Big brain evolution: comparing chimp and brain organoids (Evolution)

by dhw, Monday, February 11, 2019, 10:14 (245 days ago) @ David Turell

dhw:You are of course entitled to your belief that your God had to keep dabbling with pre-human brains in advance, to prepare them for new demands and uses, but there is less evidence for that hypothesis than there is for mine: we know that the modern brain rewires itself in accordance with new demands (the illiterate women), and despite the overall shrinkage some sections even expand according to use (taxi drivers, musicians). In both cases, the brain responds to new demands and to usage, and does not change in anticipation of them. NB: this hypothesis does not preclude design. However, if materialism is correct, then the brain is the source of new ideas – hence our lengthy discussions on dualism versus materialism, and the THEORY OF INTELLIGENCE which I proposed a year ago. But I don’t think we want to go over all that again, do we?

DAVID: No we won't go through it all over. Just a reminder that you are using current brain evidence with its five layer frontal cortex and great plasticity, that the plasticity applies to Lucy and other very early pre-human forms. Plasticity applies to what exists, and there is no evidence it can produce more advanced form of brains. Plasticity can only apply to what exists. Speciation is much more involved and requires new design.

Our subject here is the brain, not speciation in general. Current brain evidence is all we have to go on, and we KNOW that new activities and usage make changes to the brain. I thought you believed in common descent, and so I really don’t see how expansion of the brain, i.e. an increase in the capacity of existing brains through additional cells and connections, requires new design. The example of taxi drivers and musicians makes it clear that expansion of parts of the brain can result from usage.


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