From Mark Hoofnagle, writing at the Denialism Blog: the autism/vaccines fraud.
It is obvious to me that no matter what the field, the problem is crankery – the defective thought processes that allow people to believe in nonsense, no matter what obstacles reality throws in their path. Every description of every crank in every field ultimately boils down to these same factors. Cranks believe in something contrary to observable reality. They will do anything to prove it. When reality gets in their way, they ignore, subvert, lie, cheat, or obfuscate to create confusion. And when it’s proven beyond all doubt they’re wrong? That’s when the conspiracies come out.