I am looking for a less wordy version of the phrase:
'you don't [or can't] know what you don't know'
I would like something suitable for an essay format. Ideally a single word or short phrase that conveys the same concept.
This is a different question to http://english.stackexchange.com/questions/59145/usage-of-the-phrase-you-dont-know-what-you-dont-know which asks about usage without requesting alternatives.