Introducing the brain: general (Introduction)

by dhw, Sunday, February 27, 2022, 08:44 (782 days ago) @ David Turell

DAVID: Our brain has very limited ability to produce new neurons. I think God made all prior hominin/homo brains in the same form.

dhw: The fact that we generally do not produce new neurons can be attributed to the fact that complexification has taken over from production of new cells. We don’t know why, though at least I’m sure you will agree that our brain could hardly go on expanding indefinitely without dire repercussions on the rest of our anatomy. Imagine an elephant-sized head being carried around on your body. The time had to come when expansion would cease.

You have not responded to this explanation of why the brain ceased to expand, and you have not told us your own theory either.

dhw: The only difference between us is that you insist they had the extra cells BEFORE they needed them, whereas I propose that the additions were made in response to new requirements. And you still haven’t explained why your God could not have given them the same autonomy for expansion as for complexification.

DAVID: Answered many times. Our frontal cortex has a very different complex design involving specialized pyramidal neurons in five distinct layers, like nothing seen in apes/chimps.

And how does that come to mean that your God, who apparently gave our brain cells the autonomous ability to complexify, could not possibly have given the same cells the ability to add to their numbers?

DAVID: Requires a designing mind. Neurons carry our thoughts, but can't design new network arrangements. Complexification simply means the ability of existing neurons to make new dendritic connections in existing circuits as necessary.

Neurons are able to make new connections but they are not able to make new network arrangements. I’m baffled.

DAVID: Seven ounce change objection of mine not answered.

dhw: See above. If our brains had gone on expanding indefinitely, we would have been walking around balancing an elephant head on our puny bodies. Expansion had to end at some time. Now please tell us your own explanation for the end of expansion in favour of complexification.

DAVID: See above.

No explanation offered.