Moral Tribes: Emotion, Reason, and the Gap Between Us and Them

by Joshua D. Greene

Consider, for example, the analogous dilemma we face as we try to eat a healthy diet. As a perfectly healthy eater, you would identify the healthiest possible set of foods and consume only those foods, in precisely optimal quantities. If you were to maintain a perfect diet, chances are you would never eat your favorite foods, not even on your birthday. You would travel with bundles of optimal food, because, odds are, optimal food will not be available wherever you’re going. Upon receiving a dinner invitation from a friend, you would either decline, eat before, eat after, or bring your own optimal food. (BYOOF!) You would never take a date to a restaurant, or you would only take someone to restaurants that serve optimal food. And so on. If you were a food-consuming computer, maintaining an optimal diet might be a realistic goal. But as a real person with limited time, money, and willpower, trying to maintain a physiologically optimal diet is not, in fact, optimal. Instead, the optimal strategy is to eat as well as you can, given your real-world constraints, including your own psychological limitations and including limitations imposed on you as a social being. This is challenging because there’s no magic formula, no bright line between the extremes of perfectionism and unbridled gluttony. To be the healthiest that you can actually be—not in principle, but in practice—you have to set reasonable goals, which will inevitably be somewhat arbitrary, and then work reasonably hard...