Some time ago there was a spate of sniggering at the late, unlamented Donald "Rummy" Rumsfeld for speaking of unknown unknowns, known unknowns, and known knowns. I spoke in defense of Rummy at that time, suggesting only that he had left out the unknown knowns. I recently discovered that the estimable Geoff Pullum is on my side. His posting in Language Log not only defends Mr. Rumsfeld's statements but also mentions an old Persian apothegm that supplies the missing unknown knowns.