- Course Introduction
- Unit: Current Events
"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 don't know we don't know." -Donald Rumsfeld when asked how he was so sure that Iraq has attempted to or is willing to supply terrorists with weapons of mass destruction.