Knowns and Unknowns
Former US Secretary of Defence Donald Rumsfeld once mentioned three kinds of “knowledge”. There are things that we know. There are things that we do not know. An example of the latter would be the exact number of seconds a living person would survive since birth. Unless we go deep into philosophical arguments and confuse ourselves, many of us can have a fair idea of what he meant. We are aware of both the known knowns and unknowns and thus, we often can safely navigate our way through them. But then there are things that we are unaware that we do not know. They are the unknown unknowns. The last is the most dangerous as these unknowns can lead us astray. Paul Austen Murphy’s article on Medium “Rumsfeld’s Logic of Known Knowns, Known Unknowns and Unknown Unknowns” dated 8th September 2022 discusses Rumsfeld’s ideas and is a very good source for more information. He points out that there cannot be examples for the unknown unknown as once we have an example, we know the unknown. Some commentators do not agree with this view. For example, Daniel Levitin in his book “A Field Guide to Lies and Statistics” quotes Rumsfeld and says that the ‘unknown unknowns’ are dependent on our knowledge. To paraphrase one of his examples let us assume that there is a food item called “tasty meal’ that we consume daily. There, then, comes the sudden discovery that the meal is carcinogenic…
