On Boxes, Thinking Outside of the

The failure to prevent the 9/11 attacks was due not to their being unimaginable -- for they were imaginable and imagined -- but to the fact that the imaginable covers too broad a surface, which is one reason for focusing on things that have happened before; the set of bad things that have never happened but may happen in the future is well-nigh infinite. And the more information, including imaginative conjectures covering the full range of the possible, that is clamoring for the mind's attention, the harder it is for the analyst to sift the information for clues.

-- Judge Richard A. Posner,

in Preventing Surprise Attacks (2005)