“[Y]ou poisoned me with a book once. I should not forgive that. Harry, promise me that you will never lend that book to anyone. It does harm.”
“My dear boy, you are really beginning to moralize. You will soon be going about like the converted, and the revivalist, warning people against all the sins of which you have grown tired. You are much too delightful to do that.... As for being poisoned by a book, there is no such thing as that. Art has no influence upon action. It annihilates the desire to act. It is superbly sterile. The books that the world calls immoral are books that show the world its own shame.”

This exchange between Dorian and Lord Henry takes place in Chapter Nineteen, as Dorian, flayed by his conscience, pledges to live a reformed life. Reflecting on the course of his past twenty years, he confronts Lord Henry, whom he believes is responsible for leading him astray. Dorian criticizes the yellow book that, years before, had such a profound influence over him, claiming that this book did him great harm. This accusation is, of course, alien to Wilde’s philosophy of aestheticism, which holds that art cannot be either moral or immoral. Lord Henry says as much, refusing to believe that a book could have such power. While there is something seductive in his observation that “the world calls immoral . . . books that show the world its own shame,” Lord Henry’s words here are less convincing than other statements to the same effect that he makes earlier in the novel. In the latter stages of the novel, we know of Dorian’s downfall, and we know that he is anything but “delightful.” At this point, Lord Henry’s praising of Dorian makes Lord Henry seem hopelessly naïve, the victim of a philosophy whose consequences elude him.