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

by David Turell , Sunday, June 04, 2017, 18:22 (2727 days ago) @ dhw

In response to my attempt at summarizing the process you write:

DAVID: None of this fits my view of the brain/consciousness relationship as explained above. Whatever is your previously learned philosophic interpretation of dualism is getting in the way of understanding my concept, based on the brain as a receiver of a mechanism called consciousness, which none of us understand what it is or how it works, but we work with it constantly. It doesn't forcefully run my thoughts, I do.

dhw: Once again, you, your self, your mind, your consciousness, your thoughts are all one, according to your belief in an afterlife in which you, your self, your consciousness and your thoughts exist but your brain doesn’t. Yes, the brain is the receiver not the generator of thought. It has been demonstrated that thought changes the structure of the brain (densifying) and not the other way round. It therefore seems logical that the same process would apply to size – that thought led to size and size did not lead to thought.

Thoughts did not cause a giant jump in size of 200cc to reach H. sapiens. Not that much thought was required at that time. Simple language and an athletic hunting lifestyle was not that complex. You are again hypothesizing an internal drive that makes no sense. We have no known proof of how speciation works except the historical record. I prefer an external drive, God.

dhw: I’m not disputing the first part of your comment, up until “20,000 years ago…”, but you are missing out all the stages that led to the brain of 200,000 years ago. This is why earlier conceptualizations are so important. Somewhere along the evolutionary line, we get a (God-given?) small brain. Let’s take that as our starting point. If consciousness (not the brain) is the source of conceptualization, and if thought influences the structure of the brain – as shown by the article you quoted – you would have had a sequence of expansions as consciousness came up with new ideas. Conscious use demands a bigger brain, i.e. use leads to expansion: use first, size second. 200,000 years ago, expansion ends. So yes of course that final size comes before all later uses of the brain, but each expansion has been the RESULT of conceptualization, not the CAUSE, because – according to you - the brain is only a receiver and not a generator. Having reached its maximum size, the brain is then used by you/consciousness according to whatever information it provides, and when it can no longer accommodate all the new thoughts of consciousness, it densifies.

The problem with your scenario is that jumps obviously preceded use. Each level of hominin lifestyle was more complex, after each jump.

dhw: May I now ask how you know that densification only began 20,000 years ago? If this is true and, to take one extremely important example, if human language really did emerge 50,000 years ago along with changes to the vocal tracts, I find it quite astonishing that there was no densifying or restructuring of the brain at that time. How has this been established?

You didn't see this entry: Saturday, June 03, 2017, 02:21 :

http://discovermagazine.com/2010/sep/25-modern-humans-smart-why-brain-shrinking