pronoiasecret

, PhD Life Sciences & Developmental Biology, University of Dundee (2011)

They probably have explored that possibility. But perhaps that event of an absorbed twin brain has not happened yet or it is impossible of happening without serious complications. Most human chimeras have different blood DNA from their organ/tissue DNA; blood is very easy to acquire from a twin during fetal development since blood is exchanged between their bodies and the placenta and back again. This is why doctors check the Rhesus (Rh) factor of women during their second pregnancy, because the proteins from a Rh positive first child could mix with the Rh negative blood of the mother, which leads to her body developing antibodies against Rh and potentially attacking a second fetus with Rh positive blood.

Some chimera humans have partial or complete organs from a twin, often times two complete sets of genitals or part of a stomach/kidney. Sometimes it could be an entire liver or pancreas. This seems to be not overly difficult to develop, because a lot of these organs are not covered by the fetal ribcage and flesh can be transferred during fetal development.

Then there's the brain like you mentioned. The problem with the brain is that it's the most complex (and important) organ in the body and it's encased inside the skull. The skull is very prominent/developed even during the late embryonic/early fetal stages. In fact the brain and skull are one of the first things to form during fetal development. It would be extremely difficult, if not impossible, for brain matter to be transferred to the other twin. Absorbing a brain would mean absorbing a skull as well…which would be very problematic and dangerous. Other organs especially those below the ribs can be absorbed into a twin because there's no bone/cartilage structures in the way for transfer. Worst case the twin will absorb and extra rib or two in the process which isn't too much of a problem.

These are conjoined twins at the head, when the embryo failed to separate completely during fetal development.

Can you imagine what would happen if one twin was trying to ABSORB the head of the other? Catastrophic results I would imagine. Even if a brain was successfully absorbed, how would a large merged brain or two independent brains function properly inside the body? The brain controls everything in the body, unlike the other organs. You'd have too many conflicting or compromised parts trying to grow and function which would very likely result in the death of the fetus. Maybe a birth like this actually happened at some point in history, but it was 99% likely to be a stillbirth, or it died within days of being born.

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Consider these two cases:

Known Chimera, Taylor Muhl, in several video interviews claims that at the very young age of 5, she began asking her mother if she had a twin. At the time her mother reassured her that she did not have a twin, and questioned why her daughter was so persistent in believing she had. Taylor responded by saying that she just had a very strong “feeling” that this was the case. Many years later a DNA investigation of Taylor’s unusual birthmark, revealed a different set of DNA than other parts of her body, indicating that she is a chimera. So the question remains, how did Taylor come by the strong “feeling” that in the end proved to be true?
CBC News article on Krista and Tatianna Hogan who are craniopagus twins reveals astounding insights. — BC’s Hogan twins share a brain and see out of each other’s eyes: Joined at the head, their brains are connected by a thalamic bridge, providing them with neurological capabilities that make them unique in the world. The thalamus acts like a switchboard relaying sensory and motor signals and regulating consciousness. Krista and Tatiana Hogan share the senses of touch and taste and even control one another’s limbs. Tatiana can see out of both of Krista’s eyes, while Krista can only see out of one of Tatiana’s. The twins say they know one another’s thoughts without having to speak. “Talking in our heads” is how they describe it. They are proof, that two distinct brains can share information via their joined thalamus . It also stands to reason that an absorbed twin brain could influence the thoughts and actions of their host twin, and with that being the case, this ability could be used to communicate.

Krista and Tatiana share a brain and yet are normal achieving children. They influence each other’s thoughts, “talking in our heads” as they call it, so it could very well be that Taylor Muhl’s absorbed twin in “talking in our heads” fashion, conveyed to Taylor that she has a twin. Since it has been documented that complete “functioning” organs of an absorbed twin are found within their Chimera host twin, then why not too, the brain. And so it seems only logical that “twin brains” should be investigated via DNA study, brain scans, and listening to a mode of communication — influences of the absorbed twin over the thoughts of the host twin (as with the case of Taylor Muhl).

Jared Evans

You have a point with the last case. But that case involves twins attached at the head, two separate bodies and mostly two separate heads with less space than usual. We don't know what would happen if a full brain was absorbed into the other twin, with that twin owning the entirety of that brain in its head. The brain merge would be much more significant with not much space inside a normal-ish sized head.

How would this mixed brain operate inside a single body? The baby could be born with severe macrocephaly and the operation of two brains in one nervous system could pose many (perhaps fatal) problems especially if several brain parts are jumbled together or in places where they aren't supposed to be. Your case with the twins involve two brains connected at a single point, each with their own separate nervous systems and bodies for function. I honestly don't know what would happen in the case of two brains in one body

There is enough evidence to suggest the possibility of twin brains merged together (perhaps this explains the evolution of our globular brain… and the subconscious mind), and that can be speculated on… or it can be explored scientifically ie: DNA studies of the human brain. It is a very touchy subject, after all how many want to consider this possibility?! But isn’t that what research is all about… isn’t that why we progress as individuals and as a society— by coming face to face with the unthinkable, as did Bruno, Galileo, Darwin…

Jared, consider a chimera made up of twin brains whereby what appears to be a single skull is in fact half of each twin skull fused together so symmetrical that the chimerism is not visible to the naked eye. The closest we have of two brains in one skull, are Faith and Hope Howie who shared one body and skull, but had two brains joined to one brain stem. The children were born six weeks prematurely and appeared to be doing well, able to breathe unaided several days after their birth, and they were observed to sleep and cry at different times. They died nineteen days following their birth due to unknown causes, although some sources indicated that the girls died following an operation for unknown reasons. Even though they had a single skull they had two faces, and so a further investigation revealed two brains. Is this not enough then, coupled with research on Chimera Humans to consider that over a great period of time Chimerism resulted in “twin joined brains”, and that this could have played a part in the evolution to our globular head shape (evolving from Homo Heidelbergensis to Homo Sapiens over a period of 300,000 years). This is a theory worthwhile investigating via DNA.

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Nick James

Answered July 24

Why is it that people who don’t know any science always want to blame geneticists? You need an evolutionary biologist at the very least. And probably a physiologist.

I think you will find that all the examples of absorption that you refer to are for identical twins. This means that no genetic issues are involved and no tissue rejection comes into play.

Absorbed organs hook into the blood supply and grow. Regarding brains. They are very complicated organs that need a specialised large blood supply and a surrounding environment to protect the brain from all the junk in the blood supply. They are also surrounded by specialist fluid and a hard casing which supports it. It is very unlikely that you can randomly provide such a thing in a random body location.

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Consider these two cases:

Known Chimera, Taylor Muhl, in several video interviews claims that at the very young age of 5, she began asking her mother if she had a twin. At the time her mother reassured her that she did not have a twin, and questioned why her daughter was so persistent in believing she had. Taylor responded by saying that she just had a very strong “feeling” that this was the case. Many years later a DNA investigation of Taylor’s unusual birthmark, revealed a different set of DNA than other parts of her body, indicating that she is a chimera. So the question remains, how did Taylor come by the strong “feeling” that in the end proved to be true?
CBC News article on Krista and Tatianna Hogan who are craniopagus twins reveals astounding insights. — BC’s Hogan twins share a brain and see out of each other’s eyes: Joined at the head, their brains are connected by a thalamic bridge, providing them with neurological capabilities that make them unique in the world. The thalamus acts like a switchboard relaying sensory and motor signals and regulating consciousness. Krista and Tatiana Hogan share the senses of touch and taste and even control one another’s limbs. Tatiana can see out of both of Krista’s eyes, while Krista can only see out of one of Tatiana’s. The twins say they know one another’s thoughts without having to speak. “Talking in our heads” is how they describe it. They are proof, that two distinct brains can share information via their joined thalamus . It also stands to reason that an absorbed twin brain could influence the thoughts and actions of their host twin, and with that being the case, this ability could be used to communicate.

, PhD Life Sciences & Developmental Biology, University of Dundee (2011)

Answered July 24

I’m not quite sure what you mean by “explored the possibility”.

There are two things you might mean here: chimerism, where you get an anatomically normal person formed from two separate fertilisation events; and unequal conjoined twins, where the less developed twin is absorbed.

In the first case (chimeras) scientists have a reasonably good handle on the process. Indeed, we make chimeric animals in the lab (usually not specifically to study them, but as a step in the process of producing monozygotic transgenic lines). The study of human chimeras in the wild is fairly new, simply because it’s only recently we’ve been able to identify chimeras using genetic testing, since they’re generally pretty rare and are not particularly obvious when they do happen.

As for unequal conjoined twins; well, they’re basically a type of birth defect. We study them when they happen - in fact, given they tend to be much more obvious than chimeras, they’ve been studied and recorded as medical curiosities throughout recorded history - but it’s not generally something we like to deliberately cause.

I sense from your question that you might be driving at the idea that a conjoined twin with extra brain tissue might result in an individual with some kind of super-normal abilities, such as superintelligence or enchanced memory. This just doesn’t happen for one crucial reason: patterning. The brain isn’t just a formless blob, where more bigger is more better: it’s an exquisitely complicated structure that needs to be put together in a very precise arrangement. While it is true, there are probably a few very specific cases where “more of the same” would probably produce a person with some form of superintelligence - the prefrontal cortex, for example, is surprisingly modular, generic and functionally flexible - even then, it would be crucially important to preserve the architecture of connectivity. Fusing brain material via a conjoined twin is the complete opposite of that; the developmental processes that give the brain the patterning that’s so crucial to it’s function would inevitably be so massively disrupted; important parts of the brain would end up completely missing while other parts were needlessly duplicated.

Incidentally, when we see live-born, conjoined twins with craniopagus - that is, a single cranial cavity with two distinct bodies - almost always, there are two complete, distinct and separate brains inside the single cranial cavity; the nervous systems are not “wired together” in any way (although they are frequently “plumbed together” via the blood and CSF supply). While separating twins conjoined in this way is a difficult and intricate surgical challenge, as long as the brains aren’t damaged by the surgery, most of the time the twins are neurologically normal. It’s entirely possible this is survivorship bias, though - as noted above, I would strongly expect any direct fusion of brain tissue in a conjoined twin to be disastrous, and lethal to the embryo.

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Consider these two cases:

Known Chimera, Taylor Muhl, in several video interviews claims that at the very young age of 5, she began asking her mother if she had a twin. At the time her mother reassured her that she did not have a twin, and questioned why her daughter was so persistent in believing she had. Taylor responded by saying that she just had a very strong “feeling” that this was the case. Many years later a DNA investigation of Taylor’s unusual birthmark, revealed a different set of DNA than other parts of her body, indicating that she is a chimera. So the question remains, how did Taylor come by the strong “feeling” that in the end proved to be true?
CBC News article on Krista and Tatianna Hogan who are craniopagus twins reveals astounding insights. — BC’s Hogan twins share a brain and see out of each other’s eyes: Joined at the head, their brains are connected by a thalamic bridge, providing them with neurological capabilities that make them unique in the world. The thalamus acts like a switchboard relaying sensory and motor signals and regulating consciousness. Krista and Tatiana Hogan share the senses of touch and taste and even control one another’s limbs. Tatiana can see out of both of Krista’s eyes, while Krista can only see out of one of Tatiana’s. The twins say they know one another’s thoughts without having to speak. “Talking in our heads” is how they describe it. They are proof, that two distinct brains can share information via their joined thalamus . It also stands to reason that an absorbed twin brain could influence the thoughts and actions of their host twin, and with that being the case, this ability could be used to communicate.

So, the Taylor Muhl case is not compelling in any way shape or form. My basic objection here is that having the quirky idea that you have an invisible sibling is an extremely common belief that many young children have at some point. However, in most cases it goes away, and if they don’t have some reason to remember it, neither they nor their parents ever think about it again. But if something happens later that retrospectively makes that quirky anecdote have significance, it starts to be remembered differently. Memories are fickle; they are not an objective record of what happens, but get rewritten every time they are recorded, and it’s very easy for “my child said a weird thing once” to become “my child had a very strong and persistent unusual belief” - and worst of all, this usually happens without that person ever knowing that there has been a change.

The question you need to ask is this: if you assume that there is no connection between the sensation that you had a lost twin, and being a genetic chimera, should it be a surprise that some genetic chimeras also happened to be children who thought they had a lost twin? The answer is clearly no; in reality people having experiences like Taylor Muhl is exactly what you would expect to see if there were no correlation, so this just can’t be compelling evidence that something spooky is going on.

The human mind is wired to look for patterns and connections, and is extremely prone to seeing patterns that aren’t there. This is a super common phenomenon in the study of parapsychology, where people can genuinely become convinced they have psychic or telepathic abilities. In many cases they are not lying - the experiences of spooky coincidences they’ve had are perfectly real - but biases in which parts of their experiences they pay attention to and which parts they ignore causes them to build a false narrative about what their experiences mean.

This isn’t a cast iron argument to say that it’s impossible for chimerism to register at a psychological level, but based on what we know about the brain it is an extraordinary claim: this is the “huge if true, but almost certainly not true” problem. As a scientist, when you’re dealing with extraordinary claims, you need to be really careful about balancing impact with probability; the impact of an extraordinary claim being true might be huge, but when it has such a low probability of being true it might just not be a compelling thing to want to investigate. I don’t think it would be wrong to investigate this kind of connection, but the process would have to be about gradually building up a body of evidence, being extremely fastidious about rooting out biases; you really wouldn’t want to be diverting funding and research effort on researching, say, the autoimmune implications of twin chimerism.

If you’re feeling disappointed that such a huge-if-true potential fact about human brains is being neglected because nobody thinks it’s likely enough to investigate, I’d encourage you to consider that if this is a true fact about how the brain works - that incorporating genetically distinct tissue into the brain has the potential to create an “other self” that we can recognise and identify at a conscious level - then there will be other pathways to discovering that truth. Developing an accurate understanding of how the brain works, including discovering unexpected truths, is a project that many researchers are honestly and enthusiastically committed to. If you think that scientists are primarily concerned with protecting the status quo from disruptive new ideas, I can only say you’ve never been to a scientific conference. But it’s not enough to just be disruptive and new; you also need to be right.

Drawing a line under Taylor Muhl and moving on to the Hogan twins: I stand by everything I said in my original answer. Their case is exceptional to the point of being astonishing, but it is 100% consistent with everything I’ve already said. To reiterate: The brain is not an amorphous blob - the ability for it to function at all, and allow communication between different regions exquisitely depends on the correct patterning of the brain.

The extreme majority of cranipagus twins - and there have been a whole lot of them throughout history - are not like the Hogan twins. These two have an exceptionally rare circumstance where their thalami have fused in such a highly specific way that, during development when normal brains are wiring up through a single thalamus, their brains wired up in a way that linked their two brains together.

It’s also worth flagging up that this fusion can only happen early in development. Once a thalamus has made it’s connections, it simply cannot suddenly decide to rewire itself to incorporate an entire second brain, just because one happens to be nearby. If the brain could do this kind of rewiring on cue, we would be a lot better equipped to heal things like paralysis from spinal injuries. But I digress.

The special connection the twins share entirely depends on that fusion at the thalamus. Without that fusion, they would not be able to share experiences in the way that they do; they would be like all the other craniopagus twins who don’t have this remarkable ability.

It also needs to be exactly that specific fusion to have that effect. I stand by what I said before - if that fusion had occured anywhere else in the brain - say, the occipital lobe, or the hypothalamus - the result would have been a catastrophic mis-patterning of the brain, resulting either in a miscarriage or stillbirth, or profound neurological impairment (as in, anencephaly levels of neurological impairment).

And I have to point out here - those two options (stillbirth or neurological impairment) are by far the most common outcomes for craniopagus twins. When you look at beautiful, happy, functional conjoined twins like the Hogans, you have to remember that there is an enormous survivorship bias at play. For every case of happy, thriving twins, there are literally thousands who died without taking their first breaths. And even considering the ones who get through that filter, the majority of them have zero fusions of their CNS above the spinal cord, which completely disallows the kind of “in my mind” connection talked about here. I described the Hogan twins as astonishing - but they’re not astonishing in a way that challenges our understanding of brain development at all, they’re astonishing because of just how rare this kind of fusion even is. But the law of large numbers applies here: when you consider enough people, even incredibly rare things happen from time to time.

Yes, Craniopagus twins are rare, and the same was believed of chimerism in humans, however as geneticists learn more about this new field of research, many are changing their views on this. By pointing out the Hogan twins, my intention was to provide proof that #1: two brains can be neurologically wired together; #2: that individuals whose brains are wired in this way can achieve normally in mental skills; #3 that these individuals can know what the other is thinking, operate each others limbs and even share senses.

That Taylor Muhl at a young age had the thought of having a twin and then verbalized this to her mother is meaningful, especially given her later finding of being a chimera. This could be similar to the ability of the Hogan twins ability to communicate to one another by thought —“talking in our heads” as they refer to it. In other words: Taylor’s twin has relayed the thought of being a twin to Taylor via their joined neurological network). You mentioned the tendency for young children to believe they have a twin and so suggesting that this nullifies Taylor having the thought herself, however my thoughts are to the contrary— this suggests a prevalence of “twin brains” wired together so that the absorbed twin can relay thoughts to their host twin.

Oh dear. I hate to say this, but you simply have not read my reply properly. I guess I should leave it at that, but I’ve got some time on my hands, so let me talk you through where you’re going wrong.

“Yes, Craniopagus twins are rare”

No, no, no, that is pointedly not what I said. I actually sort of implied that craniopagus itself is fairly common, as birth defects go, but that’s a matter of perspective. What I said was, that among the many, many craniopagus twins we have studied, the abilities the Hogan twins demonstrate appears to be extremely rare, if not unique. If your contention is that all craniopagus twins might have the ability to share thoughts, you are categorically wrong. This is not a case of “maybe, we don’t know” - it’s a case of “we have thoroughly checked, it isn’t true”. To repeat: it is not craniopagus that I said was rare, it is specifically the Hogan twins.

“as geneticists learn more about this new field of research, many are changing their views on this”

Okay, hold up. The original question was “why haven’t geneticists explored this”. Now you’re lecturing me about what geneticists views are? Why did you ask the original question if you already had such a keen insight into what geneticists think? This whole discussion is starting to sound pretty disingenuous.

“By pointing out the Hogan twins, my intention was to provide proof that #1: two brains can be neurologically wired together; #2: that individuals whose brains are wired in this way can achieve normally in mental skills; #3 that these individuals can know what the other is thinking, operate each others limbs and even share senses.”

Nowhere in any of my responses did I dispute any of this - although I did say in my original post that this almost never happens, which is precisely true: almost never. My point is that this situation depends on an incredibly specific situation (the fusion in the thalamus) that is demonstrably not present in the extreme majority of craniopagus cases. At the risk of beating this point to death: we can do neurological tests on craniopagus twins to demonstrate that, on the whole, they do not show the remarkable abilities that the Hogan twins do. Case closed: you cannot generalise from the Hogan’s case even to other craniopagus twins, let alone to much more distantly related situations like twin chimerism.

“You mentioned the tendency for young children to believe they have a twin and so suggesting that this nullifies Taylor having the thought herself”

Again, that is not what I said. I was very careful to say that I completely believe that people in Taylor’s situation usually had an experience like this as a child. The part I dispute is that it constitutes any kind of compelling evidence Taylor was receiving messages from her chimeric twin. I even went out of my way to acknowledge that it’s not formally impossible - just profoundly, incredibly implausible, especially placed next to the possibility that this is just a coincidence. You are hanging quite a lot of really far-out speculation on one extremely flimsy piece of evidence.

“In other words: Taylor’s twin has relayed the thought of being a twin to Taylor via their joined neurological network”

What do you think the words “joined neurological network” actually means? Because, to me, a joined neurological network is a physical thing that you can fairly easily interact with and verify. The Hogan twins clearly and demonstrably have one, you can do some straightforward tests to confirm it. Virtually every other craniopagus twin ever studied demonstrably do not have one - they may have two distinct neurological networks, but they are demonstrably not joined. Taylor Muhl, as far as I can make out, only has one neurological network so there’s frankly nothing for it to be joined to. Again, if it were, this would be a super easy way to show that there was something interesting going on here - get Taylor Muhl into a MRI machine, and point to the anatomical structure that represents her supposed twin’s neurological network. That would be an instant Nature publication, I’m pretty sure.

Instead, you seem to be imagining - by invoking some vague concept of DNA and genetics - that simply by being a twin chimera, that she somehow has a whole second brain - which must be at least sophisticated enough to have enough conscious experience to communicate with Taylor like a ghost talking in her ear - and yet be otherwise completely undetectable.

Again, even granting the deeply sketchy premise that Taylor was getting messages from her incorporeal twin as a child, this simply cannot be the same mechanism by which the Hogan twins communicate. We know how the Hogan twins communicate - through their fused thalamus. That’s a tangible structure that you can see on a brain scan, and Taylor Muhl - as far as I know - does not have one. And bear in mind, Muhl’s story is that she went through years of testing to diagnose the autoimmune condition caused by her twin chimerism - if there was something weird about her “neurological network”, it’s pretty likely it would have shown up there.

I’m probably wasting my breath here - you’ve not really shown that you’re interested in actually reading my responses to understand them, just beating flimsy straw-man caricatures. I’m probably going to draw a line under the discussion here.

David, a brain scan would not necessarily show evidence of an absorbed twin brain, and that‘s why I focussed on DNA investigation as a means of determining Chimerism involving the brain(s). Consider this: even though a good portion of Taylor Muhl’s torso belongs to her absorbed twin, it was so perfectly symmetrical with her body that for years her chimerism was passed off as a large birthmark, and this belief would have continued except for DNA testing that revealed the truth. And so yes … of course, that’s also why the DNA research (if/when done) would rely mainly on people who donate their brain to science upon death.

If I’m going to answer this, you have to promise not to move the goalposts on me again, right? We’ve stopped talking about the completely unrelated case of the Hogan twins, and linked neurological networks?

So, the entire point of a genetic chimera is that despite being from two genetic origins, her body has developed as a single, unified whole (aside from the autoimmunity issue). She has the correct set of organs, and they all function together as if they belonged to the same, unified body.

I really don’t see any reason to think the brain should be any different. Your psychogical identity is not encoded at the level of individual cells, it’s produced by the network as a whole acting together, and as we’ve established, Muhl only has one network. The fact that bits of it are genetically distinct from other bits of it should not matter. Or at least, if it does matter, there’s no reason at all to expect it to produce any kind of duality of experience. That might be confusing, let me give a specific example.

Imagine, perhaps, that because of some genetic difference, one twin would have had a better memory than the other twin. This would be because there are structures in the brain associated with memory, and genes activated by the cells that make up those structures influence performance on memory tests. A chimera formed by the merging of these twins might have the first twins aptitude (good memory), or the other twins aptitude (bad memory), based on whether the memory structure was from twin A or twin B. Or perhaps the structure was composed of a mix of cells, resulting some blending of the two (an average between good and bad memory). It’s even conceivable that, because the two genetic systems are incompatible in some way, the chimera would have much worse memory than either twin on it’s own, or perhaps some synergy effect producing much better memory than either twin alone. But I think the one thing you definitely would not expect the chimera to have is the experience of both twins at the same time. It’s not even clear to me what that would mean - surely you would expect the chimera to be one thing - a chimera.

But, while I think the idea is really extremely improbable and runs counter to everything we know about developmental neurobiology, again, it is not formally impossible - the brain is complicated, stranger things have turned out to be true. But here’s the thing: even if I grant you that it’s hypothetically possible that a chimera might manifest as two separate psychological entities, Taylor Muhl’s story does not make sense as a consequence of this hypothesis.

So, Taylor’s story is that: “From six or seven-years-old, I would ask my mother all the time if I was a twin. ‘Are you sure you didn’t have another baby?’ I would ask her.”

If the idea is that there is a second identity living inside Taylor’s head, I’m very confused about how either of them came to the conclusion that there ever was a second twin or another baby. That does not seem like a natural conclusion to draw at all, especially not for a six or seven year old. How does the twin inside know that it is a twin? Or how would Taylor know that the other person inside her was a twin? Why would it not just think it was… another Taylor? Or just another part of the same Taylor? If the two parts of her brain were separate enough to be distinguishable entities, it would be much more natural to expect that Taylor would be developing with some kind of multiple personality syndrome; it’s really not what you’d expect that she would develop the idea that there was another twin that was external to her mind. It’s just not how you would expect that to manifest.

On the other hand, as I said, lots of perfectly normal kids about that age do come up with the idea that they might have had siblings or twins who for some reason aren’t around. Like I said, if one in three of all kids ask this kind of question, it follows that one in three chimeras will ask it too, without it meaning anything more for them than it did for the non-chimeric kids.

You ask, “How does the twin inside know that it’s a twin?”. My answer: If the twin inside (absorbed twin brain) had limited ability ie: could think but could not operate limbs then it wouldn’t be hard for that twin to recognize that someone other (a host twin) is in control. And if the absorbed twin brain is connected to the host twin brain via the thalamus, it’s then possible for the absorbed twin in a fashion similar to the Hogan twins ability of communicating to one another by “talking in our head”, however in the case of Chimera brains that are symmetrically joined, the host twin would misinterpret a thought from her/his absorbed twin as their own thought (why would it be suspected otherwise?). This could explain the mystery behind what we refer to as the workings of the “subconscious mind” … and the “collective unconscious”. It could be that this Quora interaction was influenced by our absorbed twin brain. Food for thought(s)?!

Okay, you are definitely moving the goalposts back and forth here. Either the absorbed twin brain is a distinct neuroanatomical entity - in which case it should be visible on a brain scan, which you admit does not apply to Taylors case. Or the cells from the absorbed twin have combined produced one, single brain - in which case there is no separate, absorbed twin brain to have these thoughts. There is only one brain.

When I pin you down on the “absorbed brain” issue you say “no no, I’m talking about genetics”, but when I try to pin you down on the implications of the genetics issue you come back saying “no, but there’s an entire separate brain in there which might be having it’s own thoughts”. These ideas are mutually exclusive; you can’t have it both ways.

It’s really clear that you’re not at all interested in finding out what the truth about the unconscious mind is, you’re only interested in having your own personal fairy story validated. You can’t just throw out all of the stuff my colleagues and I have actually found out about how the brain works, knowledge bought through long years of rigorous experiments and observation, just because you read a magazine article once. If there’s some new, undescribed phenomenon here, that’s great, but it has to be consistent with all the other evidence we’ve already gathered, or at least clearly show why previous explanations were wrong. You can’t just turn a new page, saying “maybe the mind is like this!” and pretend that all of our existing understanding never happened.

If you are thinking this is supposed to be food for thought, I’m sorry to tell you that what you are serving up appears to be exclusively cheeto dust and chocolate sprinkles. It might taste nice for a moment, but it ain’t a healthy or nutritious thing to chew on for too long.