The soul and identical twins?

Started by Daniel, July 02, 2017, 07:10:26 PM

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Daniel

What does St. Thomas or Aristotle have to say about this? Clearly the two twins are distinct individuals (and distinct persons in the case of human twins). But they were conceived as a single individual. So at what point does the twin receive its own soul and become a distinct individual?

OCLittleFlower

Since God knows what is going to happen before it does, perhaps He creates two souls prior to the division of the embryo?  And perhaps that is one reason for the strong bond between twins -- their souls once shared one body.
-- currently writing a Trad romance entitled Flirting with Sedevacantism --

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kayla_veronica

To my knowledge, the Church has not defined the exact moment of ensoulment. We must assume it begins at conception in order to make moral decisions. This is a good point though. I read recently that the split happens within 4-5 days of conception, so there isn't a huge gap there.
May the most holy, most sacred, most adorable,
most incomprehensible and ineffable Name of God
be forever praised, blessed, loved, adored
and glorified in Heaven, on earth,
and under the earth,
by all the creatures of God,
and by the Sacred Heart of Our Lord Jesus Christ,
in the Most Holy Sacrament of the Altar.
Amen.

Quaremerepulisti

The phenomenon of twinning pretty much forces the conclusion that ensoulment does not occur immediately at conception.  St. Thomas and Aristotle won't have anything to say about it specifically because they did not know of its occurrence, although St. Thomas did hold to the opinion that ensoulment occurs 40 days post-conception for males and 80 days post-conception for females.

You can't have two souls "sharing" one body unless you hold to a (heretical) Cartesian idea of the soul-body relation.  It's metaphysically impossible in Thomism, for the soul is the form of the body, and there can't be two forms for the same individuated matter.

Nor is it reasonable to think that, at the moment of twinning, God creates an additional soul which then constitutes the form of one of the separated embryos, because while it is not contrary to His omnipotence to do this, it would falsify Catholic dogma.  This human does not have a mother and father, and is therefore not a descendant of Adam.  He did not arise via natural generation but via another process.


Daniel

#4
If the soul is what contains the life, and if ensoulment doesn't occur until after conception, then how do we explain the fact that the embryo's body is alive from the moment of conception? I take it that since it has no soul, then its body must be a part of its mother's body or something? But, if that be the case, then how do we explain in-vitro fertilization? The mother's soul would need to possess two distinct bodies at once, and the mother herself would then be in two separate, discontinuous locations, which I'm pretty sure is metaphysically impossible. Moreover, if the mother has died before her egg was fertilized, then how could her soul still vivify the embryo, seeing as she is now either in heaven or hell or purgatory? Also seems metaphysically impossible.

Quaremerepulisti

Quote from: Daniel on July 04, 2017, 10:51:03 AM
If the soul is what contains the life, then how do we explain the fact that the embryo's body is alive from the moment of conception?

There is an animal soul, but not a human soul.


Daniel

#6
Quote from: Quaremerepulisti on July 04, 2017, 10:55:27 AM
Quote from: Daniel on July 04, 2017, 10:51:03 AM
If the soul is what contains the life, then how do we explain the fact that the embryo's body is alive from the moment of conception?

There is an animal soul, but not a human soul.
Wait... so each human receives three separate souls (the vegetable, the sensible, and the rational) at different points in his life? I thought that humans each have but a single soul (a human soul), and that the vegetative and sensitive and intellective faculties were merely separate powers in that soul?

edited for clarity

Quaremerepulisti

Quote from: Daniel on July 04, 2017, 10:57:15 AM
I thought that humans each have but a single soul (a human soul), and that the vegetative and sensitive and intellective faculties were merely separate powers in that soul?


This is correct; the embryo is not a human prior to ensoulment.  At the moment of ensoulment, the animal soul ceases to exist.


Daniel

Quote from: Quaremerepulisti on July 04, 2017, 11:06:46 AM
Quote from: Daniel on July 04, 2017, 10:57:15 AM
I thought that humans each have but a single soul (a human soul), and that the vegetative and sensitive and intellective faculties were merely separate powers in that soul?


This is correct; the embryo is not a human prior to ensoulment.  At the moment of ensoulment, the animal soul ceases to exist.
Oh, I see. That seems to makes sense.

JubilateDeo

Quote from: Quaremerepulisti on July 04, 2017, 09:45:53 AM
The phenomenon of twinning pretty much forces the conclusion that ensoulment does not occur immediately at conception.  St. Thomas and Aristotle won't have anything to say about it specifically because they did not know of its occurrence, although St. Thomas did hold to the opinion that ensoulment occurs 40 days post-conception for males and 80 days post-conception for females.

You can't have two souls "sharing" one body unless you hold to a (heretical) Cartesian idea of the soul-body relation.  It's metaphysically impossible in Thomism, for the soul is the form of the body, and there can't be two forms for the same individuated matter.

Nor is it reasonable to think that, at the moment of twinning, God creates an additional soul which then constitutes the form of one of the separated embryos, because while it is not contrary to His omnipotence to do this, it would falsify Catholic dogma.  This human does not have a mother and father, and is therefore not a descendant of Adam.  He did not arise via natural generation but via another process.

What about conjoined twins then?  Wouldn't they be two souls with one body?

OCLittleFlower

Quote from: Quaremerepulisti on July 04, 2017, 09:45:53 AM
The phenomenon of twinning pretty much forces the conclusion that ensoulment does not occur immediately at conception.  St. Thomas and Aristotle won't have anything to say about it specifically because they did not know of its occurrence, although St. Thomas did hold to the opinion that ensoulment occurs 40 days post-conception for males and 80 days post-conception for females.

You can't have two souls "sharing" one body unless you hold to a (heretical) Cartesian idea of the soul-body relation.  It's metaphysically impossible in Thomism, for the soul is the form of the body, and there can't be two forms for the same individuated matter.

Nor is it reasonable to think that, at the moment of twinning, God creates an additional soul which then constitutes the form of one of the separated embryos, because while it is not contrary to His omnipotence to do this, it would falsify Catholic dogma.  This human does not have a mother and father, and is therefore not a descendant of Adam.  He did not arise via natural generation but via another process.

And yet, with conjoined (Siamese) twins, two souls do inhabit the same body.  Some sets of conjoined twins share a single stomach, for example.  So parts of the body are shared, yet they have two souls.
-- currently writing a Trad romance entitled Flirting with Sedevacantism --

???? ?? ?????? ????????? ???, ?? ?????.

Daniel

#11
My guess (could be wrong) is that each conjoined twin does in fact have his own distinct body. Because essentially there's two bodies which happen to share some parts, right? Not one body that has some "unshared parts".
edit - If it were just one body, the first twin's body would be one and the same as the second twin's body. And if they were the same thing, all parts would need to be shared between the bodies of both twins. But that's not the case.

Quaremerepulisti

Quote from: OCLittleFlower on July 04, 2017, 06:09:45 PM
And yet, with conjoined (Siamese) twins, two souls do inhabit the same body.  Some sets of conjoined twins share a single stomach, for example.  So parts of the body are shared, yet they have two souls.

Yes some body parts are shared, but that does not mean two souls "inhabit the same body", which is impossible.  A soul doesn't "inhabit" a body.  A soul is the form of the body (or the form of a human) - the soul is what makes the body a human body.  It isn't possible for the same individuated matter to have two essential forms.  So each of the conjoined twins has his own separate body and those two bodies are conjoined.  But the conjoined bodies is an aggregate and not a substantial form of its own.


Lydia Purpuraria

Quote from: Quaremerepulisti on July 04, 2017, 11:06:46 AM
Quote from: Daniel on July 04, 2017, 10:57:15 AM
I thought that humans each have but a single soul (a human soul), and that the vegetative and sensitive and intellective faculties were merely separate powers in that soul?


This is correct; the embryo is not a human prior to ensoulment.  At the moment of ensoulment, the animal soul ceases to exist.

QMR, can you expand on "the embryo is not a human prior to ensoulment," please?  It seems like this could be a problematic statement (if true) for Catholics in opposing embryonic stem cell research, which, I believe, uses embryos/blastocysts only up to 4-5 days old.  But maybe I'm just misunderstanding what you're saying here?

Also, what do you mean by the conjoined bodies being an aggregate in the above post? 

Lydia Purpuraria

Quote from: kayla_veronica on July 03, 2017, 07:03:05 AM
To my knowledge, the Church has not defined the exact moment of ensoulment. We must assume it begins at conception in order to make moral decisions. This is a good point though. I read recently that the split happens within 4-5 days of conception, so there isn't a huge gap there.

I've read that the split can even occur up to 13 days, although perhaps 4-5 days is the most common time frame (?).