Human evolution: savannah theory fading; big brain (Introduction)

by dhw, Saturday, March 15, 2025, 08:56 (19 days ago) @ David Turell

The human brain

DAVID: Our agreements apply to the large existent brain , not how it got to be so big and complex.

dhw: Explained above, with the small example of the spear, extending to the huge example of new environmental conditions requiring new responses. All agreed years ago.

DAVID: You want natural evolution. I have God the designer.

You wrote that “no natural need for our big brain has ever been demonstrated.” I explained that the “natural need” arose from new inventions, discoveries and conditions which required a greater capacity for complexification than was available at each stage of the brain’s evolution. I don’t “want” anything. I offer you a logical explanation, which you agreed to years ago, and now you pretend it’s wishful thinking. Please explain why you reject it.

DAVID: The savannah theory was a phantasy based on one finding.

dhw: It is a logical explanation for bipedalism and brain expansion. Please tell us what findings confirm your theory that there is a God who performed operations on the legs, pelvises and brains of one group or multiple groups of our ancestors.

DAVID: Of course logical, but unnecessary with the known new facts.

Thank you for agreeing that it is logical. The known new facts only tell us about migration out of Africa – nothing to do with the ORIGIN of sapiens. Now please tell us what new findings support your theory of God performing his various operations.

DAVID: What is simple is we do not understand the use of evolution by God.

dhw: Even if we accept the existence of God, there is no logic that can possibly justify your theory that his sole purpose for creating life was to design us and our food and so he had to design and cull 99 out of 100 species that had no connection with us and our food. Please stop pretending that your illogical theory is the only possible explanation for evolution.

DAVID: Yes, God given or natural.

That does not lend any logic to the above theory. I have offered you alternative “God-given” interpretations of evolution’s history, and you even acknowledge their logic, but your beliefs are now fixed and your mind is closed.

Earliest humans in Europe

At 1.2 million years ago:

DAVID: this puts us out of Africa at a very early time compared to other evidence.

dhw: The movement to different environments would certainly explain different traits between members of our own species. But of course it doesn’t tell us anything about the origin of our species.

DAVID: Lucy-forms from unknown forces or God at work.

“God at work” is an equally unknown force. Why bother with Lucy if all he wanted was to design you and me?

Neanderthal sapiens mix in Levant

QUOTE: "The finding reveals that Neanderthals, modern humans and related human lineages coexisted in what is now Israel for about 50,000 years. However, it's unknown which group influenced the other and in what direction.”

The mystery deepens. We know that sapiens and Neanderthals interbred, and presumably this other unknown group did the same. Obviously they co-existed peacefully. And their shared cultures suggest sophisticated communication. The Neanderthal brain was at least as big as ours, so the big brain of sapiens is/was not unique. I wonder what was the brain size of the third homo.

DAVID: dhw's plea for origin places an emphasis on where did uprightness originate. Obviously in Africa before the great migrations into Europe and Asia. The levant was a major part of the route. The point of origin of bipedalism remains unknown. For those looking for a natural driving requirement living on savannahs is a reasonable but unsupported theory in view of all the new findings in other climates.

The new findings in other climates would relate to times when sapiens had already originated and migrated. I’m glad you recognize the logic behind the savannah theory The only alternative you have come up with is your God performing operations on the legs, pelvises and brains of a group or groups of our ancestors. Also an “unsupported” theory, and hardly reasonable when we remember that according to you, right from the beginning of life he only wanted to design sapiens plus food.