The book’s title also somewhat ironically illustrates the difficulty so many in the press seem to have grasping even the simplest nuance. When Rumsfeld explained his straightforward concept of “known knowns, unknown knowns, and unknown unknowns,” ABC’s Diane Sawyer called it a “lecture” that “confounded” the reporters in the Pentagon press room.
No, actually, it did not. It was not some mangled malapropism, or bureaucratic gobbledygook. It was a clear, perfectly lucid explanation of the challenge of making decisions with imperfect information. Any schoolchild could follow the logic, apparently just not some ADD-afflicted members of the media, who disingenuously and inaccurately mocked it as some sort of embarrassing gaffe.
...leads this over caffeinated philosophy type geek to think it would be a good idea to give a bad homespun example of each of the three Rumsfeldian epistemic categories in question. So, taking the original quote:
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.
..let's play, using a simple scenario. Say you are walking into an office building on a Wednesday morning around 1030, one you work in, and whose environment you are quite familiar with.
First, a KNOWN KNOWN: Something that you are certain you have airtight knowledge of (unless we are annoying global skeptics of course): You know THAT Some number of people are in the building.
Now, a KNOWN UNKNOWN: Given that you KNOW that some number of folks are in the building, it is still, nevertheless true that YOU DO NOT KNOW the precise number.
OK, hopefully, Sawyer's mind ain't a-swimmin' yet, so here's the last of our three categories..
THE UNKNOWN UNKNOWN: Supposing it is true that some Martians from the 123rd dimension (not our Mars, mind you, but, like I said, Martians from the 123rd dimension) are cleverly disguised as 3 of your fellow employees in the building, it is safe to assume YOU do not have the foggiest idea that this is the case, NOR do you think, in fact that the 123rd dimension, nor its Martians even exist. The concept is ridiculous, if you ever entertain it. MOST LIKELY it is something YOU KNOW NOTHING ABOUT In that case you don't know about the three, and what is more, it will probably never dawn on you that you should know this, because, given what you already believe, it is outside the realm of your background knowledge, hence not even a dead possibility, not even a possibility. Hence, an UNKNOWN UNKNOWN.