Hanlon's razor is an adageorrule of thumb that states:[1]
It is a philosophical razor that suggests a way of eliminating unlikely explanations for human behavior. It is probably named after Robert J. Hanlon, who submitted the statement to Murphy's Law Book Two (1980).[1] Similar statements have been recorded since at least the 18th century.
The adage was a submission credited in print to Robert J. Hanlon of Scranton, Pennsylvania, in a compilation of various jokes related to Murphy's law published in Arthur Bloch's Murphy's Law Book Two: More Reasons Why Things Go Wrong! (1980).[1]
A similar quotation appears in Robert A. Heinlein's novella Logic of Empire (1941).[2] The character Doc in the story describes the "devil theory" fallacy, explaining, "You have attributed conditions to villainy that simply result from stupidity."[3]
Hanlon's razor became well known after its inclusion in the Jargon File, a glossary of computer programmer slang, in 1990.[4] Later that year, the Jargon File editors noted lack of knowledge of the term's derivation and the existence of a similar epigrambyWilliam James, although this was possibly intended as a reference to William James Laidlay.[5][6] In 1996, the Jargon File entry on Hanlon's Razor noted the existence of the phrase in Heinlein's novella, with speculation that Hanlon's Razor might be a corruption of "Heinlein's Razor".[2] The link to Murphy's law was described in a pair of 2001 blog entries by Quentin Stafford-Fraser, citing emails from Joseph E. Bigler.[7][8] In 2002, the Jargon File entry noted the same.[9] The Jargon File now calls it a "Murphyism".[10]
The name was inspired by Occam's razor.[11]
A variation appears in The Wheels of Chance (1896) by H.G. Wells:
There is very little deliberate wickedness in the world. The stupidity of our selfishness gives much the same results indeed, but in the ethical laboratory it shows a different nature.[12]
A similar quote is also misattributed to Napoleon.[13] Andrew Roberts, in his biography of Winston Churchill, quotes from Churchill's correspondence with King George VI in February 1943 regarding disagreements with Charles De Gaulle: "'His 'insolence ... may be founded on stupidity rather than malice.'"[14]: 771
Douglas W. Hubbard quoted Hanlon's razor and added "a clumsier but more accurate corollary ...: 'Never attribute to malice or stupidity that which can be explained by moderately rational individuals following incentives in a complex system.'"[15]
