Until around half a millennium ago theologians in Europe believed that the universe their deity created was a reflection of its perfection--they believed that the earth was at the center of the universe (a pretty small universe at that), that the earth was fixed in space and that the other worlds (planets) revolved around it, that these orbits were perfectly circular, and that the earth's moon was a perfect sphere.
And then was born that gadfly named Galileo Galilei who just had to rock the boat with that thing called the telescope and find kinks in the neat and tidy cosmology of God's toadies. Thus among other things, when Galileo trained his 20x scope on the moon he discovered that instead of being smooth and perfectly round, the moon's surface was in fact pretty rough terrain, covered with what looked like mountains and valleys.
When he reported his various astronomical findings, the "perfectionists" of course at first didn't believe. Some even refused to peer through Galileo's telescope and see the evidence for themselves, declaring that the Devil could make anything appear through that contraption of his (mind you, there are still such kooky blokes around today attributing everything they won't have any of to maleficent supernatural entities). But of course they couldn't play the denial game forever. And so when they finally got around to swallowing their pride and accepting the observations, cognitive dissonance kicked in and the rationalization engine shifted into high gear. And thus was begotten a lame excuse to explain away the moon's jaggedness and apparent imperfection. The theologians told Galileo that while mountains do exist, there is a transparent crystalline material that fills in the valleys and crevices all the way to the top of the highest peaks; and thus this substance, like some invisible putty (of Noachian quantity), covers the entirety of the moon, making it perfectly spherical.
Not to be taken in by this ridiculous and obviously ad hoc rationalization concocted solely to save their theological belief, legend has it Galileo wryly told the nincompoops that on top of this smooth round crystalline material were even more mountains which, however, were made of the same invisible crystalline substance, mountains which of course they couldn't see and which telescopes wouldn't be able to pick up. And so the moon far from being perfectly round had all these invisible peaks jutting out. And because the theologians couldn't prove him wrong, Galileo's explanation had to be right!
Hey, two can play the game of absurdity. If those dogmatists could resort to illicit ad hocs, Galileo could as well lash back with an equally ludicrous hypothesis and whip out an argumentum ad ignorantiam to boot.
When religionists make empirical claims they better be ready to face the music when science turns up confuting evidence. But dogmatic fools like fundamentalists who still read the biblical creation myth and Noah's flood literally will stick to their delusions. And however much physical, chemical, microscopic evidence there may be to the contrary, the Catholic Church will forever go on believing that chanting magic words over crackers and fermented grape juice does turn them into the muscle cells and erythrocytes of some long dead idol of theirs. These deluded nutcases have already made up their minds what reality ought to be. They might as well have been born blind and deaf.
Copi, Irving M. and Carl Cohen. 1997. Introduction to Logic, 10th ed. Upper Saddle River, NJ: Prentice-Hall. 163, 566-567.