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South African Journal of Occupational Therapy

On-line version ISSN 2310-3833
Print version ISSN 0038-2337

S. Afr. j. occup. ther. vol.47 n.1 Pretoria Apr. 2017 




In a detective novel1 I was reading recently, the inspector investigating a particular case said the following: "A murder investigation involves known knowns, unknown knowns and unknown unknowns". He was paraphrasing the press briefing given by the United States Secretary of Defence Donald Rumsfeld2 in 2002 on the lack of evidence linking the Iraqi government to the supply of weapons of mass destruction to terrorist groups.

This categorisation of facts and knowledge is not new. In a famous l880 speech before the Berlin Academy of Sciences, Emil Dubois-Reymond3, used the term "ignoramus et ignorabimus" (meaning "we do not know and will not know") and took the position that there are limits to scientific knowledge; 'riddles' which he declared, neither science nor philosophy could ever explain because they are 'transcendent'. David Hilbert however, later suggested in l930 that this was a rather pessimistic conceptualisation of knowledge and human ability. He postulated that by considering certain problems 'unsolvable', we limit our understanding of life. He said: "In opposition to the foolish ignorabimus, our slogan shall be: We must know - and therefore we will know".3

The first category, the known knowns, involves things we know that we know, those things which we have proven beyond reasonable doubt. But we must keep at it, because if we don't, the known knowns could slip out of reach. The second are things we know that we don't know, those facts that we know we need, but have not yet determined. And then there is the third category, the facts that are there, but we don't know that they exist. We can't predict them or even see them coming. You think you've grasped or gained understanding only to find it slip away again and the more you think about them, the more confused you get. The third are the worst because no matter how much we uncover, however much we think we know, there is always something we could never have accounted for.

These three categories exist in all aspects and on all levels of life, whether it be personal, professional, societal or global. But we have to keep trying, investigating and exploring if we are to find, recognise and understand the 'unknowns'. Are we going to let them remain so elusive? No. Let's take up the challenge: Let's re-establish and validate the known knowns, explore the unknown knowns, and discover those unknown unknowns. Let's take the stance of David Hilbert almost a century ago: We MUST know, and therefore, we WILL.


Blanche Pretorius
Editor in Chief






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