Okay, I think I've figured this out.
Several posts ago, I asked whether it was reasonable to ask people who didn't have any expertise or knowledge about the issue to take a public position on the age of the earth. P. Z. Myers responded with a few arguments before doing what dogmatic atheists always do, which is call you names, tell you you're ignorant, and then characterize you as morally deficient, all in the service of saying that, yes, even if you don't have any particular knowledge or expertise on the question, you should still have a position on it.
As Thomas, my co-blogger has pointed out, it seems rather strange for anyone to say that there is some kind of moral obligation to have a position on this one scientific issue. In fact, it's rather strange for atheists, most of whom are mechanistic materialists of some form, to say anyone has a moral obligation to do anything.
But if you think about it, it actually makes sense.
To atheists, questions like the age of the earth have an almost holy status--like the doctrine of the Double Nature of Christ for Christians, or the Eightfold Path for Buddhists. The Age of the Earth is one of the Five Pillars of Atheism.
It's not only holy: it's necessary. If you're going to be an atheist, you have to believe it, since it is necessary for your system of belief, and maintaining it becomes a matter of vital necessity. There are many creationists who hold to their position for exactly the same reason: they view a literal seven day creation and a strict reading of the genealogies as necessary to their faith. For historic Christianity, however, the question is simply not crucial. Nothing important hangs on it. God could have created the world quickly or slowly.
So when someone tells an atheist he doesn't think it's a particularly important issue, they react like natives whose god has been insulted. You have defiled the holy place. And so they point their rhetorical spears at you indignantly, jump around making threatening gestures, whooping and hollering, at which point you have to make a run for it before they boil you in a pot or something.
You just don't tell these people that one of their central religious dogmas is not important. It makes the scientific gods angry. It's taboo.
Just like the religious fundamentalist, the atheist's position on the age of the earth is part of his creed. It is not just a matter of scientific importance to these people; it's a matter of moral imperative because their whole belief system is bound up in it.
This, of course, says nothing about whether the evidence is good or bad. Despite what several commentators have implied, I have never argued that the evidence for the older age of the earth is problematic. I really don't have any problem with it, other than I think holding people to particular figures two or three places to the right of the decimal point in your millions of years figure is a little silly.
The only real material difference I have with the atheist fundamentalists is that I don't need to believe it. My worldview is just fine no matter how old the earth is. To me, the age of the earth is, indeed, a scientific question. But to the atheist it is a religious question. That is the single and only reason why anyone would say you have a moral obligation to have an opinion on it.
If you step outside the theological system of the atheists, why is it that you have a moral imperative to set forth your position on the issue of the age of the earth and to be able to say that it is exactly 4.567 billion years old? There are a whole lot more fundamental scientific issues out there. Why this one?
Should everyone have a well laid out position on quantum mechanics? The origin of the earth was, presumably, a very long time ago. Quantum mechanisms are operating now.
Where is Rand Paul on the issue of quantum gravity? What does he think about string theory? What a loon he must be for failing to have a position on the issue! He must be some kind of nut.
Maybe, but only from the perspective of someone to whom scientific questions are held as religious dogmas.