Brain expansion: different theories about rapid expansion (Evolution)

by David Turell @, Tuesday, September 22, 2020, 18:12 (30 days ago) @ dhw

dhw: You keep bringing up shrinkage, and we keep agreeing that it resulted from the enhanced efficiency of complexification. Redundancy of cells is irrelevant to expansion caused by the need for more cells. Clearly the modern hippocampus couldn’t complexify sufficiently to cope with new requirements, and so it had to expand. And “perhaps" that was the situation with all or most sections of earlier brains when new requirements could only be met by the addition of cells. Why is this not feasible?

We are going round in circles because of your determination to avoid answering my bolded question above concerning feasibility.

Feasibility simply means possible. But we can't accept anything is possible. Facts: London cabbies enlarged the hippocampus. Illiterate Italian women rewired their brains and used deep structures, the thalamus and the brain stem rewiring to the cortex, not enlarging. The hippocampus is a highly conserved ancient part of the brain deep in the temporal cortex going back in evolution about 200 million years. It is specific to memory and emotional states. Our brain enlargement involved 200cc more of frontal and prefrontal cortex. I assume the previous brains set up the current usage, accepting common descent. For me using hippocampal enlargement to explain prefrontal cortex growth is a non-starter. You are explaining apples by using cranberries.

dhw: It is not clear that enlargement LED TO advances. The modern brain shows that it RESPONDS to new needs; it does not anticipate them.

My view is that God provided the larger brain in anticipation of its future use.

DAVID: You have forgotten the error discussion.

dhw: I wish I could.

DAVID: The problem for me is simple. Cells make molecular errors. Therefore God has to have hands-on control of each step in evolution.


dhw: Errors are mistakes, i.e. something goes wrong. This is self-evident when we talk about disease-causing errors. But if the behaviour of cells deviates from established behaviour in evolution, either the behaviour is an “error”, in which case goodbye to the organism, or it will produce something different and functional (hence speciation), in which case it is not an “error”... In my theory, these changes are designed by an intelligence which your God may have designed at the beginning of the whole process. They are not "errors"!

Again you want errors to run evolution. Why do the advances of evolution look so purposeful and designed? Your God gives up control, mine doesn't.


DAVID: Do your intelligent cells know when they made an error? Is it your cells that set up editing systems to correct themselves? Before or after they realized errors could happen?

dhw: What “errors” are you talking about now? If cells change in order to cope with new requirements (the brain being one example), there is no “error”! And no correction is required. That, I suggest, is how evolution advanced. Recognizing and correcting is the process with disease-causing errors, and yes, intelligent cells will know when something is wrong, and they will try to correct the errors when they happen (not before they happen!). That is how the body builds up its defences. They don’t always succeed, of course. That is because, as you point out, cells have the freedom to do their own thing, and so sometimes the “baddies” win. And to anticipate another of your objections, if God exists, he would have designed the intelligent cell.

And now perhaps you will answer the bolded and repeated question concerning feasibility.

Answered above by looking at specific brain area functions as evolution developed them. Our 200 cc enlargement was in areas that deals with interpretation of input and development of new concepts. The apes do/did just fine without this development, so why did it happen? My answer is God.


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