Brain expansion (Evolution)

by David Turell @, Monday, July 20, 2020, 17:46 (101 days ago) @ dhw

dhw: More fudge. I have agreed that the dualist’s soul’s ability to IMPLEMENT new concepts is limited by the available complexity of existing networks. (That is why they had to expand.) I do not agree that the dualist’s soul is incapable of coming up with new concepts using the available networks, if that is what your convoluted sentence implies. The example below, which we both used, could hardly be clearer:

dhw: (Spear example: old brain thinks of weapon to kill from a distance; process of development from this idea to the finished article – the artefact – requires addition to existing capacity for complexification, as brain responds to new requirements. Development or implementation leads to expansion.) Steady advance of artefacts accompanying brain expansion “proves the point”. But a) new artefacts are only one possible cause, and b) the new brain could go on to produce further advances without requiring further expansion.'

DAVID: Same old idea that a new idea drives complexity and also enlargement to happen/appear. As far as I have presented my arguments, the history of sapiens does not support your view.

dhw: Yes, you have repeated my theory and have offered no reason for rejecting it other than the fact that it is not proven. Meanwhile, I have pointed out umpteen times that the history of sapiens offers us evidence that the brain changes when it implements new requirements (not before it does so), and the process whereby minor enlargements occur within the existing capacity could be taken as an indication that the same process was in operation in former times before the brain stopped expanding and complexification took over. What have you found in the history of sapiens that contradicts my view?

I'll repeat your proposal. Older smaller less complex brain thinks of new tool (artifact) concept, but can't produce it until a new larger brain implements the idea. Correct that statement, but that is my interpretation of your theory. The sapiens history does not support it. Just stasis for 270,000 +/- years after arrival of new brain. Why stasis if a new idea is driving expansion? Implementation should be quick if under your idea of driving the expansion.


DAVID: I'll stick with God running evolution and enlarging brains and skulls and changing pelvic measurements as necessary and all at once. The necessary enlargements that advanced us to our current stage were a total of 800 cc., about 26 ounces.

dhw: Thank you for the information. How does that explain why the sapiens brain stopped expanding?

DAVID: The brain we got was so adequate it shrunk 150 cc when active use appeared.

dhw: When you say the brain we “got”, you mean the brain God “all at once” gave to a particular group of homos at the same time as he expanded their skulls and pelvises. But for some reason, he made the brains bigger than necessary.

DAVID: I've explained that, remember? The extra neuron networks and the process of plasticity allowed us to tailor our brains for our purposeful uses as they developed over time (290,000=/- years. With the thinking capacity given, God knew we would use it in many new ways light-years in advance of prior species.

dhw: Plasticity is what allowed all brains to complexify and early brains to enlarge. I don’t see how your God’s giving his group of homos an overnight injection of an unnecessary 150 cc of brain allowed anything, since whatever was injected minus the 150 ccs would have worked just the same without it.

Plasticity did not cause enlargement, just rearrangement of neuron networks. The extra 150 cc allowed us to self-tailor our brains, a very reasonable supposition.


DAVID: I'll stick with God and the evidence I have.

dhw: What evidence do you have that your God stepped in etc. as above?

DAVID: Just as I have no absolute evidence for God, your position is no evidence God does not exist, which created the website.

dhw: This discussion is not about the existence of God, but about how the brain expanded and – ultimately – how evolution works. I have offered you evidence for my theory through the workings of the modern brain. What evidence do you have for your theory?

Yes we debate at the natural level, and I find sapiens brain history does not support your theory about expansion, as above.


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