Thanks to Daniel for passing this quote along.
"It goes without saying that the fanatic is convinced that the cause he holds on to is monolithic and eternal - a rock of ages. Still, his sense of security is derived from his passionate attachment and not from the excellence of his cause. The fanatic is not really a stickler to principle. He embraces a cause not primarily because of its justness and holiness but because of his desperate need for something to hold on to. Often, indeed, it is his need for passionate attachment which turns every cause he embraces into a holy cause.
The fanatic cannot be weaned away from his cause by an appeal to his reason or moral sense. He fears compromise and cannot be persuaded to qualify the certitude and righteousness of his holy cause. But he finds no difficulty in swinging suddenly and wildly from one holy cause to another. He cannot be convinced but only converted. His passionate attachment is more vital than the quality of the cause to which he is attached."
- Eric Hoffer, The True Believer