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1/14/2018 7:24 pm  #1


Craniopagus Twins and Thomistic Dualism. Interesting stuff

Have any of you seen this?

https://evolutionnews.org/2017/12/the-craniopagus-twins-and-thomistic-dualism/

To sum it up, these two twins are connected through their brains. Their brains share a thalamus which allows for one brain to influence the other. Interestingly, they can both see what the other sees (although one of the twins specifically cannot see what the other one's right eye sees). They even are able to share mental images and say they "talk in their heads". They are highly interconnected, and yet they are clearly two different persons, and even have different personalities. Some have argued that this distinction in "selves" among two persons who so closely share so many bodily organs would be an evidence against materialism.

However, Vincent Torley thinks it is problematic for a thomistic dualist that the twins can share thoughts or "talk" in their minds. Egnor responds (and I agree with him) that the twins don't actually share immaterial thoughts themselves, just the mental images (phantasmata, be it images, sounds, smells, whatever) which, as one could expect, affects them both pretty much the same (and such phantasmata would be material in thomistic dualism). Torley then proposes a tentative experiment to see if the twins can share abstract, immaterial thought or not; if they did, it would suggest that thomistic dualism is false, if they could share mental images but not the concepts or thought-propositions themselves, then this would count in thomistic dualism's favor and suggest that it's true. Egnor thinks the proposed experiment woukd be faulty, but suggests another one: if it could be shown that the girls differ in speed and efficacy when solving mathematical problems, for example, this would suggest that the concepts really are immaterial in character.

Obviously more thought should be given into the methodology and the questions involved (not to mention the fact that first and foremost they are kids, persons, and shoukd first and foremost be able to lead good lives and the whole thing has to be ethical), but their case is still a terribly interesting one, and might be indicative of possible thought experiments and even empirical experiments for metaphysical positions and the relation between mind and body.

 

1/16/2018 8:48 pm  #2


Re: Craniopagus Twins and Thomistic Dualism. Interesting stuff

In my understanding of the relationship between soul activity and brain activity, the case is not problematic for thomistic dualism.

I start from two notions:

a. Soul activity is supported by brain activity. The soul is bound or coupled to the brain.

b. The mapping of soul activity to brain activity is unique for each brain. Each soul-brain binding or coupling develops its own "Neural Activity-Thought Mapping Language" or NATML.

Thus, a particular mental image or abstract thought is mapped to a neural activity pattern in John's brain which is different from the pattern which maps that thought in Peter's brain. The patterns may differ in one or more of the following features:
- the number of neurons involved,
- the spatial (3-D) arrangement of the neurons,
- the path travelled by the electro-chemical signal between the neurons.

In the case of these twins, since their brains are highly connected, forming a system which could be called a hyperbrain, their souls have developed either identical or at least mutually intelligible hardware mapping languages, so that the neural activity pattern that maps any thought, concrete or abstract, is either the same for both souls or is mutually intelligible, with the result in either case that their souls can communicate via the hardware layer.

The case of mutually intelligible NATML's can result from each soul having exclusive "write" right in its own hyperbrain volume and both souls having "read" right in the whole volume. Thus, when twin A sees a dog, she generates or "writes" a specific neural activity pattern in her own volume. Since twin B can "read" that neural activity pattern, she learns that it means "dog" for twin A, because twin B is also seeing the dog. Later on, when twin A just thinks of a dog, she generates the corresponding neural activity pattern, which twin B can "read" and decode correctly.

The case of identical NATML's can result from both souls being able to "write" to the same hyperbrain volume.

In summary, when one soul thinks any thought, concrete or abstract, it "writes" a neural activity pattern which the other sould can "read" - because both souls are bound or coupled to the same hyperbrain - and understand correctly - because both bindings use either identical or at least mutually intelligible NATML's.
 

Last edited by Johannes (1/17/2018 8:31 pm)

 

1/21/2018 4:58 pm  #3


Re: Craniopagus Twins and Thomistic Dualism. Interesting stuff

@Johannes,

In summary, when one soul thinks any thought, concrete or abstract, it "writes" a neural activity pattern which the other sould can "read" - because both souls are bound or coupled to the same hyperbrain - and understand correctly - because both bindings use either identical or at least mutually intelligible NATML's.


Are you saying that, EVEN IF the twins had equal mathematical speed and efficiency, that still would not be problematic for Thomistic dualism?



 

 

1/22/2018 2:28 pm  #4


Re: Craniopagus Twins and Thomistic Dualism. Interesting stuff

As for apparently making empirical tests to prove or disprove the metaphysical (and thus supra-scientific) view of Thomistic dualism / hylomorphism, I think there's an obvious method here.


If the twins really did share an intellect, then they would be unable to individually and freely contemplate a form without the other twin also contemplating it at the same time. One of them could look at a triangle and be asked what all triangles have in common and thus contemplate the universal form of triangularity, while the other could look at a square and contemplate what all squares have in common and thus receive the universal form of squareness, and if they didn't have two seperate intellects, they wouldn't be able to do that and would either be forced to receive the form of another geometrical object as well or be forced to contemplate the form of the first twin who starts the contemplation without being free to contemplate a different one.


Of course, there is the fact that they share all material thoughts and images and can even see through each other's eyes, but this doesn't seem to present much of a problem because everyone else has the capacity to look at a picture of both a triangle and square and decide to contemplate only the form of the triangle rather than the square, and even keep the square in one's imagination without abstracting from it by force of will.


But as far as we can see, the twins don't seem to have any problems when it comes to thinking about forms individually and on their own accord, so right of the bat such a simple insight could be used to defuse this craniopagus example as an apparent problem for hylomorphists.

And also, if they did share intellect, then we could likely expect problems with the use of language since one of the twins would be focusing on one proposition or thought with the exclusion of all other propositions that would need a seperate intellect to be used, which would mean the other twin would either think the same proposition without thinking any other or would be forced to abandon a contemplation in favour of another.


And that's without even including any of the more extraordinary explanations that could be used by the Thomist if the twins did have equal mathematical prowess or such apparently problematic things, such as telepathy, or something similar to how angelic intellects can instantly share thoughts with one another. 

 

Last edited by aftermathemat (1/22/2018 2:31 pm)

 

1/25/2018 2:19 pm  #5


Re: Craniopagus Twins and Thomistic Dualism. Interesting stuff

aftermathemat wrote:

@Johannes,

In summary, when one soul thinks any thought, concrete or abstract, it "writes" a neural activity pattern which the other sould can "read" - because both souls are bound or coupled to the same hyperbrain - and understand correctly - because both bindings use either identical or at least mutually intelligible NATML's.

Are you saying that, EVEN IF the twins had equal mathematical speed and efficiency, that still would not be problematic for Thomistic dualism?

Yes.

 

 

1/25/2018 4:05 pm  #6


Re: Craniopagus Twins and Thomistic Dualism. Interesting stuff

Johannes wrote:

Yes.

What about the experiment I described above, where the twins, if they share one intellect, would be unable to independently grasp particular forms and would instead either be forced to grasp a form they don't want to along with the form they already decide to grasp, or would even be completely overriden and be forced to grasp the form the other twin is grasping without freedom for an independent act of intellection?


If such a thing were recorded, would this affect hylomorphism? Or is such an idea prima facie implausible with the evidence we already have of the twins living a normal life, because if someone had a non-free intellect that was dependent upon their fellow twin on occasion, then this would entail all sorts of extreme difficulties with thought and speaking that are simply not present?

 

1/26/2018 3:55 pm  #7


Re: Craniopagus Twins and Thomistic Dualism. Interesting stuff

aftermathemat wrote:

What about the experiment I described above, where the twins, if they share one intellect, would be unable to independently grasp particular forms and would instead either be forced to grasp a form they don't want to along with the form they already decide to grasp, or would even be completely overriden and be forced to grasp the form the other twin is grasping without freedom for an independent act of intellection?


If such a thing were recorded, would this affect hylomorphism? Or is such an idea prima facie implausible with the evidence we already have of the twins living a normal life, because if someone had a non-free intellect that was dependent upon their fellow twin on occasion, then this would entail all sorts of extreme difficulties with thought and speaking that are simply not present?

It is clear that each twin has her own mind and intellect. The issue under discussion is not whether the twins have one or two intellects, but rather whether their respective intellects:

- are purely the result of the activity of their respective brains, which are both distinct and highly interconnected (the materialist position), or

- are a faculty of their respective spiritual souls, whose activity is supported by the activity of their respective brains but not identical to it (the dualist position).
 

 

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