Different in degree or kind: Egnor's take; more on gaps (Introduction)

by David Turell , Monday, October 17, 2016, 15:03 (2959 days ago) @ dhw

dhw: The authors acknowledge the mystery of the fifth type that did not stay fish and led to us. As regards primitive lungs, they drew attention to conditions in which water lost oxygen and air proved a better option, and there were different families of fish that spent days on land. It would be interesting to google the history and different forms of primitive lungs, but I’m afraid I don’t have time.

To my knowledge we have only one example of fish with primitive lung that made he transition as the authors careful analysis of walking fish tells us. Their point was to attempt to make it sound easy, which they admitted in the article.

dhw: Again, this is such a logical process that one really can’t dismiss the idea that it was the starting-point for the all-important permanent switch from water to land.

Of course a lung had to appear. We should be discussing the actuating cause of the lung

DAVID: Agreed. At times of demonstrated need, organisms adapt. ..But I still see no need for human brain enlargement. Their ape forbears did just fine until the humans crowded the Earth.

dhw: As we have said over and over again, there was no need for any advance beyond bacteria. Hence, my hypothesis that evolution progresses through a (perhaps God-given) drive not only for survival but also for improvement. In the case of humans, somewhere along the line, pre-humans developed an enhanced consciousness of the world around them. The source of consciousness generally remains the great barrier to all of our hypotheses. But in the context of your dualism (see the sapiens thread), for this awareness to be of any use, our pre-sapiens ancestors needed a larger brain to improve means of expression and of materially carrying out the instructions issued by consciousness. Hence the need gives rise to physical change, as opposed to physical change creating the need.

And again I look at the physical gap you lightly jump across. Each brain is much bigger as we go from 400 cc to 1,200 cc. Requires complex planning of bone skull shape, brain interconnections building a bigger frontal lobe, blood circulation pathways, lymphatics pathways, larynx dropping, etc.