Why are people against evolution?
This is an interesting point of view, but I have to say I'm not convinced. It's an explanation for why many people reject evolution.
My explanation is simply this: Human beings have a strong visceral reaction to disbelieve any theory which injects uncertainty or chance into their world view. They will cling to some other "explanation" of the facts which does not depend on chance until provided with absolutely incontrovertible proof to the contrary.
Eh, I don't buy it. People love chance. They want to believe that their successes are due entirely to their hard work and talent, but when the chips are down, it's handy to be able to blame it all on bad luck. If it were otherwise, no one would ever play the lottery and we'd all be Calvinists. As Abhay says, too, people are very poor judges of probability—I just don't think it's a significant problem.
It also shouldn't bias them against evolution. The idea of natural selection says that we're all, each and every one of us, the end result of a whole series of winners, and that not only that, they were better than our competition. It's a philosophy that really ought to appeal to all those people who buy into capitalist theology of the sort preached at the mega-churches…but they are one group that rejects evolution.
Lindsay is closer to the mark, I think. It's because evolution doesn't bestow a lofty purpose on us.
Mostly, evolution makes people uncomfortable because it explains how life could have emerged without any external purpose or design. Evolutionary explanations are threatening to people who assume that naturalistic explanations undercut meaning in life. If we assume that we were designed by some creator, it follows that our existence has at least some built-in purpose. At the very least, we could say that we were designed by someone for some reason. It wouldn't necessarily follow that we were designed for any good reason, of course.
I can see that this might be a contributing factor, but I have a more cynical take on it. I'm with Eric Hoffer (from The True Believer) on this one:
Faith in a holy cause is to a considerable extent a substitute for the lost faith in ourselves.
The less justified a man is in claiming excellence for own self, the more ready he is to claim all excellence for his nation, his religion, his race, or his holy cause.
I don't think the stated purposes given by religion are what's persuasive; I think nihilism could drive a fanatic. It's the cause itself that's sufficient. "Higher purpose" is just a convenient excuse to justify joining the crowd and engaging in lots of satisfying self-congratulation.
I'd add one other minor component to why people reject evolution, though: fear. One message of evolutionary history is that in addition to human beings not being the end target of evolution, we are just like every other species on the planet…and species go extinct. Only 0.1% of all the species that have existed are currently extant, and the average lifetime of a species is roughly 10 million years. Add to those fears of personal mortality the awareness that the whole human clade will someday go extinct (unless we calve off another species or two, which many would find even more horrifying), and I can sympathize with the dread biology might instill in some people.
Both Abhay and Lindsay are trying too hard to see the rejection of evolution as a rational decision driven by common personal biases. As a Gouldian, I have a different explanation: contingency. People follow a faith because of history and tradition. Most of us follow a particular religion largely because it is the one our parents followed, or that our current trusted social network follows. Rarely is it because they've been consciously shopping for a faith that fits their preferences—if that were the case, we'd see far fewer people adopting some of these crazy ideas. All this talk about chance and purpose and predictions and reason is mere rationalization after the fact.
Ultimately, what brings people together to reject evolution is a sense of identity and belonging to a group that has a non-rational anti-evolutionary dogma as a part of their social toolkit. It's not assessment of the evidence that drives them away from science, it's entirely because the evidence challenges a facet of the beliefs they recognize as distinguishing elements of their tribe. In a war between reality and their social group, they cling to their subculture. It actually makes sense, in an evolutionary and biological way: an isolated human being is not a particularly viable unit, and it's the cohesion of the clan and tribe that is more important for long-term success.
One of our jobs has to be to convince people that they can trust in science without losing their identity as Baptists/Hoosiers/Southerners/Methodists/Republicans/whatever other granfalloon they associate with. Our problem is that the leaders of certain prominent American subgroups have chosen anti-evolutionism as one of the sigils of their tribe—it's an easier marker than slicing off a foreskin or ritual scarification, I guess. It makes it hard to convince people to recognize good science when their respected authority figures are shrilly declaring that accepting good science means they are no longer Christian.


PZ - Any chance in your opinion that this is a "hardwire", not a software, cultural issue? Could it be possible that those that "must" believe in a creator/ god(s) are remnants of an older model Homo? To continue with the computer analogy, are the "religiously inclined" a Windows 3.1 release, while those able to see beyond the "gods angry with us" outlook are more of a Windows XP / Linux Homo release?