Abortion is the intentional killing of a human fetus by chemical and/or surgical means. It should not be confused with miscarriage (which involves no human intention) or contraception (which uses various technologies to prohibit sperm and egg from producing a fertilized ovum after sexual intercourse). Miscarriages are natural (if sad) occurrences, which raise no deep moral issues regarding human conduct—unless the woman was careless in her pregnancy. Contraception is officially opposed by Roman Catholics and some other Christians, but I take it to be in a moral category entirely separate from abortion (since it does not involve the killing of a fetus); therefore, it will not be addressed here.
Rather than taking up the legal reasoning and history of abortion in
The first premise of the argument is that human beings have unique and incomparable value in the world. Christians and Jews believe this is the case because we are made in God’s image and likeness. But anyone who holds that humans are special and worthy of unique moral consideration can grant this thesis (even if their worldview does not ultimately support it). Of course, those like Peter Singer who do not grant humans any special status will not be moved by this. We cannot help that. Many true and justified beliefs (concerning human beings and other matters) are denied by otherwise intelligent people.
Second, the burden of proof should always be on the one taking a human life and the benefit of doubt should always be given to the human life. This is not to say that human life should never be taken. In an often cruel and unfair world, sometimes life-taking is necessary, as many people will grant. Cases include self-defense, the prosecution of a just war, and capital punishment. Yet all unnecessary and intentional life-taking is murder, a deeply evil and repugnant offense against human beings. (This would also be acknowledged by those, such as absolute pacifists, who believe that it is never justifiable to take a human life.)
Third, abortion nearly always takes a human life intentionally and gratuitously and is, therefore, morally unjustified, deeply evil, and repugnant—given what we have said about human beings. The fetus is, without question, a human being. Biologically, an entity joins its parents’ species at conception. Like produces like: apes procreate apes, rabbits procreate rabbits, and humans procreate humans. If the fetus is not human, what else could it possibly be? Could it be an ape or a rabbit? Of course not.
Some philosophers, such as Mary Anne Warren, have tried to drive a wedge between personhood and humanity. That is, there may be persons who are not human (such as God, angels, ETs—if they exist), and there may be humans that are not persons (fetuses or those who lose certain functions after having possessed them). While it is true that there may be persons who are not humans, it does not logically follow that there are humans who are not persons. The fetus is best regarded as a person with potential, not a potential person or nonperson.
When we separate personhood from humanity, we make personhood an achievement based on the possession of certain qualities. But what are these person-constituting qualities? Some say a basic level of consciousness; others assert viability outside the womb; still others say a sense of self-interest (which probably does not obtain until after birth). All of these criteria would take away humanity from those in comas or other physically compromised situations. Humans can lose levels of consciousness through injuries, and even infants are not viable without intense and sustained human support. Moreover, who are we to say just what qualities make for membership in the moral community of persons? The stakes are very high in this question. If we are wrong in our identification of what qualities are sufficient for personhood and we allow a person to be killed, we have allowed the wrongful killing of nothing less than a person. Therefore, I argue that personhood should be viewed as a substance or essence that is given at conception. The fetus is not a lifeless mechanism that only becomes what it is after several parts are put together—as is the case with a watch or an automobile. Rather, the fetus is a living human organism, whose future unfolds from within itself according to internal principles. For example, the fertilized ovum contains a complete genetic code that is distinct from that of the mother or father. But this is not a mere inert blueprint (which is separable from the building it describes); this is a living blueprint that becomes what its human nature demands.
Yet even if one is not sure when personhood becomes a reality, one should err on the side of being conservative simply because so much is at stake. That is, if one aborts a fetus who is already a person, one commits a deep moral wrong by wrongfully killing an innocent human life. Just as we do not shoot target practice when we are told there may be children playing behind the targets, we should not abortion fetuses if they may be persons with the right not to be killed. As I have argued, it cannot be disputed that abortion kills a living, human being.
Many argue that outside considerations experienced by the mother should overrule the moral value of the human embryo. If a woman does not want a pregnancy, she may abort. But these quality of life considerations always involve issues of lesser moral weight than that of the conservation and protection of a unique human life (which considers the sanctity or innate and intrinsic value of a human life). An unwanted pregnancy is difficult, but the answer is not to kill a human being in order to end that pregnancy. Moreover, a baby can be put up for adoption and bring joy to others. There are many others who do want the child and would give him or her great love and support. Furthermore, it is not uncommon for women to experience deep regrets after aborting their offspring.
The only exemption to giving priority to the life of the fetus would be if there were a real threat to the life of the mother were the pregnancy to continue. In this case, the fetus functions as a kind of intruder that threatens the woman’s life. To abort the pregnancy would be tragic but allowable in this imperfect world. Some mothers will nonetheless choose to continue the pregnancy to their own risk, but this is not morally required. It should be noted that these life-threatening situations are extremely rare.
This pro-life argument does not rely on any uniquely religious assumptions, although some religious people will find it compelling. I take it to be an item of natural law (what can be known about morality by virtue of being human) that human life has unique value. A case can be made against abortion by using the Bible (only the Hebrew Bible or both the Hebrew Bible and New Testament combined) as the main moral source, but I have not given that argument here. Rather, this essay has given an argument on the basis of generally agreed upon moral principles. If the argument is to be refuted, one or more of those principles or the reasoning employed needs to be refuted.
Although at the beginning of this essay I claimed I would not take up the legal reasoning related to abortion, one simple point follows from my argument. In nearly every case, abortion should be illegal simply because the Constitution requires that innocent human life be protected from killing. Anti-abortion laws are not an intrusion of the state into the family any more than laws against murdering one’s parents are an intrusion into the family.
 See Scott Rae, Moral Choices, 3rd ed. (
 For an exposition and critique of Singer’s thought, see Gordon R. Preece, ed., Rethinking Peter Singer (
 On the dangerous implications of his perspective, see Francis A. Schaeffer and C. Everett Koop, Whatever Happened to the Human Race?, revised ed. (Wheaton, IL: Crossway Books, 1983).
 For a developed philosophical and legal case for including the unborn in the moral community of human beings, see Francis Beckwith, Defending Life: A Moral and Legal Case Against Abortion Choice (Cambridge University Press, 2007); and Robert P. George and Christopher Tollefsen, Embryo: A Defense of Human Life (New York: Doubleday, 2008).
 On the distinction between a quality of life ethic and a sanctity of life ethic, see Ronald Reagan, “Abortion and the Conscience of a Nation,” available at: http://www.nationalreview.com/document/reagan200406101030.asp. This was originally an article in the Spring, 1983 issue of The Human Life Review.
 See Rae, 129-133.
 See Beckwith, chapter two.