I think Jansy has put her finger on the problem I have with this sentence - - it is an ourobouros like Escher's castle stairs or like Pale Fire (the poem).
I know more than I can express in words, and the little I can express would not have been expressed, had I not known more [than I can express in words ...] and so on
Carolyn Kunin wrote: "I just ran across the often quoted statement VN made regarding his belief in a transcendent reality: "I know more than I can express in words, and the little I can express would not have been expressed, had I not known more."... It's the second "not" that throws me....
The engraver Escher