PRIMATES AND PHILOSOPHERS Part 8 docx

asked what you should do in these circumstances, most peo￾ple say that you should not push the stranger off the bridge.

Greene and his colleagues see these situations as differing

in the extent to which they involve an “impersonal” situation

such as throwing a switch, or a “personal” violation such as

pushing a stranger off a bridge. They found that when sub￾jects were deciding about the “personal” cases, the parts of

the brain associated with emotional activity were more ac￾tive than they were when the subjects were asked to make

judgments in “impersonal” cases. More significantly, the mi￾nority of subjects who came to the conclusion that it would

be right to act in ways that involve a personal violation, but

minimize harm overall—for example, those who say that it

would be right to push the stranger off the footbridge—

show more activity in parts of the brain associated with cog￾nitive activity, and take longer to reach their decision, than

those who say “no” to such actions.7 In other words, when

confronted with the need to physically assault another per￾son, our emotions are powerfully aroused, and for some, the

fact that this is the only way to save several lives is insuffi￾cient to overcome those emotions. But those who are pre￾pared to save as many lives as possible, even if this involves

physically pushing another person to his death, appear to be

using their reason to override their emotional resistance to

the personal violation that pushing another person involves.

Does this lend support for the idea of “human morality as

evolutionarily anchored in mammalian sociality”? Yes, to a

148 P ETER SINGER

7 Joshua Greene and Jonathan Haidt, “How (and Where) Does Moral Judgment

Work,?” Trends in Cognitive Sciences 6 (2002): 517–523, and personal communica￾tions. To be more specific, those who accept the personal violation show more ante￾rior dorsolateral prefrontal activity, while those who reject it have more activity in

the precuneus area.

point. The emotional responses that lead most people to say

it would be wrong to push a stranger off a footbridge can be

explained in just the kind of evolutionary terms that de Waal

develops in his lectures, and supports with evidence drawn

from his observations of primate behavior. Similarly, it is

easy to see why we would not have developed similar re￾sponses to something like throwing a switch, which may also

cause death or injury, but does so at a distance. For all of our

evolutionary history, we have been able to harm people by

pushing them violently, but it is only for a few centuries—

far too brief a time to make a difference to our evolved

nature—that we have been able to harm people by actions

like throwing switches.

Before we take this as confirming de Waal’s point, how￾ever, we need to think again about the subjects of Greene’s

research who, after some reflection, come to the conclusion

that just as it is right to throw a switch to divert a train,

killing one person but saving five, so too it is right to push

one person off a footbridge, killing one but saving five. This

is a judgment that other social mammals seem incapable of

making. Yet it too is a moral judgment. It appears to come,

not from the common evolutionary heritage we share with

other social mammals, but from our capacity to reason. Like

the other social mammals, we have automatic, emotional re￾sponses to certain kinds of behavior, and these responses

constitute a large part of our morality. Unlike the other so￾cial mammals, we can reflect on our emotional responses,

and choose to reject them. Recall Humphrey Bogart’s line in

the closing moments of Casablanca, when, as Rick Blaine, he

tells the woman he loves (Ilsa Lund, played by Ingrid

Bergman) to get on the plane and join her husband: “I’m no

good at being noble, but it doesn’t take much to see that the

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