Since the work of Mary Anne Warren, the following is accepted by many pro-choice philosophers:
- CogSkill: Personhood requires developed and complex cognitive skills, of a sort that fetuses lack, and that are had by no mammals other than humans or at most are had by humans, and some other primates and/or cetaceans.
- NonStage: When a person comes into existence, that person is a new entity that comes into existence.
I will argue that the combination of CogSkill and NonStage is not a tenable view. Thus, if CogSkill is true, personhood is a stage property, and if NonStage is true, CogSkill is false.
So for a reductio ad absurdum assume CogSkill and NonStage, and consider Sally, a normal early human infant of three months of age, with a normal loving mother, Martha. Sally's cognitive skills are rather less developed than that of a normal adult dog. By CogSkill, since dogs don't have the cognitive skills needed for personhood, neither does Sally. (This is not at all a controversial conclusion among philosophers who accept CogSkill.)
Martha loves Sally, and does so quite appropriately, and indeed shold do so: it would be absurd to deny that mothers should love their babies.[note 1] But now observe an odd thing if NonStage is also true. When personhood shows up, a new entity comes into existence. And Martha, we may suppose, loves that entity, and does so appropriately, too. Call this entity "Sally2". There are now two possibilities. Either Sally ceases to exist when Sally2 comes into existence, or Sally continues to exist alongside Sally2, or more precisely in exactly the same place as Sally2 exists.
Suppose Sally ceases to exist when Sally2 comes into existence. This is absurd. Then Martha ought to mourn Sally's demise when personhood comes into existence, and mourn it to a degree proportional to her strength of love for Sally. But while some regret for the passing of infancy may be appropriate, a mourning proportionate to the love is not appropriate. Moreover, even worse, Martha's love for Sally would give her reason to administer to Sally a drug that would prevent Sally from developing the skills needed for personhood. For personhood means the end of Sally's life on the hypothesis in question, and so Martha would be saving Sally's life by giving her this drug. And that's a horrific conclusion. In any case, I think none of the philosophers who accept CogSkill and NonStage think that Sally ceases to exist.
The remaining option for the defender of CogSkill and NonStage is that Sally continues to exist alongside Sally2. Now, Martha should now have a maternal love for Sally2. But she should surely also continue too love Sally. After all, parental love should be unconditional. Besides, nothing happened to Sally to make her any less lovable. On the contrary, surely Sally is more lovable, given that she now supports the personal activity of Sally2.
So Martha will now need to love two living beings—Sally and Sally2—with a maternal love. And that is absurd. When complex intellectual skills are gained, parents don't come to love a new living being—they love the same child, but now have additional reasons for loving that child.
If there are two living beings to love after the attainment of personhood, and only one before, then it follows that, all other things being equal, the wellbeing of a baby after the attainment of personhood should count for at least twice as much as the wellbeing of a baby prior to the attainment of personhood. And that doesn't seem right at all.
So we have reason to reject the conjunction of CogSkills with NonStage.