Evolution and humans: all over Africa (Evolution)

by dhw, Tuesday, May 08, 2018, 11:12 (2390 days ago) @ David Turell

dhw: 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?

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

“Generally” leaves a nice margin. It still makes no difference to the argument that the “soul” must expand its set of controls as it sends out new instructions, which would explain the expansion of the pfc. I notice you have ignored this suggestion.

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?

DAVID: 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.

Any major change in any organism entails cooperation between the different cell communities that make up the whole body. Since you believe in common descent, you now seem to be telling us that God has to engineer every single major physical change in every single organism that descended from the first cells. And you refuse to contemplate the possibility that your God might have designed cells in such a way that they were able to engineer all the different changes themselves – an explanation which explains the whole higgledy-piggledy history of evolution, including the changes to all brains, skulls and pelvic outlets.

dhw: 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.

DAVID: 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.

We have been over this a hundred times. There had to be a limit to expansion, or sapiens would have finished with a head the size of an elephant’s. If areas can enlarge through use, then the pfc can have enlarged through use. With that in mind, I would therefore change your last sentence to: the enhanced efficiency of complexification has shrunk the brain. In any case, both statements confirm that the brain changes through use, but there is no evidence that it changes to anticipate new uses. Or are you now turning your own enlargement hypothesis on its head and telling us that your God shrunk sapiens' brain in advance so that it would complexify more efficiently and thus allow more complex thought?

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?

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

Agreed. How does that come to mean that the brain had to expand before pre-sapiens could think of new concepts?