The authors [George and Tollefsen] are probably wrong, however, to think about our natural kind as a “what” and not a “who.” Augustine and Thomas Aquinas discovered that each human being naturally exhibits uniquely or singularly free and rational personal behavior. So each person can’t be understood as merely a part of some political community or part of a species; we exist by nature for ourselves. That’s why the God of nature can’t be a “what,” as Aristotle thought, but a “who,” and that distinction makes sense even without faith in the actual existence of a personal God. Particular leaves and cows can be thought of as “whats,” or examples of species-specific characteristics. But that way of thinking doesn’t do justice to “whos” with absolute personal significance — and thus absolute rights. Even Aristotle didn’t do justice to our freedom, because he characteristically thought (and spoke) of each of us as being more of a “what” than a “who.”
[There is no argument here, but just an invocation to Augustine and Aquinas as supposed authorities. However, the basic problem remains, whether we speak about a personal human nature or a general human nature: still the embryos are only potentially human. The other claim that absolute personal significance means absolute rights, presupposes that significance entails rights. This is a principle we can decide and adopt, not a law (of nature, of spirit, of God, or whatever). We can invent and attach any kind of ‘rights’ to a significant being, but significance as such is internal, it refers to the worthiness of a being regardless of other beings’ behaviour, therefore regardless of rights. Besides this, if we connect significance with rights, then why stop to the ‘absolute’ human nature and not go one step further to the significance of what one does with that nature. In such a case we should attach more rights to persons with a more significant life and creativity.]
The evidence that George and Tollefsen present suggests that there are only two non-arbitrary ways to consider when a “what” naturally becomes a “who.” Either the embryo is incapable of being anything but a “who”; from the moment he or she comes to be, he or she is a unique and particular being capable of exhibiting all the personal attributes associated with knowing, loving, and choosing. Or a human being doesn’t become a “who” until he or she actually acquires the gift of language and starts displaying distinctively personal qualities. Any point in between these two extremes — such as the point at which a fetus starts to look like a human animal or when the baby is removed from the mother’s womb — is perfectly arbitrary. From a purely rational or scientific view, the price of being unable to regard embryos as “whos” is being unable to regard newborn babies as “whos” — that is, as beings with absolute rights. Everyone knows that being pro-choice when it comes to killing or experimenting on actual live babies is monstrous. There is no constituency, outside a few Princeton classrooms, for some kind of pro-choice-until-age-two policy.