Introducing the brain: general (Introduction)

by dhw, Tuesday, March 01, 2022, 07:04 (996 days ago) @ David Turell

dhw: You have not responded to this explanation of why the brain ceased to expand, and you have not told us your own theory either.

DAVID: Answered previously. Our current bodies could easily handle 200cc of more brain consistent with the last enlargement. My theory is that we are the endpoint of evolution. And the elephant skull is a debate trick known as taking an idea to an illogical extreme

dhw: How much more could they handle? The process of expansion had to stop at some time. Your theory that we are the “endpoint”, by which you apparently mean the one and only purpose, does not explain why our brains have stopped expanding. Erectus was still erectus, even though his brain continued to expand.

DAVID: Which should mean to you our small expansion from Erectus to Sapiens, which you tout, contained more than just more neurons but a major new complexity, the five layer pyramidal neuron arrangement.

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.

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.

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?