Evolution and humans: all over Africa (Evolution)

by David Turell @, Monday, May 07, 2018, 18:26 (822 days ago) @ dhw

dhw: I am totally ignorant about the brain, and therefore rely on what the specialists tell me. If specialists disagree, yes, I am confused. You wrote: “The fMRI follows muscle movement and other application areas fairly easily but thought may be in frontal areas and is influenced by other areas controlling emotions, which are harder to define.” I like your “may be”. When you say emotions are harder to define, you raise the whole question of definition. Where exactly is the border between thought, emotion, memory etc.? Are the “cognitive networks” confined to the pfc? But none of this makes any difference to the following:

My 'maybe' covers your question about the borderlines of the areas. But cognition, thought, is generally only in the pfc.

dhw: If your soul can change the brain cells, why can’t it get other cell communities to change as well? Why does your God have to preprogramme or dabble every change?

We need God to control the many interlocking mutations that have to take place to make these advances: Enlarge the brain, the skull and change the mother's pelvic outlet.

dhw: But did the portion enlarge BEFORE thought could become more complex, or BECAUSE thought became more complex? As above, if the dualist’s soul is sitting in the pfc, the more messages it has to send out, the more material connections (producing the “cognitive networks”) it has to make. This means either complexification or, if the brain runs out of space, expansion, which leads us to:

DAVID: Your request for studies into enlargement of the brain have no basis of facts in which to work. All we've got is fossils to measure.

dhw: It was you who said we must “interpret past evolution by studying what we see now”. What we see now is brain changes CAUSED by and not PRECEDING the implementation of new concepts.

The sapiens evidence is very specific: areas can enlarge through use (taxi drivers) but overall the sapiens brain has shrunk 150 cc since it appeared, despite enormous use more recently. Hard to refute this obvious fact. Wide spread complexification from conceptual thought shrinks the brain.

DAVID (addendum): I've found a theoretical study about how human brain growth starts:

DAVID: this study does not help us decide our differences, but it certainly demonstrates how different our brain start is compared to other animals.

dhw: Agreed. It doesn’t help us at all! The wonderful article on porpoises is probably more to the point, as it touches on the question of borderlines between thought and emotion.

DAVID: As for what God did, I feel He was/is in charge of what evolution did/does. His work is the best explanation for the arrival of the human brain. Your theory simply accepts that.

dhw: If your God exists, then of course he was/is in charge, in the sense that he set up the mechanism for evolution, and could always interfere if he felt like it. How does that come to mean that the brain had to expand before pre-sapiens could think of new concepts?

Enlarging the brain is a complex task, since it involves skull and mother's pelvis.

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