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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 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, driver-less 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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