There are several different questions here. The first is whether, in the circumstances imagined, one would have a right to kill the developing ovum, or whatever. The second is whether a negative answer to this question would invalidate arguments in favor of the the permissibility of abortion.

Let me answer the second question first. I think the answer here is "No": At least, I don't see that there are any very plausible arguments it would undermine. If you consider, for example, the central argument of Judith Jarvis Thomson's famous paper "A Defense of Abortion", it depends crucially upon the fact that the developing fetus is dependent upon the woman's body and that the woman's body is affected by the presence of the fetus. Thomson then argues, largely by analogy, that a woman is not morally obligated to carry a fetus under those circumstances. It's this kind of argument that I take to be summed up by "a woman should have control over what happens in and to her body".

Thomson actually does consider the question whether a woman has a right to see to the death of the fetus, as well as having the right to remove it from her body. I don't recall exactly what conclusion she reaches. But my recollection is that she does not come down strongly in favor of saying the woman does have a right to see to the death of the fetus. What complicates the issue is the supposition that the woman is supposed to bear some responsibility for the fetus after its disconnection from her, and you do not say whether you are supposing that there would be such a responsibility if reproduction were oviparous. If not, then it's very hard to see why the woman would have a right to "crush" the egg. If so, however, then there is more to discuss.

What's important here is that this kind of argument, concerning the responsibility a woman would, in your example, have for the egg and its eventual human product is quite different from the control over one's body argument, and one could perfectly well have different views about them.

I think it comes down to a question of guilt or innocence. A criminal has committed a major sin, and hence deserves a major punishment: an eye for an eye, a tooth for a tooth, and a life for a life. Even just an ordinary adult will have some track-record of sin behind them -- none of us are perfect. They might not quite be evil enough to deserve to be targetted directly, but nevertheless it wouldn't be such a terrible thing if they were to become the victims of collateral damage in war. But an unborn baby, having had no opportunity to sin, is completely and utterly innocent, an unblemished soul, and consequently of greater moral worth.

As far as I can discern, that's roughly the idea that those fundamentalists have. Speaking for myself, I regard this attitude as wholly abhorrent, both antithetical to the teachings of Jesus and morally repugnant in itself. But, hey, that's just my opinion, and what do I know?

There's something else in your question that doesn't seem quite right. Allen Stairs queries your claim that the foetus (please pardon the British spelling!) is "a new person": for my part, I have some misgivings about the claim that it's "a separate entity". In what sense is the foetus separate from the mother? In the literal sense of the term, it blatantly isn't separate from her. It's inside her own body, and connected to her body through the placenta, no more separate from her than are her liver or kidneys. You might say: okay, but it's separate in the sense that it has the potential to survive in separation from her, as her liver and kidneys do not. But, for a foetus in the early stages of development, that's not true either. Many countries permit abortion, but -- except in really extreme cases where the mother's life is endangered -- only up to a certain time, that time being principally determined by the stage of development at which a foetus becomes capable of surviving outside the mother. Prior to that time, the living foetus not only isn't separate from the mother, but cannot be. You might say: fine, but what the foetus does have, even at that early stage of development, is, as it were, the potential to develop the potential to survive in separation from the mother. If left unmolested, it will eventually develop that potential, and then finally actualize it in birth. And that much does seem true.

Of course, this doesn't answer the moral question, it merely recasts it in a new form. Indeed, I fear that I may have been indulging here in the sort of subtle nit-picking that tends to give philosophers a bad name. But it's important to get the question straight before we can hope to answer it. The issue becomes one of whether this potential potential is sufficient to confer a right to life onto the foetus. Life by itself is not enough to establish a right to life. A person's kidney is alive, for instance, but it surely doesn't have a right to life. If one of a woman's kidneys is causing her harm, it'll just be removed and tossed in the bin while she carries on with the other, and no one will bat an eyelid over that loss of life. As I've indicated, the thing that sets the foetus apart from the kidney is its future potential. Is that enough of a difference to give it such an enormously elevated moral status? Some would say that it is, others would say that it isn't, and there are strong feelings on both sides. Unfortunately (not being an ethicist myself) I don't feel qualified to answer that question for you.

Allen Stairs rightly queries the claim that the foetus is already a new person: killing an early foetus is not straightforwardly killing a person -- it is at most killing something that would otherwise become a person.

Still, you might be tempted to say -- indeed, many people do say -- killing a potential person is as bad as killing a fully-fledged person.

Well, I disagree. But just asserting a disagreement is hardly very interesting. So what sort of grounds could I give to support my position? What sort of grounds could you give for yours?

At this point, we might be tempted to bandy about very general principles about the morality of killing or the "right to life" which are supposed to settle things one way or the other. Now this might help. But more likely, it will just shift the debate from a clash of intuitions about abortion to a clash of intuitions about these more general principles about killing and we will find ourselves going around in circles. What to do?

Well, at this point I think it can help to set our thinking about abortion not just in the wider context of principles about killing but in the wider context of what we think about other early foetal deaths which happen naturally, or by accident or misadventure.

Now it does seem a notable fact that while the natural miscarriage in the very early weeks of a pregnancy may be, for some mothers, a misfortune, very few people regard it as the moral equivalent of e.g. the death of a newly born baby. Suppose a young woman has accidentally become pregnant, to her distress, and then a couple of weeks after a very early test gives a positive result she has a natural miscarriage. She feels much relieved and cheered at the outcome. Her girl friends even buy her a drink to celebrate. Very few of us would morally condemn the woman or her friends for their feelings! Very few would regard the woman as morally on a par with a mother who cheerfully celebrated the death of an inconvenient baby.

Here's another notable fact. It is estimated that 25% of all pregnancies are miscarried by the fourth week. Yet no one seems to campaign for medical intervention to reduce that figure in the way that they might campaign to raise money to reduce a high rate of child deaths in a developing country. We let nature take its course, even if that course involves the spontaneous miscarriage of a very large number of "potential people".

You can probably multiply such examples for yourself. And they do suggest that -- when we turn our attention away from the intentional causing of an abortion to other 'natural' cases of early foetal death -- we do not in general seem to regard the death of an early foetus as morally on a par with the death of a child. (I'm not saying we think of it as entirely insignificant, just that we seem to give the death increasingly more weight as the foetus develops.)

But now the question obviously arises: if in practice we do not believe that the death of an early foetus is in other cases straightforwardly the moral equivalent of the death of a full-fledged person, and if we are happy to reflectively retain that general view about foetal death, then why should we think that the intentional killing of an early foetus is the moral equivalent of the intentional killing of a full-fledged person? If the natural death of a potential person doesn't matter as much as the natural death of a child (think again of all those spontaneous miscarriages), when why should the unnatural death of a potential person be thought of as particularly grave -- a sort of infanticide? I for one find it difficult to see any reason for treating the gravity of the natural and unnatural deaths very differently.

Now, there are of course various further things that might be said here (but not in the confines of a short answer!). But at least we have here a hopefully illuminating suggestion about how to start thinking about abortion. Try thinking first about the moral weight you actually do give to other kinds of embryo/early foetal death at various stagaes, in particular to natural or accidental deaths. Consider whether you are content to rest with those views you have. Now try to make your moral views about the level of seriousness of causing foetal death fit together consistently with those views about the seriousness of natural and accidental deaths.

You've raised an interesting question. The general approach you're suggesting sounds like a version of what's called "multi-attribute utility theory." Without going into detail, multi-attribute utility theory lets us make decisions even when different sorts of values are at stake. Acting in a certain way might carry a high risk of losing money, but a high likelihood of keeping a friend. Depending on my "trade-off weights" (roughly, how much I care about money vs. friendship), and depending on the possible results and their probabilities given various choices, the tools of multi-attribute utility theory might give me a way of picking a course of action. It seems at least plausible that we could reconstruct any rational way of making decisions within this framework, and so in principle, we might be able to represent the way we think about the case you've offered. But this is really just where all the hard questions start.

The first problem is that different people will weight different values differently. Some people will place a higher value on protecting autonomy of choice than others. So we might need to sort that out to make progress. But even if we assume that protecting human life is considerably more important than protecting the right to control one's body, we're still not through. Some people see the death of a fetus -- even a very early-stage fetus -- as the moral equivalent of the death of a full-fledged person such as you or I. Since abortion certainly leads to the death of the fetus, that would be a very high cost. Other people, however, just don't think about the fetus this way. In fact, they might find it difficult to imagine thinking of the death of a 6-week fetus as the same sort of tragedy as the death of someone whom we would all agree to be a full-fledged person. For these people, abortion will certainly lead to the death of the fetus, but not to the death of a person like you or me. This sort of person will weigh the costs and benefits quite differently.

Other people may be unsure just how to think about the status of the fetus, and hence about the costs and benefits of an abortion. The value of fetal life is problematic for this sort of person, and so the trade-off weights are unresolved. It's not just that they think the weight to be put on the fetus's life depends on the stage of the pregnancy. It's that at least for some stages of the pregnancy they simply aren't sure what to say. Worse, it's not clear how best to represent this sort of uncertainty. Probabilities don't really seem to capture it; it's not as though this sort of person thinks, for example, that there's a 10% chance that the 6-week fetus is a full-fledged person. Even if probabilities made sense here (and I'm not at all sure they do), it may turn out that there aren't any determinate probabilities to be had -- even so-called "subjective" probabilities.

Your general question had to do with whether we could answer questions about justice by reasoning about risk. My suggestion was that in the abstract, the answer may be yes; there are formal tools that might do the trick. But using the tools calls for putting in definite information, and we'll face two sorts of problems in cases like the problem of abortion. The first is that if we're trying to settle what the morally correct answer is, we'll find that people disagree fundamentally about what information to feed into the formal apparatus. One person's satisfactory answer will be another's "garbage in/garbage out." The second problem is that we may find ourselves unable to sort out just what we think the right trade-off weights or even the right description of the case should be. And so the upshot is that for the hard cases, we'll get dramatically different assessments of moral risk depending on what we think about the difficult questions that underly the controversy.

Just one comment, not really on the main thrust of Allen's response, but on his remark "Some people see the death of a fetus -- even a very early-stage fetus -- as the moral equivalent of the death of a full-fledged person such as you or I."

I think it is much more accurate to say that some people, when discussing abortion, proclaim that they see the death of a very early-stage fetus (we ought to say "embryo") as the moral equivalent of the death of a full-fledged person. But though some might proclaim that, very few indeed seem actually to believe it. And that is revealed by the fact that very few indeed think of the natural death of an embryo as the moral equivalent of the natural death of a full-fledged person (or indeed, of a neonate).

While the natural miscarriage in the very early weeks of a pregnancy may, for some, be a misfortune, very few people regard it as the moral equivalent of the death of a newly born baby (for example, if a woman is rather cheerfully relieved to find that she is no longer pregnant when she feared she was, then very few would regard her as morally on a par with a mother who is glad at the death of a healthy newborn). Again, who campaigns to reduce the rate of natural miscarriage in the very early weeks of pregnancy? It is estimated that 25% of all pregnancies are miscarried by the fourth week. Yet (almost) no one campaigns for medical intervention to reduce that figure in the way that they might campaign to reduce a high rate of neonatal deaths.

You will be able to multiple such examples. (Almost) no one in practice believes that the death of an embryo is in general straightforwardly the moral equivalent of the death of a full-fledged person.

Yet many claim to think that the intentional killing of an embryo is the moral equivalent of the intentional killing of a full-fledged person. It is a nice question whether that view about killing is consistent with the view about death in general.

You might also find helpful the responses to a related question: http://www.askphilosophers.org/question/1247

I am not sure what is the philosophical question here. Of course there is no general moral principle that guides the rules that you're evoking and you may imagine a huge cultural variation in different legal systems. There are legal systems which do not recognize the right to abort to a woman who doesn't want to have a child as well as there are legal systems (actually, most of them until recently) that do not oblige a man to support his child if, for example, the child is born outside a legal mariage.

The rights of women to decide upon the destiny of their future children seems a very recent contingency of some of the contemporary legal systems, and not an inevitable consequence of the difference between men and women. It is unclear in the question whether you complain of this state of affairs (that probably refers to contemporary United States) or you ask what is the underlying moral principle that justifies it. If it is the second one, I would say that there is no such a principle.

When a human child is brought into existence, whose moral responsibility is it to see that this child’s very significant needs are met? In most human societies, this responsibility has been given to its parents. It was due to the parents’ actions that this child came into existence in the first place; and, further, parents tend to have stronger instincts than others to meet the very significant needs of their progeny. For these reasons, the allocation of primary responsibility to meet the needs of immature humans to their parents generally makes good moral sense. To what extent and under what conditions this responsibility should also be shared with others and to what extent and under what circumstances this responsibility may be relinquished to others are further complicated moral questions.

You wonder whether it is fair that fathers who have had no say in whether a fetus is brought to term should be held morally responsible for meeting the needs of their progeny. This, it seems to me, is a legitimate moral question. But I wonder whether we are looking at the situation in the right way. It seems to me that so long as fathers do not take on an equal share of the responsibility for meeting the needs of their progeny, the decision whether to abort a fetus (if such a decision is to be made available to anyone) must be given to women. For, as a matter of fact, and whether fair or not, most women bear the primary responsibility for meeting the needs of their children. It seems to me that if men wish to be granted the right to play an equal role in deciding whether a fetus for which they are responsible is brought to term, they must also be willing to play an equal role in meeting the needs of their children.

For what it's worth, I find it obscure why someone would wish to pursue this course of action, but I don't find it obviously to be morally objectionable in any way I don't find abortion morally objectionable.

Suppose the woman instead removed the fetus without its being killed, and put it in some kind of suspended animation. Perhaps she thinks, "Well, maybe later I'll be ready for a child, and then I'll continue the pregnancy." It's not obvious why this would be any more objectionable than abortion, and I certainly don't see a difference between this case and the one in the question. Indeed, one might wonder whether, at certain very early stages of pregnancy, there is very much of a difference between this and what routinely happens in fertility labs.

I sometimes call this the "Ronald Reagan argument"; President Reagan was fond of a version of it that, as I recall, had to do with a man in a ditch who might or might not be dead. That also raises a preliminary issue. The question presumably isn't whether the fetus is biologically alive; it surely is. The question (or part of it anyway) is what this living being is. One common way of putting it is to ask whether the fetus is a person -- a being with the same moral standing as you or me. And so I'll put what follows in those terms.

The first thing that strikes me is that there's a glitch in the analogy. In the execution case, the being we execute is unquestionably a person who is possibly innocent. In the abortion case, the being is possibly a person, though if a person, then an innocent one.

This hardly settles the matter, of course. The reply might be that in either case, we run the risk of taking the life of an innocent person; the position of the word "possible" simply locates the source of the risk. But that's too simple. In the typical execution case, what we worry about getting wrong is a matter of fact; the person either committed the crime or s/he didn't and the concern is that we may be mistaken about that. The abortion case is different. Whether or not a fetus is a person seems to be what someone once called an essentially contested question: there may be no straightforward fact to be had. Fetuses are like paradigm cases of persons in some ways, and unlike them in others. A glance at the history of the debate makes it clear that two people can agree about all the background facts (genetic make-up, brain development, etc.) and still disagree about whether the fetus is a person. It's harder to cook up a case like that when the question is whether someone committed murder.

There's another difference: the thought of executing an innocent person makes our blood run cold when we think about it from the victim's point of view. Imagine yourself knowing full well that you've been convicted of a murder that you didn't commit, and that you're about to have your life taken away from you on the basis of a mistake. It's a horrifying prospect. Abortion holds no such horror from the fetus's point of view, because the fetus doesn't have a point of view. It has no conception of its future, let alone of itself.

Just to be clear, my point isn't to settle the abortion issue. After all, newborns don't have anything like the developed point of view of a paradigm person, but infanticide still strikes us as wrong. The point is simply that the Ronald Reagan argument, in its various versions, is too quick.