Hanlon's razor

Hanlon's razor is an adage, or rule of thumb, that states:

Never attribute to malice that which is adequately explained by stupidity.

It is a philosophical razor that suggests a way of eliminating unlikely explanations for human behavior. It is purportedly named after one Robert J. Hanlon, who submitted the statement to Murphy's Law Book Two: More Reasons Why Things Go Wrong! (1980). Similar statements have been recorded since at least the 18th century.