Proust's work has been mentioned several times recently in The New York Times Book Review, either from an "I couldn't finish it" or an "I ought to read it" point of view. So what does this quote from Le temps retrouvé say about those who won't or can't read it? "In reality, every reader, while he is reading, is the reader of his own self. . . . The reader's recognition in his own self of what the book says is the proof of its truth."
What Proust says is true only if writers, while they are writing, are the writers of their own selves. In that case, the dictum is true of all art. If painters, performers, writers are creating from their complete selves - body, mind, and emotion - their audiences will respond with their complete selves. And will believe in the truth of what they're witnessing or reading.