Another possibility is that our intuitive sense of justice is a set of heuristics: moral machinery that’s very useful but far from infallible. We have a taste for punishment. This taste, like all tastes, is subtle and complicated, shaped by a complex mix of genetic, cultural, and idiosyncratic factors. But our taste for punishment is still a taste, implemented by automatic settings and thus limited by its inflexibility. All tastes can be fooled. We fool our taste buds with artificial sweeteners. We fool our sexual appetites with birth control and pornography, both of which supply sexual gratification while doing nothing to spread our genes. Sometimes, however, our tastes make fools of us. Our tastes for fat and sugar make us obese in a world of abundance. Drugs of abuse hijack our reward circuits and destroy people’s lives. To know whether we’re fooling our tastes or whether our tastes are fooling us, we have to step outside the limited perspective of our tastes: To what extent is this thing—diet soda, porn, Nutella, heroin—really serving our bests interests? We should ask the same question about our taste for punishment.

Joshua Greene, Moral Tribes: Emotion, Reason, and the Gap Between Us and Them, New York, 2013, p. 272