As we know
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 dont know we dont know
Didnt know the context of the quote so I was surprised by the amount of derision heaped upon him for this. Especially by some highly educated BBC journalists
Was it just a case of any stick to beat a man with when you disapprove of his policies?
Or just that old English put-down: Too clever by half?
Donald Rumsfeld – the unacknowledged master of inadvertent existential poetry -
Ben Macintyre Times Books 7 June 2008
Link