فصل 37

chapter 37

The Runaway Train and the Unwanted Violinist

Philippa Foot and Judith Jarvis Thomson

You are out for a walk one day and see a runaway train hurtling down the tracks towards five workers. The driver is unconscious, possibly as the result of a heart attack. If nothing is done, all will die. The train will squash them. It’s travelling much too fast for them to get out of the way. There is, however, one hope. There is a fork in the tracks just before the five men, and on the other line there is only one worker. You are close enough to the points to flick the switch and make the train veer away from the five and kill the single worker. Is killing this innocent man the right thing to do? In terms of numbers it clearly is: you save five people by killing just one. That must maximize happiness. To most people this seems the right thing to do. In real life it would be very difficult to flick that switch and watch someone die as a result, but it would be even worse to hold back and watch five times as many people die.

This is a version of a thought experiment originally created by the British philosopher Philippa Foot (1920–2010). She was interested in why saving the five people on the track was acceptable, but some other cases of sacrificing one to save many weren’t. Imagine a healthy person walking into a hospital ward. In the ward are five people who desperately need various organs. If one doesn’t get a heart transplant she will certainly die. Another needs a liver, one a kidney, and so on. Would it be acceptable to kill the healthy patient and slice up the body to provide the organs for the unhealthy ones? Hardly. No one believes that it would be acceptable to kill the one healthy person, remove his heart, lungs, liver, kidneys, and implant them in the five. Yet that is a case of sacrificing one to save five. What’s the difference between that and the runaway train?

A thought experiment is an imaginary situation designed to bring out our feelings, or what philosophers call ‘intuitions’, on a particular issue. Philosophers use them a lot. Thought experiments allow us to focus more closely on what is at stake. Here the philosophical question is, ‘When is it acceptable to sacrifice one life to save more?’ The story about the runaway carriage allows us to think about this. It isolates the key factors and shows us whether or not we feel that such an action is wrong.

Some people say you should never flick the switch in this example because that would be ‘playing God’: deciding who should die and who should live. Most people, however, think you should.

But imagine a related case. The American philosopher Judith Jarvis Thomson thought up this version of the original problem. The runaway train this time is on a straight piece of track running towards the five unfortunate workers who will certainly be killed unless you do something. You are standing on a bridge, and next to you is a very large man. If you push him over the bridge, he is heavy enough to slow down and stop the train before it hits the five workers. Assuming you have the strength to push this man over in front of the train, should you do it?

Many people find this a tougher case, and are more inclined to say ‘no’, despite the fact that in both this case and in the case of the fork in the line and the points that you can switch the consequence of your actions is the death of one person rather than five. In fact, pushing the large man off the bridge looks very like murder. If the consequences are the same in the two cases then there shouldn’t be an issue. If it is right to flick the switch in the first example, it must surely be right to push the large man in front of the train in the second. This is puzzling.

If the imaginary situation of pushing someone over a bridge suggests physical difficulties, or you are put off by the brutality of having to wrestle the man to his death, the case can be revised so that there is a trapdoor on the bridge. Using the same kind of lever as you do in the first case with the point-switching, you can drop the large man into the path of the train with minimal effort. You just flick a lever. Many people see this as morally far removed from the fork in the line case. Why should this be so?

The so-called Law of Double Effect is one explanation of why we think the forking track case and the fat man case are different. This is the belief that it can be all right, for example, to hit someone so hard that they die but only if your intention is to defend yourself and a lighter blow wouldn’t protect you. Predictable bad side effects of an action with a good intention (in this case saving yourself) can be acceptable, but deliberate harm is not. It isn’t right to go out and poison someone who is planning to kill you. The first case is one in which you have an acceptable intention, it’s just that following through on it will result in someone’s death. In the second case you intend to kill the person, and that isn’t acceptable. For some people, this solves the problem. Other people think this principle of Double Effect is a mistake.

These cases may seem far-fetched and nothing to do with everyday life. In one sense that is true. They’re not meant to be real cases. These are thought experiments designed to clarify our beliefs. But from time to time real-life situations do arise that lead to similar decisions. For example, during the Second World War the Nazis were firing flying bombs into parts of London. A German spy had become a double agent. The British had the chance to send misleading information back to the Germans, telling them that the rockets were falling far to the north of their intended targets. This would have had the effect of making the Germans change their aim, so that instead of falling on heavily populated parts of London, the rockets would fall further to the south on people in Kent and Surrey. In other words, there was a possibility of giving information that would cause fewer people to be killed. In this case the British decided not to play God.

In a different sort of real-life situation, the participants did decide to take action. In the Zeebrugge disaster in 1987, when a car ferry sank and dozens of passengers were struggling to get out of the icy sea, a young man climbing to safety on a rope ladder froze with fear and could not move. He stayed in that position for at least ten minutes, stopping anyone else from getting out of the sea. If they didn’t get out quickly they would drown or die of cold. Eventually those in the water pulled him off the ladder and managed to escape to safety. The young man fell into the sea and drowned. The decision to pull the young man off the ladder must have been an agonizing one to make, but in these extreme circumstances, as with the runaway train, sacrificing one person to save many was probably the right thing to do.

Philosophers are still arguing about the train example and how it should be solved. They’re also arguing about another thought experiment that Judith Jarvis Thomson (born 1929) came up with. This one was to show that a woman who had used contraception but who had still become pregnant did not have a moral duty to go through with having the baby. She could have an abortion without doing something morally wrong. To have the baby in such circumstances would be an act of charity, but not a duty. Traditionally, debates about the morality of abortion had focused on the foetus’ point of view. Her argument was important in that it gave a lot of weight to the woman’s perspective. Here’s the example.

There is a famous violinist who has a kidney problem. His only chance of survival is to be plugged into a person who shares his very rare blood group. You have that same blood group. One morning you wake up to find that while you were asleep doctors have attached him to your kidneys. Thomson argues that in such a situation you don’t have a duty to keep him plugged into you, even though you know that he will die if you pull the tubes out. In the same way, she suggests, if a woman is pregnant even though she used contraception, the developing foetus inside her does not have an automatic right to the use of her body. The foetus is like the violinist.

Before Thomson introduced this example, many people thought that the crucial question was, ‘Is a foetus a person?’ They believed that if they could show that a foetus was a person, then abortion would obviously be immoral in every case. Thomson’s thought experiment suggested that even if the foetus is a person, that doesn’t settle the question.

Of course, not everyone agrees with this answer. Some people still think that you shouldn’t play God even if you wake up with a violinist plugged into your kidneys. It would be a difficult life, unless you really loved violin music. But it would still be wrong to kill the violinist even though you had not chosen to help him. Likewise, plenty of people believe that you should never deliberately terminate a healthy pregnancy even if you did not intend to get pregnant and took precautions against doing so. What the cleverly constructed thought experiment does, though, is bring out the principles underlying these disagreements.

The political philosopher John Rawls also used a thought experiment, in his case to investigate the nature of justice and the best principles for organizing society.