Arguing with conspiracy theorists is often one of the most frustrating activities one can engage in. At least new age wackjobs and religious types don't pretend to be thinking critically. You know up front that their faculties for evaluating evidence have been critically compromised.
Conspiracy theorists, on the other hand, often appear with evidence in hand and ask that you take a look at it and draw your own conclusions. At first glance this sounds like an eminently reasonable empirical request. What you don't know is that they have cherry picked the evidence, and that if you really do examine the evidence for yourself instead of following the primrose path they have laid for you they will get quite upset. If you reach any conclusion other than "the conspiracy is real" you will find that they decide that you are part of the conspiracy's disinformation campaign.
Why are these theories so popular? This New Scientist article examines just that, and even offers a hand DIY guide for making your own conspiracy theory.
So what kind of thought processes contribute to belief in conspiracy theories? A study I carried out in 2002 explored a way of thinking sometimes called "major event - major cause" reasoning. Essentially, people often assume that an event with substantial, significant or wide-ranging consequences is likely to have been caused by something substantial, significant or wide-ranging.[...]
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.
