What is the correct usage of phrase "you don't know what you don't know"? Can it be used in formal conversation/writing? I saw this sentence in the book 1Q84: It's not just you that don't know.

Understanding the Context

However, I am having trouble figuring out why (or whether) this is the correct way to write the sentence, as opposed to: ... "doesn't know" vs "don't know" [duplicate] - English Language & Usage ... The Wall Street Journal on MSN: What we know—and don’t know—about the tariff-refund process Recently one of my friends told me that there is distinct difference between 'know of something' and 'know about something' expressions. 'know of' is used when you have personal experience with wha...

Key Insights

"Know about" vs. "know of" - English Language & Usage Stack Exchange Examples: I know (about) this difficulty/problem. I know (about) Engineering. In the first sentence, it seems to me that "to know" expresses that the speaker experienced the problem/difficulty before while "to know about" only expresses that the speaker has heard or read about it. to know vs to know about - English Language & Usage Stack Exchange Earth is the only planet we know of where life exists.

Final Thoughts

This sentence is from the commentary of Planet Earth. Why it is know of in this sentence? Can it be know about? What’s the difference bet... “know of” vs “know about” - English Language & Usage Stack Exchange Why do you think that He doesn't know him from his schooldays means that he does know him? It would only have that sense if you added something like In fact, he first met him at university.