Hanlon's razor is a saying that reads:
In simpler words: some bad things happen not because of people having bad intentions, but because they did not think it through properly.
The quotation is attributed to Robert J. Hanlon of Scranton, Pennsylvania, US. According to his friend Joseph Bigler, Hanlon first used it as part of something he wrote for a compilation of various jokes related to Murphy's law. The compilation book was published in 1980 titled Murphy's Law Book Two, More Reasons Why Things Go Wrong. The name was inspired by Occam's razor.
There are many similar sayings. One example is "Never ascribe to malice that which is adequately explained by incompetence", which has been attributed to science fiction author Robert Heinlein’s short story "Logic of Empire" in 1941 and erroneously to Napoleon Bonaparte.
- In an e-mail to Quentin Stafford-Fraser, Joseph E. Bigler wrote that Robert J. Hanlon was a real person and did indeed invent this quotation. This is followed up by a later note that refers to Murphy's Law Book Two, Wrong Reasons Why Things Go More (ISBN 0-417-06450-0); not to be confused with Murphy's Law #2 (ISBN 0-8431-0674-3). The publisher of these books, Price Stern Sloan, was acquired by Putnam Berkley Group (Penguin Group (USA) History Archived 2006-04-30 at the Wayback Machine) in 1993.
- Giancarlo Livraghi, Il potere della stupidità, Monti & Ambrosini, Pescara, Italy, 2004, p. 1
- "Napoleon I on Incompetence - Quotation - MSN Encarta". Archived from the original on 2009-11-01. Retrieved 2013-01-15.