You Don't Even Know what You Don't Even Know
An interesting issue has been exposed in the current debate and it concerns known and unknown information. To some, a thing does not exist unless it is known. They argue, for example, that Saddam does not have Weapons of Mass Destruction because they haven't been shown any 'Smoking Guns'. In this case their perception is dependant on the revelations of reporters and fact finding agencies, on the truthfulness of Saddam, and the things to be there at the right time that would allow for exposure in the first place.

In effect, this approach is akin to letting the variables decide the hypothesis. Shouldn't it be the other way around? Decide a hypothesis, test it with facts and known items, and then determine whether it has been proven or disproved. In regards to this approach vis a vis intelligence gathering, this article in the New Yorker is quite illuminating. As Rumsfeld points out, there are knowns, known unknowns, and unknown unknowns! Meaning, there's stuff you know, stuff you don't know, and stuff you don't even know that you don't even know. Indeed, the old adage is relevant in this case: Does a tree falling in a forest make a sound if you are not there to hear it? The obvious answer is Yes, because experience reveals that when we are in a forest a falling tree does indeed make a sound. Removing ourselves from the forest does not mean the capacity for sound generation also disappears. Things happen even if we are not around to observe them. And knowing that fact is a very useful understanding indeed.