A brief essay James R. Kincaid in The New Yorker, January 20, 1997. I like this bit, quoting Helen Keller:
It is certain that I cannot always distinguish my own thoughts from those I read, because what I read becomes the very substance and text of my mind.
That’s found in her autobiography, where she goes on to say:
Consequently, in nearly all that I write, I produce something which very much resembles the crazy patchwork I used to make when I first learned to sew. This patchwork was made of all sorts of odds and ends–pretty bits of silk and velvet; but the coarse pieces that were not pleasant to touch always predominated. Likewise my compositions are made up of crude notions of my own, inlaid with the brighter thoughts and riper opinions of the authors I have read. It seems to me that the great difficulty of writing is to make the language of the educated mind express our confused ideas, half feelings, half thoughts, when we are little more than bundles of instinctive tendencies. Trying to write is very much like trying to put a Chinese puzzle together. We have a pattern in mind which we wish to work out in words; but the words will not fit the spaces, or, if they do, they will not match the design. But we keep on trying because we know that others have succeeded, and we are not willing to acknowledge defeat.