Interesting article from the New Scientist, reproduced in full at The Razor.
(Or if you subscribe to the New Scientist you can use this link instead)
To appreciate why this form of reasoning is seductive, consider the alternative: major events having minor or mundane causes – for example, the assassination of a president by a single, possibly mentally unstable, gunman, or the death of a princess because of a drunk driver. This presents us with a rather chaotic and unpredictable relationship between cause and effect. Instability makes most of us uncomfortable; we prefer to imagine we live in a predictable, safe world, so in a strange way, some conspiracy theories offer us accounts of events that allow us to retain a sense of safety and predictability.
So the more disaffected and disempowered you feel, the more you believe that some big shadowy organisation is responsible for events. It’s a perverse sense of self-worth: this sense that you live in an rational and orderly world instead of the abyssal, complex chaos it really is.
(via Bruce Schneier’s blog)