Evolution and humans: big brain size or use (Evolution)

by dhw, Monday, May 29, 2017, 13:44 (2733 days ago) @ David Turell

Dhw: Pre-humans had brains, and if brains are plastic and conscious demands change them, as shown by the study, it is illogical to argue that the brain changed – whether by enlargement or by complexity - before there were demands.
DAVID: You are skipping the fact that we have fossil skulls which give us brain sizes which large jumps in volume. We cannot know the brain complexity at each stage, but we can look at stone tools, use of fire, etc. to judge the level of brain use. Of course at each level of size brain plasticity responded to levels of thought and use from developed activities.

You are skipping the fact that in this same post I have discussed large jumps (saltations) and you have quoted and responded to my response below:

dhw: The “gradualness” of enlargement covers the growth from the earliest hominins to ourselves. If the different stages occurred as big jumps (= saltations), it makes no difference to the argument that the brain changes when consciousness makes new demands. We have already agreed many times that saltations are indeed a mystery and that there is no evidence for my hypothesis or for your own.
DAVID: Once and for all there is no gradualness, no 'if' about the stages. Yes, saltations, which I think come from God. And not much use until 50,000 years ago with advanced language, and 45,000 years ago with cave art. Not like the use of today, which was allowed 200,000 years ago, but not taken advantage of.

What do you mean by “not much use”? The first sapiens survived, didn’t they? And they used fire and tools and we don’t know what else in the way of language and other skills that enabled them to cope with their different environments.

There are two issues. 1) What caused the enlargement of the brain? 2) What caused all the advances humans have made over the last 200,000 years? You say we begin with an advanced form of God-given consciousness which you now agree uses the brain. According to the study you recommended, the brain changes according to the demands of consciousness. History: the brain grew larger by saltations. Implication: consciousness made demands…brain enlarged to cope with demands. Brain reached optimum size. Consciousness continued to come up with new concepts, and so the brain had to complexify in order to meet the new demands of consciousness. It could hardly be clearer, provided one believes in dualism and an afterlife as oneself.

QUOTE: These mysterious languages demonstrate the brain’s astonishing capacity to decode information from new signals – with insights that are causing some neuroscientists to rethink the fundamental organisation of the brain. (David’s bold)
dhw: Nobody will deny the brain’s astonishing capacity to do all sorts of things. But if the brain is a RECEIVER according to your beliefs, it can only have changed when changes were needed in order to decode the information being sent by consciousness.
DAVID: Thank you. Of the brain's plastic abilities work intimately with consciousness.

The intimate work consists in the plastic brain responding to the requirements of consciousness: since that is what is demonstrated by the study, it makes perfect sense that it would also apply to the enlargement of the brain until it reached its optimum size. I presume your thanks denote agreement, so why have you spent the first part of this post disagreeing?