From Robert Phillips’s interview of Philip Larkin in “The Art of Poetry No. 30” (The Paris Review: Summer 1982, No. 84):
The short answer is that you write because you have to. If you rationalize it, it seems as if you’ve seen this sight, felt this feeling, had this vision, and have got to find a combination of words that will preserve it by setting it off in other people. The duty is to the original experience. It doesn’t feel like self-expression, though it may look like it.