Judith Jarvis Thomson: Does It Matter If a Fetus Is a Person?

What is the argument Judith Jarvis Thomson proposes in A Defence of Abortion (1971), and how does she argue that it is morally irrelevant whether a fetus is a person?

Aug 10, 2023By Joseph T F Roberts, PhD Political Philosophy

judith jarvis thomson defense abortion


Debates about abortion often hang on the question of whether the fetus is a person. Pro-lifers argue fetuses are people, making abortion akin to murder. Pro-choice advocates tend to deny both that fetuses are people and, therefore, that abortion is murder.


Judith Jarvis Thomson proposed a powerful argument in support of abortion in her 1971 essay A Defense of Abortion; a key novelty of this argument is that it shows that the personhood of the fetus is irrelevant to the morality of abortion.


The Politics of Abortion

Untitled no. 5 by Paula Rego, 1998, via Google Arts & Culture


The question of the moral permissibility of abortion is rarely off the political agenda. In countries where it is still illegal (or heavily restricted), we often see calls for reform from feminist activists and their allies, and conservative opposition aimed at maintaining the status quo. This is the case, for instance, in Poland, where abortion is only permissible if continuing with a pregnancy risks the life or health of the mother, if the pregnancy is the result of an illegal act, or if the fetus is likely to develop a severe and irreversible illness.


Lively disputes, however, aren’t limited to countries where abortion is still illegal (or where it has only recently been legalized).  Abortion is still a hot topic in countries where it has long been legal. This can be seen, for example, in the US, where Roe v Wade was recently overturned, reversing the achievements of second-wave feminist activists which culminated in the landmark ruling. In the UK, where abortion has been legal since 1967, clinics are still regular targets for “pro-life” protests, leading MPs to consider laws creating “buffer-zones” that would prohibit protests around clinics providing abortions.

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Photo from a Pro-Chioce protest by Matt Hrkac, 2022, via Flickr.


Although there are many arguments made both for and against abortion, most arguments about abortion ultimately depend on the question of the moral status of the fetus. Opponents of abortion tend to argue that the fetus is a person, and, consequently, that abortion is tantamount to murder (Thomson, 1971, p. 47). Pro-choice advocates, on the other hand, often base their argument for the permissibility of abortion on the claim that the fetus is not a person. Assuming that the fetus isn’t a person, abortion is not comparable to murder.


Given that both sides of the argument disagree about such fundamental issues, it should be no surprise the parties are in deep conflict. Framed in this way, the dispute can seem irresolvable. As both parties’ arguments start from conflicting premises, it seems that there is no possibility of a middle ground.


A Defense of Abortion (1971) 

Portrait of Judith Jarvis Thomson, via MIT Philosophy.


In her seminal 1971 essay A Defence of Abortion, Judith Jarvis Thomson takes a different tack, arguing that the permissibility of abortion does not depend exclusively on the truth or falsity of the claim that a fetus is a person. To do so, she aims to show that there are cases in which abortion would be permissible even if the fetus is, indeed, a person.


Thomson’s argument for abortion doesn’t challenge the pro-lifer’s belief that a fetus is a person (her argument simply assumes this is true). Instead, Thomson takes aim at the inference that a fetus being a person means that it cannot be killed.


Views of a Fetus in the Womb by Leonardo aa Vinci, c. 1510-12, via drawingsofleonardo.com


Central to Thomson’s argument is the example of the sick violinist. Given that Thomson’s violinist example has become common currency in the philosophical debate, it is worth quoting in full:


“But now let me ask you to imagine this. You wake up in the morning and find yourself back to back in bed with an unconscious violinist. A famous unconscious violinist. He has been found to have a fatal kidney ailment, and the Society of Music Lovers has canvassed all the available medical records and found that you alone have the right blood type to help. They have therefore kidnapped you, and last night the violinist’s circulatory system was plugged into yours, so that your kidneys can be used to extract poisons from his blood as well as your own. The director of the hospital now tells you, “Look, we’re sorry the Society of Music Lovers did this to you–we would never have permitted it if we had known. But still, they did it, and the violinist is now plugged into you. To unplug you would be to kill him. But never mind, it’s only for nine months. By then he will have recovered from his ailment, and can safely be unplugged from you.” Is it morally incumbent on you to accede to this situation? No doubt it would be very nice of you if you did, a great kindness. But do you have to accede to it?”
(Thomson, 1971, p. 49)


Illustration of the violinist example, via Youtube.


Thomson’s answer is that you do not have to accede to the request. Thomson argues that this is because having a right to life is not the same as having a right to be given all the things necessary for life. The violinist’s undoubtable right to life does not give him the right to use your kidneys without your consent.


Thomson’s argument is essentially an argument from analogy. Given that we wouldn’t say that you have to support the violinist in this case, we shouldn’t say that mothers have to support fetuses in abortion cases, because both cases are, from the moral point of view, identical.


Fetuses Aren’t Sick Violinists

Pro-Life Protester’s van, photograph by Mathieu Landretti, 2018, via Wikimedia Commons.


At this point, one might object that this is all too quick. Surely there are many relevant dissimilarities between your average pregnancy and the act of abducting someone to sustain the life of a famous violinist.


First, in Thomson’s example, you have been kidnapped. If the violinist example is analogous to some pregnancies, it is analogous only to those in which the pregnancy is a result of rape.


Second, Thomson’s case focuses on what a third party (i.e., the doctor) may do, not what the kidnapped person themselves is entitled to do. Even if we accept it might be murder for the doctor to kill the violinist, if the kidnapped person unplugged themselves, the case seems closer to legitimate self-defense, which, unfortunately, results in death.


To deal with these sorts of complications, Judith Jarvis Thomson introduces a few further examples. To respond to the argument that third parties are not in a position to decide between two individuals’ right to life, Thomson provides the following case:


”If Jones has found and fastened on a certain coat, which he needs to keep him from freezing, but which Smith also needs to keep him from freezing, then it is not impartiality that says “I cannot choose between you” when Smith owns the coat. Women have said again and again “This body is my body!” and they have reason to feel angry, reason to feel that it has been like shouting into the wind. Smith, after all, is hardly likely to bless us if we say to him, ‘Of course it’s your coat, anybody would grant that it is. But no one may choose between you and Jones who is to have it.’”
(Thomson, 1971, p. 53)


Photo of birth control by Ceridwen, 2006, via Wikimedia Commons.


To deal with the objection that the violinist case is only analogous to pregnancy resulting from rape, Thomson provides a second case that is more closely analogous to pregnancies resulting from consensual sex using birth control. Thomson’s aim is to show that, even if the sex was consensual (and the acceptance of the risk of pregnancy voluntary), this still doesn’t mean that the fetus has a right to use the mother’s body. The second case goes like this:


People-seeds drift about in the air like pollen, and if you open your windows, one may drift in and take root in your carpets or upholstery. You don’t want children, so you fix up your windows with fine mesh screens, the very best you can buy. As can happen, however, and on very, very rare occasions does happen, one of the screens is defective, and a seed drifts in and takes root. Does the person-plant who now develops have a right to the use of your house? Surely not–despite the fact that you voluntarily opened your windows, you knowingly kept carpets and upholstered furniture, and you knew that screens were sometimes defective.
(Thomson, 1971, p. 59).


Together, all of these examples show that we can’t simply infer from the fact that the fetus is a person that it cannot be killed. There are some instances in which depriving the fetus (a person) of the use of the mother’s body (the resources it needs to survive) is not a violation of the fetus’ right to life.


Triptych by Paula Rego, 1998, via Lakeland Arts.


Even though Thomson argues performing an abortion does not violate the rights of the fetus, she holds that there might be occasions in which having an abortion might be impermissible. Rights are not the only things that matter morally. Even if we are entitled to do something (e.g., not share our chocolates or not allow others to use our bodies), exercising this entitlement might still be wrong in certain circumstances.


If, to give Thomson’s example, Henry Fonda can save my life simply by walking across the room and placing his cool hand on my forehead, it would be callous, self-centered, and indecent not to do it. In other words, Fonda would lack virtue. 


The reason? It is virtually costless for Henry Fonda to save my life. When it is that easy to save a life, we ought to do it. Considerations like these lead Thomson to argue that, in some cases, abortion may be impermissible. If, for example, a person was considering a late-term abortion simply to avoid the inconvenience of postponing a holiday, it would be wrong to perform it.


Strictly speaking, then, Thomson isn’t 100% pro-choice. However, given that cases in which it is costless to continue a pregnancy are hardly representative of most abortions,  for all practical intents and purposes, Thomson’s argument provides strong support for a pro-choice position.




Thomson, Judith Jarvis. (1971) ‘A Defense of Abortion’ Philosophy and Public Affairs, Vol. 1, No. 1, pp. 47-66

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By Joseph T F RobertsPhD Political PhilosophyI am currently a Post-Doctoral Research Fellow in Law and Philosophy at the University of Birmingham. Prior to this, I completed my Ph.D. in Political Theory at the University of Manchester, where I wrote a thesis on the moral permissibility of Body Modification Practices and, specifically, whether or not we have the right to pursue them without being interfered with by others. My current research focuses on the limits of consent, embodiment, and the regulation of recreational drugs.