LiveFreeOrDie

ARN has posted a <a href="http://www.arn.org/docs/odesign/od171/retina171.htm" target="_blank">document</a> purporting to refute the common evolutionist argument that the mammalian eye is suboptimally designed.

Discuss.

(Nothing like a little exercise to strengthen those debate skills).

elwoodblues

Okay. This is coming from ARN, so it's supposed to be supportive of intelligent design. But I don't see that it is.

Assume that their argument is true. It just seems to mean that evolution was working a little better than even Dawkins and Williams thought. If it works better that way, great. I really fail to see how this is some kind of decent argument for intelligent design. Maybe I'm missing something.

As an aside, I've learned a bit about this in my brain biology class. Correct me if I'm wrong (it's been awhile), but this is how it was related to me.

Over the course of the evolution of the eye, more and more 'stuff' was added to improve the functioning, processing, and resolution of the eye. Now, these additions couldn't sprout behind the eye (I can't remember why; maybe because the skull is in the way?). Instead, they had to grow _forward_ from the back of the eye. And, even though these additions partially obscured and blurred the image projected on the back of the eye, it was still a good trade-off. These structures provide initial processing of the image, hugely important for us, aiding things like motion detection, edge detection, and major feature awareness.

bluefugue

So if they're refuting the idea that it is "suboptimally designed," they are claiming that it is perfect? That it couldn't possibly be better?

Well damn, I guess my astigmatism is all in my mind...

[ January 09, 2002: Message edited by: IesusDomini ]</p>

bluefugue

Anyway how can you possibly determine what is or is not "optimal" design? What are the criteria?

Arrowman

What are " evolutionary arguments about suboptimality" anyway? Scientists do not rely on being able to demonstrate "suboptimality" (as IesusDomini says, define "optimal design"?) to support evolution. "Suboptimality" is only used as an argument against intelligent design. An organ could be optimally designed, and still have evolved, provided a plausible evolutionary pathway can be demonstrated. I don't think ARN successfully show that a plausible evolutionary pathway cannot exist for the eye.

So even if ARN are right, and the eye is optimal (whatever that is), that neither knocks down evolution not supports ID - all it does it remove one of the (hundreds of) objections to ID. Come back when you've dealt with the appendix and all the others, guys.

Which brings us to the crux of the logical argument here. What is the point of this? ID relies on the IMHO completely unscientific assertion that one can (a) demonstrate perfection that could not possibly have arisen through (currently understood) natural means and then (b) proceed from the resulting "don't know where it came from" to "it must have been an intelligent designer". All ID would do, is draw unsupportable conclusions beyond the current boundary of scientific knowledge. It's faith, not science.

And speaking of such - the mere fact that ARN publish this paper demonstrates that they are into debate and not science. They try to knock down one of the most common arguments against ID, (a) without succeeding and (b) without advancing their own "research" one iota. It's pure rhetoric, for all the footnotes.

Dr Rick

Not a very good thought at all: properly designed, the photoreceptors would maintain their orientation but all the nerves and blood vessels would be moved to the outer layer of the retina. Photoreceptor physiology could then be altered to accomodate the change and there would be no structures in the way impeding light transmission.

This partly describes the current anatomy of the vertebral retina; there is a vacular plexus on the inner side! Good design would have placed it behind the photoreceptors.

That's why a superior eye would maintain the current receptor orientation; good design would dictate repositioning the nerves and vessels.

...is a strawman.

[ January 09, 2002: Message edited by: rbochnermd ]</p>

Quetzal

Even worse, they're holding up the modern vertebrate eye as an example of their re-engineering. Squid eyes are ALREADY designed that way - and work substantially better than human eyes (try chasing prey in the dark underwater if you don't think so). Typical ID nonsense. Not only have they failed to prove "optimal design", but they've added more fuel to the "(un)intelligent engineering" refutation of their whole premise.

Next (vain) argument?

Megatron

Damnmit, Morpho! Heh... I was just looking at an article about eyes, and was going to post practically the same thing... but then I come back and you beat me to it.

Don't ask them for the next argument, though... unless you really want to sit here and refute more baseless nonsense.

Oolon Colluphid

And of course it depends on what counts as optimal. Naturally vertebrate eyes are really good – they’ve had a lot of generations’ practice to overcome the fundamental flaw (which must have been better than nothing originally ). But the eyes of birds of prey are much better than ours at seeing from distances; insect eyes see more of the spectrum; nocturnal animals see better in the dark than us; and so on.

Sure, they’re fitted for their purpose. But if we humans are supposed to be created in god’s image, the most important bit of creation with dominion over all other creatures, it’s a bit odd that we aren’t the Rolls Royce of animals, with the full available compliment of bells and whistles. Why can't we photosynthesise? It'd save so many people starving to death. Instead, we’ve got stuff very very like that of apes.

And these bozos ignore the distribution of the vertebrate eye: why is it found, flawed or otherwise, in and only in creatures which for hundreds of other, non-eye-related reasons, are considered to be related. This leads to a pretty solid prediction. I have never studied, and it’s possible no-one has, the eye anatomy of, say, Humboldt penguins. They hunt fish underwater, and so could do with a squid-like eye, or even, something different again -- god’s got a free hand with his designs, after all. I predict however that it will have a vertebrate-style, retina-in-backwards eye... that whatever other features it has that let it see really well underwater (and it may have all manner of clever stuff), it will have the retina found in other birds and other vertebrates. (Equally, penguins have hollow bones, as do other birds. For added buoyancy, of course.)

They also ignore the presence of such eyes even in creatures that don’t need them. Even though drastically reduced and covered with skin, the eyes of cave salamanders, mole rats, marsupial moles etc are still clearly of the same ‘design’ as those of more ‘normal’ vertebrates.

Just some thoughts.

TTFN, Oolon

[ January 10, 2002: Message edited by: Oolon Colluphid ]</p>

Megatron

C'mon, Oolon... you should know that one by now... those guys have eyes so, just in case he drops by, they'll be able to tell the pope's hat apart from the hats of his parishioners, and know who's way to get out of and who to crawl on and gross out.

One must maintain an image, after all...

(Hey... it was a better excuse than you'd ever get from a fundy! )