Abortion is a very controversial issue. Many people have very strong views on the subject, and unfortunately too many debates on the issue tend to degenerate into an unenlightening shouting match involving crude and emotive rhetoric, empty sloganeering, and eventually bitter personal attacks.

The purpose of this entry is to outline some of the various philosophical arguments that have been made on the subject of abortion in as even-handed a way as possible, identifying and differentiating the different areas of controversy, and presenting the arguments and possible responses. Philosophers have written a great deal on the subject over the years, and this entry can only be a brief introduction, which will hopefully serve to clarify the debate and offer food for thought. Hopefully you will find your own opinions expressed in the range of views put forward, and will find ways of supporting that view as well as challenges for that view.

A brief note on terminology. For the purposes of this entry, the term "abortion" is used as a shorthand for "induced abortion", the medical procedure performed upon a pregnant woman to remove or induce the expulsion of the embryo or foetus. The word "foetus" will be used here as a generic blanket term to refer to the embryonic as well as the foetal stage of development. The word "woman" will be used to refer to the carrier of the foetus.

It's interesting to note that even the terminology is contentious - those who are opposed to abortion tend to use "unborn child" and "mother", and it might be objected that this entry is already biased in using terms more favourable to the "pro-choice" side of the argument. However, these terms have been chosen as the most neutral terms available, and nothing significant will rest on the choice of terms. An entry detailing the empirical facts about abortion can be found here [link to edited version].

This entry will consider arguments related to two main issues. Firstly, arguments about the moral status of the foetus, and secondly, arguments about how to weigh the different rights claims of the woman and the foetus.

The Moral Status of the Foetus

To enquire about the moral status of something is to enquire into what rights and responsibilities it has, and how we ought to act towards it. Generally speaking, such enquiries are conducted in relation to the moral status of what we might call a 'standard' adult human - a 'person', to use the usual philosophical term. There has been an extensive debate about the nature of personhood - are all human beings persons? Could an alien be a person? Could a computer be a person? Are 'higher' animals persons? What rights do persons have? What is the origin of those rights? These are debates that will not be entered into here, though it is worth noting that the lack of agreement about the moral rights of adult human persons does not bode well for agreement about the moral rights of the foetus.

Absolutist views

The two most straightforward positions are what we shall call the "fully human" and "non-human" views. The "fully human" view holds that there is no moral difference between the foetus and a newborn baby, or indeed a normal adult human being. Human rights start at conception and end at death, and the moral status does not change. An abortion is the deliberate killing of a human being. As we shall see later it is possible to hold this view and believe that abortion should be permitted under some circumstances.

The "non-human" view asserts the polar opposite of the "fully human" view. An foetus is not a human being, and is just a collection of cells. On this view, the foetus is part of a woman's body and no more qualifies for human rights than, say, the appendix or the tonsils. At the moment of birth, of becoming a separate individual from the woman, the foetus becomes a baby and suddenly acquires human rights. On this view, abortion would (all other things being equal) be permissible on demand, for any reason and at any time during pregnancy. Although there are people who think this, it is quite rare to hear this view expressed openly, and it is certainly not typical of many of those who argue that abortion can be justified.

Both of these views are open to objections. It could be argued that the foetus immediately after conception is so unlike a human - literally two cells - that we might wonder why it is any more human than a sperm or egg cell. Conversely, the foetus in the last weeks of pregnancy is so like a human (or at least like a human baby), that we might wonder why it is said to have no moral status at all.

However, the basis for such objections is a moral intuition based upon appearances. Defenders of one or other of the absolutist views could argue that our intuitions on ethical issues are not always correct, and do not stand up to closer logical examination. Our intuitions are often emotive reactions, rather than rational ones. However, defenders of absolutist views would need to come up with some strong arguments if they wish to show those who do have these intuitions are wrong. Arguments about this kind of basic intuition are often very difficult to engage in in any meaningful sense.

Non-absolutist views

Non-absolutist views offer different ways to think about the status of the foetus. One view, which we might call the boundary view, is that there is a point at which the foetus ceases to be a collection of cells and becomes a person. A number of candidates points for personhood have been put forward, one of which is viability - that is, the point at which the foetus could survive independently of the mother. The problem with viability as a boundary point is that it rather depends on the quality of healthcare available, and it seems strange for personhood to rest on a variable date. Other possible boundary points are when the foetus first starts to kick (quickening). Different stages in physical development are also put forward, but all of them have some difficulty in explaining why such a monumentous change in moral status should take place then rather that at another time.

Some philosophers have argued that becoming a person is a gradual process that does not admit of any sharp boundaries. Just as the foetus starts to look more and more like a human during the course of a normal pregnancy, so it becomes more and more like a person. On this gradualist view, the closer to birth, the stronger the claim to personhood and the associated rights the foetus has.

So far, all of the views that have been considered have held that the foetus is like something else in terms of its moral status - either like a human, or like a collection of human cells. The potential person view holds that the foetus is a potential person, and therefore has a moral status that is different from actual persons (on the one hand) and mere objects (on the other). Of course, what the status amounts to is still a matter for debate, and people with very different ideas about when abortion might be permissible could hold this view. What they would have in common, however, is a belief that the foetus has a unique status which is not the same as a person or an object.

What proponents of this view reject is what they see as the false dichotomy (or choice) that absolutist views present - that the foetus is either fully human or completely without value. After all, it's possible to think that animals have rights and have value without thinking that they have the same rights as persons. But it is also possible to hold a huge range of different ideas about what rights animals have - many people would kill a fly, wasp, or spider without a second thought, but would find killing a dog or dolphin morally objectionable. Those who are attracted by the idea of a unique moral status for foetuses as potential persons still need to decide what that status is, and what rights and protections it grants.

It's worth noting briefly that all not everyone thinks that babies are fully persons in the same way as adults are. Some philosophers have argued that babies only become persons when they start developing personality traits, preferences for one thing over another, the ability to choose goals and make rational plans to achieve them, and so on. Some philosophers are uncomfortable with assigning or denying personhood on the sole basis of being homo sapiens (Peter Singer, for example, has drawn a parallel between doing this and racism and calls it "speciesism"). If personhood is not to be based on species, however, then it must be based upon characteristics - consciousness, rational planning, language, personality and so on - which very young babies and some other humans may not have. And many people are very uncomfortable with this thought.

The Story So Far

Only one of the theories about the moral status of the foetus that has been briefly outlined above will in itself settle discussions about if and when abortion is permissible. The absolutist view that the foetus has no moral status leads fairly straightforwardly to the view that abortion is permissible at any time and for any reason, provided that the woman is allowed an autonomous and informed choice. However, the opposite absolutist view, that an foetus has full human rights right from conception, does not imply that abortion is never permissible. Most people think that there are times when the taking of a human life can be justified, and if this is true, it could be that there will be times when taking the life of an unborn human could be justified.

Arguments about Rights

This section will briefly examine arguments that are related to attempts to define and to weigh up the respective rights of the woman and the foetus. It's interesting to see how many other moral controversies are directly related to ethical issues in abortion, and it's perhaps unsurprising that there's so much disagreement.

Abortion and Self-Defence

Some people have attempted to make a link between the abortion question and arguments about self-defence. Most people think that each person has the right to defend themselves, and may (under certain circumstances) even kill to save their own life.

However, this uses a rather different definition of self defence to the one used in courts of law. At least part of the reason why it is often argued that a person can use lethal force to defend herself against an attacker is that the attacker is doing something wrong. This obviously isn't true of the foetus. Part of the reason that most people think that a person is justified in killing an attacker to save her own life is that the attacker is guilty in some way, but no-one could plausibly claim that the foetus was guilty of anything other than existing.

Indeed, many opponents of abortion regularly talk of the 'innocence' of the foetus to draw exactly this contrast. However, guilt or innocence are properties of persons - we might talk about a person being guilty of a crime, but it would not make sense to talk of a gust of wind being guilty of stealing an umbrella, or a rock being guilty of falling on someone.

But there is something that can be said for the self-defence argument. If a woman's life is threatened by the pregnancy, many people think that an abortion would be justified for the same reason that a climber would be justified in cutting the rope supporting a fallen colleague about to pull them both to their deaths. The fallen climber is not guilty of anything (other than, perhaps, falling - hardly a crime), but many people think that it is better for one to survive than neither.

Can this analogy help in the abortion debate? There might be some very clear cases in which there is a choice between abortion or certain death for both the woman and the foetus. In such cases, even those who believe that an foetus is fully human and fully a person from the moment of conception might be prepared to support abortion.

But there could still be a great deal of disagreement about what level of risk would justify abortion, and at what stage of the foetus's development. There will also be disagreement over the weight to give to different kinds of harm short of death, such as non-lethal risks to health caused by pregnancy, the physical dangers of childbirth, the sacrifices needed to bring up a child, or the trauma of giving a baby up for adoption. Those who believe that the foetus is fully human would be very unlikely to accept self-defence against these kinds of harm as a justification for abortion. But some of those who believe that the foetus has some rights, but is not a person, might accept the self-defence justification for abortion in some cases.

The Priority Argument

This is the view that the woman's rights have priority over the rights of the foetus, put forward by Judith Jarvis Thomson ('A Defence of Abortion', Philosophy and Public Affairs 1971).

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? What if it were not nine months, but nine years? Or longer still? What if the director of the hospital says. "Tough luck. I agree. but now you've got to stay in bed, with the violinist plugged into you, for the rest of your life. Because remember this. All persons have a right to life, and violinists are persons. Granted you have a right to decide what happens in and to your body, but a person's right to life outweighs your right to decide what happens in and to your body. So you cannot ever be unplugged from him." I imagine you would regard this as outrageous.... (Thomson, 1971)

Thomson's view is that it would be a morally good deed for you to allow the violinist to be plugged into you, but that it is not one that is morally *required* of you - the violinist has no rights claim over you. Philosophers call this a superogratory action - one that has moral value, but one that is not required of us. Thomson argues that helping would be an act of charity, but that the moral imperative for performing this act of charity gets stronger where the required sacrifice from you is small and the expected benefit to the violinist is large. If the violinist required only an afternoon of your time, for instance, you would be callous indeed to refuse. But, argues Thomson, this does not mean that the violinist has a right to your help.

Thomson's analogy is a powerful one because the violinist (taking the place of the foetus) in her example is definitely a person with full human rights. But Thomson argues that you would be justified in giving your own interests priority over that of the violinist, even if it costs him his life. It is a little similar to the self-defence argument in that

There are a number of objections that can be made to Thomson's argument.
Those opposed to abortion object that the case above is not the same as pregnancy. The violinist and the abductee are strangers, and there are no special duties involved. Many people think that the woman has a duty to the foetus - at least in cases where she is responsible for its creation. Even in cases where she is not responsible (perhaps because of rape or - more usually - the failure of contraceptive devices), it could well be argued that the sacrifice in bringing the foetus to term and then giving him or her up for adoption is a sacrifice that most (or even all) pregnant women can be called upon to make. Thomson would not agree.

One interesting point which arises from this is the discussion about the nature of the sacrifices that one person morally ought to make for another person. If we accept that the foetus is a person and have at least some sympathy for Thomson's argument that it is morally acceptable to put one's own interests first, we have a way of thinking about different kind of sacrifices that might be involved in not having an abortion. By thinking about the limitations of what others can legitimately demand of us, we could draw a distinction between the different kinds of sacrifice that would be required.

Arguments from Personal Responsibility

Abortion, Ethics, and Law