How to Test Your Favorite Conspiracy Theory

I am of the view that incompetence, random error and sheer complexity explain most of the mistakes and strange events in our world, and that we shouldn’t readily jump to conspiracy theories. I’m pretty sure Neil Armstrong did walk on the moon, and still inclined to think (although not certain) that Lee Harvey Oswald acted alone, there is no Bigfoot and aliens have not recently visited humans on Earth.

This exercise is not merely to pile up arguments for what you believe, but also to consider how and where you might be wrong. I recently raised this question with a few friends: Which is the most underrated conspiracy theory? Even if you think conspiracy hypotheses are all likely to be false, which one is most plausible -- at least relative to the probabilities assigned by the intellectual and media mainstream.