To teach, to explain something, to answer a question, one must have a good mental model of what the listener already knows and doesn't know. Otherwise the explanation won't be at the right level and the transmission won't make sense when it gets to the receiver. Charles Babbage in his autobiographical Passages from the Life of a Philosopher writes:

... On two occasions I have been asked, – "Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?" In one case a member of the Upper, and in the other a member of the Lower, House put this question. I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question. ...

... correctly identifying the main challenge of responding!

(from [1]; cf [2] Chapter 5, "Difference Engine No. 1" final page, and Common Understanding (1999-10-08), Technical Minded (2003-07-18), Impute Motives (2009-03-18), How to Explain Anything (2016-01-28), Eagles Are All about Efficiency (2020-05-12), ...) - ^z - 2021-04-05