"Where does our sense of right and wrong come from?" David Brooks at The New York Times prefers a naturalistic explanation of moral code over a purely divine or rational one. "Moral naturalists believe that we have moral sentiments that have emerged from a long history of relationships. To learn about morality, you don’t rely upon revelation or metaphysics; you observe people as they live. ... By the time humans came around, evolution had forged a pretty firm foundation for a moral sense. Jonathan Haidt of the University of Virginia argues that this moral sense is like our sense of taste. We have natural receptors that help us pick up sweetness and saltiness. In the same way, we have natural receptors that help us recognize fairness and cruelty."