From Steven Pinker's The Blank Slate: "People have gut feelings that give them emphatic moral convictions, and they struggle to rationalize them after the fact. These convictions may have little to do with moral judgments that one could justify to others in terms of their effects on happiness or suffering. They arise instead from the neurobiological and evolutionary design of the organs we call moral emotions... The difference between a defensible moral position and an atavistic gut feeling is that with the former we can give reasons why our conviction is valid. We can explain why torture and murder and rape are wrong, or why we should oppose discrimination and injustice. On the other hand, no good reasons can be produced to show why homosexuality should be suppressed or why the races should be segregated. And the good reasons for a moral position are not pulled out of thin air: they always have to do with what makes people better off or worse off, and are grounded in the logic that we have to treat other people in the way that we demand they treat us."