Hanlon’s Razor is an eponymous adage that reads: ‘Never attribute to malice that which is adequately explained by stupidity.’
A common (and more laconic) British English variation, coined by Sir Bernard Ingham, is the saying ‘cock-up before conspiracy,’ deriving from this quotation: ‘Many journalists have fallen for the conspiracy theory of government. I do assure you that they would produce more accurate work if they adhered to the cock-up theory.’
The quotation first came from Robert J. Hanlon of Scranton, Pennsylvania, according to his friend Joseph Bigler, as a submission for a book compilation of various jokes related to Murphy’s law published in 1980 titled ‘Murphy’s Law Book Two, More Reasons Why Things Go Wrong.’ The name was inspired by Occam’s razor (simple explanations are more probable than than complex ones).
A similar quotation appears in Robert A. Heinlein’s 1941 short story ‘Logic of Empire’ (‘You have attributed conditions to villainy that simply result from stupidity’); this was noticed in 1996 (five years before Bigler identified the Robert J. Hanlon citation). Potentially, Hanlon’s Razor might be a corruption of ‘Heinlein’s Razor.’ ‘Heinlein’s Razor’ has since been defined as variations on: ‘Never attribute to malice that which can be adequately explained by stupidity, but don’t rule out malice.’
Yet another similar epigram (‘Never ascribe to malice that which is adequately explained by incompetence’) has been widely attributed to Napoleon Bonaparte. Another similar quotation appears in Goethe’s ‘The Sorrows of Young Werther’ (1774): ‘…misunderstandings and neglect create more confusion in this world than trickery and malice. At any rate, the last two are certainly much less frequent.’