The definition of the conspiracy theory … goes to the mindset of the conspiracy theorist, which is this: when presented with contrary evidence to their theory, they do not address the substance of the evidence. Instead, what they do is they systematically draw larger and larger circles around the groups of conspirators who are involved. (Jonathan Kay, Michael Coren Show Interview)
The analogy from conspiracy theories to ad hoc adjustments or immunizing procedures in science is, I would think, far too obvious.
Jonathan Kay’s blog Among The Truthers is an excellent resource explaining the mental state of conspiracy theorists.