You've met them!   Ordinary people somehow in-the-know on some incredible plots:  Sinister powers caused the Christchurch earthquake to put pressure on the New Zealand government;  CIA orchestrated nine-eleven;  Moon-landing all filmed in a studio.    They've found it on the internet so it must be true!

Here are two great tools for thinking about this stuff.  

 

In philosophy a razor is a device which allows us to shave away unlikely explanations for a phenomenon.

Occam's Razor:  when faced with competing hypotheses, select the one that makes the fewest assumptions. The simplest explanation is most often the correct one so one should not increase, beyond what is necessary, the number of entities required to explain anything.

Hanlon's Razor:  assume incompetence over malice!    Never attribute to malice that which is adequately explained by stupidity.

I haven't found a conspiracy theory which doesn't expire with two quick cuts!