Evolution and humans: all over Africa (Evolution)

by David Turell , Thursday, May 03, 2018, 15:41 (2394 days ago) @ dhw

DAVID: If a brain is built for more advanced thought by the s/s/c, why not start using it?

dhw: The obvious answer is that the new size was caused by the need for more capacity. Once the brain had expanded sufficiently to implement the new concept (now pre-sapiens could make his spear), there was no further need for change until the next major concept came along. The sapiens brain reached optimal size, and so when new concepts came along, it increased the efficiency of its complexification (so much so that it actually shrank).

DAVID: That is your theory and not obvious to me.

dhw: Then please give us your own explanation for the sapiens “gap” of 300,000 years, and the hundreds of thousands of years “gap” during which hominins’ brain size and way of life also remained static.

As before, God speciates and creates a 'next' species with more pre-frontal, frontal size and complexity. It then takes time to learn how to use the new size. The contemporary artifacts prove the point. Survival skills are limited in brain requirements, since the lifestyle is so simple. Only the current sapiens brain could have created our very complex civilization, which has erupted in the past few hundred years. And the brain shrunk by 150cc, when your proposal of a conceptual demand for explosion seams to ask for more results earlier.

dhw: Your point all along has been that there were some 300,000 years of stasis, and then there was a sudden breakthrough. This coincides with a major change in climate. Maybe in earlier periods there were no geniuses around to realize the potential. Do please tell us your own explanation. Once the turning point had come 12,000 years ago, maybe the relatively colder climes created more problems than the warmer climes (e.g. how to keep warm): you need more sophisticated forms of dwelling, which is a not insignificant factor in the advance of civilisation.

DAVID: Your points are well taken. Sapiens from Africa did face the challenges of a colder climate, but at the time they moved north because they had an advanced brain which could use its s/s/c to solve the problems. It is noteworthy that the earlier hominins did not try the northward movement. I believe at all levels of hominin development there was a delay reaching a level thought/planing to create new artifacts.

dhw: We know there was a “delay” or “gap” at all levels, including sapiens. I have offered you an explanation above. Please point out any logical flaws in this hypothesis and give us your own explanation for the gaps at all levels.

Second request for same answer as above. Remember God starts it. You seek a natural chance mechanism a 'la Darwin to explode brains. And you answer God might have doesn't get around my objection.