The following first ran in the Sept.-Oct. 2011 issue of MCCL News.
Many sophisticated defenders of abortion concede that the unborn (the human embryo or fetus) is a living organism of the human species (as a matter of scientific fact), but deny that he or she bears a right to life. That is, unborn human beings do not have the moral status of a "person," as you and I do—someone with intrinsic moral value and basic rights who ought not be killed without just cause.
To have such a status, these abortion defenders argue, one must possess certain acquired properties and/or be able to function in a particular way. Philosophers have proposed a variety of different criteria, including consciousness, self-awareness, sentience, desires and rationality. But such criteria fail to justify excluding some human beings from the community of rights-bearing persons.
Function v. being
The fundamental mistake is basing human value on characteristically-human functions rather than on simply being the sort of entity from which those functions arise (i.e., a human being). People who are asleep or unconscious do not function as persons generally do (in many respects), but they are still persons with dignity and a right to life. Abortion defenders typically reply that it is the capacity to function in particular ways (e.g., self-awareness, rationality) that is morally important, not that one is currently functioning in those ways, and unborn human beings lack such a capacity.
But there is a sense in which unborn humans do have a capacity for higher mental functions, albeit in radical or "root" form. By virtue of being a human being—a member of our species—they have the natural capacity to develop themselves by a self-directed process to the stages at which the functions characteristic of persons can be exercised, whether or not that development is obstructed by injury, disease or death. Humans have this capacity by nature.
To exclude the unborn, then, abortion defenders contend that inherent human capacities must be developed (to some extent) and perhaps immediately (or nearly immediately) exercisable in order for a human being to merit full moral respect. But this position is untenable.
Three fatal flaws
First, the proposed criteria seem inescapably arbitrary and ad hoc. The present capacity for any particular function is merely the development of a human being's underlying basic capacity for that function. But what degree of development of a basic capacity is necessary, and why? How can a mere difference in degree, rather than in kind, serve as the basis for radically different treatment (i.e., whether one has a right to life or not)? Moreover, what qualities (self-awareness, rationality, ability to feel pain, etc.) are morally relevant in the first place? Why do some qualities matter and not others?
Second, the properties that are said to confer moral worth come in varying degrees, and this entails that moral status is also a matter of degree: since some people possess more of the requisite higher mental functions than others (e.g., have developed those capacities to a greater extent), some people are more valuable than others. A 10-year-old child, then, probably has greater worth and a greater claim to life than his four-year-old sister. This position destroys any basis for equality among persons.
Third, the proposed criteria—whatever they are—inevitably exclude obvious examples of valuable persons, as many thought experiments and real-life examples confirm. They may, for example, exclude mentally handicapped or temporarily comatose people. And because newborn babies lack the immediate capacity for various higher mental functions, a number of thinkers who defend abortion also defend the permissibility of infanticide. Some believe that babies do not become "persons" meriting full respect until months or even years after birth, when they finally acquire the property or ability that the thinker in question deems relevant. But this conclusion is clearly wrong.
Conclusion: Human equality
For these three reasons, among others, it is false that we have our fundamental dignity and right to life by virtue of acquired properties possessed by some human beings but not by others. Rather, we have our dignity by virtue of what (i.e., the kind of entity) we are, and thus we have that dignity from the time we come into existence at conception. So every human being, irrespective of age, size, ability, stage of development and condition of dependency, ought to be treated with full moral respect.