You may write for the joy of it, but the act of writing is not complete in itself. It has its end in its audience. Writing is a good example of self-abandonment. I never completely forget myself except when I am writing and I am never more completely myself than when I am writing.
But the writer doesn't have to understand, only produce. And what makes him produce is not having the experience but contemplating the experience, and contemplating it doesn't mean understanding it so much as understanding he doesn't understand it.