Brain expansion: different theories about rapid expansion (Evolution)

by David Turell @, Sunday, September 20, 2020, 16:15 (35 days ago) @ dhw

dhw: I don’t know why you’ve suddenly brought speciation into it. Speciation has two levels: different varieties of cat and dog are termed species, but the broader level is cat as one species and dog as another. Even if your God dabbled expansion, you have him changing the brains of existing hominins and homos, but they were still hominins or homos, and some even interbred. But yes, I’m proposing that the same mechanism which has added neurons to the hippocampus would have added neurons to other sections of the brain when these were required. Only I propose that the modern brain/skull could not undergo another major expansion for anatomical reasons, and so complexification had to replace expansion as the main response to new requirements (with shrinkage as a result of complexification's increased efficiency).

Speciation is a major part of the story as it involves the human brain. We differ greatly from Lucy. The issue is you avoid God's role and constantly propose naturalistic mechanisms which at times masquerade as partially from God, i.e., He provides self-help mechanisms rather than direct design.


DAVID: 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.

dhw: See above for speciation. I don’t know why you slip in these derogatory adverbs - “blithely”, “easily” - and I don’t assume anything. Nobody knows how or why the brain expanded, but it’s common sense that the skull and the mother’s pelvis would have had to adapt to the new size. I agree with you completely that the evidence indicates design, but I also believe that an all-powerful God would be perfectly capable of designing a mechanism that would enable the cell communities to do their own designing. (See below for God's non-intervention)

Same approach with God-lite control of advances.


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?

DAVID: This contorted thought wants God's designed complexification mechanism to make speciation brain enlargements automatically. Not very different from God doing it directly.

dhw: Except that you have your God doing it before it’s required, whereas the cells would do it because it’s required. In my theory, the complexification mechanism and the expansion mechanism are one and the same: cellular intelligence. The cell communities complexify until they find that the new requirements (whatever they may be) can only be met by adding more cells. This is clearly what happened with the hippocampus (without God’s intervention), and there is no reason why the same thing should not have happened in earlier times. What is “contorted”?

your thought avoids all the discussion of the issue of stasis after enlargements.


DAVID: 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.

dhw: I would assume that your all-powerful God would not have set this process in motion if he wasn’t interested in the outcome (i.e. he would watch), but yes, I would also assume that if he wanted to create an autonomously intelligent mechanism to produce different species and strategies and natural wonders, he could do so. And since the history of the brain is that of an organ whose cell communities complexified and expanded to their present state of complexification and minor expansion, which you agree functions without your God’s intervention, I see no reason to assume that earlier cell communities did not do the same. And yes again, their intelligence may well have come from your God.

Once again we disagree about the qualities of God's personality. God will not do it through the agency of cells own actions. You have forgotten the error discussion. God cannot allow cell advances on their own when errors do occur. That is why in the past I mentioned slight variations from His evolutionary plans (mild errors) could possibly slip through, on his allowance of it. I think not, but it is a question to be raised and addressed.


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