The lyrics of Black and White Year’s Up:
i’m afraid silence is the song of the next age.
what we don’t know won’t hurt us.
what we don’t know won’t keep us up at night.
what we don’t know won’t hurt us. but we don’t know.
what you don’t know won’t hurt you.
what you don’t know won’t have you terrified.
what you don’t know won’t hurt you. but you don’t know.
and you won’t know that you don’t.
Ron Mader 
The counterpoint to this, is (most famously) by former Sec Def. Donald Rumsfeld who said in 2002, “There are known knowns”, in regards to the Iraqi war. (see which: https://en.wikipedia.org/wiki/There_are_known_knowns)
But the idea of the the phrase comes from a Shakespeare play (although I can’t find it directly. Darn, need to brush up my Shakespeare.) All the search references come from Jim Morrison, from The Doors, apparently quoting Aldous Huxley.
Then there’s this; “John Cleese on How “Stupid People Have No Idea How Stupid They Are” (a.k.a. the Dunning-Kruger Effect)”. > http://www.openculture.com/2014/12/john-cleese-on-stupidity-and-a-cornell-study.html