Brain expansion (Evolution)

by dhw, Tuesday, August 04, 2020, 09:14 (1361 days ago) @ David Turell

dhw: But we agree that better artefacts go together with new-size brains. They may even be the cause of new-size brains, since we know brains change in the process of meeting new requirements. We disagree on your insistence that your God must have expanded brains before homos could come up with any new concepts.

DAVID: That is our difference

dhw: You have often said that the brain causes thought, but when challenged you have claimed that I have misunderstood your shorthand. Do you now disagree that the dualist's brain DOES NOT CAUSE thoughts but complexifies/expands in RESPONSE to the thoughts of the dualist's soul? Please answer without equivocation.

DAVID: Repeat, as always. The soul can only work with the brain it is given and its level of complexity which controls the level of thought complexity allowed. The brain will respond by complexification of areas used and may have tiny areas of enlargement with extra neuron networks from intense use. But soul's thought does not cause large expansion as seen in fossils.

A bit of wool here, but the key part is your agreement that the dualist’s brain RESPONDS to the thoughts of the dualist’s soul. Your final sentence is another way of saying that the same process of brain responding to thought did not apply when larger expansion was required. You do not and cannot give any reason for this authoritative declaration.

DAVID: Sapiens history of stasis does not fit your definition of stasis. Moroccans did not show new artifacts in the discovery of sapiens fossils.

dhw: I keep pointing out that NOBODY KNOWS the causes of expansion, and I asked why you were so fixated on artefacts as the only possible cause. My definition of stasis is a period during which there are no changes. We don’t know what caused Moroccan enlargement, but we do know there were no changes for approx. 270,000 years, which = stasis. Now please tell me your definition of stasis, and why my definition does not fit the history.

DAVID: You've changed emphasis. Your original theory about expansion was that an earlier brain had a brilliant idea which forced an expansion so it could be implemented. I pointed out that the Moroccans came with no new artifacts, and the long following stasis disproved your theory. That makes sense to me, while your original theory doesn't fit sapiens history.

How have I changed emphasis? I have never said that the only possible brilliant idea was a new artefact!!! Once more: NOBODY KNOWS the cause of expansion, but we both took the spear as a concrete illustration of the process. Out of interest, I’ve looked at the early stages of this discussion, under “Introducing the brain: half a brain is just fine.” On February 19 I bolded the following: “pre-sapiens brains expanded when the capacity was too small to meet new requirements (e.g. the implementation and usage of new means of survival). The expanded brain would suffice for so many thousands of years until it could no longer cope with more advances, and so it expanded again.” What part of my theory has changed? As for the Moroccans, yet again: we don’t know what caused the expansion, but whatever the cause, once again there was a long period when there were no further new ideas or experiences or changes in conditions that required any major change in the brain. This is entirely consistent with my theory.

DAVID: What don't you understand about the word 'reorganized'? It describes the complexification and helps explain the shrinkage as unnecessary neuron circuits are dropped.

Then we agree. You claim that your God had to dabble in order to "reorganize" the sapiens brain, but complexification and minor expansion can be explained as part of the ongoing development from one brain to the next. The basic structure remains the same. (Shrinkage was simply the natural result of complexification making certain cells redundant – no dabble required there either.)

DAVID: I'll stick with God running evolution as we know it.

dhw: […] why do you keep harping on about “God running evolution”, as if your God could not possibly have run evolution by designing a mechanism that enabled the brain to expand as well as to complexify without his intervention?

DAVID: See my thoughts about your expansion theory above. If your idea is true under the deluge of ideas we sapiens have had our brain should have expanded, but complexification made it shrink.

And that is why I have emphasized the fact that if our brains had continued to expand, we would have finished up with elephant-sized heads. And so it had to stop expanding. You couldn’t and clearly still can’t grasp that obvious fact. Complexification took over, and was so efficient that the brain shrank.

(On the subject of errors, see the posts on God’s errors and your theory.)