From The Boston Globe:
“Two things fill my mind with ever renewed wonder and awe the more often and deeper I dwell on them,” wrote Immanuel Kant, “the starry skies above me, and the moral law within me.” Where does moral law come from? What lies behind our sense of right and wrong? For millennia, there have been two available answers. To the devoutly religious, morality is the word of God, handed down to holy men in groves or on mountaintops. To moral philosophers like Kant, it is a set of rules to be worked out by reason, chin on fist like Rodin’s thinker. But what if neither is correct? What if our moral judgments are driven instead by more visceral human considerations? And what if one of those is not divine commandment or inductive reasoning, but simply whether a situation, in some small way, makes us feel like throwing up?
This is the argument that some behavioral scientists have begun to make: That a significant slice of morality can be explained by our innate feelings of disgust. A growing number of provocative and clever studies appear to show that disgust has the power to shape our moral judgments. Research has shown that people who are more easily disgusted by bugs are more likely to see gay marriage and abortion as wrong. Putting people in a foul-smelling room makes them stricter judges of a controversial film or of a person who doesn’t return a lost wallet. Washing their hands makes people feel less guilty about their own moral transgressions, and hypnotically priming them to feel disgust reliably induces them to see wrongdoing in utterly innocuous stories.