I’ve recently had an online debate with a pro-choice girl, who made the argument that an embryo, even though it is alive since conception, is not a human person until a later stage of developement, because it has not yet the cognitive faculties (such as intellect and will ) that are part of what a person is.
I’ve noticed that the common definition of personhood, even in Catholic philosophy and theology (though the Church hasn’t made any dogmatic definition on the subject yet, as far as I know ), at least since the time of Boethius, is “individual substance of rational nature” (Liber de persona et duabus naturis contra Eutychen et Nestorium, III ).
Thus, theologians such as Saint Thomas Aquinas developed three fundamental criteria of personhood:
- individuality: a person is distinct in itself and from the others;
- substantiality: a person is a union of matter and form, not for accident;
- rationality: a person has an intellectual nature, wich involves at least the potentiality of consciousness.
An embryo meets the first two criteria, but not (at least in actuality ) the third one, because it still doesn’t have a functioning mind immediately after conception. That’s also why Saint Thomas Aquinas didn’t recognized the embryo as a human person until a later stage of developement (even though his argument was philosophical rather than biological, the question being about insoulment ).
I’ve answered this argument by stating that an embryo, since the moment of conception, has already in itself all the necessary elements to develop into a conscious being, and such developement will naturally and necessarily occur if no external contingent cause interferes, so it’s reasonable to treat it as a human person with basic human rights.
She admitted her inability to prove my counterargument wrong, but still wasn’t covinced by it.
So, I have two questions:
- Is the traditional and common definiton of personhood necessarily incompatible with the current understanding of the Church on the human nature of the unborn? If so, should Catholics abandon it? If think abandoning that definition for a new one would be tricky, because it could have serious implications in Christology and Trinitarian theology…
- Do you find my counterargument convincing? If not, why?