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

by dhw, Sunday, March 04, 2018, 12:07 (281 days ago) @ David Turell

dhw: So do you accept the argument that anyone under 25 is not responsible for his criminal actions because his brain is not yet fully developed and so his nice kind s/s/c couldn’t express itself properly?
DAVID: Perhaps the s/s/c he created from birth is not so kind. He creates his own s/s/c attributes. You imply his s/s/c is separated from him!

I am following up on your claim (Feb. 19) that “judgment about the consequences of any new action by an individual is impaired or limited until the development of the prefrontal cortex is complete”, which you say happens at 25. This can only mean that either the cortex and not the s/s/c is responsible for making judgements or, according to your latest theory, the s/s/c can’t get the cortex to obey its instructions. Which is it?

dhw: And do you believe that a dementia sufferer actually knows what is going on but is simply unable to communicate that knowledge?
DAVID: Medically, many demented actually recognize their impairment and try to cover it over in conversation.

In my earlier post I specified extreme cases, so will you now answer the question?

dhw: Pre-sapiens brain expanded. Implementation of concepts requires brain modification. Pre-sapiens brains may well have complexified (modification) but eventually needed greater capacity and expanded (modification). There has to be a limit to expansion unless you believe sapiens could function with an elephant-sized head, and so complexification took over (so efficiently that there was shrinkage).
DAVID: Complexification of a network with possible shrinkage does the whole job. You constantly forget the bony case must be coordinated with the enlargement as well as the mother's birth canal must be adjusted to the new-sized baby head. This can only happen by design.

It does the whole job NOW. We are trying to explain why the pre-sapiens brain expanded. Of course the skull had to expand as well. Modifications to one part of the body may well require modifications elsewhere, whether your God did it or he endowed cell communities with the means of doing it themselves. You appear to believe that your God is incapable of devising a mechanism that can work without his interference.

DAVID: Einstein's brain is a point in my favor. His conceptual area was almost a centimeter thicker than the average human, but his overall brain was the same size as the rest of us. He was obviously born a genius. (Page 209 of The Atheist Delusion)

dhw: If you are a dualist, the obvious conclusion is that the thoughts of his genius s/s/c created ever greater complexity within the conceptual area and even expanded it within the given capacity of the brain. More evidence for my hypothesis. But if there were no limits to expansion, we would have elephant-sized heads. The brain responds to the s/s/c. Concept first, brain change second.

DAVID: What a contorted answer! His genius resulted from the enlarged area from birth, because we know complexification causes shrinkage! Please lets use factual material. Perhaps you know Einstein is the only known sapiens who had brain area expansion abilities, and the rest of us don't.

The contortions are entirely yours. If his genius resulted from the enlarged area, you have provided rock solid evidence for materialism (which of course may be correct, but you the dualist are supposed to reject that theory). How do you know his “conceptual area” was thicker from birth? You keep telling us that the cortex isn’t fully developed until the age of 25. His skull was clearly able to accommodate the extra centimetre, whether he had it from birth or it developed with his great thoughts. Who knows, your own cortex might be a centimetre thicker than mine. Have you had it measured? Shrinkage is believed to have taken place over the last 10,000-20,000 years. I suggest that some cells have become redundant as a result of the efficiency of complexification. That doesn’t mean the brain shrinks every time we implement a concept! According to you, then, we’ll end up with a pin-size brain!

dhw: Diet is a common explanation for brain expansion, though as you point out, this theory has nothing to do with expansion. I share your scepticism. But the conventional diet theory does equate brain expansion with lighting the fire of intelligence, to which you as a dualist ought to be fiercely opposed, since you believe that intelligence springs from the s/s/c and not the material brain.
DAVID: No. Intelligence springs from the s/s/c being able to use an advanced brain in size and complexity.

Strange, I thought you’d agreed (a few dozen times) that the s/s/c is the thinking, experiencing, remembering, decision-making you, both in life and in death. Now apparently, in the afterlife you believe in, you will leave your intelligence behind because you haven’t got a brain to use.


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