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.
It’s unlikely you need to be reminded that these words are Donald Rumsfeld’s attempt to explain America’s invasion of Iraq. But, said Marcus de Sautoy in a fine talk at 5×15 stories on Monday night, they are unfairly maligned. He was promoting his new book, What We Cannot Know: Explorations on the Edge of Knowledge, and said that in fact Rummy was onto something. In science, this schema works perfectly as a way of describing the theoretical that has been proved in observation (known knowns), that hasn’t been proven (known unknowns) and the could one day be theorised and perhaps proven (unknown unknowns). That’s how science works.
Strangely, de Sautoy pointed out, the Secretary of Defense missed out a category: unknown knowns. Or perhaps not that strangely. For as Slavoj Zizek has pointed out, aren’t unknown knowns exactly those types of subconscious motivations and reasons for action that are our true motivators. The exact type of motivations that might push a country into a distant war, without naming the true reason why that war should be fought