The reason he didn't talk about "unknown knowns" is that it would have been an admission of fault.
Two of the 911 hijackers were well know to be senior Al Qaeda operatives by the CIA, but inexplicably they were allowed to enter the states, and the FBI was not alerted to their presence. Although they were 'known', what they were up to wasn't, and they weren't being watched. Unknown knowns.
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Prufrock Lucifer, son of the morning!, Wed 10 Dec 2014, 16:05,
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