It is as good as I had power to make it — by myself. Had I been nervous about its being a perfect piece, and with that view asked advice, and trembled over every page, it would not have been written; for it is not in my nature to fumble — I will write independently. — I have written independently without Judgment. I may write independently, and with Judgment, hereafter. The Genius of Poetry must work out its own salvation in a man: It cannot be matured by law and precept, but by sensation and watchfulness in itself — that which is creative must create itself — In Endymion, I leaped headlong into the sea, and thereby have become better acquainted with the Soundings, the quicksands, and the rocks, than if I had stayed upon the green shore, and piped a silly pipe, and took tea and comfortable advice. I was never afraid of failure; for I would sooner fail than not be among the greatest.
John Keats, in an 1818 letter to his publisher, responding to critics of his poem “Endymion” (punctuation as in original)