Hanlon's razor

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Hanlon's razor is an adage, most commonly attributed to one Robert J. Hanlon,[1][note 1] which is generally stated as:

Never attribute to malice that which can be adequately explained by stupidity.

Sometimes "incompetence" is used instead of "stupidity".

Guises and corollaries[edit]

Therefore you speak unskillfully, or, if your knowledge be more, it is much darkened in your malice.
William Shakespeare, Measure for Measure

Hanlon's razor is essentially a special case of Occam's razor. Occam's razor states that, assuming equal explanatory power, the simplest solution (formally, the one with fewest assumptions) should be preferred. Assuming intent is a big assumption, but we all know that (other) people can be, and seemingly more often than not are, idiots and even intelligent people make mistakes. The razor is most often invoked in the context of trying to refute a conspiracy theory: where a conspiracy is perceived, with no other evidence available, it is more likely to be ineptitude or apathy than malice that results in the problem.

The statement has also been seen in the guise of "cock-up before conspiracy", based on a statement about the media and government by Margaret Thatcher's press secretary, Bernard Ingham.[2] The Wikipedia rule "Assume good faith"Wikipedia[note 2] is a nicer rephrasing of this rule, noting that idiots at least have their hearts in the right place, despite being ten times as damaging.[note 3]

The razor also has a corollary in Clark's law (named after J. Porter Clark, and based on Arthur C. Clarke's Laws), which states that "any sufficiently advanced incompetence is indistinguishable from malice". A further observation was made by Alexandre Dumas fils,Wikipedia commenting on the fact that idiocy is all-pervasive, whereas intentional malice tends to go away occasionally. Dumas appeared to be quite sure of which he preferred to happen:

I prefer rogues to imbeciles, because rogues sometimes rest.

It appears to be something Dumas said,[note 4] not something he wrote, but is a fairly true point (and a very popular quote).[3][4] German general Kurt von Hammerstein-Equord[5][6] came up with a still more elaborate version:

I divide my officers into four groups. There are clever, diligent, stupid, and lazy officers. Usually two characteristics are combined. Some are clever and diligent – their place is the General Staff. The next lot are stupid and lazy – they make up ninety percent of every army and are suited to routine duties. Anyone who is both clever and lazy is qualified for the highest leadership duties, because he possesses the intellectual clarity and the composure necessary for difficult decisions. One must beware of anyone who is stupid and diligent – he must not be entrusted with any responsibility because he will always cause only mischief.

There is also a quote commonly attributed to Albert Einstein:

Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe.[7]

More completely[edit]

Cribbing from a LessWrong commenter:[8]

  • Never assume malice when stupidity will suffice.
  • Never assume stupidity when ignorance will suffice.
  • Never assume ignorance when forgivable error will suffice.
  • Never assume error when information you hadn't adequately accounted for will suffice.
  • Therefore, never assume malice when information you hadn't adequately accounted for will suffice.

See also[edit]


  1. But also to science fiction author Robert Heinlein, based on assumptions that "Hanlon" is a mishearing of "Heinlein".
  2. This is a rule that is shared by most sensible wikis, including this one.
  3. Wikipedia acknowledges that good faith is not always sufficient. See the Wikipedia article on Wikipedia:Competence is required.
  4. In the original French, "J'aime mieux les méchants que les imbéciles, parce qu'ils se reposent." Or various other renderings, e.g. "Je préfère le méchant à l'imbécile, parce que l'imbécile ne se repose jamais" ("... because the imbecile never rests") or "Si je devais faire un choix, entre les méchants et les imbéciles, ce serait les méchants, parce qu'ils se reposent."


  1. http://en.wikiquote.org/wiki/Robert_J._Hanlon
  2. "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." Brisbane Times – Case of a misplaced point
  3. It's apparently mentioned in Histoire de la littérature française (900-1900): Le dix-neuvième siècle by Léo Claretie.
  4. A Yahoo! Answers page suggests it was Dumas' response to Victor Hugo saying "Les méchants envient et haïssent; c'est leur manière d'admirer." ("The wicked envy and hate; it's their form of admiration.") Then again, this is Yahoo! Answers.
  5. Enzensberger, Hans Magnus; Martin Chalmers (December 1, 2009). The Silences of Hammerstein. USA: Seagull Books. p. 87. ISBN 978-1-906497-22-4. 
  6. Enzensberger, Hans Magnus (2008). Hammerstein oder Der Eigensinn. Germany: Suhrkamp Verlag KG. pp. 77–78. ISBN 978-3-518-41960-1. 
  7. In reality, the quote appears to have been said by Fredrick S. Perls, in the 1969 book "In and Out the Garbage Pail". See Oxford Reference.
  8. http://lesswrong.com/lw/372/defecting_by_accident_a_flaw_common_to_analytical/31kb?c=1