You don't read Gatsby, I said, to learn whether adultery is good or bad but to learn about how complicated issues such as adultery and fidelity and marriage are. A great novel heightens your senses and sensitivity to the complexities of life and of individuals, and prevents you from the self-righteousness that sees morality in fixed formulas about good and evil.
A novel is not an allegory.... It is the sensual experience of another world. If you don't enter that world, hold your breath with the characters and become involved in their destiny, you won't be able to empathize, and empathy is at the heart of the novel. This is how you read a novel: you inhale the experience. So start breathing.