Trolley Problem Ethics

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Area: History and Social Studies, Other Areas
Grade Level: High School & Beyond, Middle School, Primary/Elementary School
Topics: deontology, ethics, trolley problem, utilitarianism
Estimated Time Necessary: 1 hour

Lesson Plan

Introducing Utilitarianism and Deontology
This exercise can help introduce students to the basics of utilitarian and deontological ethical frameworks.
Investigating ethical viewpoints
Students will have an opportunity to reflect on their own ethical judgements.

See the Lesson Attachment link above for a PDF of this lesson plan.


Introduce Scenario 1:1

1:1: You are a train driver. As you are driving you look ahead and see 5 people trapped on the tracks. There is no way that you will be able to stop the train before running them over and killing them. You notice that just before them there is a side track that you can take, but on that side track is 1 person who is trapped on that tracks.

This leaves you with two choices: You can continue on the track you are on and you will run over and kill the 5 people trapped there. Or you can turn the train onto the side track and run over and kill the 1 person trapped there.

What are you going to do? Why?

This scenario aims to get students to search within their own ethical intuitions and decide for themselves what the appropriate ethical solution is in this situation. It is expected that most students will choose to take the side track option where they kill the 1 person instead of the 5. This will lead into the following scenarios. This scenario can be introduce in various ways, including reading this script, accompanying this script with image such as these: 1:1, 1:2, or by viewing extracts from The Good Place, Season 2, Episode 5 which introduce these scenarios in video format.


  • How did you make your decision?
  • Did you make your decision based on a principle or did you make it based on the consequences which would result?

Explicit Teaching:

Utilitarianism is an ethical system which bases decisions on the consequences of actions. This system looks only at the outcomes of situations in order to decide upon the best course of action. This means that nothing matters other than the outcomes, i.e. you can perform any action whatsoever, as well as it produces positive outcomes. E.G. you can murder anyone you like as long as it has positive outcomes, such as murdering 100 people to save 101 people from death.

Deontology is an ethical system which bases decisions on principles. This system requires you to follow set principles in order to decide upon the best course of action. This system is founded on unbreakable principles – what those principles actually are differ, but what is fundamental is that there are inviolable principles. In contrast to the utilitarian approach, evaluation of the outcomes is irrelevant, only adherence to the principles. E.G. if it is a principle not to perform murder, then you can never murder anyone for any reason; you cannot murder 1 person to save 1 billion lives. The outcomes don’t matter.

This will introduce two of the primary ethical systems; utilitarianism and categorical morality. The students will have already made an ethical decision based on their own intuitions, now they will be able to understand how to better apply reasoning to their ethical decision making.

Which system did you use to decide upon your course of action in the first scenario (1:1)?

If you based your decision on the number of people who will die, you have used a utilitarian ethical system. This is because you decided to act based on the consequences. And the consequences here were either 1 person is going to die, or 5 people are going to die.

If you made you decision by referring to a principle you used a deontological ethical system.

The students, having learnt some basics of these two ethical systems will be able to apply these systems to their own thinking.

Split class into groups and get them to develop a principle to follow based on their intuitive decision in the first case (1:1)


Introduce Scenario 2:1

2:1: You are a doctor in a small town hospital. You are the only doctor in the whole hospital. There has been a train accident and you have 5 people come in who are in critical condition. There is also 1 person who is in ultra critical condition and needs extensive surgery. You have to make a decision: Either you can perform the extensive surgery on the 1 person in ultra critical condition, but while you are doing that, that 5 other people will die. Or you can save the lives of the 5 people in critical condition, but while you are doing that, the 1 person in ultra critical condition will die.

  • What decision does your principle dictate you make?
  • Is that the decision you would choose to make intuitively?

Introduce Scenario 1:2

1:2: There is a train which is about to run over 5 people who are stuck on the tracks. You are not the driver this time, this time you are up on a bridge overlooking the train tracks. The driver will not have enough time to stop before he runs over the 5 people. You notice next to you that there is a very fat man that weighs more than a train who is also standing on the bridge. You realise that if you push this man off the bridge he will stop the train in its tracks before it runs over the 5 people. However, the fat man will die.

Are you going to push the fat man off the bridge, killing him in order to save the 5 people? Or are you going to do nothing and watch the 5 people get run over by the train?

Does your decision work with the principle you developed earlier?

Introduce Scenario 2:2

2:2: You are a doctor. This time, you have 5 patients, all of whom require an organ transplant. One needs a heart, another a lung, another a liver, etc. They are all about to die and there is no chance that the organs will be available in time and there’s no chance for their survival. In the meantime, a perfectly healthy man comes in for a regular check-up. You notice that he is a perfect match for all 5 people.

You realise that you can kill this healthy man, take his organs and give them to the 5 people. Will you kill this man so you can harvest his organs and transplant them into the 5 people? Or will you let the 5 people die so this 1 healthy man can live?

Their principle is scenario 2:1 is expected to be something along the lines of; “the less people who die the better.” It is expected that scenario 2:1 will result in their intuitive response and their principle being in line: they save the 5 people. It is expected that students’ intuitive response in scenario 1:2 will conflict with their principle before, as students will not want to push the fat man off the bridge. It is expected that students’ intuitive response in scenario 2:2 will conflict with their principle before as students will not want to kill the healthy man

Did the principle you developed work in all four situations?


  • Can you think of a new principle which would work in all of these situations?
  • Utilitarianism and deontology are both seen in the extreme over these four cases. It is unlikely that students will have followed one or the other in all four cases.

Review & Reflect:

  • What have you learnt about how we think ethically?
  • What is hard about finding a method to act ethically?

Discussion Questions

  • How did you make your decision?
  • Did you make your decision based on a principle or did you make it based on the consequences which would result?
This lesson plan was created for PLATO by: Ben Kilby.