Big brain evolution: brain size and intelligence (Evolution)

by David Turell @, Saturday, April 14, 2018, 21:29 (247 days ago) @ dhw

DAVID: The point we disagree upon is brain complexity in life in this way: since the s/s/c must interface with the brain and rely upon it to functionally think, only a more complex brain allows more advanced thought.

dhw: What does “functionally think” mean? In life the s/s/c thinks and relies on the brain to implement its thoughts, as you stated quite explicitly: “the obvious dualism of material brain and immaterial personality/thoughts implemented to appear through the work of the brain.” You keep agreeing and then trying to disagree through obfuscation. According to your dualistic beliefs, only a more complex brain allows implementation of more advanced thought. Modern science shows that the brain changes in response to implementation and not before it.

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. 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. In general we do know that the current human brain is smaller than those of 100,000+ years ago whuile developing much m ore complex use. The Neanderthal brain was bigger in size, and they didn't survive, although we are coming to realize they had more aesthetic ability than we first thought. .


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.

You know full well that the s/s/c uses the pfc to produce concepts and thoughts during life.


DAVID: The history of sapiens is compatible with my approach: we are present for 315,000 years with big brains, but have only learned how to use them in extreme complexity (as shown by our artifacts) in the past 10,000 years. 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: We have dealt with this over and over again. We don’t know what concept caused the final expansion. We only know that the skull stopped expanding x years ago .... Our immediate ancestors did not think the thoughts we thought ten thousand years ago!They thought the thoughts that caused the final expansion.


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:

dhw: From then on, new concepts required additional complexification (probably resulting in overall shrinkage) or restricted expansion.

Can't avoid that point

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).

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.


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