Quote

US Defence Secretary Donald Rumsfeld is quoted to have said: "Reports that say that something hasn't happened are always interesting to me, because 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 don't know we don't know."

That of course clears it all up ;-)

I got this pice from here and you canlisten to him here