A lot of folks have made fun of Donald Rumsfeld’s remarks in the lead up to the Iraq War.
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.
Certainly, at the time, I was one of the folks who reacted with derision to Rumsfeld’s remarks. But the older I’ve grown, the more I’ve actually come to like the classification of knowledge pertinent to the decision-making process.
There’s a nice symmetry to the classification system as well, with one glaring omission: What are “unknown knowns”?
Slavoj Žižek has proposed that “unknown knowns” are “the disavowed beliefs, suppositions and obscene practices we pretend not to know about, even though they form the background of our public values”. That’s an interesting definition, and certainly a useful rhetorical device for the point Žižek was making at the time, but I find it lacking. In particular, it doesn’t fit in with the narrative structure of the rest of Rumsfeld’s quote, which would indicate that an “unknown known” is “things we do not know that we know.” The obvious interpretation of Žižek’s statement is that “there are things that (almost) everyone knows, but no one acknowledges,” but this doesn’t actually seem to be the equivalent of something that is known but not known (unless perhaps, one is a rock star philosopher with delusions of authoritarian grandeur), but rather just something you don’t talk about in polite company (and perhaps, even, with yourself).
I think a better take on the definition of an “unknown known” is “that knowledge which we already possess, but which is not accessible in the decision-making process for reasons of either misunderstanding or ignorance.” This is a take which, I think, is on firmer ground with respect to the process by which decisions — and, in fact, discoveries — are made. A brief survey of the history of science or engineering, for example, will reveal that many “discoveries” are in fact less about new ideas, and more about putting existing ideas which were previously regarded as separate together in context. (This is a theme that Harry Harrison explores extensively within “The Hammer and The Cross” trilogy, which is a really excellent read, even if it jumps the shark a bit in the final volume.) Alternately, “known unknowns” might be regarded as information known within some parts of an organization that is inaccessible to other parts because of political infighting, deference to authority, the fact that no one has ever thought to ask, etc.
It’s worth noting that Žižek’s more polemic definition might be considered a special case of this one.
In any event, I think this is a more useful way of conceptualizing the concept of an “unknown known.” It’s certainly more useful in day-to-day life. I think it’s also more interesting in the broader social context as well, since it suggests that the process of discovering “unknown knowns” may be a “low-hanging fruit” — and perhaps even one of the primary drivers — of social and technological progress.
The identification of “unknown knowns” with knowledge that exists but whose distribution is so poor as to make it largely inaccessible is also a strong argument for the preservation of human culture and thought. “Unknown knowns” are likely to be the type of human knowledge that is the most vulnerable to loss (becoming either “unknown unknowns” or, as is the case with so many historical mysteries, “known unknowns”), and whose loss we will likely feel the most acutely (even if we do not know why).