Former US Defence Secretary Donald Rumsfeld copped a lot of flack for some of his observations as a key player in second Bush Adminstration. Clumsy and obtuse though some were, he often had a good point to make. One of my favourites: “There are known knowns. These are the things we know that we know. There are known unknowns…things we know we don’t know. But there are also unknown unknowns. These are things we don’t know we don’t know.”
The question is: How to identify those unknown unknowns?