Ronald Brak

Because not everyone can be normal.

Thursday, October 06, 2005

Intelligent Design, Eyeballs and Mad Scientists with Scalpels!

A post I wrote on Intelligent Design is now in the Tangled Bank! How cool is that? I’ve really arrived as a blogger now. The total number of comments my blog has received has more than doubled today. In the comments the subject of eyeballs were brought up. Now personally I like eyeballs and happen to have two of them myself. I’m very attached to them. (Mainly via the optic nerve.) I happen to know a lot about their internal structure on account of a cheap pair of glasses I used to have that under the right conditions would reflect the inside of my eyeball for my visual delight. Often when I was riding my bike in the rain at night a ghostly image of my own retina would be laid on top of everything. It was like cycling through my own aqueous humour.

Intelligent Designers, or as I tend to think of them - creationists, are also fond of eyeballs. In discussion they love to pull out eyeballs (ouch!) and say that they are an example of irreducible complexity. I’m not sure just what irreducibly complex means, but from the way they use it I think its meaning is, “I’m right, you’re wrong, so there, nyah-nyah-nyah!” They then might go on to say that eyeballs are comprised of a multitude of specialized parts, each of which is dependant upon the others to function and so the eye could never have evolved by any step by step process, because half an eyeball is useless.

This idea is has been dismantled by plenty of clever people, including my nighttime companion, Richard Dawkins. However I’d like to add my own macabre take on this.

If I were to take a scalpel to your eyeball and cut the muscles that control the focusing of the lens, then you wouldn’t suddenly go blind as this system was removed. Instead, you’d just lose the ability to focus on close objects, which is something almost everyone experiences, as they grow older. Your vision wouldn’t be as good, but you’d still have vision. If I were then to use my scalpel to disable your iris, again you wouldn’t go blind, you’d just find it hard to adapt to different light levels. If I removed your lens completely, everything would be out of focus, but you’d still be better off than with no eye at all. If I were to go as far as cutting your eye in half and sealing it off with glad wrap, then you’d have very little vision, but still perhaps enough to avoid walking into walls. If I were to continue to slice away and leave you with just a fragment of your retina, then you really wouldn’t be able to see, but you could still tell the difference between night and day, which is better than nothing.

So next time someone says the eye proves Intelligent Design because half an eyeball is useless, just tell them the above story and perhaps you’ll convince them of the error of their ways. Or more likely you’ll just gross them out. But that’s fun too.


At 6:42 AM, Anonymous Anonymous said...

Irreducible complex is a term meaning "it won't work without all the parts". Neo-Darwinism, Natural Selection work gradually. So the idea here is some things look like they can't work that way because they are so complex. I think the term is used more on protiens or enzymes then on body parts. The argument against it (IC) is usually that sure it just wasn't selected for until it was complete. Before completeness, it was harmless, so no selection was made against it. And it just spread across the population. PZ would probably explain it better.

At 3:23 AM, Anonymous dre said...

or better, some aspects of each organ or trait were in fact useful to the organisms which bore them before said organs or traits were "complete", just not to the extent that they are useful in their "complete" states, which are probably not final states at all.


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