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

by dhw, Thursday, May 18, 2017, 13:40 (2744 days ago) @ David Turell

dhw: And so if consciousness (the self) can exist independently of the brain, the “back and forth” in our lifetime can only consist in the brain providing consciousness with information, and consciousness then instructing the brain to control the rest of the body. Only if you reject the NDE scenario in which “we” (the self) exist as pure consciousness can you claim that the brain uses “us”/consciousness.
DAVID: I don't reject the NDE scenario. I consider consciousness as an entity which is received by our brain and is used by our brain. We don't know what consciousness is. It is not material. We experience it and work back and forth with it. All animals have the conscious activity and controls you mention above, but not the deeper self-awareness we enjoy. This has always implied to me a universal consciousness in which we all partake are varying levels.

You are jumping around like a cat on a hot tin roof in order to avoid the point I am making, which concerns the implications of your belief in the NDE scenario. In a nutshell: if you believe that our identity/”we”/the self, in the form of consciousness without body and brain, continues after death (as apparently experienced by NDE patients), then it can only be consciousness/”we”/the self that uses the brain, and not the other way round.(See below)

dhw: This has implications for the problem of which came first: brain enlargement allowing function, or function enlarging the brain…
DAVID: All of the evidence from studies of our ancestor fossils is brain enlargement allows certain levels of anthropologic activity. Each enlargement allowed more complex activity. 200,000 years ago sapiens activity was not what it is today, but the brain had arrived!
dhw: The evidence shows that enlargement accompanied certain levels of activity. It cannot possibly tell us which came first: the enlargement allowing the activity or the need for the activity causing the enlargement. That is the big debate.

DAVID: I'm still insisting that speciation of a larger brain precedes any new extensive activity which is what the enlargement allows.

You always insist that your beliefs are correct, even when they are contradictory. If “we” are our consciousness (as per NDE experiences), which contains all our memories, feelings, thoughts and ideas, then how can the brain precede the IDEA of a particular new activity? Does the spade invent the idea of digging, or does the idea of digging invent the spade? With your NDE-based, immaterial identity, does the brain come up with new ideas, or does your consciousness (= you) come up with new ideas and use (and if necessary change) the brain as its tool to implement them? (Even now, though on a very minor scale, we/our consciousness can make changes to brain and body through exercises that activate the neurons or enlarge the muscles.)

DAVID: This thought follows from the fact that the gaps from Lucy to habilis to erectus to us are huge with gaps from 400cc to 1,200cc with no itty bitty changes. Please remember 200,000 years ago we had 1,200cc, but how much did we use it back then? Obvious.

I’m not sure how your question supports your claim that the brain uses us/our consciousness. As regards itty bitty changes, like you, I can only rely on what the experts tell us about the evolution of the human brain. Wikipedia disagrees with you:

Evolution of the brain - Wikipedia
https://en.wikipedia.org/wiki/Evolution_of_the_brain

The evolutionary history of the human brain shows primarily a gradually bigger brain relative to body size during the evolutionary path from early primates to hominids and finally to Homo sapiens. Human brain size has been trending upwards since 2 million years ago, with a 3 factor increase. Early australopithecine brains were little larger than chimpanzee brains. The increase has been seen as larger human brain volume as we progressed along the human timeline of evolution (see Homininae), starting from about 600 cm3 in Homo habilis up to 1736 cm3 in Homo neanderthalensis which is the hominid with the biggest brain size. The increase in brain size topped with neanderthals; since then the average brain size has been shrinking over the past 28,000 years. The male brain has decreased from 1,500 cm3 to 1,350 cm3 while the female brain has shrunk by the same relative proportion.[1] (My bold)

Apparently this shrinkage may be accounted for by more efficient arrangement and wiring, which I would suggest offers an answer to your last question. Clearly the brain cannot go on growing indefinitely, and so in order to accommodate the increasing demands of consciousness (I’m still following your dualist NDE line of thinking) it has to complexify its inner workings.