unknown unknowns
Blind spots undiscovered
Unknown unknowns are things we don't know that we don't know—gaps in knowledge we're not even aware exist.
Contrasted with known unknowns (questions we know to ask but can't yet answer), unknown unknowns represent blind spots that can't be planned for because we don't know to look for them.
The phrase gained currency after Donald Rumsfeld used it in a 2002 press briefing about intelligence gaps: The real danger isn't what we know we don't know—it's the unknown unknowns.
- black swanDark-feathered Australian waterfowl
- wild cardUnpredictable factor in play
- out of left fieldWholly unanticipated and startling
- intangiblesThings beyond physical grasp
- risksPossible negative outcomes
Donald Rumsfeld · discovery · hidden variables · black box · uncertainty · unpredictability · terra incognita · uncharted territory · epistemic humility · mysteries · surprises · ambiguities · ignorance · metacognition · unintended consequences · innovation · contingency · confirmation bias
- Data Gapscoverage gaps
unknown unknownsknown knowns
Facts consciously possessed
known unknowns · awareness · certainty · understanding · comprehension
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