At the Panda’s Thumb, Gary Hurd told an interesting story of career day at public school. Gary is a forensic archeologist and incidentally has written a number of books and articles including this one on evolution. Teaching evolution was not his purpose on career day—it was simply telling second graders what he does for a living. Because he brings archeological finds and equipment such as bones and tools I’m sure his career is pretty fascinating to kids. His whole career is a walking, talking refutation of Dembski's "Design Inference." I'd love to sit Dembski and Hurd down side by side with some irregular rocks and have them each identify them as "designed or not" and the reasons why. The results would be fascinating but I digress.
One side benefit career day is meeting people in other careers you might not normally meet, like judges, actors, performance artists and even “preachers.”
As Gary’s story unfolds, “Preacher Mike” was a little unclear on the concept of "Career Day." Instead of telling kids what a “preacher" does, he felt the need to actually preach to the kids about the evils of archeology. The “preacher” had presumed that Gary had already indoctrinated the wee ones into the pleasures of satanic evilution and wanted to make sure the kids were saved from that menace. Ultimately, since the preacher couldn’t’ distinguish between telling kids what preachers do from actually preaching to them, he was booted from career day.
Gary comments (with my emphais added):
“Mike the Preacher believes in a conspiracy against God, inspired by Satan, that has control of the American schools. This Satanist conspiracy has as its agents all scientists and teachers who are actively trying to corrupt innocent children through public education. The fact that Preacher Mike was tossed out of Career Day only reinforced his paranoid delusion.”
In the post"s comments a commenter, self described as “Your Conscience,” reinforced that observation that many see that evolution can only be the product of a grand conspiracy:
“ People don’t question heliocentrism because it can be tested and verified in many ways. Now common descent and speciation. Nope, never seen anything close to testing and verifying that theory. Have seen some pretty cool drawings of ape-like creatures turning into humans based on fossilized bone and tooth fragmants. Creative imagination does not equal good science.
Why do Darwinian fundamentalists believe that people who don’t worship naturalism simply need more education.”
I couldn’t resist that challenge and I responded that fundamentalists do indeed challenge geocentricism with the same ferocity as they do evolution and referred him to my favorite site, the Geocentric Challenge
Now I happen to be Catholic and I believe that religious fundamentalism makes for equally poor theology as it does science, so I chose to pick a Catholic fundamentalist site (and give my readers a chance to pick up a cool $1000). Other commenters posted other sites demonstrating that people do too question heliocentricism in spite of the evidence. Here are some more examples:  
These all happen to be religious fundamentalist sites all arguing that evolution is held in place only by a grand conspiracy of scientists educators and atheists. There are other conspiracy theories put forth by people from a wide range of views across the political spectrum. Conspiracy theorists are not limited to religious fundamentalists, the right wing or any particular group. They come from all directions.
What they do have in common is that they all confront a vast amount of scientific, medical or technical evidence that is opposed to the conclusion that the theorists seek to confirm. All of this vast work, the entire sum of human knowledge, in the case of biology, is simply dismissed as part of a grand conspiracy. that's how the overwheling evidece is confronted--a simple calim that large groups of peopel made it up.
There are two underlying assumptions about conspiracy theories that are almost universally untrue. First, the conspiracy theory assumes that large numbers of people can keep a secret. This is almost never true. The CIA and the KGB, are both dedicated to secrecy, and both
actively engaged in conspiracies, yet neither ever demonstrated any particular ability to keep information secret. Even the Mafia had security breaches and the Manhattan Project lost the grandaddy of all secrets before the first atom bomb was even detonated. Conspiracy theorists strongly overestimate the ability of any large group of humans to keep secrets.
The second assumption of conspiracists is that people doing their jobs will intentionally choose to conceal the evidence for truth—even when it is against their own personal financial interest. Pastor Mike, for example, is essentially arguing that 30,000 biology PhD’s are all conspiring to conceal the great secret that Evolution is a fraud. Yet, any biologist that demonstrates a major error in evolution will certainly go down in history as the man who showed up Charles Darwin. Honors, fame, perhaps Nobel Prizes, fortune and the undying gratitude of the Christian Right await the turncoat biologist. Certainly, at least one of the scientific conspirators in Evolution would be willing to endure the wrath of his colleagues in return for this kind of fame and fortune. Unless Human Nature fundamentally changes, there is no way that people who know the truth will conceal that truth as part of a conspiracy when disclosure will lead to untold riches. This holds true for all fields, whether science, medicine, religion or technology. Whistle blowing is a lucrative field but difficult to break into because the competition is so fierce. This will always be so.
I think it’s a fair, when somebody like Pastor Mike or “Your Conscience” suggests Evolution is part of a grand conspiracy, that we ask them to explain what makes the evolution conspiracy different from recognizably “kooky” theories like heliocentricism, AIDS conspiracies or holocaust revisionism.
I don’t believe there is any principled difference.