“There are things we know we know about. There are things we know we don’t know. And there are things that are unknown unknowns. We don’t know that we don’t know”

Said by ‘Donald Rumsfeld’ of course

Many find it a mouthful and confusing but, to me, it’s important that we can clearly define the difference between those things and always seek out what we don’t yet know we don’t know. Always be on the lookout for interesting facts which help us build up a picture of reality.