Dr. Amy Tuteur's blog, Logical fallacies speaks to the shibboleths of "vaccine rejectionism." With her permission, I'm reposting her distillate List of Fallacious Arguments.  "It is important to understand that they are, by definition, false. It is also important to be able to identify them. When they are present, they usually indicate that the person asserting the fallacies is wrong."

The Hebrew shibbōleth means stream but the contemporary interpretation or use is "a word or saying used by adherents of a party, sect, or belief and usually regarded by others as empty of real meaning."

Ad Hominem: attacking the person instead of his argument

This is the oldest one in the book and comes in very handy when you don’t know much about the subject under discussion. The favorite insult of vaccine rejectionists is a “shill” for Big Pharma or for Medicine. So the first rule of thumb in evaluating any argument of vaccine rejectionists is to the look for the insult. If it’s there, you know that the person using it has already conceded that they have no idea what they are talking about.

Inflation of conflict: Arguing that if some doctors disagree, all doctors know nothing.

Vaccine rejectionists search the newspaper and the web for any doctor that disagrees about any aspect of vaccination and then announce that there is so much “conflict” in the field that no doctor can be trusted.

Burden of proof: Requesting a standard of proof that is impossible and then declaring if the impossible standard for proof is not met, the claim must be false.

Vaccine rejectionists insist that only a randomized, cross over, double blind study is “proof” of vaccine efficacy or safety, although such a study cannot be done because it is unethical. After pointing out the absence of such (unethical) studies, the vaccine rejectionists declares that vaccines must therefore be ineffective and dangerous.

Argument to the future: The claim that we might not have any evidence that vaccines are unsafe, but that evidence might be discovered in the future.

This is a favorite argument among vaccine rejectionists who are familiar with the fact that there is no scientific evidence that vaccines cause autism and copious scientific evidence that they don’t.

Argument from false authority: This is why people believe Jenny McCarthy and Suzanne Somers. If someone is a celebrity, the thinking goes, they must be right.

False cause: Assuming that because one thing followed after another, the first must have caused the second.

Vaccines are in widespread use and the diagnosis of autism has been rising. Therefore vaccines cause of autism. The central defect of this type of argument should be obvious. It’s like saying, “The use of the Internet has risen and the diagnosis of autism is rising. Therefore, the Internet causes autism.

Argument by generalization: This fallacy is enjoying renewed popularity during the H1N1 outbreak. The vaccine rejectionist declares: “The CDC says we are experiencing an epidemic of H1N1. I know lots of people and not a single acquaintance has H1N1. Therefore the CDC is lying.”

Appeal to complexity: The subject is so complicated that not all answers are know, therefore, my guess is just as good as any scientific theory.

We’ve all seen this one in action. The vaccine rejectionist says, “No one knows what causes autism, therefore my opinion that vaccines cause autism is just as valid as any scientific theory.”

Argument by uninformed opinion: Vaccine rejectionists make no effort to learn about immunology or virology. Nonetheless they are shocked, that their personal opinions about vaccines are not treated with respect.