Brain expansion (Evolution)

by dhw, Friday, July 17, 2020, 10:27 (105 days ago) @ David Turell

dhw: We agree that the dualist’s immaterial soul must use the material brain, but why is its abstract thought limited to the capacities of the neuron network?

DAVID: Simple analysis. Bigger more complex brains are related directly to advances in artifact complexity. Complex brain allowed the appearance of more complex thought by the soul.

dhw: I don’t disagree with this. Once the brain has expanded/complexified, then of course it will contain more information for the dualist's soul to work with, and will have developed more skills to enable it to implement the soul’s ideas. But this doesn’t tell us why the brain expanded in the first place, and it doesn’t mean that the dualist’s soul cannot have new thoughts using the existing brain!

DAVID: It can have new complex thoughts limited by the complexity of the existing living brain with which it must work. Advances in successive fossil/artifacts tell us this.

It is the amount of information the brain makes available that limits the dualist's soul's capacity for thought, but that doesn't mean new thoughts can't arise out of EXISTING information. Each new complexification is the RESULT of thought. Advances in artefacts will result from the thoughts of the dualist’s soul using existing information, and the implementation of the thought will CAUSE complexities. In my theory, it will have CAUSED expansion when the capacity for complexification was exceeded by the requirements of the new thought.

DAVID: More talk around your original explanation that anatomically the head could get too big!!!

dhw: This is not “talk around” anything! Once more, I propose: the brain stopped expanding because a bigger head would have caused anatomical problems. Complexification took over, and was so efficient that the brain shrank. You want the brain to start expanding again because there is now room for expansion […]. Although there are indeed minor expansions, I am asking you why the brain should abandon its successful method of complexification and revert to expansion though it doesn’t need to.

DAVID: A non-answer. There was no anatomical problem and wouldn't be, since we know our brain/skull shrunk by 150 cc in the recent past. The bold is weird. I do not expect any new expansion.

You wrote that the shrinkage “could be easily added back, if necessary, but isn’t. Your anatomical problem is not reasonable.” I don’t see how the non-necessity for 150cc removes the anatomical problem, so let me explain it yet again! We don’t know why our brain stopped expanding, but “reason” should tell you that if it had continued to expand indefinitely, we would have ended up with a head the size of an elephant’s! And you don’t think this would have caused anatomical problems? The brain stopped expanding, complexification took over, and when sapiens had lots of new ideas resulting in lots of complexifications, the latter were so efficient that some of the brain’s cells became redundant. How does this contradict any aspect of my theory?

DAVID: Your 'minor' expansions are simple local additions of a few new neurons in the hippocampus, nothing more. Making a mountain out of a tiny molehill.

I’m pointing out that the autonomous mechanism for expansion is still present. And so it is perfectly possible that in former times, before complexification took over, the same mechanism led to overall expansion.

dhw: […] Sapiens’ brain history offers the evidence that the brain complexifies and expands on a minor scale IN RESPONSE to new requirements. Therefore it is not unreasonable to suppose that the pre-sapiens brain also complexified and expanded IN RESPONSE to new requirements, as opposed to expanding in anticipation of them. But in order to forestall yet more flogging of dead horses, let me repeat: once the brain had expanded, of course it could come up with more new ideas. If it didn’t, there was stasis, both with pre-sapiens and with sapiens.

DAVID: I'll stick with God drives the complexification in evolution and you can hope for natural causes. New requirements (bolded) is pure Darwinism. We will never agree what advances evolution but we both agree design is required, designer unnamed by you.

I'm not “hoping” for anything, but I'm looking for logical answers to our questions. If God exists, then he would have designed the mechanism I am suggesting. Are you denying that the modern brain complexifies and expands on a minor scale IN RESPONSE to new requirements? If you accept that it does, why do you refuse to accept the possibility that it did the same in the past. Whether the theory is “pure Darwinism” or not is irrelevant.
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Under "Synapse complexity":

QUOTE: Brains can be viewed as vast ensembles of highly diverse and dynamic synapses that shape and store information as it travels through the networks of neurons that generate and interconnect those synapses. There are more than 100 trillion synapses per human neocortex, and each synapse is itself a highly complex entity, comprising thousands of diverse and cooperative signal-transduction proteins.

One might expand this observation to cells in general. All organs and organisms are “vast ensembles” (I call them “communities”) of interconnecting cells (I use the term “cooperating”), each in itself a highly complex entity. And all of them shape and store information.


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