01
Imagine you're watching a runaway trolley barreling down the
tracks straight towards five workers who can't escape.
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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.
03
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.
04
It's popular because it forces us to think about how to choose when
there are no good choices.
05
Do we pick the action with the best outcome or stick to a moral code
that prohibits causing someone's death?
06
In one survey, about 90 percent 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.
07
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.
08
The five lives outweigh one, even if achieving that outcome requires
condemning someone to death.
09
But
people don't always take the utilitarian view, which we can see by
changing the trolley problem a bit.
10
This time, you're standing on a bridge over the track as the runaway
trolley approaches.
11
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.
12
To utilitarians, the decision is exactly the same: lose one life to save
five.
13
But in this case, only about 10 percent of people say that it's OK to
throw the man onto the tracks.
14
Our instincts tell us that deliberately causing someone's death is
different than allowing them to die as collateral damage.
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It just feels wrong for reasons that are hard to explain.
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This intersection between ethics and psychology is what's so
interesting about the trolley problem.
17
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.
18
For example, men are more likely than women to say it's okay to
push the man over the bridge.
19
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.
20
Researchers have studied the brain activity of people thinking
through the classic and bridge versions.
21
Both scenarios activate areas of the brain involved in conscious
decision-making and emotional responses.
22
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.
23s
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.
24
"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.
25
But new technology is making this kind of ethical analysis more
important than ever.
26
For
example, driver-less cars may have to handle choices like causing a
small accident to prevent a larger one.
27
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.
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If we want these actions to be ethical, we have to decide in advance
how to value human life and judge the greater good.
29
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.
