The most famous thought-experiment of contemporary philosophy, first described by Philippa Foot, goes roughly as follows:
Suppose a runaway train is hurtling down a track headed toward five innocent people who will surely be killed if the train is not stopped or diverted. The brakes on the train have failed and there is no other way of stopping it, but the driver can divert the train on to a side-track, where one innocent person is standing. This person will surely die if the train is diverted. Should the driver divert the train on to the side-track?
In the last decade or so, this thought experiment has been put to very many people around the world and the results indicate that the overwhelming majority of people respond in the affirmative. That is, the vast majority of people believe that it is right for the driver to sacrifice one innocent life in order to save five. This in turn suggests that most people are thinking along utilitarian lines in responding to this thought-experiment. Diverting the train is the right thing to do, people seem to think, because it is the option that results in the least amount of suffering or, in other words, produces the greatest amount of happiness for all those concerned.
It has also been demonstrated, in other thought-experiments, that there are sharp limits on how far most people are willing to push these utilitarian intuitions. In a famous variation on Foot’s though-experiment, Judith-Jarvis Thomson, imagined the following:
Suppose that a runaway train is hurtling down a track heading for five innocent people, who will surely be killed if the train is not stopped or diverted. In this case, there is no side-track on to which the train can be diverted, but there is a bridge passing over the track with a very large man on it. The man is large enough to stop the train if he were pushed on to the track, but he would surely die in the process of stopping the train. Suppose that a bystander is standing on the bridge next to the large man and is strong enough to push him on to the tracks. Should he do it?
The options presented in this thought-experiment are very similar to those presented in Foot’s original thought-experiment: in both cases, the person in question can do something that results in the death of one innocent person in order to save the lives of five innocent people. However, while the cost-benefit analysis is identical in the two cases, responses to these thought-experiments diverge dramatically. Whereas most people believe that the driver should divert the train in the first case (thereby killing one to save five), most people believe that the bystander should not push the large man on to the track (even though he too would save five by killing one).
Why do these two thought-experiments, which embody precisely the same cost-benefit analysis, provoke such different responses? One of the best answers to this question comes from Joshua Green, who claims that neuro-physiological studies show that people engage in a utilitarian calculation in both cases, but in the second case (the so-called Footbridge problem), the thought of pushing a man on to a track evokes a strong emotional reaction (indicated by increased activity in the regions of the brain associated with emotions), which somehow overrides or vetoes the utilitarian calculation. In short, when people are asked to think about one person being sacrificed in an “up close and personal” way, they recoil from the utilitarian calculation. In the lecture shown below, Greene presents this explanation in the context of his model of ethical judgment and its neurological basis.
Given the foregoing, one can perhaps make predictions on how most people would respond to other thought-experiments involving cost-benefit analyses similar to those presented by Foot and Thomson. The general principles, it seems, are the following: the greater the good produced, the less harm that is involved, or the less direct the harm, the more people will tend to apply utilitarian thinking.
For instance, imagine a scenario somewhat like Foot’s original thought-experiment but one in which the numbers are changed such that an even greater good results from diverting the train. Imagine that instead of there being five people who can be saved by diverting a train on to a track containing one person, one billion people can be saved by diverting the train on to a track containing one hundred people. If one could save one billion people by doing something that results in the death of one hundred people (in an indirect way), should one do it? Most people, it seems, would say “yes.” Indeed, if people respond affirmatively in Foot’s original thought-experiment, it is unimaginable that they wouldn’t respond affirmatively in this case as well.
And suppose that the scenario is modified further so that the harm involved is much less severe than death. Leaving aside the fantasy of runaway trains, imagine that one could save the lives or at least relieve the suffering of some 1.2 billion people living in conditions of abject poverty by doing something that was a minor annoyance to another 100 people. Should one do it? Most people, it seems, would say “yes.” Again, it is difficult to see how one could say “no” while at the same time saying “yes” to Foot’s original though-experiment, for the harms involved are less direct and less severe, and the benefits produced are far greater (or at least involve many more people).
As it turns out, the question just posed is not merely theoretical; it is a question that confronts us all and in a very real way. Oxfam has just concluded a study which indicates that the “$240 billion net income in 2012 of the richest 100 billionaires would be enough to make extreme poverty history four times over.” In other words, the extreme poverty that currently affects approximately 1.2 billion people on this planet could be eliminated by taking one-quarter of the 2012 net earnings of the richest 100 people on the planet.
So here’s a prediction: most people would agree that it is right to take one-quarter of one year’s income from 100 people in order to eliminate extreme poverty for 1.2 billion people.
And, if so, the question then becomes “Why don’t we do it?”
