But this is a bit of a cheap joke:
"One of our famous 21-century philosophers, Donald Rumsfeld, very famously summed up states of knowledge in this very cryptic answer that he gave to questions about weapons of mass destruction in Iraq... And he got given a foot in the mouth award by the Plain English Speaking society for this response."
It would have been amazing if Rumsfeld had come up with this distinction between knowns and unknowns himself — it would have shown him to be extraordinarily wise or articulate. But, as Wikipedia confirms, Rumsfeld was just parroting someone else’s classification, supplying it with an explanation, either his own or someone else's, who knows. This is the same as what the media does with Putin: he patronizingly, imperiously belches up someone else’s honestly thought through opinion, like that time with liberalism having outlived its purpose, and the media happily joins in chorusing isn't it remarkable what he said.