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

by dhw, Wednesday, February 19, 2020, 13:53 (1739 days ago) @ David Turell

DAVID: God is a great designer allowing and preparing for future possibilities of use.

dhw: … if God exists, of course he is a great designer! That does not alter the fact that the brain changes as usage dictates. It does not change in anticipation of usage.

DAVID: The human brain was initially evolved with this degree of plasticity to handle whatever requirement the future could throw at it. Only foresight in design could have done this. […] The first hominin brain had no idea as to what was coming in terms of complex usage, yet our brain developed in advance of the usage across fossil gaps of major proportions, 200 cc at each jump. God at work.

dhw: Once more you are trying to defend your whole evolutionary thesis that your God preprogrammed or dabbled every new step before it was required. You simply ignore the one fact we know about brain development, which is that the brain RESPONDS to new needs through complexification and even enlargement of individual sections, and does not change in anticipation of them. All brains have to be plastic, or they could not learn, remember, communicate, devise survival strategies etc. You now force me to repeat my proposal: pre-sapiens brains expanded when the capacity was too small to meet new requirements (e.g. the implementation and usage of new means of survival). The expanded brain would suffice for so many thousand years until it could no longer cope with more advances, and so it expanded again. It reached maximum capacity with H. sapiens (further enlargement would damage the rest of the body), and so complexification took over, and this proved so effective that there was even some shrinkage. Development then took the form of complexification, because every change, as we know for a fact, is a RESPONSE to usage, and not a preparation. We do not know of any “development in advance of usage”!

DAVID: I can accept the entire story, reflecting its Darwinian presuppositions, as showing the requirements for advancement, but produces no explanation for why the brain size jumped 200 cc each time a more advanced fossil species arrived. Your proposal requires tiny changes a la' Darwin's inadequate theory.

You quote my theory and then you ignore it! I have bolded the relevant section. The proposal does NOT require tiny changes. The brain expanded when it could no longer cope with new requirements.

Under "tiny brain":

QUOTES: "A tiny brain can run a big body in ancient an animal:"
QUOTE: "The researchers suggest that because N. acreensis had few predators to outwit, a large brain simply wasn’t worth the maintenance costs."

dhw: The brain responds to needs! You could hardly wish for a clearer example. Expansion was not required so the brain did not expand!

DAVID: Using a weird double negative argument proves nothing. Nothing required, nothing done.

Perfectly logical. Just as something required, something done explains why certain actions are performed!

DAVID: Of course with a more complex life style/requirements the brain MUST be bigger. Our discussion is how it happens. Note, only after large gaps in size, which you really never explain by simply saying the jump was needed.

I have explained the jumps over and over again, and I have explained why they happened (new requirements required a greater capacity). How the jumps happen is a different subject. Your theory is that 3.8 billion years ago your God provided the first cells with a programme for brain jumps - along with every life form, econiche, natural wonder for the rest of time – or he popped in every few thousand years to add 200 cc, because for some inexplicable reason he knew H.sapiens (the only species he really wanted) would need about 1400 cc but decided to do it in stages. My proposal is that the cell communities of which all organisms are composed followed precisely the same pattern we observe in the modern brain, and adjusted themselves to new requirements. And even today, complexification is accompanied by expansion in certain sections, according to the requirements of individuals.