Brain expansion: different theories about rapid expansion (Evolution)

by David Turell , Saturday, September 19, 2020, 15:34 (1309 days ago) @ dhw

DAVID: Same lame non-answer. We only know of new hippocampal neurons appearing. That should apply to ancient brains and nothing more. The response in our brain is the only fact we have on which to base theory.

dhw: And the response in our brain is always that it changes in order to meet new requirements. Sapiens brain stopped expanding. We don’t know why, though I have offered what I consider to be a feasible explanation (further expansion would have created major problems for the whole anatomy). Enhanced complexification REPLACED overall expansion, but we still have evidence that the brain is capable of adding new cells when necessary. And so…yet again…why is not feasible that the mechanism which now adds cells to the hippocampus when needed to meet new requirements, also added cells to other parts of the brain when overall expansion WAS possible and was needed to meet new requirements?

DAVID: Our only proof of concept is what we know. You are supposing a mechanism that we do know naturally existed in the past based on the few enlargements in our current brain.

dhw: Yes, I am using what we know of the modern brain as the basis of my theory. It is not proven, but why do you think it is not feasible?

Because it is such a stretch from what we know as fact. Our adult brain will add some neurons, I presume to enhance collecting memories, in the hippocampus. This is in living brains already enlarged by a volume of 200 cc average through speciation. Living brains cannot tell us how speciation occurred naturally, especially when I add the bony issues from father, mother and baby as contributions to the problems. You blithely assume cellular intelligence handled it easily. I say the evidence indicates design by God is required.

DAVID: Same stretch of enormous imagination.

dhw: I don’t find it any more “enormous” than the idea of your God stepping in time after time to perform operations on groups of hominins and homos to enlarge their brains, skulls and pelvises, although he knew all along that the only brain he actually wanted to design was that of H. sapiens.

DAVID: I'll stick with God while you search for a natural cause of brain enlargement.

dhw: My proposal does not exclude God. It simply takes his possible involvement back to designing the mechanism for what you call a “natural” enlargement, as opposed to having him conduct countless operations not just on hominid and homo brains, but also for every evolutionary innovation in life’s history, apart from those which he had preprogrammed 3.8 billion years ago.

DAVID: We don't know if He pre-programmed or dabbled or both. The enlargements were not natural in my view.

dhw: We don’t even “know” if he exists, but I will continue to wear my theist’s hat for the sake of argument. You have admitted that you use the word “natural” to mean without God’s intervention. You have also admitted that the modern brain’s complexifications and minor expansions do take place without God’s intervention. Therefore there is a mechanism for complexification and minor expansion that meets new requirements without God’s intervention. Same question: why is not feasible that the same mechanism, designed by your God, was in operation at a time when the brain needed a lot more cells to meet new requirements?

This contorted thought wants God's designed complexification mechanism to make speciation brain enlargements automatically. Not very different from God doing it directly. Our difference revolves around concepts of God's personality. Under your idea my God wouldn't have to keep careful watch. Accepting your idea my God would watch and be sure His goal for enlargement was properly met with the new neurons in proper number, placement, and connected organization, as potentials in the newborn. But you think intelligent ells can do it by themselves, not knowing where the intelligence came from. Intelligence requires mentation at a high level. I'll stop there.