Introducing the brain: general (Introduction)

by dhw, Wednesday, March 02, 2022, 11:41 (995 days ago) @ David Turell

dhw: I am quite happy to accept the theory that all expansions would have involved new neurons creating complex connections in response to new requirements which exceeded the complexification capacity of the existing neurons. That is the nub of my proposal – as opposed to your own, which was that new neurons were added just to hang around doing nothing until they were required for some as yet unknown future requirement.

DAVID: Homo sapiens 315,000 years ago sure used their brains just like we do. Illogical as usual.

Of course they used their brains like we do, meeting requirements with complexifications, but our new thoughts, ideas, discoveries, inventions and requirements have produced more and more complex connections (complexifications) instead of the expansions that previous homos needed in order to meet new requirements.

dhw: The new neurons are added for the same reason as complexification: to handle new work. And I suggest that this is what species do generally: they reorganize themselves in order to handle new conditions. And if your God creates the mechanism for autonomous complexification, I continue to ask why you think he couldn’t have done the same for enlargement, which fulfils the same purpose as complexification.

DAVID: Our brain has no real facility for enlargement. Your argument fails in that we see our current frontal lobe arrangement as a very complex design that neurons alone could not create. Our living predecessors don't show any of it.

dhw: I have asked you before why you think our brain stopped enlarging and complexification took over. I don’t know what you mean by “no real facility”. Are you then saying that the current size of the skull won’t allow any enlargement, and if so, are you agreeing that any further enlargement of the skull would create anatomical problems? As regards the frontal lobe, my argument is that neurons can and do create complex designs – and you keep agreeing that your God does not intervene in the process of complexification! All of our living predecessors have frontal lobes, but clearly ours are far more complex. So are you saying that chimps and early homos autonomously developed their own frontal lobes, and only ours required your God’s intervention?

DAVID: My point remains God designed all evolutionary new-sized brains with new complexity. The only new designs existing neurons create is new dendrite branches and connections, but no new neurons except in the hippocampus.

New neurons in the hippocampus provide evidence that autonomous expansion is possible. You have always agreed that complexification takes place without your God’s intervention. The addition of new cells would only result in “new complexity” if those cells were used to meet new requirements, as opposed to hanging around doing nothing. To complete the picture, new connections are the result of the complexification process which would have taken place in all previous brains, but which is now so efficient that expansion is no longer necessary, and indeed some previously useful cells became redundant (shrinkage).

DAVID: As for anatomic requirements, some Erectus were as tall as us with smaller brains , i.e., no need for new anatomy to prop up the skull when we arrived. Forget your elephant head ridiculous point.

Obviously our skull was large enough to accommodate the relatively small number of new cells. Our question is why it has stopped expanding, and complexification has taken over almost completely. You still haven’t given us your own explanation. Mine is that it could not have gone on expanding indefinitely. Why is that ridiculous?