The Supposed Rights of the Fetus


Russell Blackford

(first published 2002 in Quadrant magazine)

Issues arising from actual or proposed scientific research on human embryos have introduced a renewed urgency to the long-running public policy debate about the moral rights of human zygotes, embryos and fetuses. The debate inevitably provokes participants to make familiar claims about the ethical acceptability or otherwise of abortion, since the arguments about abortion and embryo research share some of the same logic.

Underlying issues relating to potentiality arise in all these arguments, though they can be brought out most clearly in a discussion of abortion, where there is a deliberate intention to end the development of a living organism that is clearly human (in the sense of its species membership). Furthermore, arguments based on the developmental potential of a zygote, embryo or fetus have been developed in their most sophisticated form in the context of the abortion debate.

I propose to revisit the implications of fetal potentiality—the potential for a fetus to become a fully-developed human being—for the ethical permissibility of abortion. Except where specific distinctions need to be made, I will use the word "fetus" somewhat loosely, to refer to all stages of development from fertilisation to immediately before birth. I will argue that abortion does not violate any interest of the fetus that we are ethically obliged to respect. This does not rule out the possibility that some kinds of abortions are ethically impermissible for other reasons. For example, it might well be ethically impermissible for a woman to have a very late abortion, or to decide on an abortion purely because of the sex of the fetus. If so, however, the source of this impermissibility must be found elsewhere than in the mere fact that the fetus is a potential person or that it has some interest that is entailed by its potentiality.

If we reject arguments based on potentiality in the context of the abortion debate, it follows that we must also reject them in the context of debate over research on embryonic stem cells, or other research involving the destruction of human embryos. Indeed, there are broad implications for public policy in respect of contentious bioethical issues.


The most sophisticated arguments that fetal potentiality does matter may be those developed by Jim Stone in two well-known articles published in the Canadian Journal of Philosophy, in 1987 and 1994 respectively: "Why Potentiality Matters" and "Why Potentiality Still Matters." In arguing that a fetus has serious interests that are harmed if it is aborted, Stone suggests that it has an interest in completing its normal developmental path in growing to become a human adult. To prevent this from happening is to inflict a serious and ethically impermissible harm on the fetus.

Stone suggests, with some reason, that "it is time we quit attacking straw men", i.e. defending abortion by attacking unsophisticated concepts of potentiality. Clearly, it is desirable that anti-abortion arguments based on fetal potentiality be examined at their strongest, especially since such arguments have implications for other aspects of public policy in the field of bioethics. Accordingly, I have structured this article around Stone's argument and concepts. This provides a degree of focus and unity, while also ensuring that the concept of potentiality under discussion is one designed to avoid obvious absurdities.

Stone acknowledges that a fetus's mental and physical capacities are inferior not only to those of a human adult, but also to those of many adult non-human animals. It follows, in his view, that no obligation arises from any ethically significant physical or mental capacities that a fetus possesses. He suggests that any strong ethical claim to protection that can be made on behalf of a fetus must appeal to its potential to grow and develop into an adult human being, "for nothing else can justify it."

I follow Stone in accepting the uncontroversial point that no fetus has such capacities as those for self-awareness, reason and reflection. However, without additional argument, it is far from clear that nothing else whatsoever, apart from potentiality, can justify ethical restraints on how we treat a fetus. There might be other sources of ethical standards according to which abortion is impermissible.

For example, there might be important utilitarian considerations to take into account before we simply treat fetuses however we like, such as adverse social consequences that might flow if abortion became very common. In principle, this might justify an ethical rule against abortions. Again, Stone assumes that the mere fact that a human fetus belongs to our particular species is ethically irrelevant, but this is not clearly so. As recognised in antiquity by the much-maligned Greek sophist Protagoras, one source of our ethical standards might be the need for human beings to distinguish themselves from and compete successfully with other species, in order to survive. If that is so, there is a broadly consequentialist justification for a rule against harming beings of our own species.

Accordingly, no assumption should be made that potentiality is the only consideration that could justify an ethical standard against which abortion is impermissible. Still, it is difficult to identify other considerations strong enough to rule out early abortions (or, indeed, embryo experimentation). The point made by Protagoras, and discussed more recently by the philosopher J.L. Mackie, would not seem to have application to an early fetus that has received minimal, if any, social recognition and familial investment.

Stone introduces the idea of "strong potentiality", arguing that a fetus is, in a strong sense, "a potential adult human being". Since he believes that no ethical right to life is entailed merely by membership of the species homo sapiens, he poses the central question as: "When and in virtue of what do members of the species homo sapiens … acquire a right to life?" In answering that question, he emphasises that certain "goods" are typically enjoyed by adult human beings, including self-awareness, social interaction, and the possibility of moral stature. The argument is that a fetus has the capacity to develop into a being which is capable of enjoying these goods, and that this is prevented by abortion.

Stone's concept of a person, borrowed from John Locke, is that of a being which has "reason, reflection and self-awareness". Stone sees adult human beings as typically possessing those characteristics, and thus being persons. These characteristics are closely linked to the goods that he sees a fetus as being deprived of if it is aborted, and therefore prevented from developing into a human adult. Stone's argument, then, can be revised, without any material distortion, along the lines that to abort a fetus is to frustrate its potential to develop into a person and enjoy goods typically available to persons living socially with other persons.

The plausibility of the argument depends on distinguishing two senses in which we might claim that A is a potential B. The first, "weak", sense requires only that A is a causal element in the production of the relevant B and that the physical matter of A will be, or will help produce, that of the B. In this sense, a human sperm cell is a potential adult human, and thus a potential person. However, it appears absurd to suggest that any serious wrong is committed if a sperm cell is destroyed. Thus Stone requires a more restricted concept of potentiality.

The "strong" sense of potentiality developed by Stone adds an additional requirement that "A will produce a B if A develops normally and the B so produced will be such that it once was A." In other words, A will, "normally", become a B. In developing a similar concept of potentiality, Stephen Buckle has explained the idea of "becoming" along the lines that, if A develops and becomes a B, then A's identity is preserved.

For Stone, a fetus has a strong potentiality to become a person. If it develops normally, it will become a person that was the fetus. Since he considers strong potentiality to be ethically significant, this "establishes the fetus's right to life", even though an ovum or a sperm cell has no rights at all, since neither, by itself, can become a person. Much of Stone's argument is spent in attempting to show that no absurdities follow from seeing the potentiality of a fetus as morally significant, since such things as sperm cells, eggs, and systems of sperm cells and eggs that have not yet been united possess only weak potentiality.

However, Stone's definition of strong potentiality also requires a concept of what counts as "normal development". He defines this in terms of an entity having a nature of such a kind as to determine a developmental path. In the case of biological entities such as a fetuses, he refines this further. Such an entity "develops normally if it follows to the end the developmental path primarily determined by its nature which leads to the adult stage of members of its kind."

One way of responding to the argument is to test the coherence of this idea of "normal" development. In a reply to Stone's first (1987) article, also published in the Canadian Journal of Philosophy, John Andrew Fisher argued that a fetus can take various developmental paths, at least in principle, so we cannot identify one path as normal. Stone, however, has clarified what he sees as "normal" development in this context. He proposes that identity is maintained if there is no genetic alteration, or only a minor one, and any developmental path that follows from the genetic code of an animal can be considered normal.

As explained by Stone, the physical organisation of an entity such as a fetus, particularly its genetic code, reveals what can be considered normal for its development. An entity's nature and its normal path of development are to be understood in terms of what might be called the entity's functional "design", which might, of course, arise from evolutionary processes, not from the deliberate actions of any intelligent designer (we can use the expression "quasi-design"). This does, indeed, appear to be a coherent account of "normal" development, imposing an intuitively comprehensible natural restriction on what kinds of potentiality can be considered "strong".


Stone argues that strong potentiality is ethically significant in the case of a fetus because the actualisation of its nature will benefit it, in so far as it will enjoy such goods as self-awareness, social interactions, and the possibility of moral stature. In short, it has an interest in growing up.

From this, he suggests that a fetus has a right to receive care and protection:

I submit that we have a prima facie duty to all creatures not to deprive them of the conscious goods which it is their nature to realize. As the good grows greater, our duty grows stronger and harder to override. Self-awareness, I believe, is greater than mere sentience; hence we have a powerful duty to protect and care for human infants as well as the infants of any species the adult members of which have self-awareness.

In this respect, a fetus's right to life is derived in the same way as that of a baby which has actually been born: an "infant". In each case, the right to life is merely the corollary of our supposed ethical obligation to care for it, protect it, and assist its development to personhood. Speaking of infants, but insisting that exactly the same argument applies to a fetus, Stone argues that we owe them "care and protection because death harms them terribly" by depriving them of goods such as self-awareness.

Conversely, Stone argues, weak potentiality does not matter, ethically, because if a first creature does not become a second creature, but merely produces it in some other way, "that first creature has no conscious good of its own, hence no welfare or rights." This provides an explanation as to why his contentions about strong potentiality do not flow over into weak potentiality, which could have absurd results.

One way to test the sophistication and persuasiveness of this argument is to examine how well it fares against arguments that it is permissible to destroy potential persons. In his celebrated (or perhaps notorious) study, Abortion and Infanticide (1983), Michael Tooley discusses six such arguments, four of which he considers successful. These arguments were not devised to answer Stone's specific argument, but they are sufficiently comprehensive to give an indication of how successful Stone's argument is in avoiding obvious rebuttals or absurd consequences. I will consider them in order.


1. "Reprogramming" persons

First, Tooley discusses the argument that it would be ethically impermissible to "reprogram" an actual person by giving the person a new set of "beliefs, attitudes and personality traits". In the case of a human being, this would presumably require extensive neurophysiological alterations. Tooley suggests that it is not wrong to carry out such reprogramming at the potential person stage. The argument concludes that the best explanation for this difference may be "simply that it is not wrong to destroy potential persons".

Tooley does not believe that this argument succeeds, since it does not eliminate the possibility that it is wrong to destroy potential persons simply because they are intrinsically valuable entities. In any event, the argument is ineffective against Stone's line of argument for another reason, which Tooley does not identify.

On Stone's account, the kind of loss that a potential person suffers when it is destroyed is different from the kind of loss that a person suffers from being "reprogrammed". Presumably, the reprogrammed person suffers a loss of psychic integration, access to lived experience, and similar goods—losses that a potential person cannot suffer. However the potential person suffers a different loss: the opportunity to have any self-awareness at all. It is not surprising that different kinds of losses can be inflicted on persons from those that can be inflicted on potential persons, and Stone offers a plausible account of what kind of loss can be suffered by the latter.

2. Cloning the space explorer

Tooley next considers an argument advanced by Mary Warren in which we are invited to imagine that a space explorer is captured by aliens who propose to create hundreds of thousands of human beings from the cells of his body, destroying him in the process. Our intuition is that the space explorer is entitled to escape from this situation, though it means that many persons fail to come into being.

Tooley does not think that this argument is effective as it stands because a conservative could deny that human cells are potential persons, even if some science fictional technology could be used to develop them into persons (as might indeed be the case if cloning by somatic cell nuclear transfer were perfected). Indeed, Stone restricts his criteria for strong potential personhood quite closely; in particular it involves some kind of functional design, or evolutionary quasi-design.

As Tooley puts it, Warren would need to employ a further premise: that there is "no morally significant interpretation of 'potential' according to which human foetuses, but not human cells, are potential persons." A philosopher such as Stone, writing broadly in the natural law tradition, could reject that premise. Stone has a coherent concept of strong potentiality that would not be instanciated by a somatic cell, even if technologies such as reproductive cloning became available.

3. The unrestricted potentiality principle

Tooley argues that it is necessary to base the argument against destroying a potential person on a wider principle which he calls "The Unrestricted Potentiality Principle". It is worth considering his formulation of this, because it can then be compared with Stone's concept of strong potentiality:

The destruction of a potential person is intrinsically wrong, and seriously so, where X is a potential person if and only if X is an entity, or system of entities, that has all, or almost all of the properties of a positive sort that together would be causally sufficient to bring it about that X gives rise to a person, and where there are no factors present within X that would block the causal process in question.

He argues that we are required to adopt such a broad principle because it cannot be relevant whether or not the entity in question is biological, so long as it is capable of giving rise to a person. Furthermore, it is possible that a person could be a system of entities, rather than a single entity, or that a system of entities could rise to it. Accordingly, a potential person might be a system with spatially separated parts.

All these points should be granted to Tooley. Perhaps it is possible that a sufficiently complex, intricately connected non-biological entity or system could become conscious and self-aware. Thus the principle is correctly expressed in a general form to apply to non-biological entities and to systems of entities.

While this is persuasive, Tooley's formulation of the principle is wider than any which Stone's argument requires. For Stone, it is important that A is organised in such a way that it has the potential to become a B, not merely "give rise" to it. Thus, counter-examples to the principle enunciated by Tooley do not necessarily refute Stone's argument.

For example, Tooley discusses the case of a machine which contains a sperm and an ovum, and has the capacity to fertilise the ovum, then nourish the resulting being. Imagine the machine has started, but fertilisation has not yet occurred. Tooley suggests that few people would consider interfering with the machine to be seriously wrong. However, Stone could reply that this example contains no entity, or system of entities, that has been wronged in the sense that it has been deprived of the opportunity of growing into personhood. In this example, neither the total system, the machine, nor the individual sperm or ovum has the capacity to become a person.

While Stone's argument about fetal potentiality depends upon a principle that cannot be restricted to non-biological entities and to systems of entities, it is legitimately restricted to those entities and systems that can actually become persons because of their functional design, or quasi-design. Any counter-examples must be framed consistently with that restriction.

4. Almost active potentialities

Tooley notes that we must speak of an entity or system that is a potential person "having all, or almost all, of the properties that are causally sufficient", since a human fetus cannot, by itself, become a person. He then offers the counter-example of a woman and a collection of sperm as a system that is capable of giving rise to a person, though the system could be destroyed by spermicide. But, Tooley says, it seems absurd to suggest that the use of spermicide involves any serious wrong.

Again, this is not a counter-example to Stone's line of argument, since it postulates no entity or system of entities that could ever become a person. Tooley is correct that a conservative argument must use principles broad enough to deal with an entity, or a system of entities, that might require something further, such as some kind of care, if it is to become a person. But Stone's argument cannot be invalidated by counter-examples in which no entity or system is prevented, if deprived of care, from developing into a person.

5. The moral symmetry argument and the responsibility to produce persons

Tooley devotes most of his analysis to an argument based on "moral symmetry", the principle that there is no ethical significance in the mere distinction between acts and omissions. He argues that this principle entails that the destruction of a fetus is prima facie no more seriously wrong than intentionally refraining from fertilising a human ovum. Accordingly, if destroying a fetus is seriously wrong, so is intentionally refraining from fertilising an ovum. But that conclusion would be seen by most people as absurd.

However, even if the principle of moral symmetry is accepted, Stone's argument remains unscathed. Stone argues that there is an independent principle that we not harm the interest of a potential person in becoming a person. If this is accepted, it is significant that, where we simply refrain from creating a potential person at all, there is never an entity whose interests are harmed. On Stone's account, the ethical equivalent of killing a potential person would be allowing it to die, not simply refraining from procreation.

6. Moral comparability principles

Finally, Tooley argues that we can derive strong ethical conclusions even if we adopt various principles related to the moral symmetry principle, though weaker than it. However, such arguments again assume that there is no independent principle that we not harm the interests of a potential person by denying it personhood. Against the argument advanced by Stone, this sixth argument also fails.


Consideration of the arguments advanced by Tooley suggests that Stone's arguments and concepts do not involve obvious absurdities and are not open to easy refutation. However, Stone's case succeeds only if we accept the general principle that it is ethically impermissible to deny assistance to any entity, biological or otherwise, or any system of entities, that is functionally organised to become a person and enjoy associated goods such as self-awareness.

It is not obvious that we should accept such a principle. Indeed, the principle faces serious difficulties, which can be seen when we consider a claim made by Feinberg, which Stone attempts to refute:

Without awareness, expectation, belief, desire, aim, and purpose, a being can have no interests; without interests he cannot be benefited; without the capacity to be a beneficiary, he can have no rights.

Here, Feinberg denies that an insentient potential person has interests at all. Furthermore, even if Feinberg is wrong in this respect, and there is something that can, with all propriety, be called an "interest" in having the opportunity to become a person, where does this get us? What is the source of our ethical obligation to respect and further this particular kind of interest?

Stone believes that such an interest must exist and must be ethically significant. His argument depends on the fact that, like the unborn, the newborn have very undeveloped mental and physical capacities. If the interest does not exist, he says, "we cannot harm a baby by killing her painlessly", a proposition that he considers counter-intuitive. If our intuition is justified, so he argues, a potential person not only has an interest in growing into a person; that interest must also be one which gives it a right that we respond in certain ways.

The difficulty with this argument is that it appeals to our strong intuition that it is ethically impermissible to kill a baby, while falsely suggesting that the source of the impermissibility must be the baby's interests and rights.

There is no universal intuition, across human societies, that a newborn baby, much less a fetus, has interests, rights or ethical entitlements. It does seem that all human societies accept that, once a child is born it is morally wrong to kill or injure it, at least once a certain time has elapsed and it is on the path to adulthood. But that is not because it is seen as holder of ethical rights. Since this attitude is manifested even in societies that practice infanticide, its explanation is likely to be the instinctive bonding of parents with children, the significance accorded to a new member entering into the community, and the community's hopes for its future, which are literally and symbolically bound up with the birth of children. As Mary Warren and others have suggested, the importance of these considerations is a more likely source of ethical standards in respect of the treatment of very young children.

Furthermore, it is implausible that the source of ethical obligations towards children in our own society is a principle that potential persons have rights. Paul Gomberg has pointed out that our society appears to recognise a separate set of ethical standards relating to our duties to our offspring, which he calls the morality of nurturance. Its "central norm" is a duty imposed on parents "to nurture their offspring, to provide them with sustenance and guidance until they reach self-sufficiency."

The difficulty this poses for Stone is that widely-acknowledged ethical standards associated with nurturance appear capable of distinguishing an increasing responsibility to care for a fetus as it develops in the womb. However, this is inconsistent with Stone's belief that any potential person suffers the same loss if it is destroyed before it reaches personhood. It appears that, at least for many people in our society, the source of ethical standards in how they treat children (including during pregnancy) is actually inconsistent with Stone's account.

Stone might, of course, argue that such nuanced ethical standards are simply wrong, but nothing he says addresses this. Their existence makes it less likely that his own account of fetal interests and rights and rights is required to provide a basis for common intuitions about the impermissibility of harming a baby, or even a fetus at a late stage of development. Accordingly, consideration of the standards recognised by our own society, and by human societies in general, suggests that Stone is left without another example, other than the situation of a fetus, to support his view that potential persons, as such, have interests which we are ethically obliged to respect. He is forced to generalise from a class of one member—and the very class that is controversial.

Furthermore, even if potential persons were recognised as having an interest in attaining personhood, it is not clear why that interest should impose an obligation that we further it. It is at least as intuitively plausible to suggest that we are ethically permitted to live our own lives and that this includes pursuing our own interests, even at the expense of the interests of others, unless there is some sound reason why we should be restrained from doing so.

In principle, there may be a variety of such reasons that we might recognise as requiring us to restrain the purely selfish pursuit of our own interests. However, it is not clear what reason could apply in this case. Even if we speak of a fetus, or another potential person, as having an interest in becoming a person, exactly what harm does it suffer if the interest is not met?

It cannot experience any frustration of its desires, because it has no desires. The mere failure to meet this interest does not inflict any pain. It does not experience fear, so the wrongfulness of our action cannot consist in inflicting upon a entity something that it fears. Nor has it begun a life whose coherence or value may be ruined by being cut short. We do not reveal ourselves as cruel if we terminate the development of a merely potential person painlessly, or with minimal pain. It is difficult, in short, to see why the interest is one that must command our respect. It seems to be a totally theoretical interest. It might unkindly be called a contrived one.

Since there are no real-life situations that are closely analogous to abortion, we are forced to think of imaginary examples, but these do not seem to assist Stone. For example, we could imagine that a powerful computer has been developed, and has been programmed in such a way that it will continually upgrade itself and eventually reach self-awareness. Are we now under an ethical obligation to provide it with electrical power until such a time as it becomes self-aware? Perhaps we must ascribe to the computer a right to continue in existence, without being reprogrammed, once it has become a person, but it is not obvious that we are ethically obliged to supply it with a continuous source of electricity prior to that point.

Yet this device seems to have a "nature" in an analogous sense to the genetic program of a fetus. Unless specifically religious considerations are introduced, or some kind of quasi-religious significance is imputed to functional "design" arising from biological evolution, the situations of the fetus and the advanced computer cannot be distinguished. There is, of course, no typical outcome here, if the computer is one of a kind, but this does not seem to matter if it otherwise has all the features of strong potentiality for personhood. Furthermore, we can alter the thought experiment to imagine a world where such devices are commonplace, so we can speak sensibly of a typical adult member of its kind.

Many people shy away from such science fictional examples, but they are a useful way to examine the underlying logic of ethical arguments and isolate our intuitions on precise issues. The important point here, however, is not so much that the science fictional scenario is a counter-example to Stone's argument. It is that he does not have an example at all on which to base his exhortation that we adopt a strong potentiality principle. An attempt to find examples merely shows that they are: (1) rather far-fetched (if that matters); and (2) not supportive of Stone's intuitions. It is difficult to imagine any example that supports his intuitions, unless we are prepared to argue from analogy with human abortion, which is exactly the action whose ethical permissibility is in question.

Thus, Stone's argument against abortion, based on the strong potentiality principle, is either ultimately groundless or circular.

In conclusion, a coherent account can be given of a kind of potentiality for personhood that is possessed by a fetus and is not possessed by other entities such as sperm cells, ova, and somatic cells, by women who have had sexual intercourse, or by science fictional devices that might lead to the creation of an adult human being. It can then be argued that this kind of "strong potentiality" has an ethical significance, without leading to the absurdity of ascribing ethical significance to other kinds of potentiality, such as that possessed by a sperm cell.

Such an argument resists many of the typical counter-arguments directed at potentiality as an ethical consideration in the abortion debate. However, it requires that we ascribe interests to entities that are unable to suffer any pain or frustration if their so-called interests are not met. Even if an interest of that kind can be recognised at all, a further argument is required as to why it is one that should be respected and furthered, imposing an ethical restriction on our self-regarding conduct.

It appears that no such argument is available. An ethical rule to the effect that such interests must be furthered cannot be found by generalising from other cases, for no other real-world cases are salient. The case of infanticide (or even that of late-term abortion) is easily distinguishable. Consideration of science fictional cases does not advance the argument any further. Accordingly, although a coherent account of "strong potentiality" can be developed along the lines suggested by Stone, it does not adequately ground an argument against abortion. Arguments against abortion, or against certain kinds of abortions, need to be based on some other source of ethical standards than moral rights that are supposedly entailed by potential personhood.

Accordingly, arguments based on strong potentiality fail when deployed in the abortion debate. For precisely the same reasons, they must fail in any public policy debate in the field of bioethics, when legislative prohibitions are urged, based upon the supposed rights of zygotes or embryos. The implications for the current debate about stem cell research are obvious. When rational analysis is applied to the strongest arguments put by conservatives against harming such entities as human embryos, the arguments fall apart.

Thinkers in the natural law tradition may be able to follow Stone in strengthening their ideas with concepts of functional quasi-design taken over from the field of evolutionary biology. They may be able to persuade some others to abstain voluntarily from practices such as abortion and stem cell research on human embryos, but the moral principles relied upon are not universally accepted. Nor is there any rationally compelling basis why they should be, or why they can legitimately be imposed upon society as a whole. It is time to reject those arguments once and for all as a basis for setting public policy in the field of bioethics.


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