Miscellany (General)

by dhw, Monday, May 10, 2021, 13:10 (1084 days ago) @ David Turell

BATS
dhw: You say you believe in common descent, and I’m asking why you think it’s impossible for bats to have descended from an earlier life form.

DAVID: Sudden appearance implies God might have dropped in an addition, as in the Cambrian.

I know what it suggests. I am asking why you, who believe in common descent, think it’s impossible for bats to have had an ancestor, and why you should take it for granted that every stage of speciation, going back hundreds or even thousands of millions of years, should have left us with a complete fossil record of itself.

Seals
dhw: Your quote follows on from:
“This has happened multiple times, with groups like whales, sea turtles, sea cows and crocodiles, all evolving from land-dwelling ancestors that have adapted themselves for a life at sea.”
No inference or mention of random mutations. Adaptation is not random, and what is wrong with the suggestion that adaptation to new environments helps us to understand diversity?

DAVID: Of course there is diversity, which Darwin tells us comes from random mutations

The article contains no reference to random mutations, so I don’t know why you tried to dismiss it as “typical Darwin think”, or why you objected to the statement that adaptation to new environments helps us to understand diversity.

The obstetric dilemma
DAVID: The pelvic cells knew the independent baby skull size had grown. Really? Whew.

dhw: How else do you think adaptation functions? Conditions change (bigger brain), and either the cells RESPOND (change pelvis) or the organism dies.

DAVID: A total non-answer. How did the pelvic bony cells anticipate the bigger baby head? You just prefer non-thought in considering the obstetric dilemma. 'Respond' requires anticipation.

My proposal is that the cells did NOT anticipate the bigger head, and “respond” is exactly the opposite of “anticipate”! The process would be that the pelvis finds itself having to cope with a bigger head. Either it expands or it’s goodbye to mother and child. Initially, I have no doubt that the latter would have happened all too frequently. But in some cases the response would have enabled mother and child to live, and those are the cases which would have led eventually to the adapted form of pelvis surviving as the norm. Still not perfect by any means, but adequate for general survival. Do you really imagine that your God stepped in to provide a ready-made new pelvis, and therefore all Lucy-mothers survived?

Erectus speech
QUOTE: "The available evidence then strongly suggests that erectus invented language more than a million years ago. In so doing, Homo erectus changed the world more than any creature since, including their grandchild, Homo sapiens."

dhw: At last some common sense. To my mind it is absurd to imagine that our predecessors did not have their own language in which to communicate. But I think the above quote is highly exaggerated. The world of erectus would still have been very much the same as that of his predecessors and of early sapiens. Our modern world of cities, technology, institutions, means of transport etc. would be totally unrecognizable to erectus. Language complexifies when new words and structures become necessary. Of course we use these once we have them, but I don't think language produces the new concepts it expresses.

DAVID: The ability to express abstractions in speech and print is what did it. Erectus did think in simple abstractions making stone tools, rafts, etc.

A sort of chicken and egg situation, perhaps. I suggest that new words and constructions became necessary as humans came up with new ideas which required new forms of expression. But of course, once these forms of expression existed, they would have been used to generate new ideas as new knowledge was passed on to more and more “thinkers”.