The Trolley Problem: Six Dilemmas
The trolley problem asks whether you would sacrifice one person to save five. Most people say yes once and no a moment later, when one detail changes. Play six versions and find out which rule you are actually following.
Six dilemmas · about 4 minutes
Five lives or one.Six versions. Is your rule consistent?
Each round changes one detail of the classic trolley problem. Choose, then see what the change was testing and how your answer compares with tens of thousands of people in published studies.
Where the problem comes from
Philippa Foot described the first version in 1967, in a paper about abortion and the doctrine of double effect. Judith Jarvis Thomson gave it its name in 1976 and added the footbridge, loop and transplant cases in 1985.
In 2001 Joshua Greene scanned people's brains while they answered. Hands-on cases like the footbridge lit up emotional regions; impersonal cases like the switch engaged areas linked to deliberate reasoning. That became the basis for his dual-process theory of moral judgment.
Three ways to answer
Utilitarianism
The right act produces the best outcome. Five lives beat one, in every version, including the surgeon.
Deontology
Some acts are wrong whatever the outcome. Killing is different from letting die, and people may not be used merely as a means.
Doctrine of double effect
Causing harm as a side effect of doing good can be allowed; causing harm as the means to that good cannot. This is why the switch and the footbridge feel different.
Frequently Asked Questions
What is the trolley problem?
The trolley problem is a thought experiment in ethics. A runaway trolley will kill five people unless you divert it onto a side track, where it will kill one. Philippa Foot introduced it in 1967 and Judith Jarvis Thomson named and extended it. The point is not the answer to the first case but why people answer differently when small details change.
What is the "right" answer to the trolley problem?
There isn’t an agreed one. A utilitarian says pull the lever and push the stranger, because five lives outweigh one. A Kantian or deontological view says you may not use a person merely as a means, which rules out pushing. The doctrine of double effect allows the switch but not the push. The experiment is useful because it forces you to say which principle you actually hold.
Why do most people pull the lever but not push the man?
In the switch case the one person’s death is a side effect; in the footbridge case it is the means of saving the five, and it requires physical force. Joshua Greene’s brain-imaging research found that personal, hands-on harm triggers a strong emotional response that tends to override the cost-benefit calculation.
Can I use this trolley problem game in class?
Yes. It is free, needs no login, and works on phones, iPads and Chromebooks. Six dilemmas take about 4 minutes. Students can send each other challenge links to compare answers, and it pairs well with the veil of ignorance simulator, which has a full lesson plan.