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by Adam Carter
So, how are your moral mathematics skills? It’s a good talent to have in military combat or when embarking on the hypothetical rescue missions provided by ethical dilemma wizard Derek Parfit in his book Reasons and Persons. Calculators and consciences ready? When you and your friend combine to save 100 lives, you should personally get credit for saving fifty or (100/2) of the total number saved, correct? And further, you should always act so as to save as many lives as you can, agreed? Simple enough. This is called the ‘share-of-the-total’ view, in which each produces his share of the total benefit. But does this really work? Test yourself:
The First Rescue Mission
I know all of the following. A hundred miners are trapped in a shaft with flood-waters rising. These men can be brought to the surface in a lift raised by weights on long levers. If I and three other people go to stand on some platform, this will provide just enough weight to raise the lift, and will save the lives of these hundred men. If I do not join this rescue mission, I can go elsewhere and save, single-handedly, the lives of ten other people. There is a fifth potential rescuer. If I go elsewhere, this person will join the other three, and these four will save the hundred miners.
A) STAND ON THE PLATFORM WITH THE OTHER FOUR
B) GO ELSEWHERE AND SINGLE-HANDEDLY SAVE 10 LIVES
If you agree with the ‘obvious’ logic of the ‘share-ofthe- total’ view, then in the first mission, you will choose A): jump on the platform and attribute 20 (100/5) lives to yourself, which is more than the 10 lives you could have saved going elsewhere. As Parfit suggests, this is clearly the wrong answer. In joining the others on the platform, you actually contribute nothing; the hundred will be saved with or without you – thanks to the fifth rescuer – and the 10 would die without your help. So rather than being responsible for saving 20 (100/5) you are responsible for saving zero. So the correct answer is “B.”
The Second Rescue Mission
As before, the lives of a hundred people are in danger. These people can be saved if I and three other people join in a rescue mission. We four are the only people who could join this mission. If any of us fails to join, all of the hundred people will die. If I fail to join, I could go elsewhere and save, single-handedly, fifty other lives.
A) JOIN THE OTHER THREE RESCUERS ON THE PLATFORM AND SAVE 100 LIVES
B) GO ELSEWHERE AND SAVE 50 LIVES SINGLE-HANDEDLY
In the second mission, the ‘share-of-the-total’ view again yields the wrong answer. Fifty lives is greater than 25 (100/4), however this mistake in moral mathematics would leave the 100 drowining miners dead. Instead of “save 50 versus save 25 yourself,” the case is more accurately “save 100 versus save 50”; the three-man rescue team needed you this time. Answer: A.
Although the ‘share-of-the-total’ view can seem like a theoretically-sound strategy, we see that it does not work. We should choose the action whose consequence is that people are benefited most. Chuck the calculators.