Evolution and humans: recent cave studies (Evolution)

by dhw, Sunday, June 18, 2017, 12:58 (2713 days ago) @ David Turell

dhw:It is not a matter of heavy use versus light use. The brain grew because there was room for it to grow without making the head too big for the body. Only when further expansion would have proved damaging to that balance did densifying replace growth. (I suggest that shrinkage is just a minor side effect of densification, which has become increasingly efficient.) The first manufacture of weapons would have demanded a veritable explosion of abilities: the concept of sharpening stone and attaching it to a shaft required finding the means of sharpening the stone and of making the attachment, experimenting to find the correct balance between shaft and tip, muscle coordination for the very act of throwing the spear. Of course it all seems very minor now, but we take for granted every new step taken by our ancestors. Concept first, brain "adjustment" (= expansion) second, realization of concept third.

DAVID: What do the paleontologists find in their studies? They look at the produced artifacts by each hominin at a new brain size. Lucy had none we3 now of, but she still climbed trees based on anatomy and her brain size was chimp size. She was bipedal. At each of the next 200cc (average) increase the artifacts improve until we reach H. sapiens with a giant frontal lobe still in the stone age until 10,000 years ago and Native Americans in it until 500 years ago, and some remote tribes basically still there. Simple logic tells us as they received larger brains, they learned to produce more, and when the brain is intensively used it shrinks which is a small adjustment. There is no evidence to the opposite that beginning to use it enlarges it by 200cc, which based on the shrinkage size should have occurred in smaller steps, which are non-existent. Obviously, size first use second.

Have palaeontologists proved that a 200 cc (average) increase occurred BEFORE improved artefacts appeared, as opposed to the appearance of improved artefacts coinciding with a 200 cc (average) increase? I don’t understand your reference to shrinkage and smaller steps. I thought shrinkage only started to occur 12,000 years ago, when the maximum size had long since been reached, and so densification took over from enlargement. We should also be quite clear about your own theory. Are you saying that at regular intervals, your God dabbled with the brain, increasing its volume by 200 cc (average), and only after each increase were humans able to come up with new concepts? If so, how does this fit in with your belief that concepts are the product of the conscious self, which is independent of and survives the death of the receiver brain?

I’d better repeat that I am basing these arguments on YOUR beliefs. I remain undecided between dualism and materialism.