Big brain evolution: changes in sapiens skull shape (Evolution)

by dhw, Monday, January 29, 2018, 13:42 (2488 days ago) @ David Turell

dhw: If the soul does the thinking, it does not depend on complexification or expansion of the brain to do its thinking!
DAVID: The s/s/c uses the brain to think in the living human. I view the s/s/c as software using the brain as computer. Sorry you won't accept this theory. The s/s/c using the brain sees to the implementation which obviously requires extensive planning or physical practice: throw the spear, learn to read, etc. I'm not sure what your concept of brain implementation implies, as compared to mine of 'putting into practice'.

Almost identical to my hypothesis, except that the s/s/c does not USE the brain to think. The s/s/c (software) does the thinking, and it uses the brain (computer) to give material form or expression to its thoughts/concepts (or “put them into practice”). And that is why it is topsy-turvy for you to claim that the pre-sapiens s/s/c could not think of its new concepts until the brain had already expanded. It is the implementation/”physical practice” of the new concept that complexifies or expands the brain, as you yourself explain later in your post.

dhw: You keep agreeing that the soul does the thinking, and that new thoughts cause complexification: for a dualist it cannot be complexification of the brain that CAUSES thought.
DAVID: Sorry. The s/s/c uses the brain as a computer and it is use of the brain which causes it to ADD complexity and shrink from new uses.

Why “sorry”? Complexification means adding complexity! The “soul” has the idea, it uses the brain to implement the idea, and yes, yes, yes at last, this CAUSES the complexification, and when the pre-sapiens brain capacity was no longer adequate, implementation CAUSED the addition of new cells, as you explain below. (Shrinkage in sapiens results from the efficiency of complexification, which has made some cells and connections redundant.)

DAVID: See my definition of implementation above. I disagree with your theory. S/s/c software uses brain as a computer. Implementation is the brain learning to handle a new process, throwing, reading, etc., by a few new neurons and lots of connective branching.

Precisely. When the pre-sapiens brain had exhausted its capacity for complexification, it implemented the soul’s new concepts (knapping flint, binding stone to shaft, throwing etc.) by adding NEW neurons and connections, and the addition of NEW cells led to expansion. You’ve got it!

dhw: After the pre-pre-sapiens brain had expanded, new concepts and their implementation once again caused complexification until once again the CAPACITY was unable to cope, and so once again the brain had to expand. Process repeated until we get to sapiens, whose brain cannot expand any further.
DAVID: We don't know it can't expand a little further, but I agree this is most probably an endpoint which proves it is God's goal.

Since it hasn’t expanded, it’s not unreasonable to assume that further expansion could unbalance the anatomy. One might assume that this applies to most organisms. Ants might have trouble if their heads expanded to elephant size. But who knows? Nothing to do with proving God’s goal.

DAVID: Sapiens artifacts took 270,000 years to begin to appear after enlargement. Mind the gap, as in the Underground
dhw: …just as erectus spent one or two million years faffing around doing nothing special with his own enlarged brain, sapiens (according to you) faffed around for a mere 270,000 years before the geniuses appeared, and their dualistic souls came up with brilliant new concepts…
DAVID: Why couldn't the erctus brain have some erectus geniuses around like we have to advance as quickly as we have? Your theory can't answer that, because the rapid advance like sapiens histroy requires a sapiens brain to do it. You have a theory which is entirely backwards.

And why did your God leave Homo erectus hanging around for one or two million years, when all he wanted was Homo sapiens? Mind the gap, indeed. However, my hypothesis answers all your questions. Organisms are autonomous, and every evolutionary advance originates with individuals/groups of individuals. So long as they survive, there is no need for change, but evolution also advances through a drive for improvement. After one or two million years of comparative zilch, genius erectus conceived some sort of improvement (we don’t know what) which required NEW neurons and connections, as a result of which the brain expanded to sapiens size. Sapiens also survived perfectly well for a mere 270,000 years, but then some genius came up with new ideas for improvement. The rest, as they say, is history – improvement builds on improvement. Sapiens brain couldn’t expand any more, so implementing any more new ideas now led only to further complexification of the brain (so efficiently that the brain has shrunk). A logical chain of cause and effect, and if your God exists, he set it all in motion by endowing cells/cell communities – including hominids, hominins and sapiens – with their autonomous intelligence. Now tell me what part of the history is not explained by this hypothesis.