Big brain evolution: brain size and intelligence (Evolution)

by dhw, Sunday, April 15, 2018, 12:44 (246 days ago) @ David Turell

DAVID: First, in life the s/s/c cannot think without being attached to the brain. That is not obfuscation, but fact. You keep trying to portray the s/s/c that can function on its own as a totally separate actor in life. Not so, as we have both agreed.

The obfuscation was that the s/s/c relied on the brain to “functionally think”, when you keep agreeing (but then disagreeing) that the s/s/c does the thinking while the brain functions as the implementer of those thoughts. The only total separation talked of in these discussions is your belief that the s/s/c which interacts with the brain in life can continue to think, feel, remember, observe and take decisions when there is no brain to interact with. That is why dualists normally believe that in life the s/s/c and brain interact in a process which you yourself summed up as: “the obvious dualism of material brain and immaterial personality/thoughts implemented to appear through the work of the brain.” Of course in life they function together, but the dualist s/s/c’s immaterial thoughts and concepts precede implementation and therefore do not depend on the size of the brain. As you say, that is “obvious dualism”.

DAVID: Modern science studies an already established human brain of very large prefrontal and frontal cortical size, and doesn't tell us, in any way, how it arrived at that end point.

Agreed.That is why there are different hypotheses.

DAVID: Thus only a larger brain with an expanded thought area (prefrontal cortex) allows for the development of highly complex concepts, as proven by the artifacts at each level of brain complexity in earlier hominin fossils.
dhw: The artefacts are the material implementation of the immaterial thoughts. If you wish to argue that the pfc PRODUCES the concepts/thoughts, you are once again embracing materialism, which may be correct but is not what you profess to believe.
DAVID: You know full well that the s/s/c uses the pfc to produce concepts and thoughts during life.

No I don’t. As above, if I were a dualist and believed that a conscious, thinking s/s/c survived the death of the pfc, the “obvious dualism” would be that the s/s/c was responsible for producing concepts and thoughts during life, and used the pfc and the rest of the brain to provide information and – as you keep agreeing – to implement its thoughts. I remain on the fence between dualism and materialism.

DAVID: If our most previous ancestors had 'immaterial thoughts' that required expansion (your 'push' concept) why was there a delay of 305,000 years for those thoughts to appear and be implemented?
dhw: Our immediate ancestors did not think the thoughts we thought ten thousand years ago! They thought the thoughts that caused the final expansion.
DAVID: The bold is your 'push enlargement' hypothesis stated as fact. While all we know is shrinkage in size of the human brain, while its use is vastly increased, which you admit…

All we know is not shrinkage. We know that the modern brain responds to new concepts by complexifying and by partially expanding within the given limits of the skull (and I suggest that shrinkage is merely a by-product of efficient complexification). You had mistakenly argued that my hypothesis meant our immediate ancestors had thought all our modern thoughts but we waited 305,000 years to implement them. I corrected this misunderstanding. But yes, it’s all a hypothesis and not a fact.

dhw: It takes individuals to come up with new ideas. For 305,000 years, things carried on without any major advance – just as they had done for hundreds of thousands of years with the non-advancing species that preceded sapiens (a fact which you like to ignore).
DAVID: I've not ignored the point at all. I've pointed out in the past that early humans only had 'survival skills'. They managed fire in their caves and wore animal skins for covering, not much different than H. heidelbergensis. So heidelbergensis did not think up a larger brain, as you keep declaring.

You keep on about the “delay” of 305,000 years. I explain it by pointing out that just like pre-sapiens, sapiens survived perfectly well with what he had – as you have just confirmed. It takes special minds to come up with innovations. Nobody “thinks up” larger brains. My hypothesis is that early brains expanded when existing brains did not have the capacity to implement new concepts. We don’t know what concepts would have triggered expansion, but new ideas for artefacts are one possibility.


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