Act Utilitarianism

11.10.2017 |

Episode #3 of the course Thinking morally: An introduction to utilitarianism by Jack Coulson


Today, we will learn about “Act Utilitarianism.” It is called this because it contains one central moral direction: “to act in the way that will achieve the greatest good for the greatest number of people.” To illustrate, we are going to explore so-called “Trolley Problems.”


What Is a Trolley Problem?

Trolley problems (propagated by, amongst others, Philippa Foot) are a mainstay of ethical thought. There are myriad different trolley problems, all variants on this basic structure:

1. A trolley is out of control hurtling down some tracks.

2. Some people are in its way.

3. You, seeing this, have the option to flick a switch to change the direction of the trolley.

4. If you change the trolley’s direction, it will hit a different group of people.

For instance:

a) You see five people on the track. If you switch the trolley’s direction, it will hit one person.

Act Utilitarianism says flick the switch. Many are squeamish about this, feeling that there is something particularly wrong with choosing to kill that one person, while simply allowing the five to die is not as ethically challenging. For Act Utilitarianism, though, these concerns have no importance to one’s decision. The intuition that putting someone in danger, who previously wasn’t, is wrong is further tested with this variation.

b) You can stop the trolley from hitting five people by pushing a very fat man in its way.

Once again, Act Utilitarianism asks us to push, but many intuit that this is, essentially, murder. Worse than a), the fat man is not simply incidentally killed by the action that saves five, he is purposefully used. Similarly, consider the related thought experiment.

c) A doctor has a healthy patient and five patients who need organs for transplant in order to survive. Should the doctor kill and harvest the healthy person’s organs to save the others?

Act Utilitarianism, on the face of it, condones the actions of the doctor because the math is the same; in all three examples, the outcome is either:

1. Five people die.

2. One person dies.


More Complicated Trolley Problems

Act Utilitarianism takes into account all the ramifications of any action. Consider Experiment A again. Imagine that the five people on the original track are all average citizens, but the one person who is on the alternative track is a scientist. The scientist is about to cure all cancers. Now Act Utilitarianism might suggest that we should let the five die, in order to save more lives in the long term.

Finally, consider this:

d) A trolley is heading toward an Olympic runner; it won’t kill her but it will take her legs. A switch can be flicked, but the trolley will instead hit a world-class pianist and cripple her hands. Both would be equally personally devastated by being hit.

Act Utilitarian now asks us to consider this question: “If the impact on those hit is the same, the best thing to do is to save the one whose life is going to create the most utility for others.” In summary, Act Utilitarianism defines the morally right thing to do as the thing that will maximize Utility.

Finally today, if you have been put off by the theoretical nature of these examples, I suggest that you learn about driverless cars and try out Moral Machines’s scenarios for yourself. Answering trolley problems has become not only a useful way of thinking but also a real problem for engineers.

Tomorrow, we will go into more detail of the utility problem.


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Recommended book

The Problem of Abortion and the Doctrine of the Double Effect by Philippa Foot


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