Tetragametic Chimeras and the Human Soul

A Tetragametic Chimera is an extremely rare situation in which two different zygotes have  become one, by one’s being absorbed into the other. In effect, it means that the one life form left will have two different sets of DNA. Now, the theological problem arises when one realizes what the commitment to the human soul existing at the moment of conception commits one to saying that, in the case of Tetragametic chimerism, either one biological organism has two corresponding immaterial souls, or else that at least one person died at an extremely early stage after conception. I think the suggestion that there are two souls corresponding to one human body is simply misconceived and requires a Cartesian, rather than Hylomorphic, idea of the soul and it’s relation to the body. Certainly it would be unacceptable on a Catholic theology. However, the alternative seems grim: it entails that a human person died in the process of coming to term from a zygote. Is this a problem? Well, it seems to me that it is no more a problem than a miscarriage. It certainly isn’t a conceptual problem, and so poses no inconsistency for philosophical theology, and moreover it isn’t even as emotionally trying as miscarriages are, since at least with Tetragametic Chimerism there remains a living person who is brought to term. This is an example of natural evil.

What is interesting, I think, is to consider that it could be much more common than it is. It is extremely rare in human reproductive processes, but not nearly as rare in rodents like mice. However, it isn’t difficult to imagine a logically possible world in which the ratio of human Tetragametic Chimerism was greatly increased, and posed an emotional problem for people with respect to accepting the Catholic doctrine of the soul’s existence from the moment of conception. As it stands, it is a rather esoteric objection rarely brought up, but interesting to think through.

Finally, if somebody wishes to use the curious case of Tetragametic Chimerism against the Catholic doctrine that the soul exists from the moment of conception, then not only can the Catholic explain that this poses absolutely no conceptual problem (being an instance of natural evil) to the commitment to the soul’s real existence from the moment at which conception occurs (when some organism is no longer identifiable with it’s parents, or as a part of either of its parents, from a biological perspective), but the Catholic can go further. The Catholic can make the issue into a moral argument against in vitro fertilization since the likelyhood of Tetragametic Chimerism is significantly increased in in vitro fertilization.

The curious case of Tetragametic Chimerism also presents an interesting thought about sexuality, since sometimes the human Chimera has both male and female DNA. What, then, are we to say about such a person – are they male or female? Could they be ordained to the Catholic priesthood? I think if this makes it obvious that maleness and femaleness are accidental features of human persons, and not determined by substantial form (in other words, souls are not ‘naturally’ male or female). Of course, for the person who thinks they are, they could simply say that the original two zygotes were two persons, one male and another female, and whichever absorbed the other is the person who survived – even if we cannot know which one absorbed which. For prudential reasons the person who believes that souls are naturally either male or female would want to presume that human Chimera’s cannot be ordained. However, I think such thought experiments demonstrate both that there is no coherent way to make sense of maleness of femaleness as natural features of the substantial form corresponding to individual souls, and that things like the sacrament of ordination preclude women’s ordination by reason of the form of the sacrament rather than the matter (since the matter does not require a person who naturally is male if there is no such thing, but rather the form requires a person who is male by physical disposition).

I take it I’ve exhausted the interesting dimension of Tetragametic Chimerism in relation to Catholic theology and apologetics.


About tylerjourneaux

I am an aspiring Catholic theologian and philosopher, and I have a keen interest in apologetics. I am creating this blog both in order to practice and improve my writing and memory retention as I publish my thoughts, and in order to give evidence of my ability to understand and communicate thoughts on topics pertinent to Theology, Philosophy, philosophical theology, Catholic (Christian) Apologetics, philosophy of religion and textual criticism.
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9 Responses to Tetragametic Chimeras and the Human Soul

  1. Pingback: Scientific Proof that The Blessed Virgin Mary is “Blessed for all Generations”

  2. I’m very interested in this question from a slightly different angle. I don’t find the idea that one soul dies off very compelling. It seems to me that the two life forms merge so the two souls must be present in the resulting body. I don’t see how this is a problem for Catholic teaching. Certainly a child born without arms still has a soul. As I understand chimera, one genetic code may have created the heart and another the skeletal system. Just because they coexist in the same macro-body doesn’t mean they aren’t divisible bodies. Thus I see no problem with two souls.

    This brings me to what I think is most interesting. The soul is not the consciousness. This is a fundamental error that people seem to make. If there is something eternal about us, it is not our thoughts and feelings–it is something more fundamental. A Chimera certainly feels like a single person. Are you (or the church) suggesting that our conscious feeling of individuality comes from the soul? That strikes me a weak conjecture, so I doubt it. I may disagree strongly with Catholic theology, but it is always extremely well reasoned.

    • Hello Frankly Curious,

      Interesting thoughts. However, on this point I’m ready to stick with the Catholic Church’s teaching that whatever part of us does survive the death of the body, as well as ‘animate’ the body, is that which grounds our personal identity and relationship with God, and that by which we exercise free will and have moral agency. In short, the soul does have something do to with consciousness, and this is, I think, the only reasonable way to talk about a soul at all. In fact, I think you will find the same to be true among all philosophers, from Plato to Plantinga, since though their theories of what the soul is or how it can be identified often differ, hardly anybody speaks of the soul as something which does not involve the grounding of our rational faculties and personal identity. This is true even, and perhaps especially, of those philosophers who have denied the existence of the soul – they knew exactly what it was they were saying didn’t exist. Of course there are always exceptional cases, such as Aristotle who may be read as suggesting that there is only one human soul which is the form shared by all individual human persons (there are not individual human souls, but even then there would be, I think, individual substantial forms). Even for Aristotle the soul has something to do with consciousness.

      Moreover, I think that the existence of the soul (as the immaterial ground of consciousness) can be demonstrated, and thus I think that arguments from consciousness (etc) or the reality of free will can serve as good arguments for Theism precisely because they demonstrate the existence of a soul which is analogous to the kind of thing God is supposed to be – an immaterial and personal being. Souls are at home in a Theistic universe, and they are not quite at home in a Naturalistic universe.

      In the Catechism of the Catholic Church it says:
      “363: In Sacred Scripture the term “soul” often refers to human life or the entire human person. But “soul” also refers to the innermost aspect of man, that which is of greatest value in him, that by which he is most especially in God’s image.” The soul, on the Catholic view, does, therefore, have something to do with free will, personality, relationality, personal identity, et cetera. Even if you disagree with Catholic Theology elsewhere and for other reasons, it seems outrageous to me to disagree with it here. To deny the existence of the soul altogether would be more reasonable than postulating something you want to call ‘soul’ but which isn’t the ground of all these characteristic features of a human person. What, if I may ask, do you think the soul is exactly if it is not the ground of consciousness, and all those other things I’ve named? Do you believe that one single person can have more than one such soul? Can the soul really survive the death of the body, and in what way can the soul be identical to the person if the person is not identical to the soul?

      • Thank you for your thorough reply! I wish I had an answer for you regarding the soul. I understand what the Greeks generally thought about the soul, but that’s not really what we are talking about here. I’m trying to get to the base of what a Christian (for example) thinks will go to heaven. (Actually, I understand that JWs believe they will have physical bodies and live on this earth. I have no difficulty understand this.)

        My questions don’t really come from thinking about the soul but rather consciousness. I’ve watched people age and die and it is very clear that people are not a single thing over time. To put it differently: my feeling of continuity (e.g. that I’m in some way the same thing that I was as a child) is an illusion.

        I don’t necessarily believe that I do have a soul. But certainly if God did make me with an eternal soul, it must be something more than my consciousness. This is probably where we part company because you seem to think that consciousness is something more than just chemical processes in the brain. Actually, we know that who we are (or who we think we are) is dependent not just on the brain but on the entire body. Thus, if I as a conscious entity am going to live on without my body, how do I do that? There must be some core thing that we all are; it certainly can’t be all the many stray thoughts that flit through mind at any given time. (Kind of like this comment…)

        I find all of this thinking comforting because from my perspective I’m always dying. So even if I died today and went to heaven, it wouldn’t be the conscious being who “Frank” was at, say, 5 years old who would be in heaven. You see what I mean? There is a question of time here. And perhaps that provides a way forward. My conception of God certainly has to be outside of time. (Frankly, only negative theology really makes sense to me.)

        As you can see, I’m groping around here. Fundamentally, I would like to find a theology that is consistent with current thinking in neuroscience and cosmology. In general, the Catholic Church has been very open to this kind of thing. I mean no offense to other forms of Christianity, but the Catholics have long had the major intellectual fire power. This is why when I started thinking about chimeras, I searched for Catholic teachings. But the “one dies off” thinking leaves me cold. However, I will give more thought to what you wrote above. If you have any thoughts on what I’ve written, I would be very interested. There are not a lot of people who even think about this kind of stuff!

  3. Well, as a Theologian I feel like thinking about this kind of stuff is practically my day job :P. Interesting thoughts and comments, and I do have a few additional things to say in response.

    First, the Jehovah’s Witnesses are actually in agreement with Catholics on the point about our eventual life on earth with bodies, since the Catholic Church proclaims that the soul apart from the body is not constitutive of a human person, and that ultimately at the end of the world we will all be raised again bodily and face the final and public judgment – so Catholics too believe in a new heavens and a new earth, and that mankind will glorify God and enjoy him forever with physically resurrected bodies. The difference comes in here: that the Jehovah’s Witnesses believe that the soul can, and many will, cease to exist altogether. The Catholic view recognizes with Plato that the soul is a simple substance (i.e., it is not comprised of parts, and therefore cannot be dissolved or destroyed by any natural process), and that for it to cease to exist would require God to annihilate it, which would be an action contrary to the act of creation. Catholics therefore believe that all souls, whether of those in fellowship with God or those not in fellowship with God, are imperishable and will survive forever into eternity.

    You mentioned that you think that your personal identity is itself an illusion, but it seems to me difficult to imagine you having an illusion if there isn’t a ‘you’ to be in the intentional state we call ‘illusion’. Now, I entirely agree that people change over time, and even radically change. They change character, and often, due to brain damage or development, they change in every way possible. However, I think for us to acknowledge that they have changed, we have to presume more fundamentally that there is an identity over time (without identity over time from one state to another, any talk of ‘change’ is actually unintelligible). For example, when a doctor diagnoses a person as having alzheimer’s disease (because they cannot recall who they are or cannot recall members of their family), or having amnesia, what the doctor is presuming is that such a thing as amnesia exists. However, amnesia, as a diagnosis, presumes identity – if my mother has amnesia, then it is SHE who has amnesia and cannot recall who she is (she may thus seem like a different person, but she is actually the very same person). Remember that what Catholics mean by the soul, therefore, is not something like personality, but rather we mean that which grounds personality and identity over time. Without such identity things like moral blame or praise make no sense, and neither can we account for states of intentionality, or the existence of libertarian free will which we apprehend by immediate introspective reasoning.

    You suggest in your comments that consciousness is no more than merely chemical processes in the brain. Here, I want to join Leibniz in saying that such a suggestion is absurd, but also I want to join Aquinas in saying that the reason there is a relation of dependence between the soul and the body is that Plato’s view (later to be repeated by Descartes) is mistaken. First, Leibniz: Leibniz challenged his early modern contemporaries on this point by inviting them to imagine that we could construct a physical brain which was so large relative to us that we could walk into it and observe the functions of this machine. He says: “That being so, we should, on examining its interior, find only parts which work one upon another, and never anything by which to explain a perception.” I continue to agree with this intuition, I think that any attempt to explain consciousness according to reductionistic or materialistic (or naturalistic) analysis is doomed to failure because it fundamentally misunderstands that states of intentionality cannot supervene, reducibly or irreducibly, on material compositions or relations between material compositions, (nor can it supervene on the flow of energy, etc). If you would like to further explore arguments from consciousness then I recommend looking into the writings of J.P. Moreland, a Christian Philosopher who has done some very impressive work in this area, and I would also invite you to take a short read of this argument: http://www.peterkreeft.com/topics-more/20_arguments-gods-existence.htm#10
    Particularly think carefully about the quotation from H.W.B. Joseph.

    On the other hand, you are clearly right to think that the mind or ‘soul’ is dependent upon the body. In fact, in the Catechism of the Catholic Church it says that the soul must be thought to be the ‘form’ of the body (thus substance-dualism is misconceived). Where Plato or Descartes conceived of the soul as some immaterial thing which might occupy a body, Aristotle and Aquinas argued that the soul is that principle which animates a body, and by reason of which a body may be said to be alive. Thus, when people object to the existence of the soul by demonstrating a correspondence between the physical brain and the supposedly immaterial mind, they bring challenges which are problematic for Plato and Descartes, but are not problematic for the Catholic Church whose teaching is exemplified in St. Thomas Aquinas. St. Thomas, in fact, had already argued that when men suffer damage to the head they often change character, and even when they become inebriated their conscious state, and not just their body, changes. The soul is obviously effected by the body because the soul is the form of the body. Nevertheless, the soul is itself immaterial (since it cannot possibly be explained as a phenomenon of the collision of particles on any scale). Theologians often argue back and forth about what features of the soul clearly are not grounded in physical states of the brain, and the most obvious and common are: consciousness, the exercise of libertarian free will, and the kind of rational intuition needed at the most basic level (which Gödel proved we must have).

    In short, if you want a theology which is consistent with current neuroscience, take the theology of St. Thomas Aquinas which the Catholic Church continues to uphold and point people towards (on this point). You might be surprised by what you find.

    You say that you find it comforting to think that you do not persist over time, so that you can be identified with the ‘Frank’ who was five years old. I would first like to point out that even in making that affirmation you are presuming your own identity (for YOU find it comforting). In fact, even to say, as you do, that ‘you’ will think about the points I’ve made presumes, in a properly basic way, that ‘you’ exist as a subject. So, I think if we’re careful enough about our natural use of language, reference and meaning, we can already tell that we all presume our own identities in speech as well as in thought, and in fact such a thing is indubitable and self-evident. However, to speak to the point about whether it really is comforting to think that you do not exist as a subject whose identity persists over time, I think we may have reasons to be quite uncomfortable with such a suggestion. For instance, it would mean, as C.S. Lewis noticed, that when we fall in love with somebody we do not love a person, a ‘subject’, but rather we love an object or a mere thought about an object. If you have ever been in love, though, I think you will find such a view intolerable. Yet. as Lewis also noticed after his wife passed away, if she does not exist as an immaterial subject, then she never did; “I mistook a cloud of atoms for a person.”

    Therefore, I think we have more reasons to be uncomfortable with the suggestion that we are not immaterial subjects than we have reasons to be uncomfortable with the suggestion that we are. I also think that if we are attentive to our language, and if we simply engage in careful introspective reasoning, we can recognize that we all fundamentally presume our existence, and we know that we exist as subjects in a surer way than we know anything else.

    Finally, concerning God, I agree with you that God is outside of time, and that negative theology makes good sense of God. However, I would only add that St. Thomas Aquinas developed an entire (and, to my mind, entirely successful) doctrine of analogy in order to explain how we can predicate truly and positively concerning God by predicating neither univocally nor equivocally, but analogously. I would invite you to take a look at Medieval philosophy of language and see what you think about St. Thomas’ view of predicating true things of God analogously.

  4. Normal Distribution says:

    And if I take that embryonic chimera and reseparate them in the lab are there two souls again? Are one or both of them the original ones? Do souls get created everytime I perform the manipulaiton of fusing together and then separating the embryonic cells? If I split them into 4 parts do I get 3 extra souls with every iteration?

    • Normal Distribution says:

      These pitches are right down the middle of the strike zone but they seem to be unhittable. If it’s any consolation, they have been thrown at many a theologian and church leader and no one has ever even tried to swing at them, much less make contact. No responses here for months – we see the batter going down looking…again.

  5. Jaron says:

    Well, if you believe that we have magical little supernatural parts to us that exist outside of the physical limitations of reality…then you can make up any kind of answer you want to solve this conundrum can’t you? After all, you aren’t limited by the laws of physics, or even the limits of space and time. Must be nice have no limitations on what fairy tale mumbo jumbo you have to make up to fit with what you see in the real world.

    • Hey Jaron,

      I can’t help but notice that your comment seems to insinuate that physicalism is more reasonable than Christian Theism. I think it is worth disabusing you of that sentiment. Notice that even among the most intelligent naturalists, like W.V.O. Quine, it is conceded that something beyond the physical must exist (for instance, Quine thought that sets must exist). The point is that physicalism is not preferred in philosophy because it doesn’t make good sense of the world (which is precisely what philosophy aims to do). It doesn’t make good sense of consciousness as we experience it, it doesn’t make good sense of our moral experience, it doesn’t make good sense of mathematics, it doesn’t even make good sense of itself (since physicalism cannot give us an explanation for why the sum of all physical things exists). Physicalism is in poor repute among the intelligentsia because it is spectacularly inadequate as a worldview. Notice that there are no good arguments for its truth, and many good arguments to think it is false. It is only because of a naive scientistic enlightenment fervor that the naturalistic zealot carries its flag.

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