Hanlon's razor is a saying: 'Never attribute to malice that which is adequately explained by stupidity'. It has come to be called Hanlon's razor (similar to Occam's razor) after an author of the same name who put the saying in a book he was compiling in 1980. However, the idea is much older than that.

Put simply, the saying means that if something goes wrong, it's much more likely that someone made a stupid mistake than that there is a sinister plot or conspiracy afoot to cause disruption. Examples of this idea can be found as early as the 18th century, when Johan Wolfgang von Goethe remarked that carelessness and misunderstanding were much more common than evil and dishonesty, and caused a lot more trouble.

Especially in these times, when the internet is full of stories about evil conspiracies, I think we should all remember Hanlon's razor before we start believing in wild theories. The fact is, there are a lot more incompetent people than there are evil ones, and they do cause a lot more trouble.