Introducing the brain: half a brain is just fine (Introduction)

by David Turell , Friday, February 21, 2020, 20:11 (1519 days ago) @ dhw

dhw: Your view of dualism is pretty confusing. The soul makes ideas: erectus’s soul would like to fly but his soul, which makes ideas, relies on his brain to come up with ideas about how to fly? Anyway, it makes no difference to the argument. Whatever may be the source of ideas, it remains a fact that nobody has ever seen a brain complexify or expand in anticipation of new ideas. All changes we know of take place as a response to new ideas.

dhw: The bold is a statement as if fact. All we can know from the past is brains enlarged and then new processes and new concepts appeared. Erectus never had concepts habilis exhibited or then H. sapiens developed. Larger brains required for the conceptual advances.

DAVID: Yes, I agree previous brain functions and perhaps plasticity was an early form of what our brain does now. But nothing you have proposed tells us how the brain enlarged 200 cc per gap.

dhw: I have explained that in post after post after post! Just as the cell communities cooperate in modern brains to produce complexification and minor enlargements, in the past they would have cooperated to produce major enlargements when the existing capacity was unable to meet new requirements.

You may explain but I don't accept your theory

DAVID: We have the example that refutes you. Our current brain with all its new uses and demands for even more new uses shrunk 140 cc from 30,000 years ago.

dhw: In post after post after post I have explained that once complexification took over from enlargement (the body could not take more enlargement), it proved so efficient that the brain did not need so much capacity. I have even asked you for your own theory. (Did God pop in? “Sorry, guys, I gave you a bit too much.”) You have not replied.

God gave us all the brain required with its plasticity/local complexification abilities.

DAVID: Your 'new requirements' were what? When H. sapiens appeared 315,000 years ago what were the demanding new requirements that forced the brain to suddenly enlarge 200 cc?

dhw: I’m really sorry, but I wasn’t around 315,000 years ago and I wasn’t around at the time of the earlier expansions either. We do have archaeological evidence that new brain size coincided with new weaponry, and so an example which I have repeated over and over again would be pre-human X has a new idea (spear) which requires totally new ways of thinking, moving, calculating and coordinating, and so the IMPLEMENTATION of the idea leads to expansion of the cell community (and its container) which has to create new functions for itself. Hence pre-human Y with the bigger brain. The same process as in the modern brain, in which the cell community complexifies or expands on a smaller scale when it has to IMPLEMENT new ideas.

An early erectus brain lacks the capacity, as you admit, so cannot know what a habilis can know or imagine. Your view presents us with a totally illogical theory. What pushes brain committees of neurons if they do not know what they do not know and cannot know? You theory still requires the push of foresight.

DAVID: There are currently indigenous tribes now extant that live in roughly the same fashion as 315,000 years ago, with the same sized brain as the rest of us. They just haven't bothered to learn how to use it as we do, but they appear to have the same size, really unrequired. Point, same sized brain but haven't used it for new 'requirements'. Size and complexity first, use second. God supplies brain size as He evolves organisms.

dhw: You keep asking me how I think the brain expanded. Now you want to know why, once it is in place, some people use it more than others! The pre-sapiens brain would have expanded because of requirements. Once it had reached its present size, all sapiens would have it. Some sapiens have more requirements than others and so use their brains more, presumably complexify more, and even undergo minor expansions, but have also shrunk because of the efficiency of complexification. What do you think should happen? Do you want your God to pop in and shrink the indigenous tribes’ brains back to pre-sapiens’ size?

Please understand the indigenous simply haven't bothered to use their big brain. They just like it as it is. Note the illogical bold. The indigenous have not required the big brain so why did they get a big one? The Homo Hobbits had a small brain and lived as the indigenous until 30,000 years ago before disappearing. Why didn't they get the required big brain? Your 'requirements' argument is still totally illogical based on our knowledge of human evolution.