Joe Marino writes:
"There are known knowns. These are things we know that we know. There are known unknowns. That is to say, there are things that we know we don’t know. But there are also unknown unknowns. There are things we don’t know we don’t know."
When and where did he say this? That’s one thing I know that I don’t know.
Joe, and now you shall know. According to Wikipedia:
The above statement was made by Rumsfeld on February 12, 2002 at a press briefing where he addressed the absence of evidence linking the government of Iraq with the supply of weapons of mass destruction to terrorist groups. It was criticised as an abuse of language by, among others, the Plain English Campaign. However, linguist Geoffrey Pullum disagreed, saying the quotation was "completely straightforward" and "impeccable, syntactically, semantically, logically, and rhetorically."
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", 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." Moreover, one may criticize Rumsfeld’s statement for omitting the most dangerous type of unknown: the "unknown known". That is, as Josh Billings famously expressed it, "It ain’t what you don’t know that gets you into trouble. It’s what you think you know that just ain’t so". Indeed, Rumsfeld was really discussing an "unknown known" which provided faulty justification for the war—members of the Bush administration claimed that the Iraqi government possessed weapons of mass destruction (see Rationale for the Iraq War), but it just wasn’t so.
Now you know more than you want to know about that which was unknown to some and known to others, which is also a big problem with the Shroud of Turin.
Picture is from Jason Linkins blog in the Huffington Post: