Big brain evolution (Evolution)

by dhw, Thursday, January 18, 2018, 14:24 (2499 days ago) @ David Turell

dhw: Soul thinks of new concepts; brain provides information and is used by soul to implement concepts. Soul of small-brained hominin has idea. Implementation of idea requires new abilities/greater capacity, and brain expands.
DAVID: As miraculous as my God doing it. I don't believe the small brain has an idea before expansion. The bigger brain has the new idea and implements it, per artifacts appearing with it. DHW's idea is discontinuous with the earlier brain having the idea which then can't happen until he new brain appears.

Now you, the dualist, tell us that the bigger brain has the new idea! Dualists believe the self/soul/consciousness has the ideas, but on Wed, 17 January you dispense with your dualistic soul altogether! As for discontinuous: no. Soul of hominin with small brain has idea, and effort to implement idea causes brain to expand, so appearance of artefact and appearance of enlarged brain coincide in one continuous process. The discontinuity lies in your dualistic version, which you have suddenly forgotten about: sudden expansion of BRAIN for no reason, but only then can SOUL come up with new ideas.

dhw: […] now that new concepts of sapiens' immediate predecessor have been implemented, we have sapiens’ brain which can no longer expand without nasty anatomical consequences.
DAVID: There is no reason why the brain could not expand more. It was 150 cc bigger earlier in sapiens existence. If there is no reason for it to expand it supports my contention that this is God's goal/endpoint for evolution.

So your God decided to stop expansion, whereas you can envisage current humans in current conditions with elephant-sized heads, and you don’t think that would pose problems for the rest of the anatomy. I can’t.

Dhw: For 270,000 years (David’s figure) soul of sapiens does not come up with major new concepts, but whatever it does come up with is dealt with by complexification.
DAVID: If the erectus brain forced the appearance of the sapiens brain size, why did it take 270,000 years for the implementations to start? Each stage of brain size is disconnected by time.

Wrong sequence! Pre-sapiens hominin had new concept; implementation of new concept expanded brain to sapiens size. 270,000 years passed before more new concepts required major changes to sapiens brain. Expansion not possible, complexification sole means of implementation. It took (according to you) 270,000 years for the "geniuses" to produce major new concepts - peanuts by comparison with habilis, erectus & Co. Incidentally, I don’t know where your figures come from. Most websites suggest sapiens goes back 200,000 not 300,000 years, but nobody knows for sure, just as nobody knows for sure when erectus became extinct (one website suggests as recently as 20,000 years). Perfectly feasible that pre-sapiens co-existed with sapiens – one would not expect EVERY pre-sapiens brain to expand. But that's just by the way.

dhw: […] the soul uses the brain to gain information and to IMPLEMENT its concepts, not to do its thinking for it.
DAVID: The soul uses the brain to think!

The soul (if it exists) uses the brain to provide the information it thinks about, and it uses the brain to implement its ideas. You have agreed to this over and over again (see your post under “brain damage”, 13 January at 01.05), as exemplified by your facile computer image, in which the software (soul) provides the idea, and the brain (computer) implements it.

dhw: ”Genius” pre-sapiens’ small brain has concept of spear, and implementation of concept forces expansion – just as concept of reading and writing forces new complexifications in brains of illiterate women.
DAVID: That is not expansion, but shrinkage!

Of course it’s not expansion! Yet again: the sapiens brain can’t expand any more, and so complexification is the sole means of implementation. Complexification is so efficient that some cells and their connections are no longer needed – hence shrinkage.

dhw: Once more: concept formed by soul with current brain; implementation changes brain – precisely as described so vividly in your post of 2 December under “learning new tasks”.
DAVID: Stop. I've told you a previous size increase in brain was implied, but not clear the way I wrote it.

I accept that you didn’t mean it that way, but I cannot think of a better description of the process I am proposing.

DAVID: Your point about a physical limit agrees with my point that current sapiens are/were God's goal all along.
dhw: Physical limit has nothing whatsoever to do with your God’s goal. All species reach a certain size, with limbs, head etc. in proportion to the rest of the body. We may assume that the dimensions are optimum under current conditions. Maybe in a billion years, there will be new conditions, with elephant-sized ants, ant-sized elephants, and humans...well, who knows?
DAVID: Of course it is God's goal. We survived well with it until 30,000 years ago when concepts and implementation exploded. Proof that our current brain is not needed for survival, but despite Darwin's theory about survivability as a major driving force, it is here.

I have added improvement to survivability as a major driving force. You are discussing this with me, not with Darwin.