Human evolution; savannah theory fading (Introduction)

by David Turell , Saturday, August 06, 2022, 17:38 (627 days ago) @ dhw

Brain expansion

DAVID: Don't forget evolution is a process is which new processes build on earlier ones. Don't you think our brain is built from previous functioning brains, so why can't complexification be previously present?

dhw: You are repeating what I keep telling you! Previous brains complexified until their capacity for complexification could not cope with new requirements, and so they expanded. Ours followed the same process, but then it stopped expanding and complexification took over almost completely.

All under God's designs.

DAVID: A designer would logically design a brain for free usage which would implies shrinkage could occur as brain complexifies.

dhw: But past brains did not shrink, which implies that their powers of complexification had reached a limit, and so new cells were needed to cope with new requirements. Only in our case did the brain stop expanding.

Best explained as God's design. See new entry re a non-shrinkage theory.

dhw: […] you have not yet given us your own theory as to why our brain stopped expanding and reverted to enhanced complexification instead. Please tell us.

DAVID: You constantly fail to think as a designer would. God made our brain oversized so we could develop its use as we willed. Free will!!! It was so complete in its capacities further enlargement was never necessary. I view us as a finished endpoint.

dhw: Why “oversized”? This is your theory that your God gave us “excess” cells, but a) they could hardly have been excessive if they served the purpose of giving us free will, and b) you have already agreed that habilis and erectus would also have had free will, i.e. WITHOUT those cells! But I can accept the logic that enhanced complexification made further expansion unnecessary, since that is clearly what happened.

We cannot tell from fossil brain pans whether excess neurons existed or not.

dhw: The question then is why and how cells became able to enhance their ability to complexify. Chicken and egg: were they forced to do so because further expansion would have presented problems, or did they do so spontaneously, thereby rendering expansion unnecessary? If your God intervened, as you believe, whichever answer you give will refute your claim that the extra cells were excessive, and one can only ask why he bothered with all the preceding stages of brain development if all he ever wanted was the brain we now have. But as you have told us repeatedly, you can’t find any reason for this, and it makes sense “only to God”. What WOULD explain the many stages is that your God gave cells the ability to design their own improvements - but you have closed your mind to this possibility,

I've not closed my mind to complexification in which cells design their own improvements.

Human evolution; new study says our brain did not shrink
QUOTE: "Multiple hypotheses on causes of reduction in modern human brain size need to be reassessed if human brains haven't actually changed in size since the arrival of our species."

DAVID: if true, this changes the whole tone of our discussion about modern humans. It means complexification occurs without shrinkage.

dhw: It makes no difference at all to the above arguments, but simply removes one area of discussion. We still have to explain why our brain stopped expanding.

Easy to explain: God made it adequate for all our present and future needs. I remind you it arrived 315,000 years ago ready for full use as we desired to use it in our future. But you illogically deny it didn't arrive with overcapacity but enlarged to fill only new current requirements. One of your dodges.