Brain expansion: different theories about rapid expansion (Evolution)

by dhw, Friday, September 04, 2020, 09:01 (24 days ago) @ David Turell

DAVID: Once again you have our brain inexplicably expanding. Areas in our brain make tiny enlargements for specialized tasks, nothing more. No evidence for your theory.

dhw: I have provided a theoretical explanation for the unexplained expansion, and the fact that our brain – which no longer expands – still makes small enlargements may be regarded as evidence that the brain is capable of making enlargements. And the evidence for your divine dabble is….?

DAVID: The obvious need for a designer.

dhw: I don’t have a problem with your argument that the mechanism must have been designed, and now that you have confirmed that this mechanism for the brain’s adaptability is autonomous, I doubt if even you would believe that the same mechanism could not have existed in pre-sapiens brains.

DAVID: I'm sure it did, but the small use by early hominins did not result in shrinkage as now.

Of course it didn’t. Shrinkage only occurred when the complexification process proved so efficient that certain cells were no longer needed. Prior to that, the requirement was for more cells, and so my proposal is that the mechanism produced more cells, as it does now when certain parts of the brain require them.

dhw: [...] You insist that all the changes must have happened simultaneously, whereas I propose that the skull would have responded to the expansion of the brain, and the pelvis would have responded to the expansion of the skull. All cell communities have the same ability as the brain to adapt by reacting to new requirements, but this does not happen overnight! Firstly, we can’t expect a complete, inch-by-inch fossil record of all changes to brain, skull and pelvis. Secondly, there may have been countless deaths in childbirth before the cell communities could adjust themselves to the new size. Even today, childbirth is an extraordinarily painful procedure. Thirdly, Dad’s contribution would not have suddenly changed from one generation to the next! And fourthly, your “designer” is not the subject under discussion. For the sake of argument, I am accepting his existence, and we are discussing the likeliest explanation for the brain’s expansion. His invention of a mechanism enabling intelligent cell communities to cooperate in adapting organs and organisms to meet new requirements would provide an explanation for brain, skull and pelvis expansion as well as for every innovation, adaptation, econiche, lifestyle, strategy, natural wonder etc. in the history of life.

DAVID: The designer is under discussion because I believe God is the master designer for all speciation.

You have simply ignored all my answers above to all your questions. “For the sake of argument I am accepting his existence…”

DAVID: The enlargements of 200 cc are not tiny adaptations.

“We can’t expect a complete inch-by-inch fossil record of all changes to brain, skull and pelvis.”

DAVID: They require the neurons to tell the bone cells of the skull we are going to overproduce the head size in the baby. And some cells in the process must tell the mother's pelvis, change shape and size of the bony birth canal.

They don’t require advance notice (“we are going to”). The cells in the skull respond to the expansion of the brain, and the cells in the mother’s pelvis respond to the increased size of the baby’s skull. But the latter process will no doubt have taken time, and there may well have been countless deaths in childbirth. Even today the process is extremely painful.

DAVID: All you have done is gloss it over again and offer a sop to a God who gives all cells an autonomous adaptive mechanism under your intelligent cell theory with no basis, when we know molecular errors can occur.

You wrote: “our brain has the adaptability to react to any and all physical and mental and emotional demands we place on it” and you have agreed that it reacts and adapts without God “stepping in”. The brain is a community of cells, and if he can give those cells the autonomy to react and adapt, why should he not have given the same autonomous ability of adaptation to all the body’s cells? See the errors thread for errors.

DAVID: New body designs need careful guiding by God. And you have never explained how cellular intelligence appeared naturally in cells, without God help. I know you have no answer other than the evidence cells react intelligently.

Of course I haven’t explained the source. Nobody knows the source of life, and nobody knows how speciation came about. That is why we can only theorize. But I keep repeating: your God may be the source. And yes, my evidence for cellular intelligence is that cells act intelligently.

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