Evolution and humans: all over Africa (Evolution)

by David Turell , Thursday, May 10, 2018, 18:31 (2387 days ago) @ dhw

dhw: I’m quite happy to accept that the enlargement is in a “thought area”, but you don’t seem to be receptive to the fact that new thoughts will require new connections to the rest of the brain if they are to be implemented. Those connections will have to begin in the “thought area”. Hence expansion.
DAVID: Almost all the expansion is frontal cortex compared to ape brains. The implementation areas are not much changed.

dhw: Yes. So please comment on the explanation I have offered above.

The apes have the same implementation areas we have with the same connections. You can't get around that the major area of enlargement is frontal lobe, but of course, there is some enlargement elsewhere.

dhw: There had to be a limit to expansion, or sapiens would have finished with a head the size of an elephant’s.
DAVID: This is your unproven concept. No facts involved.
dhw: Of course. Nobody’s hypothesis has been proven – and that includes your own. Otherwise there would be nothing to discuss. However, that doesn’t in any way negate the logic of my argument. And I notice you have ignored the point that even your own shrinkage hypothesis now has new thoughts changing the brain instead of God changing the brain before the s/s/c can have new thoughts.

DAVID: Shrinkage is evidence only in sapiens brains which are highly complex to begin with. But I've proposed shrinkage might have occurred in earlier forms, as a degree of brain plasticity present in earlier hominins, which process we inherited. Shrinkage negates your point that the pressure of thinking new concepts forces enlargement of brain and skull.

dhw: You hypothesize that it might have shrunk (no evidence for that at all), and then claim that your hypothesis negates the need for expansion! Shrinkage is irrelevant, because the brain did expand, and our question is why! You say it was because the brain needed extra materials before it could THINK of new concepts (= materialism). A dualist would argue that it needed extra materials to implement the new concepts provided by the thinking soul. And yet you claim to be a dualist. Lastly, you are still ignoring the point that even your own shrinkage hypothesis now has new thoughts changing the brain instead of God changing the brain before the s/s/c can have new thoughts.

We know God gave the brain plasticity; therefore the brain could shrink on its own as it pruned unnecessary areas. My form of dualism is not the one you constantly define. I believe the immaterial soul must use the brain networks to think in life. I have every right to my interpretation of a dualistic philosophy.

DAVID: I am discussing the complexity of this species change, to create a larger front of the brain: new skull and different mother's pelvis.

dhw: That is a fact, and I am not disputing it, so why do you keep bringing it up? In any case, I answered it in the same post: “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.”

DAVID: I keep bringing it up because the speciation is so complex, and God has to do it. It is not 'now' that I have God running evolution. It is an 'always' concept of mine, and you know it.

dhw: And that is the point at issue between us, as described above. I propose (theistic version) that your God might have given organisms an autonomous inventive mechanism to engineer speciation. Your version of an IM does not even go as far as allowing the weaverbird to design its own nest. So do you think your God was incapable of designing my version of the IM?

Of course He could have created an IM, but I'll repeat my view: I see His goal as humans and God was going to steer evolution to that point by maintaining some steering controls. I frankly think major evolution is over, and only variations will appear as responses to environmental or other stresses.