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

by David Turell , Thursday, June 08, 2017, 16:35 (2723 days ago) @ dhw

DAVID: We have no proof that thinking concepts enlarges the brain.

dhw: We have no proof that your God fiddled with the brain to enlarge it, or that the enlargement of the brain was the CAUSE of conceptualization, but you seem to believe it. And you may well be right, but that makes you a materialist.

Your statement is wrong as to my view. A larger brain allowed a more complex use of consciousness and therefore allowed complex conceptualizations to appear, if desired by the human using his brain. Not a cause, not required.

dhw: We do, however, have proof that “thinking concepts” causes changes to the brain, so why assume that 200,001+ years ago changes to the brain caused the thinking of concepts, and 200,000 years ago the process was reversed?

Again backwards. A big brain allows for more complexity of thought, but does not cause it. One must look at how the humans lived and what they were required to do to survive. Humans were still stone age until 10,000 years ago, and American Indians until 400 years ago when Eastern people arrived and showed them some differences! Little advanced meditation was required. Hunt, gather, interact in small groups, early religious thought, domestication of animals. The advanced thinking that began to appear has recently made the brain slightly smaller. One cannot turn that around because the recent change occurs within the same species, not a way to compare to the big jumps in size as hominins advanced to humans. That would imply small brain size changes in fossils as they advanced, not found.

DAVID: What we have is a little used H. sapiens brain from 200,000 years ago finally being completely used in the past 10-12,000 years of real civilization and the brain densifies and shrinks, all the opposite of your struggling theory to find an internal drive, not an external change by God.

dhw: You make it sound as if your personal belief is somehow the default position! The densifying of the brain is living proof that thought precedes structural change, and so that is quite clearly an internal drive. It may have been devised by your God (the external force), just like the process of thought enlarging the brain. The fact that the brain had reached maximum size 200,000 years ago and thereafter needed to densify rather than expand offers us a seamless process of thought expanding and then densifying the brain. As above, your theory has the brain changing before it can conceptualize, and then suddenly you reverse the process and have conceptualization changing the brain. Not much logic in that. The rest of your post acknowledges the correctness of all my arguments, so in fact your only objection to my hypothesis is that it isn’t yours.

A total mischaracterization of my view. See above.