Hanlon’s razor
Etymology
Commonly credited to a Robert J. Hanlon, whose formulation was submitted to a 1980 joke book of "Murphy’s law" variants, though the exact attribution is murky and disputed. Similar sentiments appear earlier, including a line often linked to Goethe and Napoleon, so the idea is old and the name relatively new. "Razor" borrows the metaphor from Occam’s razor: a principle for cutting away needless assumptions, here the assumption of bad intent.
noun phrase · /HAN-lunz RAY-zer/
The rule of thumb that you should not attribute to malice what can be adequately explained by stupidity, carelessness, or incompetence.
What it names
A check on paranoia in daily life: most slights and screw-ups are the result of ordinary human sloppiness, not a plot aimed at you.
Example
When the client ignored three of my questions, I invoked Hanlon’s razor and assumed an overflowing inbox rather than a deliberate snub.
Related idea
Occam’s razor favors the simplest explanation in general; Hanlon’s razor applies that instinct specifically to human motives, where incompetence usually beats conspiracy.