*bong noises*Knowledge is knowledge about the own knowledge.
Does one know what one knows?
Perhaps only as far as one does not know what one does not know about what one knows.
what time is it?*bong noises*
Ancients have thought a lot about all this! I recommend you read this (ignore any religious aspect and think of it as an epistemology): https://en.wikipedia.org/wiki/Pramana - in particular ponder on the main ways of gaining knowledge (see the section on six pramanas): evidence/perception, inference, comparison & analogy, postulation/implication, non-perceptions/negative proof, and testimony of past/present reliable experts. This goes far beyond Rumsfeld's stupid categorization of {known,unknown}x{knowns,unknowns}Knowledge is knowledge about the own knowledge.
Does one know what one knows?
Perhaps only as far as one does not know what one does not know about what one knows.
Not knowing that one does not know is knowledge. Ignorance is knowledge. Double negation. What is problem?*bong noises*