None So Blind

Today's post also comes from Answers in Genesis. The old saying goes that there are none so blind as those who will not see, and this article illustrates that perfectly. The AiG writer has the evidence for evolution right in front of him, but refuses to believe it. The article is called Eyeless fish in caves.

'We read about fish that live in caves. They can’t see, and they have scars where most fish have eyes. Were they created like this?’

No. Mutation and selection have changed them from a state in which they had eyes to one in which they don’t. The following is almost certainly what happens in such situations.

A population of fish that have eyes begins to live in underground environments that have no light. Their eyes are then useless to them. However, organs do not ‘degenerate’ just because they are useless. The information to produce eyes is copied and passed on, generation after generation.

Even fish that live in light occasionally have copying ‘mistakes’ as this information is transmitted. These ‘mistakes’ are called mutations. They corrupt and damage the information. When a fish living in a light environment has such a mutational defect which causes its offspring to have no eyes, this defect does not have very much chance of being passed on generation after generation.

The reason is simple—a fish without eyes is normally at a tremendous disadvantage. Sight helps fish catch their food and avoid being caught for food themselves. Natural selection will thus tend to eliminate this defect.

But what about those fish that have come to live in caves? Sooner or later, the same eyeless defect will occur here as well. Only this time, it does not give any disadvantage, so it is not eliminated. In fact, it gives advantage. The fish that have eyes can bump into things and injure their eyes, also they can get diseases of the eyes, both possibly leading to death. The fish that carry the eyeless (defective) information can’t get any of these problems. These eyeless fish thus have a greater chance of passing on their genetic information (carrying this defect) and so in time, natural selection will ensure that all the fish are eyeless.

All of this information is basically true. There are indeed such fish. The writer has gotten so much right, but watch as he blows it all in the last paragraph.

Note that this is a ‘downhill’ change. Complex, functional information coding for eye manufacture has been corrupted or lost. Such a decay process gives no evidence at all for the belief that complex organs have arisen by such processes—it only shows how this information can be lost in a fallen world.

D'oh! So close, and yet so far. This last paragraph shows that the author doesn't know much about evolution. This is not, as the author claims, a 'downhill' change. For one thing, the information coding for eye manufacture has not been lost. Blind cave fish begin to develop eyes before they are hatched, but then something actively stops the process and causes flesh to grow over the malformed eyes. Even when the eye lens from another, sighted fish is transplanted into the blind fish, it is covers over in the same manner. (Science 289 (28 July): 631–3) No trait has been lost, instead a new one has evolved.

Even if the genes for growing eyes had been lost in the cave fish, this would still be an example of evolution. Evolution is undirected, it follows whatever path maximizes the ability of an organism to reproduce. Evolution cannot go backwards, only forwards. Even when a trait is lost, evolution is still going forwards. The irony is that the first part of this article is, as far as I can tell, completely accurate. It demonstrates evolution in action. But the author has completely missed the point. The blindest of all are those who see, and then avert their eyes to deny their sight.