Profile

Cover photo
Andre Sourdiffe
1,272 views
AboutPostsPhotosVideos

Stream

Andre Sourdiffe

Shared publicly  - 
 
Andre Sourdiffe originally shared:
 
The eye is a marvel of engineering. There are those, however, who think the eye shows very poor design since they wish to avoid the idea of a designer at all costs. Lets examine the case for the evolution of the eye, made by those antitheists. It starts with a just-so story. A just-so story is an attempt to explain something for which there is no evidence. It is an attempt to fill in the gaps in Evolution so that they are not so obvious. Here is the just-so story for the eye. At first, there was a light sensitive spot that appeared on the skin of some animal. Then more of them appeared. The spots then bunched together in one area of the skin. Then a depression formed in that area under the spots. A clear membrane formed covering the area of the spots. Ultimately, a working eye was formed as a result of the clear membrane forming the shape of a ball, enclosing the spots within. There is more but you get the idea.

The first thing I notice is that, if you read the story without a bias toward evolution, it looks very much like there was a designer involved. How else do you explain the spots coming together in one place and in the right location for an eye? And, what drove the appearance of a clear membrane, again in the right location? Another issue is the survival value of spots that merely respond to light and dark. How does the existence of those spots help the organism that has them? It gets worse. These spots are portrayed as simple. They would be anything but. Dr. Michael Behe has shown that even a ‘simple’ light sensitive spot requires a dazzling array of biochemicals in the right place and time to function. He states that each of its ‘cells makes the complexity of a motorcycle or television set look paltry in comparison’. This doesn't include the changes required to the animal's brain to be able to interpret the signals from the spots or the nerves connecting the spots and the brain.

The proponents of this just-so story attack the design of the vertebrate eye, which is what we have. They claim that if there was a designer of the eye he might want to go back to remedial engineering school. I'm paraphrasing a bit here. While they admit that the eye works very well, they claim that the engineering of the eye is not very elegant and lacks the qualities of proper engineering. Why would they make such a claim? It is because they think our eye is stupidly wired back to front, something no decent designer would do. They further state that any engineer would naturally assume that the photocells would point towards the light, with their wires leading backwards towards the brain. He would laugh at any suggestion that the photocells might point away, from the light, with their wires departing on the side nearest the light. Richard Dawkins is a vocal proponent of this idea, along with other antitheists.

Unfortunately, Dawkins, and company, never checked with an ophthalmologist, who would have set them straight. George Marshall, the Sir Jules Thorn Lecturer in Ophthalmic Science, stated in reply to Dawkins:
‘The idea that the eye is wired backward comes from a lack of knowledge of eye function and anatomy.’
Dr Marshall explains that the nerves could not go behind the eye, because that space is reserved for the choroid, which provides the rich blood supply needed for the very metabolically active retinal pigment epithelium (RPE). This is necessary to regenerate the photoreceptors, and to absorb excess heat. So it is necessary for the nerves to go in front instead.
It’s important to note that the ‘superior’ design of Dawkins with the nerves behind the photoreceptors would require either:
The choroid in front of the retina—but the choroid is opaque because of all the red blood cells, so this design would be as useless as an eye with a hemorrhage!

Photoreceptors not in contact with the RPE and choroid at all—but the photoreceptors would be slow to regenerate, so it would probably take months before we could drive after we were photographed with a flashbulb, as another ophthalmologist, Joseph Calkins, points out.

Another creationist ophthalmologist, Dr Peter Gurney in a detailed article, pointed out all the above with the RPE, but pointed out another use: extracting excess heat.
The above section shows that inverted wiring is necessary for vertebrate eyes to work—but that is the direct opposite of what evolutionists claim would be the ‘correct’ wiring.
Note that the evolutionists’ claim is actually undercut by their own assessment of squid eyes, which despite being ‘wired correctly’, don’t see as well as vertebrate eyes, according to the evolutionists themselves.

Now these claims regarding the poor design of the eye are more in the nature of a religious argument rather than scientific. The eye works really well so the arguments regarding its poor design certainly don't have any foundation, not based on the performance of the eye. Now, these claims have even less foundation, because....

Dawkins’ claim that the nerves obstruct the light has been falsified by very new research by scientists at Leipzig University. They showed that the vertebrate eye has an ingenious feature that overcomes even the slight disadvantage of nerves in front of the light receptors.
The light is collected and funneled through the nerve net to the receptors by the Müller cells, which act as optical fibres. Each cone cell has one Müller cell guiding the light to it, while several rods can share the same Müller cell.
The Müller cells work almost exactly like a fibre optic plate that optical engineers can use to transmit an image with low-distortion without using a lens. The cells even have the right variation in refractive index for ‘image transfer through the vertebrate retina with minimal distortion and low loss.’
Indeed, Müller cells are even better than optical fibres, because they are funnel-shaped, which collects more light for the receptors. The wide entrances to Müller cells cover the entire surface of the retina, so collect the maximum amount of light.

Now, how is it possible that something like this could develop? Scientists spent many years trying to develop the fiber optic technology we use today for data communications, and many other things. It was very difficult to find the exact materials that would transmit light without distortion. The thought that random processes could produce organic materials that could transmit light with sufficient fidelity is incredible. How could they provide the amazing sight we enjoy? It seems ludicrous. The very existence of these optical fibers in our eyes would seem to put to rest the argument that the eye is poorly designed. It hasn't though, faith in evolution is very strong with some.

Here are some additional points to consider regarding the eye:
The muscles that move the eye up and down and side to side.
The iris that is able to open and close to adjust for light intensity.
The lens that is adjustable to change focus.
The cornea, the clear protective covering.
Eye lids, eyelashes and eyebrows to protect the eye.
There is a blind spot at the back of the eye where the blood vessels and nerves connect. The blind spot is in a different place in each eye. That means the blind spot isn't obvious when using both eyes. The brain also seems to edit out that blind spot even when using only one eye. (Also, the blind spot is very tiny located on the edge of the vision area and unlikely to affect sight much)
The eyes work as a team. There is no rod connecting the two. The brain keeps the eyes aligned.
The optic nerve connects to a section of the brain that is able to interpret what you see.
An eye is useless if what you see can't be understood. The brain must be able to interpret the images it receives.

So, what does this list mean? It means that the complexity doesn't end with the eye itself. The entire vision system is extremely complex. The brain has been designed to work with the eye. When we look at something close than look away and back again, our eye instantly adjusts to maintain focus. When we look at bright light the eye shrinks the iris. If needed, it also increases the blood supply to deal with increased heat. Your eyes are kept synchronized by your brain so that they both stay aligned. The eye lid reacts with amazing speed, closing when an object comes flying at it, even when you don't consciously notice it coming. The internal pressure of the eye must be regulated and kept within a certain range.

This is just a small taste of the complexity of the eye. Talk to an ophthalmologist if you really want to know just how complex the eye, and the systems that support it, is.

The bottom line? The level of complexity involved here far exceeds the capabilities of evolution to produce it. The just-so story is just a story, and not a very good one at that.

I want to thank creation.com for some of the source material I used here.
1
Add a comment...
Work
Occupation
Network Administrator
Basic Information
Gender
Male