Whatever is going to be, is learning from what is; whatever is happening is possessed by whatever has already happened, and "If each word wins us a victory over nothingness, it is only to subject us further to its power", wrote Cioran the pessimist. Nothing is fated until it happens. Everything present is its own premonition. The ruin from Ossian occurred to the writer of Romance, and I was interested to see that Ann Wroe in her book on Shelley described the poet working in a way that was not like that Radcliffian leap from one phrase into another; instead, she said, he would mark down the rhythm of the poem (that was the main thing, the propelling thing) and spaces were often left blank, waiting to be filled in later with some word that wouldn't sound out of place.
Before this I imagined Marguerite Young rolling from word to word in her sentences but Miss MacIntosh, My Darling depends so much on rhythm that the Shelley method could have been used instead and it would have had the same result: she could have written it one way or the other way, and there is no rule that says you have to write one word after another, or even a book in order. John Crowley once said that he starts his books in the middle, and the landscape to right and left of that island a whitened tundra where the moss whistled to the wind.
So the shape of a finished thing doesn't always let you know how it was done, and mystery novels, no matter how many observed details they include, will never be realistic; they are attuned to an a-real philosophy, or a hopeful one.
All of Young's words are her own, she's not a quoter, or if she's quoting or misquoting excerpts then she doesn't give herself away. She resuses herself but not anyone else; large areas of Miss MacIntosh are made of words that have already been used, as all books are, if you want to be pedantic, everybody lifting everybody else's "the" and "but" and "I", doing this without remorse or shame because nobody ever detects them, or everybody does but nobody calls them out, we are this collective of thieves, and you have to reach a higher status of word before people start shouting plagiarism or sequel. You have to reach the arena of proper names, and even then you can disguise it. I could write a serious book about a girl named Alicia and, as long as I was careful, nobody would know that she belonged to Lewis Carroll, whose own name cannibalised the words Charles Lutwidge Dodgson.
"This pseudonym was a play on his real name; Lewis was the anglicised form of Ludovicus, which was the Latin for Lutwidge, and Carroll an Irish surname similar to the Latin name Carolus, from which the name Charles comes," explains somebody on his Wikipedia page. They refer you to Morton Cohen's 1996 book Lewis Carroll: a Biography for proof, but none of the Carroll biographies I've been able to actually get my hands on around here will support the theory, although they don't support any other theory either, they just don't mention it at all. In my local Carroll biographies it's as if he pulled the name out of nowhere and relied on nothing, nothing inspired him, there was no forerunner, only pure Carroll.
(n.b. Wroe's book is an alchemical biography, Becoming Shelley, devoutly researched, which is more than I did for those Carroll biographies, scuffling around in the UNLV library among the England 1800s shelves under D, Dodgson, with the black weight of Dickens falling to my left and Eliot nesting like Eagles on the right.)