Trent Horn – excerpts from a Catholic Answers Article –
Some pro-lifers say we should just abandon the concept of personhood. They say “person” is a term that confuses the issue and so we should just stick to the argument that it is wrong to kill innocent human beings and since the unborn are innocent human beings it follows that it is wrong to kill them.
But abortion defenders can undermine this approach by appealing to the common intuitions we have about “persons” that are separate from our intuitions regarding of human beings. For example, in her 1973 article “On the Moral and Legal Status of Abortion” philosopher Mary Anne Warren asks us to consider this example:
Image a space traveler who lands on an unknown planet and encounters a race of beings utterly unlike any he has ever seen or heard of. If he wants to be sure of behaving morally toward these beings, he has to somehow decide whether they are people, and hence have full moral rights, or whether they are the sort of thing which he need not feel guilty about treating as, for example, a source of food. How should he go about making this decision?
…Warren goes on to say our space traveler would probably look for at least one of the following five criteria: Consciousness, reasoning, self-motivated activity, communication about an indefinite number of topics, and self-awareness…
In fact, nearly ten years after its initial publication Warren added a post-script to her article saying, “One of the most troubling objections to the argument presented in this article is that it may appear to justify not only abortion but infanticide as well . . . There are many reasons why infanticide is much more difficult to justify than abortion, even though if my argument is correct neither constitutes the killing of a person.”
Warren goes on to say that infanticide is only wrong because of practical reasons, like because we as a society value infants and “so long as most people feel this way, and so long as our society can afford to provide care for infants which are unwanted or which have special needs that preclude home care, it is wrong to destroy any infant which has a chance of living a reasonably satisfactory life.”
… we should identify persons not as individuals who currently have certain valuable abilities (which can be gained and lost over time), but as members of kinds whose nature is to develop those valuable abilities. We can summarize it this way: a person is an individual member of a rational kind.
All of this shows that modern accounts of personhood fail because they do not explain deep-seated moral intuitions almost everyone has about the way the world works: All human beings, including infants and young children, have the same basic rights and dignity. While the modern view leads to what McMahan calls “distressingly insecure foundations,” the classical view of human dignity and the nature of personhood (which logically entails the pro-life position) is our best chance at securing the equal rights and dignity for all members of the human community.