Ethical Theory Spring 2019

Thomson’s Argument


We talked about problems facing Thomson’s argument about abortion.

The first problem concerns the violinist case. In the violinist case, “you” are kidnapped and hooked up to the violinist. But most, though not all, pregnancies are not the result of non-consensual actions like kidnapping. That appears to be an important difference.

The second problem concerned Thomson’s attempts to distinguish between things that people should do for one another and things that they must do.


Our question is what the right to life gives a person a right to have. Thomson’s proposal is that it gives you the right not to be killed unjustly. That’s not incredibly helpful. Now we’re asking “what makes a killing unjust?” and it’s not obvious that this is going to be easier to answer than “what does the right to life give you a right to have?”

However, Thomson has identified a class of acts that she thinks are clearly unjust. So we can start from there and see how far we get. Thomson thinks that it is unjust to go back on voluntary transfers of rights. To illustrate what a transfer of rights is, suppose that I give you my pencil so that it’s yours and not as a loan. What happens when I do this is that I extinguish my right to the pencil and create your right to the pencil. I thereby transform the pencil from something that was mine into something that is yours. Magic! Anyway, Thomson thinks it would be unjust if I were to take the pencil from you after having done that.

So we have one example of the kind of act that would be unjust, at least, according to Thomson. As it happens, this seems to line up nicely with the major problem that her argument faces. Her argument relies on an analogy between the violinist case and abortion. But as Ariel said, the person connected to the violinist was kidnapped. Most cases of abortion are the results of voluntary behavior and not anything violent or coercive like kidnapping. That appears to be an important difference. And Thomson’s remarks about injustice seem to explain why it would be an important difference. If the woman who wants an abortion had voluntarily given the fetus a right to use her body, then it would be unjust to take it away. There is nothing resembling a voluntary surrender of rights in the violinist case and so it does not appear to be a case of injustice. That is the problem with which we started.

Let’s suppose we are talking about a pregnancy that is the result of voluntary intercourse. And let’s suppose that there was an attempt to avoid pregnancy by using some form of normally reliable birth control. There is clearly a voluntary act that leads to the pregnant woman being attached to a fetus. But do we count this as voluntarily giving the fetus the right to use her body? It’s not easy to say.

We talked a lot about the difficulties in determining when a person is responsible for an outcome that he or she could have avoided. A lot depends on what the alternative courses of action are. In the case at hand, the alternatives are things like never having intercourse, having yourself sterilized, or only having intercourse with sterile partners. If you don’t do those things, you know you’re running the risk of pregnancy.

It might be fruitful here to return to the violinist case. There are things that you could have done to avoid being kidnapped. You could have hired bodyguards to protect you or damaged your kidneys in a way that makes them unsuitable for being tapped by others. If you don’t, you’re running the risk of being kidnapped and hooked up to a violinist. But I would find that an odd thing to say. If I didn’t hire bodyguards or damage my kidneys, I don’t think it would be right to say that I ran that risk voluntarily and that therefore I am responsible for the fact that the violinist depends on using my body to live.

But maybe all this shows is that you don’t know that you would run the risk of being kidnapped by a violinist. After all, unlike pregnancy, that just does not happen in our world and so it would be a bizarre thing to expect people to try to avoid.

Maybe the right way to think about it is the way Jacob put it: we try to limit people’s responsibilities so they will be free to do things that we think it is reasonable for them to want to do. One of those activities is walking down the street without body guards to protect you from being kidnapped. Is having intercourse using less than perfect birth control another?

This is where Thomson would come in with examples about opening the windows when there are burglars or people seeds about. Opening the window is the most reasonable thing in the world, after all. However, I’m not sure what I think about these examples. While I don’t think I’m required to care for a robber who comes through an open window, I don’t think I’m allowed to kill him either. And if people grew like plants then maybe I would treat them like I currently treat people or maybe I would treat them like plants. I just don’t know how I would think if I were in that world and I’m not at all sure that the answer would tell me much about what it makes sense to think in this world.

One thing that I believe after having taught this article for a long time is that the question is probably not framed in a helpful way. The question, to remind you, is whether the pregnant woman who wants an abortion may not have one because she voluntarily gave the fetus the right to use her body. If so, Thomson believes, having an abortion would be an unjust killing and so a violation of the fetus’s right to life; if not, then it isn’t an unjust killing and it isn’t a violation of the fetus’s right to life. However, this way of putting it seems off to me for two reasons. First, the fetus isn’t there to be given the right to use the mother’s body. When the relevant voluntary action occurs, the fetus doesn’t exist and so it can’t be the recipient of a transfer of rights. Second, transfers of rights normally have to be done intentionally. You can be liable for harms you inadvertently cause but you usually have to intend to transfer your rights in order to do so.

It’s possible that the reason why we’re unsure of what to say about the voluntariness point is that Thomson’s way of framing it as a question about transfers of rights does not really get to the heart of the point that Ariel originally articulated. I suspect that we might find it more fruitful to think about cases in tort law rather than those involving property. But that’s just a guess.

Should and must

Let’s leave the voluntariness point aside and take up a different question: what are people required to do for others? Where does carrying a fetus to term fall on this moral spectrum?

  1. Mandatory because you would treat someone unjustly if you did not do it; someone else has a right that you do it; you owe it to another person to do it.
  2. Mandatory but not something anyone has a right that you do. It would be wrong of you not to do it but you wouldn’t wrong anyone in particular if you didn’t do it
  3. Something that ought to be done but not strictly mandatory. Any decent person would do it
  4. Strongly encouraged. You don’t have to, but you really ought to.
  5. Praiseworthy. You don’t have to and you would deserve praise if you did it.
  6. Desirable. It would be a good thing if you did it.
  7. It’s a worthy thing to do. It’s a fine thing to do, but not everyone does.
  8. It’s a matter of indifference whether you do it or not.

Thomson approaches this question by looking at two cases: minimally decent samaritanism (which is mandatory) and good samaritanism (which is somewhere around “praiseworthy”). Her point is that the things we require people to do for others don’t come close to the cost of nine months of pregnancy plus the emotional costs of either raising a child or putting one up for adoption. She doesn’t know exactly where the line between minimally decent samaritanism and good samaritanism falls, but she is sure that pregnancy is far from the line on the optional, good samaritan side. This is less of an argument than a question: why should pregnancy be the only exception?

Hutch noted that a utilitarian will say that there is no line to be found. What we have are conventions about responsibility that have arisen for a variety of historical reasons and that these conventions have no special moral status. The only sensible way to figure this out is using something like the utilitarian principle.

Zach gave an example from the other end of life. Suppose I want to ignore my elderly parents and enjoy my life. I think it’s pretty clear that this is not a great thing to do. But am I running afoul of the requirement to be a minimally decent samaritan or am I just failing to be a good samaritan? I might be doing what I am allowed to do, but acting like a selfish and ungrateful person, kind of like the boy who won’t share the chocolates.

Key Points

These are the things you should know or have an opinion about from today’s class.

  1. Why the violinist case seems to be different from most abortion cases.
  2. The difference between good samaritanism and minimally decent samaritanism.


Thomson, Judith Jarvis. 1971. “A Defense of Abortion.” Philosophy & Public Affairs 1 (1): 47–66.