Posted: Jun 24, 2014 3:06 pm
by DavidMcC
halucigenia wrote:
DavidMcC wrote:
It is not a strawman. I now have a page reference for the bad biology:
"Climbing Mount Improbable", chapter 5, page 153, Fig,5.14 from Nilsson and Pelger.
The reader is left to assume that the "fish" referred to in the fish-eye sequence is a vertebrate fish, because othing to the contrary is mentioned in the text. The sequence I have referenced is not the only one I know of, but it is the only one that I can find at the moment.
I accept that RD was not the instigator of this mistake, but he certainly propagated it, aided and abetted, it seems, by an aquaintance of his, who works for Nikon!
Well, there's no reference there to the backwards retina, nor to molusk eyes at all, never mind “one extra step to turn the retinae inside out”.
Come on, admit it, you were making this up all along. :nono:

DavidMcC wrote:You can kid yourself, maybe, but I have found another old reference, this time in "The Greatest Show on Earth", chapter 11, "History written all over us", p354:
"But now, suppose I tell you that the eye's 'photocells' are pointing backwards, away rom the scene being looked at. The wires connecting the photocells to the brain run all over the surface of the retina... That doesn't make sense...". (My bold) His problem might be that Nikon don't make self-maintaining CCD arrays, so his technical advice was bad from the start. (He quoted his Nikon friend at some point, on camera design.)
Quite, as I thought, this is a separate claim from the sequence of possible steps to form a modern vertebrate or cephalopod eye. It is a claim that the initial arrangement "...The wires connecting the photocells to the brain run all over the surface of the retina... That doesn't make sense..." rather than anything about its subsequent evolution to form a "camera" type eye which then had to take “one extra step to turn the retinae inside out”.
His point, and the title of the chapter "History written all over us" confirms this, is that it is historical happenstance that the structure of the eye in vertebrates happened to be the way that it is in respect of the inverted retina and that it became the way that it currently is with respect to its current functionality simply because of this, rather than because of the foresight of an intelligent designer.
Well of course there were no "foresights of an intelligent designer". HOWEVER, the inverted retinal structure turned out to be a lucky break for the vertebrates. Without that bit of "bad design" we would have the same problems as invertebrates with our eyes failing after only a few years in a photopic environmnent, or having to ut up rwith the "cheap and cheerful" stalk-eyes of some lobsters, or as with many ant species, having short-lived servants to collect the food while the queen stays underground, etc , etc.
Even if Nikon did decide to make self-maintaining CCD arrays, without referencing vertebrate eye structure, do you think that they would have started off with a CCD array "pointing backwards" and build from there, or do you think that at some point they would even take the step to turn the array the other way around and re-design from there as you have suggested that Dawkins thought happened in the evolution of the vertebrate eye? Are you suggesting that this would be "good/intelligent" design practice? :ask:
Building a self repairing CCD array that requires software to ignore the wiring running all over the surface and the point at which all the wiring all goes through the array at one position might make it possible but it would still seem like a kludge to me. :dunno:

Oh, gosh, where to start! It's a pity that my original posts in richarddawkins.net are lost, because I went to great lengths there to marshall the evidence. Maybe NineBerry can actually supply the missing content as he claims?

On the photoreceptors "facing the wrong way", that was one of RD's worst mistakes. They DO NOT FACE BACKWARDS! What actually happens, if you know the biology, is that the photo-receptor cell body guides the light through to the outer segment, where the opsin discs are. This narrows the aceptance angle for light received by any one photoreceptor, at the price of losing some of the light (but light that would only cause resolution and glare issues in any case).