11-17-2012, 10:30 AM
â [T]here 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 â there are things we do not know we don't know.â
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 â there are things we do not know we don't know.â
âUnited States Secretary of Defense, Donald Rumsfeld