A Load of Bright
An atheist's views on religion and the supernatural

What Good is Half an Eye?


I’m sure that by now, most readers will be aware of the debate that took place on ABC Nightline between Christians Ray Comfort and Kirk Cameron, and atheists Brian Sapient and Kelly of the Rational Response Squad. Many bloggers have put their two cents in on this one, and I don’t think there’s really anything I can add that hasn’t already been covered.

Having said that, I would just like to pick up on one point that Ray Comfort argued in his opening address – the human eye and its ability to prove without any shadow of a doubt, through its wondrous complexity, the existence of an intelligent creator. The irony of this claim, was that it caused my wondrously complex human eyes to roll uncontrollably in disbelief that this argument is still being used!

The argument is supposed to go that the eye is so complex and intricate, that it could not possibly have evolved through natural selection. Each part is useless without the other parts, and it either works as a complete unit, or not at all. This argument, which has also been applied to other parts of animals’ bodies, has been refuted by evolutionists time and time again. For more on this, Ebonmusings has a particularly good article, What Good is Half a Wing?.

We know that the human eye evolved from more primitive forms. This Wikipedia article explains how early eyes worked.

The earliest predecessor of the eye was a simple patch of photosensitive cells, physically similar to receptor patches for taste and smell, called an “eyespot”. Eyespots can only sense ambient brightness: they can distinguish light from dark, but can not distinguish shapes or determine the direction light is coming from. Some organisms covered the spot in transparent skin cells for protection. Eyepatches are found in nearly all major animal groups, and are common among lower invertebrates such as the unicellular euglena. The euglena’s eyespot, called a stigma, is located at its anterior end, has a red pigment, and allows the organism to move in response to light, often to assist in photosynthesis.

I would like to add to the evidence illustrating this passage, by pointing out that we still have eyespots today. What’s more, I can prove it. Please take part in this fun, simple experiment. All you will need to do is find a lamp, and then follow these instructions.

1. Have the lamp next to you, plugged in, but switched off. Make sure that you can see the bulb directly. Remove the shade if necessary.

2. With the lamp still off, locate the switch and hold it in your hand ready.

3. With the lamp still off, stare at the bulb.

4. Now, close your eyes as tightly as you can. Really squeeze them shut, so absolutely no light can get through, although keep your eyes pointing in the direction of the bulb.

5. Keeping your eyes shut the whole time, switch the lamp on. Wait a few seconds. Switch it off again. Back on. Off again. On. Off.

What do you notice? You can see whether the light is on or not, even with your eyes shut. This is exactly the type of vision that earlier, less evolved versions of the eye offered their owners. It may seem primitive, and of course it is, but with predators in pursuit, it could easily have been the difference between life or death. It would definitely have increased chances of survival, and there is no question that natural selection would favour it. That’s how much use a lot less than half an eye is, Mr Comfort!

When open, our eyes are truly amazing in the detailed information they offer us. We see colours, shapes, perspective, etc. But when covered by our eyelids, they are effectively eyespots, the very tools that aided our ancient ancestors. While, for all intents and purposes, useless to us now, at least in comparison to what we’re familiar with, we cannot underestimate how much of an advantage this would have been in the past.

The much deeper irony of creationists like Comfort appealing to the eye as evidence of design, is that it is actually one of the most amazing examples of natural selection we have. It is an even more compelling example when you consider that, as Richard Dawkins points out, the vertebrate eye has evolved many times independently.

When one says “the” eye, by the way, one implicitly means the vertebrate eye, but serviceable image-forming eyes have evolved between 40 and 60 times, independently from scratch, in many different invertebrate groups. Among these 40-plus independent evolutions, at least nine distinct design principles have been discovered, including pinhole eyes, two kinds of camera-lens eyes, curved-reflector (“satellite dish”) eyes, and several kinds of compound eyes.

I really do wonder what more can we say? If the likes of Ray Comfort are still recycling this argument in the face of so much contradictory evidence, I doubt that our wondrous, complex eyes will ever see its long overdue demise.

7 Responses to “What Good is Half an Eye?”

  1. I read someone else’s comment, that creationism is for stupid people.

    That is so condescending, but, hey, the truth can sometimes hurt.

  2. I am unable to watch the debate since I have no access to streaming video.

    If the likes of Ray Comfort are still recycling this argument in the face of so much contradictory evidence,

    My big question: Are we really getting the message across?
    I’m hardpressed after the typical debate to list any facts or pieces of evidence provided by either side. All the debates I’ve seen or, more accurately read transcripts of, end up degenerating into vague, dueling philosophical points of view, where theism has its best and only shot of making its case. The discussion always ends up getting diverted to ULTIMATE origins instead of discussing the evidence we have about nature since the big bang. I never saw a list of all the many transitional forms beyond archaeopteryx until I went to the Talkorigins website. I never heard atheists or evolutionists bring up anything else.

    While I’m on my soapbox, why doesn’t anyone discuss the weaknesses of OT history as demonstrated by archaeology?
    It seems like we’re pulling punches in the public sphere; or am I just not seeing it?
    I read ABOUT the debate. Sounds like the God Squad was hopelessly outgunned.

  3. Polly said:

    why doesn’t anyone discuss the weaknesses of OT history as demonstrated by archaeology?

    Ebonmusing’s article Let The Stones Speak covers this brilliantly.

  4. I don’t get why any reasonable person would bother debating with the likes of Comfort and Cameron. What’s to be gained? As far as I’m concerned, neither the atheists nor the Christians were served by having that foursome of circus freaks spar over the air. The four principals, however, garnered plenty of publicity for themselves; I suppose that’s all they were after. Do you think perhaps they were in collusion?

  5. @Tobe38: Let the Stones Speak is a great resource and a real eye-opener. So far, I’ve only read the conquest section. I plan to get back to the rest. Pretty damning stuff! And, I even e-mailed Adam some feedback on that article, asking the same question, “Why on Earth is this the first I’m hearing about this?” We should be proclaiming the truth from the rooftops.

    Debates typically don’t bring out all the really good arguments that we have at our disposal. It’s no wonder Xians can still boldly make false claims about evolution and archaeology with impugnity, dragging out “crocoducks” *sneer* and other strawmen. The facts are definitely on our side, we’re just not using them to great effect.

  6. Not only do eyes evolve, they also devolve. I just watched the “Caves” episode from Discovery’s “Planet Earth” series. There are many types of cave-dwelling creatures who live in the dark. They used to live outside where eyes were useful. But now they have adapted to other forms of lightless navigation by sensations of pressure, vibrations, or echolocation. Many of these fish, insects, etc. still have vestigial eye spots or buds which are in the process of disappearing.

    So we have evidence not only of evolution, but devolution of very complex structures. The echolocation and vibration sensitivity which replaced vision in cave dwellers is equally complex to the visual system.

    Dawkins discusses echolocation at length in “The Blind Watchmaker.” He postulates that the brains of bats interpret the signals they receive as a type of visual information.

    Modern research has shown that blind people can learn to walk around labs and offices unaided using a video camera attached to electrodes placed on their tongue. After a while, the blind people report being able to actually “see” objects which they are only aware of as a pattern of changing sensations on their tongue.

    http://www.msnbc.msn.com/id/12459883/

    So not only can we observe changes in “visual” methods occurring over many generations, but we can create a new “visual” sense in humans straight away by wiring them up in the lab. In other words, brains are almost infinitely adaptable–proving they were not “designed” to operate in any particular way.

  7. Know where the evolution of the eye was first described?

    In On the Origin of Friggin’ Species by Means of Natural Selection by Charles Friggin’ Darwin, that’s where. Comfort could have at least used a remotely mysterious structure like the bacterial flagellum.


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