THE PRINCIPLE OF INDIVIDUALITY and identity behind the concept of personhood of the fetus has some potential hiccups arising from some curious qualities of the fetus during the early part of its development. In answering the metaphysical status of the fetus one needs to consider some of the issues arising from the potential for fission (or twinning) and the totipotency of the embryonic cells during the first few days of its existence. Until the formation of the so-called "primitive streak" (a structure which establishes the bilateral symmetry in the embryo formed through a process called gastrulation, which is the precursor of the spinal chord, and which is formed within 10-14 days of fertilization), the embryo has the potential for twinning.
Human zygote showing formation of the "primitive streak"
around 13 days after fertilization
Prior to the formation of the primitive streak, then, the embryo may separate into identical twins, and even these twins have the capacity for twinning. The question arises: how can there by an individual prior to gastrulation and the formation of the primitive streak since there is the potential of more than one individual with identical genetic makeup developing?
Moreover, up until the eight cell stage, each one of the cells in the embryo is "totipotent," which means it has the capacity, if removed from the embryo, to develop into a separate zygote and fetus itself. How can there be an individual human being at this time if one of his cells can be taken from him and develop into another individual that is identical to him genetically? Isn't human personality formed sometime after these quirks are passed and the individual is set?
It is for these reasons that some argue that the individuality of the fetus, and hence its personality, cannot arise until after the formation of the primitive streak. The argument runs thus:
The issue puts us in the middle of an interesting realm demanding the interplay of embryology, metaphysics, and the application of sound moral principles and prudence. In this multi-disciplinary realm, there are some questions that may be not be answerable, at least under the current state of science. What happens to the individual A after twinning? Does the person A "die," replaced by A1 and A2, two new persons so that A is, in a manner of speaking, the sacrificial "parent" of the siblings A1 and A2? Or does A's personal identity continue after twinning as A1, with A2 being a new person? Or, something that does not seem particularly likely, is A before twinning composed of two persons who subsequently split? Or, even less likely, does A not even exist until after twinning when two persons are first conceived? The religious question, separate and apart from the philosophical and moral one, is when does the soul become infused with the body?
As interesting and perhaps insoluble as these questions may be, they do not detract from the fact that prior to gastrulation the zygote remains an actual human individual being, though one perhaps with the potential of splitting into two or more through twinning or because of of the totipotent nature of the stem cells prior to their becoming pluripotent and specialized. In the vast majority of cases, in any event, monozygotic twinning does not occur, and so the question actual versus potential individuality and personhood between fertilization and the formation of the primitive streak is not at issue. Moreover, these issues really do not affect the heart of the matter, as the embryo prior to twinning or while its embryonic cells are totipotent is still an identifiable actual human being, although one with the unique capacity or potential to give rise to others:
Oderberg, 17. The fact that post-twinning the two individual persons cannot trace their identity to fertilization does not mean that there is an "indeterminate number of individuals" or that there is no "individual" actual person prior to twinning or during the time that that individual's cells are totipotent. As Oderberg concludes:
More, in light of the uncertainty with respect to these matters, we ought to be aware of the great significance of these questions, and ought to be prudently biased in favor of protection of all innocent life from the moment of fertilization which, for the vast majority of births anyway, is the same as conception. As Pope John Paul II wisely taught in his encyclical Evangelium vitae (which purports to state the natural law's voice on the matter):
Evangelium vitae, No. 60 (citations omitted). Between the life of the embryo and the needs of those outside the womb, we are judge. This puts us in a place already perilous to justice: Nemo iudex in causa sua. No one ought to be a judge in his own cause. And if circumstances require that we be the judge of our own cause, we ought to be aware of the inherent conflict of interest, and grant presumption to the party without voice, who has no advocate to advance his cause. In the absence of a pleader, we must appoint our conscience the advocatus ad litem, the attorney at litem. And if we listen to the still voice of conscience, we shall hear the advocatus embryonis humani pleading softly but fervently, vehemently from the moment of fertilization: Vivit! Vivat! He lives! Let him live! For it is אָדָם, adam, man, one of us!
Human zygote showing formation of the "primitive streak"
around 13 days after fertilization
Moreover, up until the eight cell stage, each one of the cells in the embryo is "totipotent," which means it has the capacity, if removed from the embryo, to develop into a separate zygote and fetus itself. How can there be an individual human being at this time if one of his cells can be taken from him and develop into another individual that is identical to him genetically? Isn't human personality formed sometime after these quirks are passed and the individual is set?
It is for these reasons that some argue that the individuality of the fetus, and hence its personality, cannot arise until after the formation of the primitive streak. The argument runs thus:
- Only indivisible entities can have moral status.
- Twinning means that an embryo divides into several embryos,
each one a separate entity. - Therefore, as long as twinning is possible, the embryo is not
an indivisible entity. - Twinning is possible up to the point when the formation of
the primitive streak has been completed. - Therefore, embryos are not indivisible until after the formation
of the primitive streak has been completed. - Therefore, embryos cannot have moral status until after the
formation of the primitive streak has been completed.
Monozygotic twinning
The issue puts us in the middle of an interesting realm demanding the interplay of embryology, metaphysics, and the application of sound moral principles and prudence. In this multi-disciplinary realm, there are some questions that may be not be answerable, at least under the current state of science. What happens to the individual A after twinning? Does the person A "die," replaced by A1 and A2, two new persons so that A is, in a manner of speaking, the sacrificial "parent" of the siblings A1 and A2? Or does A's personal identity continue after twinning as A1, with A2 being a new person? Or, something that does not seem particularly likely, is A before twinning composed of two persons who subsequently split? Or, even less likely, does A not even exist until after twinning when two persons are first conceived? The religious question, separate and apart from the philosophical and moral one, is when does the soul become infused with the body?
As interesting and perhaps insoluble as these questions may be, they do not detract from the fact that prior to gastrulation the zygote remains an actual human individual being, though one perhaps with the potential of splitting into two or more through twinning or because of of the totipotent nature of the stem cells prior to their becoming pluripotent and specialized. In the vast majority of cases, in any event, monozygotic twinning does not occur, and so the question actual versus potential individuality and personhood between fertilization and the formation of the primitive streak is not at issue. Moreover, these issues really do not affect the heart of the matter, as the embryo prior to twinning or while its embryonic cells are totipotent is still an identifiable actual human being, although one with the unique capacity or potential to give rise to others:
In terms of the metaphysics of embryo identity, twinning should be looked at in the same way as any case of division of a cell (or group of cells). The 'parent' cell ceases to exist on division and the 'daughter' cells come into existence. The simple fact is that not all human beings come into existence at fertilisation--some do so a few days later if there is twinning. Twins (identical ones, that is) will not be able to trace their identities back to fertilisation. For them, conception occurs at division (hence one of the reasons why 'conception' and 'fertilisation' are not synonymous).
Oderberg, 17. The fact that post-twinning the two individual persons cannot trace their identity to fertilization does not mean that there is an "indeterminate number of individuals" or that there is no "individual" actual person prior to twinning or during the time that that individual's cells are totipotent. As Oderberg concludes:
The moral of the story as far as fission and totipotency are concerned, then, is that the individuality of the embryo is not influenced by what it might do (for example, twin) or what can be done to it (separation into totipotent cells).Oderberg, 19.
More, in light of the uncertainty with respect to these matters, we ought to be aware of the great significance of these questions, and ought to be prudently biased in favor of protection of all innocent life from the moment of fertilization which, for the vast majority of births anyway, is the same as conception. As Pope John Paul II wisely taught in his encyclical Evangelium vitae (which purports to state the natural law's voice on the matter):
Some people try to justify abortion by claiming that the result of conception, at least up to a certain number of days, cannot yet be considered a personal human life. But in fact, "from the time that the ovum is fertilized, a life is begun which is neither that of the father nor the mother; it is rather the life of a new human being with his own growth. It would never be made human if it were not human already. This has always been clear, and ... modern genetic science offers clear confirmation. It has demonstrated that from the first instant there is established the programme of what this living being will be: a person, this individual person with his characteristic aspects already well determined. Right from fertilization the adventure of a human life begins, and each of its capacities requires time-a rather lengthy time-to find its place and to be in a position to act". Even if the presence of a spiritual soul cannot be ascertained by empirical data, the results themselves of scientific research on the human embryo provide "a valuable indication for discerning by the use of reason a personal presence at the moment of the first appearance of a human life: how could a human individual not be a human person?"
Furthermore, what is at stake is so important that, from the standpoint of moral obligation, the mere probability that a human person is involved would suffice to justify an absolutely clear prohibition of any intervention aimed at killing a human embryo. Precisely for this reason, over and above all scientific debates and those philosophical affirmations to which the Magisterium has not expressly committed itself, the Church has always taught and continues to teach that the result of human procreation, from the first moment of its existence, must be guaranteed that unconditional respect which is morally due to the human being in his or her totality and unity as body and spirit: "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."
Evangelium vitae, No. 60 (citations omitted). Between the life of the embryo and the needs of those outside the womb, we are judge. This puts us in a place already perilous to justice: Nemo iudex in causa sua. No one ought to be a judge in his own cause. And if circumstances require that we be the judge of our own cause, we ought to be aware of the inherent conflict of interest, and grant presumption to the party without voice, who has no advocate to advance his cause. In the absence of a pleader, we must appoint our conscience the advocatus ad litem, the attorney at litem. And if we listen to the still voice of conscience, we shall hear the advocatus embryonis humani pleading softly but fervently, vehemently from the moment of fertilization: Vivit! Vivat! He lives! Let him live! For it is אָדָם, adam, man, one of us!
No comments:
Post a Comment