Zygotes are not persons
Editor: I would sin by omission if I did not proclaim the good news that the Catholic Church is truly the One, Holy, Catholic, and Apostolic Church, and so, to quote the article "Infallibility" from the old Catholic Encyclopedia, it "is, by a special Divine assistance, preserved from liability to error in her definitive dogmatic teaching regarding matters of faith and morals." Proving this is beyond the scope of these brief responses, however, and I have tried my best to argue in a secular manner, instead of appealing to, e.g., the authority of the Church in order to prove that we have an immortal soul from the moment of conception. So (1) the truth of Catholicism and (2) separation of Church and state are topics for another time, and right now I do my best to argue from non-controversial premises.
J: i find it kind of hard telling a teenage girl in high school that she can't get an abortion after a few weeks of finding out she's pregnant.
Editor: Granted it is a very tough situation to be in, but the right to life is fundamental and logically prior to any discussion of women's rights. Abortion is harmful to the woman, as well, and is an assault not only on the unborn child, but on the woman herself. And there is no such thing as a right to kill an innocent person, and below I show that the earliest life in the womb is a person (who clearly happens to be innocent).
J: (although i will agree that after the brain begins to develop, it is certainly out of the question.)
Editor: That's a start; so right off the bat you believe in the immorality of abortion at any point 40 days or later after conception.
J: the problem with calling the fetus a human in such early stages is the simple lack of brain activity, so there's really no consciousness there to begin with,
Editor: It is better to define a person as "an individual substance of a rational nature," as Boethius does. This definition encompasses the essential properties of personhood, but your definition is inadequate. Consciousness, reasoning, sentience, and the ability to communicate are not necessary for personhood because comatose individuals do not have these traits. Unlike your inadequate definition of personhood, Boethius' definition can account for why individuals in comas are still persons. This is because it does not construe personhood in a functionalist paradigm; i.e., his definition does not necessitate that the rational nature is being exercised, but rather that the rational nature is present. Even though the early collection of cells does not yet exercise rationality, the nature of the early collection of cells inevitably progresses toward a rational function that must proceed from what the developing being is by nature. It is impossible for a zygote to have undeveloped capacities for rational function (a function of personhood) unless the zygote is the kind of being that has such capacities for rational function; i.e., a being must already be a person at the start of its existence (in this case at the zygote stage) in order to develop a human brain needed for the present and immediate capacity to function as a person. In its earliest stages the human is not a potential person, but a potentially functioning actual person.
J: and, in context with christian principles, the spirit has not yet begin to develop.
Editor: On the contrary, it is official Church teaching that the zygote is already animated with a rational soul, i.e., that the zygote is a person from its very start. The following quotation comes from the Congregation for the Doctrine of the Faith's Instruction Donum vitae, I, 1: AAS 80 (1988), 79 on the Vatican website:
Thus the fruit of human generation, from the first moment of its existence, that is to say, from the moment the zygote has formed, demands the unconditional respect that is morally due to the human being in his bodily and spiritual totality. The human being is to be respected and treated as a person from the moment of conception; and therefore from that same moment his rights as a person must be recognized, among which in the first place is the inviolable right of every innocent human being to life.J: at this point, we simply dont know enough about the first origins of our consciousnesses in the womb to make any judgment as to the humanity of terminating cellular life.
Editor: Above I disproved the notion that a person comes to exist only if he at one point achieves consciousness. Personhood must begin at the moment of conception if you are to avoid manifold absurdities. But if we did not know when personhood begins, would it not be better to err on the side of caution?
J: but, i'll let you make the last point and we can just agree to disagree haha
Editor: I thank you for graciously letting me make the last point, and I sincerely hope that my argumentation was compelling so that you can come to adopt the right viewpoint on this crucial issue. Thank you for being charitable and willing to hear me out, J. May God forgive me if I have not helped to change your mind.
Post-script: So ends the dialogue for the time being. What do you think?