"SAYINGS" !

"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".

Donald Rumsfeld, 2002