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  • Imagine you're watching a runaway trolley barreling down the tracks straight towards five workers who can't escape.

  • You happen to be standing next to a switch that will divert the trolley onto a second track.

  • Here's the problem.

  • That track has a worker on it, too, but just one.

  • What do you do?

  • Do you sacrifice one person to save five?

  • This is the "trolley problem", a version of an ethical dilemma that philosopher Philippa Foot devised in 1967.

  • It's popular because it forces us to think about how to choose when there are no good choices.

  • Do we pick the action with the best outcome or stick to a moral code that prohibits causing someone's death?

  • In one survey, about 90% of respondents said that it's okay to flip the switch, letting one worker die to save five.

  • And other studies, including a virtual reality simulation of the dilemma, have found similar results.

  • These judgments are consistent with the philosophical principle of utilitarianism, which argues that the morally correct decision is the one that maximizes [the] well-being for the greatest number of people.

  • The five lives outweigh one, even if achieving that outcome requires condemning someone to death.

  • But people don't always take the utilitarian view, which we can see by changing the trolley problem a bit.

  • This time, you're standing on a bridge over the track as the runaway trolley approaches.

  • Now, there's no second track, but there is a very large man on the bridge next to you.

  • If you push him over, his body will stop the trolley, saving the five workers, but he'll die.

  • To utilitarians, the decision is exactly the same: lose one life to save five.

  • But in this case, only about 10% of people say that it's okay to throw the man onto the tracks.

  • Our instincts tell us that deliberately causing someone's death is different that allowing them to die as collateral damage.

  • It just feels wrong for reasons that are hard to explain.

  • This intersection between ethics and psychology is what's so interesting about the trolley problem.

  • The dilemma in its many variations reveal that what we think is right or wrong depends on factors other than a logical weighing of the pros and cons.

  • For example, men are more likely than women to say it's okay to push the man over the bridge.

  • So are people who watch a comedy clip before doing the thought experiment.

  • And in one virtual reality study, people were more willing to sacrifice men than women.

  • Researchers have studied the brain activity of people thinking through the classic and bridge versions.

  • Both scenarios activate areas of the brain involved in conscious decision-making and emotional responses.

  • But in the bridge version, the emotional response is much stronger.

  • So is activity in an area of the brain associated with processing internal conflict.

  • Why the difference?

  • One explanation is that pushing someone to their death feels more personal, activating an emotional aversion to killing another person.

  • But we feel conflicted because we know it's still the logical choice.

  • Trolleyology has been criticized by some philosophers and psychologists.

  • They argue that it doesn't reveal anything because its premise is so unrealistic that study participants don't take it seriously.

  • But new technology is making this kind of ethical analysis more important than ever.

  • For example, driverless cars may have to handle choices like causing a small accident to prevent a larger one.

  • Meanwhile, governments are researching autonomous military drones that could wind up making decisions of whether they'll risk civilian casualties to attack a high-value target.

  • If we want these actions to be ethical, we have to decide, in advance, how to value human life and judge the greater good.

  • So, researchers who study autonomous systems are collaborating with philosophers to address the complex problem of programming ethics into machines,

  • which goes to show that even hypothetical dilemmas can wind up on a collision course with the real world.

Imagine you're watching a runaway trolley barreling down the tracks straight towards five workers who can't escape.

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B1 US TED-Ed trolley dilemma ethical track sacrifice

Would you sacrifice one person to save five? - Eleanor Nelsen

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    Sabrina Hsu posted on 2017/01/13
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