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

by David Turell @, Wednesday, May 31, 2017, 18:17 (194 days ago) @ dhw
edited by David Turell, Wednesday, May 31, 2017, 18:37


DAVID: Remember complex use started 10,000 years ago, with very simple use before then. The vast brain was there waiting for uses to appear. Now we see the new effect.

dhw: And still you ignore all the previous arguments, even though you acknowledge them again below! Yes the vast brain was waiting, and the question is what originally caused it to expand. The brain responds to usage. Concepts first, brain response second (dualistic view). The brain expanded through usage. Approx. 200,000 years ago, after approx. a couple of million years of saltatory enlargements through usage, it reached homo sapiens size and stopped growing. Subsequently usage resulted in densifying because otherwise the balloon would have burst.

This is entirely backward. Compare brain size to known activity from archeological findings. Human activities were simplistic until 10,000 years ago, but advanced after each enlargement. Your approach totally ignores the jumps in size demonstrated by the fossils, and with each jump pre-human activity becomes a little more complex. The brain modifies itself by increasing complexity within size, and therefore density appears with the current shrinkage in size. Your dualistic view is not mine.

DAVID: I would agree to all of this in a way, except the consciousness/me/self are the same and so I produce the uses and concepts which modify a brain that is already large and can handle the conceptual processes as they appear.


dhw: There is no “except”. I am the one who keeps reminding you that consciousness/me/self are all the same. That is the essential element of your dualism which tells you that it is consciousness that modifies the receiver, and so it is only logical that enhanced consciousness caused the receiver to enlarge, and not enlargement that caused enhanced consciousness.

Based on my comments above, I find your analysis totally illogical. You are ignoring the gaps. Giant jumps in size with little advancement in use.


dhw: And if I were a dualist, I would oppose any view that made the evolution of consciousness dependent on the growth of the brain. As a dualist, you have agreed with all of this. And yet suddenly, for no clear reason, you think a bit of shrinkage invalidates it all.

DAVID: Not at all. Shrinkage tells us the a highly used brain can become more dense and shrink and is simply a measure of the new usage. I've said in the past and again now, enlargement of the brain made it a better more competent receiver of consciousness. Size first, use second.

dhw: Yes, shrinkage tell us that the brain can shrink, and usage makes it become more dense. And yes, enlargement made the brain a more competent receiver. Here once again is the dualistic sequence: usage leads to brain enlargement, but once the size has been fixed (say, 200,000 years ago) it already exists before the new thoughts arrive and require greater density instead of enlargement. Usage first, size second, further usage third, density fourth.

Your dualistic theory makes no sense. If Lucy's brain is about chimp size, what she uses it for is bipedalism. There isn't evidence of much more brain use. Tree dwelling still exists. What changes are the motor areas for walking. 600 cc's later we see stone tools, perhaps learned spear throwing. How much real mentation? Where is all the push for enlargement? Your approach implies a gradual enlargement. Not present in fossils. You are saying hominin thoughts were so explosive, the brain and skull simply jumped to a new use. Human history teaches us we had to learn to use our new big brain which has existed for 200,000 years. Important use started with modern language about 50,000 years ago, cave art, etc. Which brings up the point, when did building shelters start? not long ago, and that requires conceptual planning of structure. And the brain's response to all the new use is to shrink, not expand as you propose. What is true now has to be true with the early Homos. Not much use, no shrinkage, but sudden expansions, not explained by your theory.


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