My Book On Evolution

Personally, I don't have a problem with the notion of the process of evolution "inventing" things. I look upon it as a kind of shorthand for saying that through the process of evolution certain structures arise which seem like inventions that solve certain problems encountered by living things in their struggle for existence. It's a bit like Richard Dawkins' use of the word 'selfish' in conjunction with the concept of genes.Of course I can't be entirely sure about Mike's intended meaning when he uses these constructs, but he could be forgiven for it, because it makes it easier to discuss the substance of the argument without having to deal too much with its form. Mike is a stickler for formal logic, but unfortunately he gets it wrong very often, so these turns of phrase could also be viewed as a stylistic improvement on an otherwise muddled thought process.

Let's compare an otter, a seal and a dolphin. They all have a similar bauplan, namely a mammalian skeleton with four limbs with five digits each.In the otter, the forelimbs are still functional as arms with grasping hands. On land the otter moves more or less like a typical four-legged mammal, but in water it assumes a more torpedo-like form and proves to be an excellent swimmer, although it hardly uses its arms for this purpose.The seal also has forelimbs with outwardly recognisable digits, although they are mostly concealed inside what is beginning to look more like a fin than an arm. But a seal can still scratch itself with its nails. On land it moves in what seems to be a rather clumsy way, but in water a seal is even more agile than an otter. Its forelimbs are better suited for swimming than for walking, having taken on a more fin-like form.The dolphin, although completely helpless on land, is arguably the best swimmer of the three and its forelimbs are almost identical to those of a shark. Their only purpose seems to be for swimming. Still, if you look at the skeleton of a dolphin, you can see five digits, analogs of those of the otter and the seal. But they are completely enclosed inside the dolphin's fin-like forelimb, and it has no use for them whatsoever, it seems.Even though the aquatic nature of these three animals has evolved independently, here we have an example of an arm, a fin, and something in-between. And yes, all are viable and "complete", from the viewpoint of the animals themselves.Edited by Parasomnium, : No reason given.

Mike, have you abandoned this thread?