There are known knowns

"There are known knowns" is a phrase from a response United States Secretary of Defense Donald Rumsfeld gave to a question at a U.S. Department of Defense (DoD) news briefing in February 2002 about the lack of evidence linking the government of Iraq with the supply of weapons of mass destruction to terrorist groups.^[1]

Rumsfeld stated:

Reports that say that something hasn't happened are always interesting to me, because as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – the ones we don't know we don't know. And if one looks throughout the history of our country and other free countries, it is the latter category that tend to be the difficult ones.^[1]

Rumsfeld's statement may have been inspired by a presentation of Nassim Nicholas Taleb's 2001 book Fooled By Randomness in the DoD.^[2][3][4] Taleb discussed financial events and the black swan theory, which was elaborated in his 2007 book The Black Swan: The Impact of the Highly Improbable. The core message of The Black Swan is that unknown unknowns are responsible for the greatest societal change.^[4] In an April 2013 TED talk, Kirk Borne, a former NASA big data scientist, claimed that the term spawned from a post-9/11 briefing he had given the then Homeland Security transition team.^[5]

Reaction

The statement became the subject of much commentary.^[6]

The Plain English Campaign gave Rumsfeld its Foot in Mouth Award, which it presents to statements that run counter to its goal of ensuring "public information is delivered in a clear manner."^[7] Linguist Geoffrey Pullum stated the quotation was "completely straightforward" and "impeccable, syntactically, semantically, logically, and rhetorically".^[8]

As for the substance of his statement, Rumsfeld's defenders have included Canadian columnist Mark Steyn, who called it "in fact a brilliant distillation of quite a complex matter",^[9] and Australian economist and blogger John Quiggin, who wrote, "Although the language may be tortured, the basic point is both valid and important ... Having defended Rumsfeld, I'd point out that the considerations he refers to provide the case for being very cautious in going to war."^[10]

Psychoanalytic philosopher Slavoj Žižek says that beyond these three categories there is a fourth, the unknown known, that which we intentionally refuse to acknowledge that we know:^[11] "If Rumsfeld thinks that the main dangers in the confrontation with Iraq were the "unknown unknowns", that is, the threats from Saddam whose nature we cannot even suspect, then the Abu Ghraib scandal shows that the main dangers lie in the "unknown knowns" – the disavowed beliefs, suppositions and obscene practices we pretend not to know about, even though they form the background of our public values."

German sociologists Daase and Kessler (2007) agree with a basic point of Rumsfeld in stating that the cognitive frame for political practice may be determined by the relationship between what we know, what we do not know, what we cannot know, but Rumsfeld having left out what we do not like to know.^[12]

The event has been used in multiple books to discuss risk assessment.^[6][13]

Rumsfeld named his autobiography Known and Unknown: A Memoir, and The Unknown Known is the title of Errol Morris's 2013 biographical documentary about Rumsfeld.^[14]

See also

• Epistemic modal logic
• Dunning–Kruger effect
• I know that I know nothing
• Ignoramus et ignorabimus
• Ignotum per ignotius
• Johari window
• List of political catch phrases
• Ludic fallacy
• Outside Context Problem
• Relevance paradox

References

External links

• February 12, 2002, Press conference – The reporter asks the question that leads to the "known unknowns" response at approx. 37:19
• DoD News Briefing – Secretary Rumsfeld and Gen. Myer, February 12, 2002 11:30 AM EDT Transcript of the briefing