Conspiracy theory

Conspiracy theory is an idea that some secret group of people are doing bad stuff and hiding it all from ordinary people.
 * 1) Conspiracy theories can exist because someone with psychiatric problems has strange ideas. Alternatively a group of people with psychiatric problems can get together and encourage each other to believe wild ideas.
 * 2) Conspiracy theories can exist because some enterprising businessman/businesswoman or corporation hopes to make money selling material about imagined conspiracies to the gullible public.
 * 3) Finally conspiracy theories can exist because there is a real conspiracy and people are trying to draw public attention to what's happening.

Sorting out the sensible conspiracy theories from the junk conspiracy theories isn't always easy.