Analogical Reasoning in Ethics

This argument is valid, so, following the normal procedure, we can ask whether the premises are true. The first premise seems plausible, and it is accepted in most moral theories. Most people also accept the second premise. Consequently, the discussion usually focuses on the third premise—on the similarities and dif- ferences between Thomson’s story and abortion in a pregnancy due to rape.

First, consider these similarities between Thomson’s story and abortion after rape:

1. Both the fetus and the violinist are on or near the Earth.

2. Kidnapping is immoral and illegal, like rape.

3. The hospital stay lasts nine months, like pregnancy.

4. The violinist is innocent and a human being, like the fetus (given our present assumption).

5. Unplugging the violinist is supposed to be killing, like an abortion.

Now here are some differences between the situations:

6. The fetus cannot play the violin, but the violinist can.

7. The person who is plugged into the violinist might not be female.

8. The person who is plugged into the violinist cannot leave the hospital room, but pregnant women can still move around, even if they have some difficulty.

9. Abortion involves killing, but unplugging the violinist is merely refus- ing to save.

It is obvious that some of the similarities and differences are not relevant. It does not matter whether killing occurs near the Earth. Killing is usually wrong, even on the starship Enterprise. It is also accepted that differences in musical talent and in sex cannot justify killing. The other similarities and differences on our list do seem important. They each concern harm and re- sponsibility, matters that must be considered in reaching a moral judgment about these actions. The force of Thomson’s analogical argument is that the very features that lead us to conclude that it would not be wrong to unplug the violinist are also found in the case of pregnancy due to rape. Further- more, there are no relevant differences that are important enough to over- ride the significance of these similarities. These considerations, if correct, provide a reason for treating the two cases in the same way. If we agree, as Thomson thinks we will, that it is not wrong to unplug the violinist, then we have a reason to conclude that abortion after rape is not wrong either.