Friday, April 13, 2012

How NOT to argue against evolution

by Tom Gilson

There are good arguments against naturalistic evolution, the belief that all species developed through unguided random variation and natural selection.1 There are also bad arguments. There are some that are so bad they do not qualify as arguments at all. Here are some things I’d really rather never hear anyone ever say again:

When can I evolve to put some clothes on?
If we descended from the apes, why are there still apes?

Evolutionary theory does not require that descendant populations or species must replace their ancestral species. If the descendant species occupies a different ecological niche, there is no reason at all to expect that it would replace its ancestors. Even in the same niche, whether one replaces the other is a matter of relative fitness, competitive success, and probabilities that almost amount to luck.

If evolution is true, where are all the living links between us and the apes?
Applied correctly, I think this could be an interesting argument, but the way I stated it here (and the way I have heard it) doesn’t work. The reason is the converse of the preceding answer. While evolution does not require that predecessor species be eliminated, it certainly does allow for it. If early humans out-competed their ancestors in similar niches, their ancestors would certainly have gone extinct. And competition is not the only explanation. If our predecessors were unfortunate enough to be concentrated in a location where they suffered a natural disaster, they could have been wiped out that way, too.

(Where this argument gets interesting is that it seems that even if it doesn’t work for humans, somewhere in the natural world we should see a graduated transition from one species to the next. Ring species probably qualify, but I’d like to see a series where the beginning and end points are more distinct.)

If evolution is true, why are there homosexuals? They don’t reproduce, so natural selection should have eliminated them.
This objection misunderstands almost everything. It assumes that there is no homosexuality except by birth, and that homosexuality is a simple heritable trait. Even if that were (which it isn’t), the argument still would not go through on its own. It also assumes that homosexuality is associated with no other adaptive trait, no characteristic that might help the population at large in its reproductive success. (Think of how sickle-cell trait provides protection from malaria.) I could go on, but those few false and/or unexamined assumptions are enough to show that this argument assumes way too much.

The world was created 10,000 years ago, so there was no time for evolution to happen.
This is just begging the question. If we could establish that the world was only 10,000 years old, then we would also establish everything else that’s at issue in these kinds of arguments. But we won’t accomplish that. In fact I consider the premise false, so in my considered opinion the argument fails on that count alone. Suppose, however, the premise might be true: in actual practice, the argument could never go anywhere. No believer in evolution would give it a fraction of a moment’s thought. It’s a conclusion drawn from a source they do not trust, and it contradicts a lot of information that they do trust, so it’s a useless line to pursue.

The eye is too complex to have come about by chance.
First, no evolutionist thinks anything came about just by chance. It’s chance plus the power of natural selection. Second, this argument concerning complexity is just too simple to have any force to it. Suppose for the sake of argument that it’s true: the eye (actually there are many versions of “the eye” in nature) really is too complex to have come about through naturalistic evolution. As an argument this is still much too weak to be any good. It needs definitional rigor, field observation, laboratory study, and much more behind it. Maybe with that it could succeed, but most people who raise it have no clue what it would require to make it go through.

Evolution leads to immorality.
This one is wandering in the neighborhood of the truth, but not close enough to work.
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