#156 Table for one.. or two?

#156 Table for one.. or two?

Tetragametic Chimerism is one of the weirdest things I have ever heard of. And it does seem to me that it has implications for the view that “personhood” starts at the moment of conception. At the very least, it highlights just what a peculiar and counter-intuitive view that is.

If you’re interested in more on Chimeras, this episode of the Radiolab podcast is definitely worth listening to.

That’s all for now, have a good night!


Discussion (35)¬

  1. PJSW says:

    I just saw an episode of House about this the other night! It might have been a rerun, though. I think their depiction of the patient was way over the top… he repeatedly hallucinated aliens and the show seemed to suggest that it was a feature of the chimerism.

  2. EveryZig says:

    It must be the extra soul floating around 😛

  3. chaospet says:

    Oh yes, I did forget to mention to that chimeras are highly prone to vivid hallucinations, typically of aliens, but on occasion of a headless Bing Crosby. Nobody really knows why.

  4. Wm Tanksley says:

    Yeah, CSI did one with a chimera too. I don’t recall anything about hallucinations; no doubt their crack team of fact checkers missed their usual meeting with House’s crack team of fact checkers.

    Crack. Crack, crack, crack.

  5. LEGION says:

    could it be that one soul is chosen over the other? Or perhaps, since god is said to be all knowing, each zygote has half a soul, and they are combined as one when joined?

    Or the basic default to any philosophical problem, “I am right, if you say otherwise I will find you and your family”

    Ahh nothing like brute force to solve mankind’s greatest intellectual barriers.

  6. Wm Tanksley says:

    chaospet, I don’t see why chimeras influence this particular debate at all. Whether you believe in mystical souls or not, surely you don’t argue that a chimera is less than any other fetus.

    And chimerism isn’t really that different from other cases where one twin dies during early pregnancy; normally the mother’s body will absorb and destroy the dead twin’s constituent cells, but in this case the other twin absorbs the material.

    There are some interesting philosophical questions regarding end-of-life issues, since it’s not clear at what point the absorbed fetus is actually dead. The only thing that’s clear is that we’re not dealing with a question about the beginning of life; whether or not you think that the fetuses are persons, they are definitely distinct lives from each other and from their mother; their biological lives have already begun. Unless you have an additional, mystical definition of “life”, that’s the only way the argument can go.

    In summary, therefore, human chimerism is made out of people. You’ve gotta tell them! Chimerism is people!!!!!!

    -Wm

  7. chaospet says:

    I’m not suggesting that chimeras don’t eventually become people as much as anyone else. My point is that chimeras end up being very peculiar for those who hold the view that the two zygotes are already persons before chimerism.

    It is different from a case of one twin absorbing or destroying the material of the other; all of the cells from both zygotes continues to thrive and develop into the organs of the chimera. Some organs will be formed from the cells of zygote A, and cells from zygote B will form the other organs. So, if A and B were already people, what has happened to them? Does one “win” and continue to survive? Are they both destroyed to form a new person C? Or do both people continue to live in one body? There is no clear satisfying answer, so chimerism creates a difficult puzzle for those who hold the view that zygotes are truly people.

  8. Dustin says:

    If you think tetragametic chimerism is something wait til you hear about heteropaternal superfecundation!

  9. BG says:

    chaospet, I’m not sure why any of your three explanations in your 12:46 post are unsatisfying, besides the fact that there are multiple explanations. Is this your argument:

    Since you believe X, I would like to ask you question Y.
    I can answer question Y in a number of ways, all of which are plausible, and wouldn’t contradict anything else you believe. However, since there are multiple explanations and you haven’t decided which one to accept, you should reject belief X.

  10. EveryZig says:

    He never said it disproves the ‘fetuses have souls’ thing in the post; he just says it adds complications.

  11. chaospet says:

    BG: “all of which are plausible”

    This is what I what deny. In fact, I explicitly suggested the opposite. None of those seem plausible to me at all. Does it seem plausible to you that one or the other person “wins”, or that either of them is destroyed, when all of the cells from both zygotes continue existing and multiplying? And if so, can you explain how this happens, and how we are to determine which person, A or B (or neither), continues to exist after chimerism? If so, I’d love to hear your answer. Or do you really think it is at all plausible that two distinct people continue to exist in a single body? I’d love to hear how that is supposed to work.

    The point (as EveryZig says) is not that chimerism provides a knockdown refutation of the view that zygotes have souls/are persons/etc. It just highlights some very peculiar and counter-intuitive consequences of that view that proponents will need to grapple with.

    Dustin: Do tell!

  12. Wm Tanksley says:

    chaospet, I don’t understand. Why does it matter whether we know for certain what happened to the two original zygotes? The questions and possibilities you raise are good, but none of them by themselves would disprove the personhood of the zygotes before the fusion.

    In particular, I’m puzzled by you bringing up “there is no clear satisfying answer.” Yet the answers you propose are all clear by any criterion I can think of. I suppose I could add an answer that is more satisfying: both die, and the resulting embryo is a philosophical zombie. I admit that I don’t know which of your answers are correct, but it seems to me that in any specific case only one of the possible answers can be true. How is that not clear? And all of the possibilities you propose seem to be compatible with saying that both fetuses are persons (by your assumption ad argumentum, of course).

    From a different perspective… I see what you’re saying, that all of the biological constituents of both fetuses survive (as indicated by cells with distinct DNA signatures), but the same thing happens partially in other fetal absorption cases, and since there are sometimes two distinct survivors in those cases, it occurs to nobody to question the humanity (or personhood) of the results. If those cases don’t challenge the personhood of the fetus, why should this?

    I’m just not seeing any way to use this to challenge anything on either side. Yes, it’s an interesting unanswered question; but no, the presence of uncertainty doesn’t seem to me to defeat any argument.

    Let’s take yet another perspective. You think that your observations of tetragametic chimerism prove that the fetus is not a human being. Okay, that’s fine; what was your null hypothesis? What did you see, specifically, that proved that it’s not possible that things could be “that way”? What *might* you have seen in fetal development that would have convinced you that you might be wrong?

    -Wm

  13. chaospet says:

    Wm: “If those cases don’t challenge the personhood of the fetus, why should this?”

    I never challenged the personhood of the resulting fetus.

    “You think that your observations of tetragametic chimerism prove that the fetus is not a human being”

    In fact, I did not claim this. I am merely suggesting that chimerism creates a complicated, peculiar puzzle for those who think that zygotes ARE really people from the moment of conception (a puzzle that those who are not inclined to view single celled organisms as people won’t have to deal with). The puzzle is what to say about what happens to those two distinct people after they are fused via chimerism, and how to explain what happens. As you say, you don’t know which answer is correct – and I can’t readily see any way that we could discern which answer is correct, hence the puzzle.

  14. Wm Tanksley says:

    chaospet: “None of those seem plausible to me at all.”

    Oh, I see — that’s what you meant by “clear or satisfying”. I apologize. Satisfying, in this context, means “plausible.”

    Let’s look at the possibilities.

    Both might die and be replaced by nothing. That does seem implausible. (I suggested that, not you.)

    Both might die and be replaced by God. Again, implausible; I won’t cover why, but I’m sure you agree, although possibly for different reasons.

    Both might die, combine, and the residue form a new person (in a way similar to how the non-person gametes form a new person). Plausible.

    One might live and replace the other. This seems perfectly plausible; I don’t see why you reject it. I don’t see why we’d have to determine which person continued (nor how we’d determine it).

    Both might live and combine. Plausible. Some theories of consciousness suggest that we’re a network of subpersonas, so I don’t see how it would be possible to distinguish a “true person” living in the same body as you from a subpersona, especially if you grew up in that situation (nonetheless, this suggests the possibility of experimental verification, if we can more clearly define subpersonas).

    -Wm

  15. Wm Tanksley says:

    “I can’t readily see any way that we could discern which answer is correct, hence the puzzle.”

    It’s a splendid puzzle (much like the rest of life), but your comic suggested many times that it might require a revision of someone’s views, and I just don’t see any interpretation of it that could possibly DO that. The best I could imagine is that someone’s view might make them prejudge that one of the possibilities couldn’t actually happen (for example, you don’t think it’s possible that one would live and the other die).

    From a naturalistic point of view, it seems to me that the question has roughly the same answers — although the entire concept of “person” is entirely meaningless there, and has to be substituted with the concept of “individual”, perhaps “conscious individual”. Some of the suggested answers actually still have meaning in that framework.

  16. chaospet says:

    “Both might die, combine, and the residue form a new person (in a way similar to how the non-person gametes form a new person). Plausible.

    One might live and replace the other. This seems perfectly plausible; I don’t see why you reject it. I don’t see why we’d have to determine which person continued (nor how we’d determine it).”

    I don’t see how even in principle we could distinguish between these possibilities – that is, between A surviving, B surviving, and A&B both dying and a new person C being formed. Even in principle, what would you look for to determine which is the case? That is why asserting any one of those as the answer seems implausible to me, and why I think you are left with a peculiar, challenging puzzle.

    “Both might live and combine. Plausible.”

    Really, to me this seems least plausible of all. Theories of consciousness aside (after all, on the view that a zygote is truly a person, consciousness must be distinct from the question of personhood), I just don’t know how to make sense of the idea of two distinct, full persons inhabiting the same body.

    “but your comic suggested many times that it might require a revision of someone’s views”

    Sure, that is one reasonable way to react to the puzzle. If calling zygotes “persons” leaves you with a difficult, counter-intuitive puzzle, and not doing so doesn’t, then (other things being equal) that speaks in favor of the alternate view. But again, that does not mean I take chimeras to prove that zygotes aren’t people – chimeras just highlight some of the strange, challenging results that such a view leaves you with.

  17. Emil says:

    It is always possible to somewhat defend a view, even substance dualism and similar/related views. That does not imply that that view is plausible in any way. Substance dualism is utterly implausible but not incoherent or impossible AFAIK. Why waste time defending it? Obviously it is a relic from religions. It should share their fate.

  18. Canuovea says:

    So… What is difficult is the fact that if you claim something like A and B both die and a new person C comes along how do you show that? Why that and not B survives (or whatever genes code mostly for the brains etc)? It does present an interesting problem for someone who believes that personhood begins at conception. They cannot really show what happens, nor can they really know. And religion (if that is indeed the basis for said individuals claims about personhood) is not about to explain either because it really can’t spontaneously come up with solutions as quickly as a non-religious argument. It would seem to be a bit odd if the Pope suddenly had a revelation in which God explained how chimeras work. Saying that personhood doesn’t start at conception would allow for an easy out here. That does not mean, of course, that it is correct. Just because we do not understand something completely is no reason to throw the entire thing away. This does not directly contradict the idea of personhood at conception, just brings up some interesting questions. Woo, anyway my input for the moment.

  19. Wm Tanksley says:

    chaospet, I don’t know how to distinguish between any of those three you listed; but you’re jumping the gun. Philosophers can’t even define personhood, much less how to tell the difference between two persons. Our best approach is to say that we experience that most humans are persons, and it’s dangerous to exclude any humans from personhood; we also suspect that it’s possible for personhood to present itself in other guises aside from human, but we don’t have any confirmed instances.

    In a field with that kind of ambiguity, I don’t see how this minor confusion between three out of the five possibilities I mentioned could be problematic. I’m pretty impressed that the remaining two can in principle be distinguished.

    “I don’t see how even in principle we could distinguish between these possibilities”

    In principle, *if* we could distinguish between persons at all, we could build an experiment based on induced chimerism between zygotes selected to display very different personality traits. We could then measure those personality traits to attempt to see which of the theories there had any predictive power. (Of course, your weren’t asking for an experiment to prove that personhood starts at birth, and I’m not proposing one; this experiment only distinguishes how personality traits are affected by chimerism.) If you find this experiment morally abhorrent, we share a common opinion :-). If you don’t, I understand.

    If your objection is that my conditional is false, because we don’t know how to distinguish between persons at all, I agree — but that’s not an objection to identifying when personhood begins.

    “I just don’t know how to make sense of the idea of two distinct, full persons inhabiting the same body.”

    I think you’re jealous that the voices in my head only talk to me. Seriously, though: What do you mean by “distinct, full persons”? I didn’t use those words. Given the awful definition of “person”, why do we need to add “distinct, full” to it?

    I think a major part of my problem with this debate is that you’re blaming all the issues raised by the philosophical concept of “person” on this specific belief. These issues are raised by the concept of personhood, not by the specific time someone believes personhood arises. Dr. Singer gets around this nicely by entirely discarding the concept of “person”, and instead talking about specific capabilities. I (respectfully) think his work is radically undermined as well, but at least he doesn’t base his morality on a completely undefined concept like “person”. The problem for this debate is that if you’re going to accept Singer’s arguments, you’re pretty much going to have to accept his conclusions as well (he reasons VERY well from his premises, try watching him debate), and I don’t see you proposing that.

    “Theories of consciousness aside (after all, on the view that a zygote is truly a person, consciousness must be distinct from the question of personhood),”

    I agree with you that conscious can be untied from thought (which is a function of a developed brain, which a zygote doesn’t have), which makes me agree with your basic premise here. You’ve got a good point, but it’s beside the one I was trying to make. My point was that the personality that would eventually manifest would be based on the fact that the human had two persons. Would that human have two consciousnesses? I don’t know.

    Besides that, personality is — so far as I know — tied to consciousness, but not every person is conscious at all times. We don’t kill sleeping or comatose people on the ground that they’re unconscious. If a “person” (ad argumentum) has never been and by nature will never be conscious, we can’t know anything about its personality — by any attempt to define “person” that I’ve ever seen. You might say that the person emerges (mechanically) after awareness, or you might say (oppositely) that awareness allows the person to make itself manifest.

    -Wm

  20. BG says:

    It seems like chimeras make a case against life beginning at conception the same way that dark matter makes a case against modern cosmology. Dark matter is a phenomenon that’s difficult for scientists to explain. There are a number of theories as to what’s going on, each with its own limitations/problems. Given that there’s no clear and satisfying explanation to the problem of dark matter, scientists should have reason to be somewhat skeptical of modern cosmology, and the physics it’s built upon.

    Is this analogy valid?

  21. chaospet says:

    “I don’t see how this minor confusion between three out of the five possibilities I mentioned could be problematic.”

    I think this is at the core of where I disagree with you; I don’t think it’s a minor confusion, it’s a deep, intractable problem. Certainly we have no agreed upon precise theory of personhood, but we can in most cases tell the difference between persons on the basis of things like personality traits, memories, etc. Zygotes possess none of those traits however. When you slap the label “person” on an entity like a zygote that possesses none of the traits we ordinarily associate with persons, then you open the door for all sorts of new philosophical puzzles (and defining personhood is already puzzling enough, as you rightly point out); the chimera case is one vivid example of that.

  22. Wm Tanksley says:

    Why should we NOT kill zygotes? One possibility is that it’s because, metaphysically, they’re persons. Another possibility is that it’s because, physically, they’re unique human beings, and humans are a sentient and intelligent race.

    If the reason is physical, it’s quite possible that everything about chimerism has a physical explanation. The fact that I’m a substance dualist doesn’t mean that I use it as the premise for every argument; in particular, I don’t use it for this one.

    “Why that and not B survives (or whatever genes code mostly for the brains etc)?”

    The parenthesis here would support the physicalist explanation.

    “And religion (if that is indeed the basis for said individuals claims about personhood) is not about to explain either because it really can’t spontaneously come up with solutions as quickly as a non-religious argument. It would seem to be a bit odd if the Pope suddenly had a revelation in which God explained how chimeras work.”

    I think one of the problems with religion, when understood in that sense, is that it would NOT be odd if the Pope had that revelation. Of course the Church didn’t need to reveal facts about how the soul interacts with chimerism earlier; people didn’t even know about it before, so if the Church _had_ addressed it nobody would have know what they were talking about.

    “Saying that personhood doesn’t start at conception would allow for an easy out here. That does not mean, of course, that it is correct.”

    That’s my problem with the comic. I don’t see how finding hard to solve questions shows anything. Reality is hard to solve.

    OTOH, I shouldn’t complain. I got not one, but THREE jokes in one comic. A comedic trinity, neither confounding the plotlines nor dividing the essence. Three stories, yet one frame. (I could go on, but the allusion would either be completely missed or get very boring.)

    -Wm

  23. chaospet says:

    “I got not one, but THREE jokes in one comic.”

    And if you count the hovertext, then in fact there are four jokes! A quartinity?

  24. Wm Tanksley says:

    “quartinity”

    Heretic.

  25. Michael says:

    Does that mean that when Goethe’s Faust says “Two souls, alas! are dwelling in my breast!” he is referring to tetragametic chimerism ?

  26. EveryZig says:

    About the revelation with the Pope, most versions of God seem to be in the business of not telling people things. (Whether that is so people figure things out themselves or for other reasons is a different conversation entirely.)

  27. Wm Tanksley says:

    “Dark matter is a phenomenon that’s difficult for scientists to explain.”

    On the contrary. Dark matter is an explanation that had no phenomenon to back it up — there were (until just recently) no direct observations that required the hypothesis of dark matter. All physicists knew was that if their theories held any correspondence, there had to be something that interacted directly with gravity but not light. That was called “dark matter”.

    We’ve now observed dark matter by watching galactic collisions — the dark matter doesn’t collide (since it doesn’t interact), so it keeps moving while the majority of the regular matter gets left behind; we can then see the light from behind get distorted by the gravitational forces.

    So now dark matter has both theory and phenomenon to back it up.

    The fetus being a person has neither theory nor phenomenon, so I’m not surprised you and chaospet reject it. It’s a good reason why it’s a bad idea to ground prolife arguments on that; one doesn’t have to bring up the question of chimerism to defeat those arguments.

    So I guess I need to ask… What work does Chimerism do here? It doesn’t raise any objection that isn’t perfectly clear from previously known arguments.

    -Wm

  28. Wm Tanksley says:

    chaospet: “I think this is at the core of where I disagree with you […] When you slap the label “person” on an entity like a zygote…”

    But I don’t. You do. My first post in this thread said, “whether or not you think that the fetuses are persons…” I’m willing to argue this either way, if someone else will provide the definition for “person”; I’ll decide whether I want to use it, but I’ll argue this either way. I’m also willing to argue this dualistically and physicallistically (ouch, it’s not possible to spellcheck a non-word), although I do have to assume objective morality.

    But the weak point that chimeras expose is inherent not in the claim that a person’s a person at conception, but rather in the fact that the concept of person isn’t defined and isn’t definable, and no possible exists to differentiate it, except tests that are based on peripheral things like differences in temperament (which artifacts are demonstrably present in things that are NOT argued to be persons).

    -Wm

  29. Wm Tanksley says:

    “About the revelation with the Pope, most versions of God seem to be in the business of not telling people things.”

    I don’t get why you say that. The Pope exists only because he (allegedly) has a special authority derived from God to tell people things. Most versions of God seem to be ONLY in the business of telling people things; if they got busy with turning water into wine more often instead of only telling people things, I think even Hitchens himself might pay more attention to them. (Not knocking Hitchens, by the way. I’m more of a cocktails guy, but I admit the water-into-wine trick would make my ears perk up too.)

    -Wm

  30. Canuovea says:

    I think the point of the comic was an if/then kind of statement. Chaospet doesn’t say he actually believes that a zygote is a person, he is looking at a hypothetical situation.

    If you accept these premises, then… WTF? You need to think about it…

    Premises:
    A person comes into being at conception
    A single person has a soul
    A chimera begins as two zygotes
    Each zygote is a person and has a soul
    The two zygotes fuse to create one zygote

    Conclusion: Don’t look at me, I don’t know. What happens to the two people (who are people because they were zygotes)? And if each has a soul, are there two souls in one zygote? Or does one soul get left behind? Does one die? If so which one?

    Of course if you don’t accept the premises (pretty much any of them) then there is no problem. Also just because we cannot figure it out doesn’t mean that a zygote isn’t a person, its just going to cause a head scratching session. I think the head scratching session was Chaospet’s point.

    Though I know that I couldn’t argue well from that position, (well maybe I could). I don’t pretend to understand the mechanics of a person being a person at conception.

    As for the Pope, I’m just saying I would find it odd if the Pope suddenly had a revelation to explain this away. Other people would probably take it in stride. I mean, every religious organization has said some things that (at least) appear pretty odd. Like declaring their own infallibility (but I’d rather not get into that, well, I would like to, but I doubt everyone else would be interested, I can go on about anything I know even a little about).

    Ah but what if the comic is in fact a hierarchy and NOT a trinity? It has clearly been ordered from top to bottom, not in a triangle. And it starts with the one that would normally appear in the comic, then the one that is more likely than the other two in real life, then the one that would never happen, but we want to. The hover text is an overarching position that can be anywhere and apply to all of them. It links them together, but is separate from them (because it doesn’t actually apply to any of them, but is instead a random musing)! Furthermore if turned on it’s head it isn’t as funny… or is it?… Okay… that was a little much. Oh well.

  31. chaospet says:

    “But I don’t. You do.”

    I know you don’t. Neither do I. As Canuovea says, the comic is just making a conditional claim: if you say that zygotes are people, then chimeras create substantial puzzles for you.

    Again, though we lack a precise definition of personhood, I think we obviously do have a strong sense of how to differentiate people in ordinary circumstances on the basis of things like psychological traits. And indeed, it is very common in the debate over criteria of personhood to appeal to this intuitive sense of what counts as a person for counterexamples. For instance, when John Locke says that personhood and personal identity is all about memory, we come up with all sorts of counter-intuitive results that challenge the idea. Such examples don’t strictly disprove Locke’s account, but they do provide some reason to question it and search for a more viable alternative.

    My suggestion is only that the revelation that tetragametic chimeras exist, that two zygotes can fuse and develop into a single entity, plays the same sort of role in creating a challenge for those who think personhood requires nothing more than a sperm and egg cell fusing to form a full set of DNA.

  32. Wm Tanksley says:

    “As for the Pope, I’m just saying I would find it odd if the Pope suddenly had a revelation to explain this away. Other people would probably take it in stride. ”

    Oh, okay; I think I can read this as saying that you’d find it a little suspicious (perhaps “a little too convenient”). I misunderstood before — I thought you were saying that you’d never expect them to do something like that. Yeah, I’d take it in stride… There’s only one thing I don’t expect from the modern Catholic Church, and that thing _nobody_ expects anyhow.

    chaospet: okay, I dig that. And I do agree that it’s very important to dig away at the boundaries.

    Huh. This isn’t supposed to happen. I’m not used to agreeing with you.

    -Wm

  33. chaospet says:

    Michael: Makes sense to me!

    Wm: This is a bit creepy…

  34. liosis says:

    Aw, alternate two leaves me with a warm fuzy feeling inside.

  35. […] love philosophy humor, so it tickled my fancy when Chaospet submitted “Table for one.. or two?” A wrench is thrown into the idea that personhood begins at conception; hilarity […]

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