Kluge: The Haphazard Construction of the Human Mind (Houghton Mifflin; 2008)

One historical example of how visceral feelings affect moral choice is the unofficial truce called by British and German soldiers during Christmas 1914, early in World War I. The original intention was to resume battle afterward, but the soldiers got to know one another during the truce; some even shared a Christmas meal. In so doing, they shifted from conceptualizing one another as enemies to seeing each other as flesh-and-blood individuals. The consequence was that after the Christmas truce, the soldiers were no longer able to kill one another. As the former president Jimmy Carter put it in his Nobel Peace Prize lecture (2002), "In order for us human beings to commit ourselves personally to the inhumanity of war, we find it necessary first to dehumanize our opponents."

Both the trolley problem and the Christmas truce remind us that though our moral choices may seem to be the product of a single process of deliberative reasoning, our gut, in the end, often also plays a huge role, whether we are speaking of something mundane, like a new car, or making decisions with lives at stake.

The trolley scenarios illustrate the split by showing how we can get two different answers to essentially the same question, depending on which system we tap into. The psychologist Jonathan Haidt has tried to go a step further, arguing that we can have strong moral intuitions even when we can't back them up with explicit reasons. Consider, for example, the following scenario:

Julie and Mark are brother and sister. They are traveling together in France on summer vacation from college. One night they are staying alone in a cabin near the beach. They decide that it would be interesting and fun if they tried making love. At the very least it would be a new experience for each of them. Julie was already taking birth control pills, but Mark uses a condom too, just to be safe. They both enjoy making love, but they decide not to do it again. They keep that night as a special secret, which makes them feel even closer to each other. What do you think about that? Was it okay for them to make love?

Every time I read this passage, I get the creeps. But why exactly is it wrong? As Haidt describes it,

most people who hear the above story immediately say that it was wrong for the siblings to make love, and they then begin searching for reasons. They point out the dangers of inbreeding, only to remember that Julie and Mark used two forms of birth control. They argue that Julie and Mark will be hurt, perhaps emotionally, even though the story makes it clear that no harm befell them. Eventually, many people say something like "I don't know, I can't explain it, I just know it's wrong."

Haidt calls this phenomenon — where we feel certain that something is wrong but are at a complete loss to explain why — "moral dumbfounding." I call it an illustration of how the emotional and the judicious can easily decouple. What makes moral dumbfounding possible is the split between our ancestral system — which looks at an overall picture without being analytical about the details

— and a judicious system, which can parse things piece by piece. As is so often the case, where there is conflict, the ancestral system wins: even though we know we can't give a good reason, our emotional queasiness lingers.

When you look inside the skull, using neuroimaging, you find further evidence that our moral judgments derive from two distinct sources: people's choices on moral dilemmas correlate with how they use their brains. In experimental trials like those mentioned earlier, the subjects who chose to save five lives at the expense of one tended to rely on the regions of the brain known as the dorsolateral prefrontal cortex and the posterior parietal cortex, which are known to be important for deliberative reasoning. On the other hand, people who decided in favor of the single individual at the cost of five tended to rely more on regions of the limbic cortex, which are more closely tied to emotion.*

What makes the human mind a kluge is not the fact that we have two systems per se but the way in which the two systems interact. In principle, a deliberative reasoning system should be, well, deliberate: above the fray and unbiased by the considerations of the emotional

*Fans of the history of neuroscience will recognize this as the brain region that was skewered in the brain of one Phineas Gage, injured on September 13,1848.