Brain Expansion (Evolution)

by dhw, Wednesday, April 29, 2020, 15:49 (1667 days ago) @ David Turell

dhw: It is the process of tackling new tasks that changes (complexifies) the modern brain, and I propose that the same process would have changed (expanded) the earlier brains. Now tell me why you find that illogical.

DAVID: It is an illogical extension from what we know about our very advanced different brain which shrank from hard thought, with no sign of expansion except in tiny designated areas from its very advanced complexification mechanism. You've seized on the latter because it fits your hopes for a non-god natural expansion. All hope, no support anywhere.

Nothing to do with “non-god”, since your God may be the designer of the mechanism. Once more: if hard thought caused shrinkage, we would not have any brain left! Our brain shrank, as you keep agreeing and forgetting, because complexification – which took over when the brain stopped expanding - proved to be so efficient that part of the brain became redundant. I have “seized on” the fact that the brain changes IN RESPONSE to new demands, so try again: why is it illogical to suppose that it did NOT do so in earlier times?

DAVID: We both agree the hardest part is new design. Putting the design together is easy, but I admit there may have to be a little easy trial and error.

If it’s the very first design of its kind, there could be a lot of trial and error. So what? Our disagreement concerns “hard thinking” as the cause of expansion (me) or the result of expansion (you).

DAVID: I note your theorizing does not fit my practical experience using our current advanced brain, which complexifies easily and shrank 150 cc. We do not know if previous hominin brains had any shrinkage before expanding. My guess is they did not as the drive was always for enlargement as God evolved each step.

What has your practical experience taught you that I have not agreed to? Of course there would have been no shrinkage in previous brains. The whole point of my theory is that whatever complexification may have taken place would not have been efficient enough to cope with new demands, and that is why the brain had to expand!

dhw: Why would the thinking soul depend on the non-thinking brain's expansion before it can think of a new idea based on EXISTING information? Your statement above [“Build a big enough complex brain and it can then conceive of what it couldn’t think of before” fits in perfectly with materialism, with the brain as the source of thought.

DAVID: I have never agreed to this distortion of my thoughts. For the last time, hopefully: the soul uses the brain to form thinking and concepts. [dhw: Yes, that is dualism.] It can only form advanced concepts if the brain it is given to use allows more advanced concepts than the last smaller brain, which in my view is always the case. That view is based on known history: each brain size advance is in the frontal and prefrontal areas where such thought takes place.

You constantly resort to the nebulous word “allow”. If by that you mean the brain must be large enough for the initial concept to be developed and produced, we are in agreement. We only disagree on the vital question of timing. You constantly agree that the dualist’s soul uses the brain to gather information and to implement (= design and produce) its concepts. So why would the brain need to expand if the soul is only using EXISTING information to form its new concept? Small brained homo has new idea: kill from distance. You claim that God has to expand his brain BEFORE his soul can think of this. I propose that this is the thought that triggers the process of hard thinking, which in turn expands the brain. (But once expanded, it can cope with new ideas until the next “big one”, which leads to the next expansion.)

DAVID: The problem with your theory is it is a lonely thought only in your brain. Leaving the natural level of our discussion, I believe God ran evolution and expanded each brain giving it much improved conceptualization capacity for the soul to work with. Our current brain is not at all like previous brains in its thought capacity and complexification process

The dualist’s brain does not have a “conceptualization” or “thought” capacity, as the dualist’s soul does the conceiving and thinking. That’s one of the problems with your theory, remember? But yes the increased amount of information and capacity for implementation will provide lots more material for the soul to use.

DAVID: Remember our adult brain does not grow new neurons in the cortex but does in the hippocampus. Enlargement is due to more dendrites and synapse connections and more astrocytes, not neurons. How does that fit your 'theory'? In your view the previous brains had to be totally different and ours somehow developed as the oddball!

Since the brain stopped expanding and gave way to complexification, of course it had to have more connections and its response process is different! How does that come to mean that the early homo’s frontal and pre-frontal cortex had to expand before his soul could have a new idea based on EXISTING information? And how does it prove that the brain had to change in anticipation of new tasks and not in response to them?