating in the opposite direction with no evidence.
dhw: You continue to ignore the other event we know of, which is that the brain complexifies (rewires ) IN RESPONSE to new tasks imposed on it (e.g. the illiterate Indian women who learned to read). Shrinkage would have begun after the brain had reached optimum size, and complexification had taken over.
DAVID: You keep skipping over in your reasoning the fact that shrinkage is only seen after a brain is enlarged, although you recognize the sequence. The cause of enlargement is not proven by that observation. A particular size is reached with gaps in the fossil story. It is not epigenetic, while the shrinkage is.

You have quoted my answer! Once the brain had reached optimum size, complexity took over from enlargement. The efficiency of complexification would then eventually have led to less volume. Nobody knows the cause of enlargement (hence hypotheses concerning diet, upright posture, cooking, random mutations, divine dabbling), but since we KNOW that new concepts RESULT in rewiring/complexification, it is not unreasonable to suggest that in earlier times new concepts RESULTED in expansion.

dhw: Why would it [the brain] expand/complexify in anticipation of ideas that have not yet been thought of?
DAVID: My point. Simply, the brain can't by itself. It needs God as an outside agent to do it.

So only God can expand the brain, but the brain can complexify of its own accord, or do you believe your God dabbled with the Indian women’s brains before they learned to read?

DAVID: Thanks again for offering God lite…
dhw: I don’t know what you mean by God lite. A God who invents a mechanism that creates an evolutionary free-for-all with the option of the occasional dabble is just as much a God as one who designs every single innovation, lifestyle and natural wonder so that he can have a relationship with one particular species.
DAVID: God lite is your way of introducing God by having Him create a semi-autonomous mechanism which is still God in action. He dabbles!

That is not God lite, it is control lite.

DAVID: Speciation is planning in advance.
Dhw Speciation is major changes to the anatomy. It is you who insist that they must be planned in advance, as opposed to being responses to the challenges and opportunities offered by the conditions in which organisms find themselves.
DAVID: Yes I insist as well as my ID friends.

As a matter of interest, do your ID friends insist that their God fiddled with ape anatomy before apes left the trees, designed eight stages of pre-whales before they entered the water, and planned weaverbird’s nests, toxin-swallowing snakes and skull shrinking shrews in order to keep life going until he could produce Homo sapiens’ brain? A simple yes or no will do.


Complete thread:

 RSS Feed of thread

powered by my little forum