Evolution and humans: big brain size or use (Evolution)

by dhw, Tuesday, June 06, 2017, 15:14 (169 days ago) @ David Turell

dhw: You continue to ignore your own avowed belief that consciousness and the self can exist independently of the brain, which is only a receiver. If you truly believe this, I simply cannot understand how you can also believe that consciousness and the self are incapable of increased conceptualization until the receiver brain increases its size.
DAVID: My thoughts come from the fact that chimps are conscious with their 400cc brain, but do not show evidence of consciousness. Consciousness appeared as brain size grew, and more complex use of the brain (based on demonstrated activities of daily living) appeared with each jump in brain size. In H sapiens full use appears to have taken place over 200,000 years, and caused the brain size to densify and shrink a little.

You could hardly make it clearer that you believe the (expanded) brain was the source of (expanded) consciousness. It may well have been. Congratulations on your decisive embrace of materialism. Unfortunately, this totally contradicts your other belief that consciousness is an entity separate from the brain and the body, comes from God (not from the brain, which is only a receiver), and returns to God complete with your identity once the brain and body are dead. You can only remove this contradiction if you argue that the jumps and complexities were the result and not the cause of increased consciousness.

dhw: For example, the concept of killing prey with a throwable shaft that has a sharp tip would require a new use of brain and hands and various muscles in order to manufacture and use the shaft. Perhaps this would require an expansion of the brain (a leap), or alternatively there could be new wiring among existing cells (= densification/complexification), without expansion. It is this second scenario that I am asking about here – generally, not just in relation to tools: how can we know that once the brain had reached its homo sapiens size, there was no densification (complexification) during the 180,000 years that preceded shrinkage, e.g. during the evolution of language?
DAVID: Of course there was a degree of complexification during the first 189,000 years of H sapiens, but a critical mass of complexity to cause densification only came 11,700 years ago. And since then the brain has been used in massive new ways. Civilization as we know it is less than 10,000 years old!

Thank you. The brain reached its maximum size 200,000 years ago, and apparently there was a degree of densification/complexification for 188,300 years, then an unexplained intensification of densification/complexification 11,700 years ago. (Wonderful language, this, and amazing mathematical precision!) Having already hung around for 188,300 years doing a “degree” of complexifying, the big brain can hardly have been the cause of the sudden intensification, so this can only have come about through an increase in consciousness which caused complexification because the brain could no longer expand in response to the uses which consciousness demanded of it. Ergo, increased consciousness does not depend on increased size of the brain. Go back to the beginning: just as increased consciousness causes complexification, it must also have caused expansion.


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