A more positive interpretation could be something like "I can't express what I want to say without going into topics that I know you have no familiarity with. But I'm aware of that and am not just insensitively bombarding you with jargon."

Indeed. This is a six (printed) page letter, and already at a page or two in I wouldn't be surprised if it would take that many textbooks (how many printed pages?) to get SAW from where ever she left off (I don't recall maths being very prominent in classics/philosophy departments; note AW's description of a field) to where she could have a hope of seeing the moon itself, beyond the finger pointing at it.