Good artists simply exist in what they make, and consequently are perfectly uninteresting in what they are. A great poet, a really great poet, is the most unpoetical of all creatures. But inferior poets are absolutely fascinating.
Lord Henry shares his ideas about artists, including Basil, with Dorian. Lord Henry repeats the idea throughout the novel that interesting people cannot be good artists because artists must give their entire selves over to their work. He sees art as basically a different realm from life itself, suggesting that artists do not relate meaningfully to the world, having invested everything of themselves into their art.
How little you can know of love if you say it mars your art! Without your art you are nothing.
Dorian responds to Sibyl after she explains that, now that she has experienced real love, she can no longer professionally act. Dorian lashes out because her pursuit and excellence in the art of acting played a large role in her appeal. Just as he believes nothing in his life has any significance compared to his beauty, he sees Sibyl’s art as essential to her personality.
I am so glad that you have never done anything—never carved a statue, or painted a picture, or produced anything outside of yourself! Life has been your art. You have set yourself to music. Your days are your sonnets.
After Dorian laments what has become of his life, Lord Henry remarks on the accomplishments Dorian has made. Just as Lord Henry believes that artists put all of themselves into their art, he sees Dorian as having put all of himself into living well and enjoying life. If Dorian had tried to do anything else, he could not have been as fully committed to his way of living. However, the reader knows that because Dorian has put so much into the spectacle of his life, he has never contemplated his own soul.