Why I’m Still a Young-Earth Creationist, Even Though It’s Getting Increasingly Lonely over Here
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In the evolutionary system, mutations get you the possibility of change in living organisms. But the changes are random and thus are not directional; they’re not going to get you to anything that looks like a line of development, which is what the term evolution means. You need a mechanism to give the force of change some sort of direction. That mechanism, as proposed by Charles Darwin in On the Origin of Species, is natural selection.
Much has been written on the topic, but perhaps the best known is Richard Dawkins’s The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe without Design. Dawkins speaks reverently of the concept, divine in its simplicity: the many random changes that don’t work die out and are thus discarded, while the relatively few random changes that enhance the organism’s ability to survive and reproduce are preserved in future generations. What you end up with, then, is a whole bunch of stuff that works pretty much perfectly, giving the appearance that someone planned that way. But there is no Someone; he’s superfluous.
It’s indisputable that organisms are more likely to survive if they’re capable than if they’re not. So the idea works great in theory—and in practice, up to a certain point. As long as the changes are relatively simple, you can just work your way up the long slow ramp, after the fashion Dawkins suggests in Climbing Mount Improbable. But the data don’t seem to match the metaphor; as Michael Behe noted in his work Darwin’s Black Box, there are many structures in nature that would require multiple changes to occur simultaneously in the organism in order to confer any advantage for natural selection to, well, select. Behe coined the term irreducible complexity.
(And yes, I know that Behe is an old-earth creationist. I don’t think that invalidates his observations to the extent that they are observable and verifiable.)
Perhaps the example most often cited is the eye. To have any vision at all, the human needs an opening in the epidermis; an eyeball, containing a light opening (pupil), a translucent center (vitreous humor), and a light-sensitive retina; an optic nerve to carry the retinal output to the brain; and an area of the brain (the thalamus and, eventually, the visual cortex) to process what’s coming up the pipe. And all that needs to be tied into the circulatory system, or the whole kaboodle shuts down after a few seconds. If any one of those links in the chain is missing, you have no vision and hence nothing worth selecting by the blind watchmaker.
That’s a lot of stuff to evolve at once.
Dawkins has responded to this apparent problem by observing that there are ways to develop increasing vision over multiple generations in small, incremental steps. In what he seems to think is the coup de grace for Behe and his fellow benighted, he notes that some of those steps are observable in nature. But what he does not do is demonstrate that the examples from nature are in any way related to one another (though he does call them “relatives” in passing); he does not demonstrate a chain of development over time. He speculates that many different kinds of eyes developed independently, but again he does not demonstrate a sequence of development for each, or any, of them. In the standard college freshman English course, we call that assuming your conclusion, and it gets you an F on your research paper.
Some old-earth creationists have suggested a workaround for irreducible complexity. In his “progressive creationism,” Hugh Ross posits that at certain unbridgeable gaps in the process—say, the first life, or the first vertebrate, or the first human—God stepped in with an act of special creation. This is a concept referred to as “the God of the gaps,” and to my mind it seems far simpler, if you’re going to bring God into it, to bring him in in the way he described in the first place.
Recall that I’m expecting a high standard of evidence to draw me away from the evidentially supported elevated source of the Scripture. Showing how something might have happened is not showing that it did. And so irreducible complexity remains a problem for the process of natural selection and thus for the evolutionist.