"Data" is not knowledge: it is neither conoscere (noscere, connaître, kennen...) nor sapere (scire, savoir, wissen...). 

The English language lacks this distinction. 

Knowledge in whatever form requires a knower to be known, the full reality of which is a fact in turn; an event that may itself become known by the knowers, so that "they know that I know that I don't know" does in fact become a distinct possibility. 

(This is certainly a curious result).