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

by dhw, Wednesday, November 01, 2017, 12:23 (406 days ago) @ David Turell

Dhw: We know bodies and brains change IN RESPONSE to different demands. If your God created the mechanisms that enable them to do so, why do you insist that he has to change bodies and brains IN ADVANCE of new demands?
DAVID: Because the advances could not occur unless the abilities were available. The ability to have upright posture preceded the descent from the trees. Lucy walked upright but still had long muscular arms to show she also used the trees.

Perhaps when her species left the trees and began to walk upright, their long arms were still useful and enabled them to continue spending time in the trees. Isn’t this just as likely as your God suddenly dabbling with a bunch of apes up in the trees, fiddling with their bodies, and telling them to go walk on the ground except when they felt like going back up the trees?

DAVID: The only response we know about brain use is to shrink not enlarge!

Nobody knows why the brain expanded. But since we know the brain alters its structure (rewiring) IN RESPONSE to demands made on it, why do you find it illogical to hypothesize that expansion was also the result of response to demand, and shrinkage came about when rewiring took over from expansion?

DAVID: “…expanding hominid brains before there is any reason for them to be expanded" is God allowing them to get to a more advanced mental status.

An extraordinary claim for a dualist, who believes that the mental state does NOT depend on the brain. If the “soul” exists, it would provide the advanced thinking, and if the existing brain could not implement the “soul’s” new ideas, it would have to expand/complexify. You have it the other way round: the brain expands/complexifies and then apparently says to the “soul”, “Now I'll be able to make the tools you haven’t yet thought of.” (NB as usual, I am replying to your arguments, not taking sides in the debate between dualism and materialism, which I think may be reconcilable.)

DAVID: In my view God creates advances by 'suction' pulling advances forward by design. You believe in 'pushing' from behind. Two very different interpretations which will not be resolved, since you are so fixed upon avoiding God as a necessary designer.

At no time have I ever offered any hypothesis that does not include the possibility of God as a designer. I am not an atheist. You reject my theistic hypothesis because you are “fixed upon” a personal interpretation of your God’s intentions, even though it does not explain most of evolution’s history.

dhw: just as in my hypothesis organisms evolve because of the drive for survival and/or improvement: they do not change before the needs and opportunities arise.
DAVID: Yes, environmental changes foster epigenetic adaptations. Species change require advanced planning and is a process we do not understand. but it is obvious planning and design are required. Again we have two very different views of the requirements for new species to appear. It cannot be a bit-by-bit stepwise process. The fossils do not show it as Gould repeatedly pointed out.

My hypothesis allows for saltations as well as “bit-by-bit” processes such as the eight-stage whale and the multi-staged history of hominins, hominids and humans. I agree that we do not understand the process, and I agree that design is required. I do not agree that the design has to be planned in advance. Epigenetic adaptations require design, which is carried out by the cell communities RESPONDING to environmental changes. That is clear evidence of a mechanism (possibly designed by God) for physical changes as a response. There is absolutely no evidence for physical changes in anticipation of environmental changes that have not yet happened.


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