Human evolution; savannah theory fading (Introduction)

by dhw, Sunday, August 07, 2022, 11:06 (628 days ago) @ David Turell

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.

DAVID: All under God's designs.

What does that mean? In the past, you have agreed that the process of complexification works autonomously, without his intervention. Why should the process of expansion not have done the same? But I don’t have a problem with the theory that if God exists, he would have designed the mechanisms enabling cells to multiply and to complexify.

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.

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

That is not the point. If you say God gave us excess cells which resulted in our having free will, (a) the cells were NOT excessive, and (b) how could habilis and erectus have had free will without the new cells you say God gave us for that purpose?

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.

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

As above, in the past, you have actually accepted that brain complexification was autonomous, but your beliefs seem to fluctuate. Even if you are now only open to that proposal, it’s a great boost to the theory that if God exists, he provided cells with the intelligence to “design their own improvements” throughout the history of evolution. Thank you.

Human evolution; new study says our brain did not shrink
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.

DAVID: 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.

Of course it didn’t arrive with overcapacity! Capacity relates to size (the number of cells). At all stages, the brain evolved by increasing its capacity as soon as its existing capacity proved inadequate to deal with new requirements. At each stage, it then complexified until once again it needed greater capacity (hence expansion). The same process went on until some new requirement once again resulted in the expansion to our current capacity. Then once again complexification took over (the capacity remained adequate) – but eventually, when new requirements arose, instead of increasing capacity (= expansion), the process of complexification was enhanced, thereby rendering further expansion unnecessary (but we don’t know why complexification took over from expansion). There was never any overcapacity at any stage, except possibly when our complexification process proved to be so efficient that cells which had previously been NECESSARY became redundant (hence shrinkage, though that is now being questioned).