There are unknown unknowns

The term unknown unknown refers to circumstances or outcomes that were not conceived of by an observer at a given point in time. The meaning of the term becomes more clear when it is contrasted with the known unknown, which refers to circumstances or outcomes that are known to be possible, but it is unknown whether or not they will be realized. The term is used in project planning and decision analysis to explain that any model of the future can only be informed by information that is currently available to the observer and, as such, faces substantial limitations and unknown risk.

The term unknown unknown has become famous since Secretary of Defense Donald Rumsfeld used it under intense questioning in 2002. Its appearances in pop culture reflect in the apparent silliness and/or candid exploration of epistemic discernment characteristic of Rumsfeld's discourse.

Usage

Donald Rumsfeld made the following statement at a Defense Department Briefing on February 12, 2002:

There are known knowns. There are things we know that we know. There are known unknowns. That is to say, there are things that we now know we don’t know. But there are also unknown unknowns. There are things we do not know we don’t know.

This statement is an accurate transcription based on the video of the original press briefing. The Department of Defense transcript is inaccurate and lacks the same poetic quality as the original quote. Donald Rumsfeld's statement won the 2003 Foot in Mouth award from the Plain English Campaign, and is also hailed as an example of found poetry.

The term was in use within the United States military establishment long before Rumsfeld's quote to the press in 2002. The earliest known use of the term comes from a paper entitled Clausewitz and Modern War Gaming: losing can be better than winning by Raymond B. Furlong, Lieutenant General, USAF (Ret.) in the Air University Review, July-August 1984:

To those things Clausewitz wrote about uncertainty and chance, I would add a few comments on unknown unknowns--those things that a commander doesn't even know he doesn't know. Participants in a war game would describe an unknown unknown as unfair, beyond the ground rules of the game. But real war does not follow ground rules, and I would urge that games be "unfair" by introducing unknown unknowns.

The term has also found a place in decision theory and risk analysis. Maluf, Gawdiack and Bell begin their 2005 analysis of the risks inherent in space exploration, ON SPACE EXPLORATION AND HUMAN ERROR: A paper on reliability and safety, this way:

NASA space exploration should largely address a problem class in reliability and risk management stemming primarily from human error, system risk and multi-objective trade-off analysis, by conducting research into system complexity, risk characterization and modeling, and system reasoning. In general, in every mission we can distinguish risk in three possible ways: a) known-known, b) known-unknown, and c)unknown-unknown. It is probable, almost certain, that space exploration will partially experience similar known or unknown risks embedded in the Apollo missions, Shuttle or Station unless something alters how NASA will perceive and manage safety and reliability.

Rumsfeld Quote in Popular Culture

Rumsfeld's famous explanation of the unknown unknown has been variously skewered by his critics in popular media.

• In The Boondocks animated series, the character Gin Rummy, a representation of Donald Rumsfeld, makes several references to unknown unknowns.
• The band No Use for a Name used the entire aforementioned quote in their song Fields of Agony (Acoustic) on the record Rock Against Bush, Vol. 2.
• In "Lil' George and Lil' Tony Blair", an episode of Lil' Bush, Lil' Rummy makes a reference to the unknown unknowns.
• The Joan Jett song "Riddles" features the full unknown unknowns quote.

See also

• List of cognitive biases
• Quasi-empiricism in mathematics
• Ignoramus et ignorabimus
• I know that I know nothing
• Johari window

External links

• Transcript of Defense Department Briefing, February 12, 2002
• Video of "Unknown unknown" talk on YouTube
• CSPAN archive video of the Defense Department Briefing, February 12, 2002