Carlton J. Patrick.
While serving as Secretary of Defense under George W. Bush, Donald Rumsfeld once responded to a reporter’s question by famously dividing knowledge into three categories: known knowns (the things we know we know), known unknowns (the things we know that we don’t know), and unknown unknowns (the things we don’t know we don’t know). Though he was criticized for his quip, Rumsfeld’s division contains much insight, particularly as it pertains to the scientific enterprise, which is concerned with identifying natural phenomena and then methodically investigating and cataloging the properties of the phenomena into working bodies of knowledge. In other words, science is frequently the process by which unknown unknowns are systematically converted into known knowns.