Introducing the brain: why so big? Part two (Introduction)

by David Turell , Wednesday, July 17, 2024, 19:02 (127 days ago) @ dhw

DAVID: Our 300,000-year-old brains were much too large for just survival needs when that brain appeared.

dhw: For 290,000 years all the cells were used for survival. They were not just hanging around. When new conditions/ideas/discoveries triggered the cultural explosion, the existing cells complexified, presumably because further expansion would have caused problems for the rest of the human anatomy.

DAVID: You haven't responded to the concept the brain of 300,000 years ago was oversized and overly complex for current survival then.

dhw: It wasn’t! And I responded, but you don’t seem to have followed the argument. The sapiens brain expanded 300,000 years ago to meet new requirements, and for 290,000 years ALL the cells were devoted to the same purpose: survival. They may well have undergone a small degree of complexification during that time (we have no way of knowing), but 10,000 years ago, new requirements arose, and so the SAME cells complexified because expansion was no longer practicable.

Thank you. All 300,000-year-old neurons were alive and at work at the level required then. Then at 10,000 years ago they all were available for all the new uses. You've made my point.

DAVID: Of course, all neurons were functional, while minimally used. We all know about 'future' complexification occurring later, not in the present. Stop dodging.

dhw: The fact that the same cells complexified later, and the same cells met all later demands, does not mean the original brain was oversized and overly complex! The whole brain (whose size never changed until shrinkage, caused by increased efficiency of complexification) ) was NEEDED for survival.

Scurry about, but the view of oversized on arrival is obvious. Oversized does not mean unused in a minor way initially. Now it does math, music singing, gymnastics, puzzles, etc.

DAVID: Your quote is correct: "The early cells were able to meet all new demands" for all future years!!!

dhw: Thank you. That does not mean they were superfluous for 290 years!

Of course they were.

DAVID: I never said neurons then did nothing. But they didn't do the tasks I described above. But note, they were prepared for those tasks 300,000 years ago.

dhw: Now what are you saying? That 300,000 years ago, your God programmed the brain cells to respond to all current requirements AND to all those that would arise 290,000 years later? You have agreed several times that your God would not have intervened to direct every single complexification throughout the history of brain development. Now you’ve got him operating on a few earlier homos to put new cells in their brains, complete with a programme for every single innovation that will take place 290,000 years later. And you moan about Darwinian just-so stories!

Not your just-so! Those cells were there to be complexified 10,000 years later. The brain can't complexify unless enough neurons are there to fill new requirements.

DAVID: Thank you for admitting the possibility of God.

dhw: After 16 years you still didn’t know that agnosticism, unlike atheism, allows for the possibility of God!

DAVID: I know your position. You don't recognize you criticize God more than half the time.

dhw: Irrelevant to my agnosticism. In any case, I criticize your theories about your God, which make him imperfect, inefficient, and schizophrenic. I also ask questions (theodicy), and I present alternative theories which show him to be highly efficient and not in the slightest schizophrenic. Where is the criticism of God?

Plese open your rigid brain. God is not schizophrenic; my two views are.

DAVID: Our very large and complex frontal lobes are a giant jump from ape brains.

dhw: That does not mean that our large and complex frontal lobes were created “de novo” by your God. Even in your theory, you have your God operating on existing brains.

DAVID: Yes, taking Lucy's brain and then enlarging and complexifying it in large steps.

dhw: Nothing “de novo”, then. Thank you for agreeing.

DAVID: Our frontal lobe with five layers of specialized pyramidal neurons has no predecessor. It is de novo.

dhw: It is not the frontal lobe that has no predecessor, but the new additions. If you wish to claim that every single “evolutionary novelty” (Shapiro) indicates your God starting over again; “afresh; anew; from the beginning” (definition of “de novo”), then so be it. Exit common descent. But don’t tell us that your God takes an existing brain and then enlarges and complexifies it.

Of course He uses previous brains, not as highly complex as ours.