Big brain evolution: changes in sapiens skull shape;addendum (Evolution)

by dhw, Friday, February 23, 2018, 12:06 (291 days ago) @ David Turell

TONY: Mature is subjective. What are the objective qualifiers for maturity, as DHW asked? What qualifies those particular qualifiers as valid benchmarks? What objective benchmark are these fMRI readings being set against? Another subjective opinion of maturity? Emotional control? I know people of every generation that fail at that.
DAVID: You are making everything black or white re' maturity. In general I agree with your point of view, but neuroscience tells us brain development takes up to age 25 to be initially complete. The current issue of Nature has several articles on the problem of defining adolescence and specifically the issue of risk taking. Take a look at one of the available articles or all of them:

I hope Tony himself will reply***, but meanwhile let me admire your use of language. “Initially complete” is a wonderful expression. Once more: the brain continues to develop throughout our lives, and so – just like the immaterial s/s/c – its development is never completed. You ask elsewhere when adolescence ends. In relation to all the immaterial attributes we have been discussing – judgement, decision-making, emotion, thought analysis – there is no borderline. Some teenagers are a darn sight more mature in these fields than some adults. You say you are a dualist and believe in the existence of the “soul”. So why do you continue to cling to neuroscience which is confined to what is material? The articles you quote always cover activities in the brain. They cannot tell us whether those activities CAUSE our immaterial attributes or respond to them. (See final comment on all subjects raised here.)

*** I see Tony HAS replied, and emphasises the role of experience. I agree totally with his response.


dhw: ...the brain has to have the requisite means to express and implement the thoughts/feelings/decisions etc. of the s/s/c. The plastic brain is the requisite means, and each new experience establishes the new connections.
DAVID: Yes. We see initial developmental change and then plasticity changes.

Plasticity is what enables the brain to change. The question is what CAUSES the brain to change. So let’s spell it out again: the dualistic s/s/c’s thoughts, feelings, decisions CAUSE the brain to respond, and if the experiences involved are new, they CAUSE the brain to change (as confirmed by the example of the illiterate women).

DAVID: If the prefrontal area is not complete, the s/s/c cannot make fully adult judgments, because it must liaise with a fully functioning prefrontal cortex to do that. This supports my theory that brain complexity comes before complex thought is developed.

Dhw: The prefrontal area is never “complete” so long as it is capable of new complexities! Please explain what you mean by “fully adult judgements”. You accept that the s/s/c does the thinking and the brain does the expressing and implementing. Once the implementation/ expression has been mastered, then of course the complexity is there for subsequent use, but cometh the next new concept, cometh the next new complexification. Thought comes before the brain change that implements/expresses it.

DAVID: Agreed that there is development and then further complexification.

But material development itself has initially come about through the need for expression/implementation. It’s an on-going process: immaterial thought/concepts etc. (whether complex or not) come before material change – the exact opposite of your theory that brain complexity comes before complex thought/concepts etc..

TONY: So, we shouldn't allow people to be considered adults until 25?
dhw: I would take that two steps further: 1) we shouldn’t allow people to be considered responsible for their actions until 25? 2) If judgement depends on the “completion” of the pre-frontal cortex but, as Tony and I have pointed out, the pre-frontal cortex continues to complexify AFTER 25, then we shouldn’t allow people to be considered responsible for their actions at any age? Exit free will, exit responsibility, and adults who commit murder, rape etc. can blame their wretched pre-frontal cortex for their mature or immature judgement (apparently depending on age). Tony’s remaining posts highlight the general chaos of David’s materialistic dualism and the inadequacy of the tests with admirable clarity. (However, I hope eventually to continue my efforts to reconcile dualism and materialism!)

DAVID: I must use materialism type science to study how the brain and the s/s/c combine. I have presented the science finding regarding age 25 and risk taking. All sorts of so-called brain impaired crimes are defended on that basis for no good reason I can see. I think at last you understand how I think the s/s/c and brain work together.

It is you who keep insisting that thought depends on a fully functioning pre-frontal cortex. If you now agree that the s/s/c does the thinking, the brain provides information and expresses/implements the thoughts of the s/s/c, the brain changes as a result of implementing the concepts, wishes, emotions, ideas etc. of the s/s/c, thought therefore comes before brain change, and consequently it is absurd for a dualist to argue that the brain has to expand before the s/s/c can THINK new thoughts, then we will have agreed on how the s/s/c and the brain work together.


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