Remember11 [spoilers] - Siblingering Consciousness

The question is on why some consciousnesses (like Kokoro and Satoru) do not teleport alongside their bodies, which is why they experience what seems to be a personality transfer.

My theory: A consciousness inside the teleporting circle remains in its time and place (does not teleport) if and only if there exists one of its sibling consciousnesses within the same circle at the same time, i.e., there are two (or more) consciousnesses that are siblings to each other. The consciousness of the older sibling would seek the body of an older sibling, and similarly for the younger sibling.

Some small variations:
- The sibling consciousnesses simply need to be close to each other within some distance, regardless of whether both are inside the circle or not. Any conscioueness inside the circle who has a sibling nearby will linger during the teleportation.
- It's possible that the siblings only need to be close to each other at some time before the teleportation (as opposed to the time of the teleportation). So one sibling might leave the circle or even die, while the remaining sibling's consciousness is fixed as lingering if a teleportation occurs within some period of time afterwards.
- Flexibility on the definition of a "sibling", like on whether half-siblings (one common parent) count. Definitions involving genetic similarity face the challenge of explaining why Utsumi in July 2011 didn't linger. One possible definition that I think would work is for consciousnesses that are unaware that they have a close consciousness nearby (so Utsumi 2011 does not linger since she knows that the babies inside her are her children).

Some points:

- This theory requires Hotori to be Kokoro's younger sister. Kokoro not recognizing Hotori's name suggests that Kokoro isn't aware that she has a sister, or at least isn't aware of her sister's name. It's possible that Kokoro's parents were separated and Hotori is the child of the parent who didn't gain custody of Kokoro.

--- It may be worth noting that the writers did plan to have Hotori with a bigger role, so it's plausible that she has such a backstory with Kokoro which was later decided as being unrevealed in the final release.

- Most space-time transfer events involve both Kokoro and Hotori being inside the Cabin circle, both Alpha and Beta inside the Center circle, and both Satoru and Keiko/Sayaka inside the SPHIA circle. This causes all three pairs to remain at their time and location (without teleporting), resulting in the "personality transfers".

--- Most Bad Ends are consistent with this theory, where even if Kokoro or Satoru dies, the survivor's consciousness still lingers during teleportation (since its sibling is still inside the circle) and briefly observes the corpse, but is unable to occupy the dead vessel.

--- A notable exception is the Genocide at SPHIA, where Satoru and Kokoro still exchange bodies despite Keiko's being killed by Utsumi. My guess is that Keiko/Sayaka's consciousness was still alive briefly after the body was killed, which is when the teleportation occurred.

--- For the first teleportation in Day 7, nobody experiences a personality transfer. This is because Hotori is dead in the Cabin circle (her consciousness expires when Kokoro finds her before the teleportation), the Center circle is vacated, and Satoru walks outside the SPHIA circle.

--- Then there is the very first teleportation in Day 1, where nobody experiences a personality transfer but the two Yunis switched places. For this case, Kokoro was outside the Cabin circle, Utsumi did not enter the Center circle yet, while Sayaka's consciousness did not manifest inside the SPHIA circle yet.

- Regarding Sayaka not manifesting inside the SPHIA circle during the first teleportation, this is hinted during Satoru Day 2 (January 12th), where Sayaka/Keiko tells Satoru that the previous night (January 11th) was the first time they met. The flow of the conversation seemed to imply that while Sayaka/Keiko was lying about not knowing Satoru's name (she heard it from Yuni), she was telling the truth about meeting Satoru for the first time. Satoru's internal monologue confirms this as well, speculating that the current personality is a brand new one that was only born in January 11th. The important question is on what time in January 11th this birth occurred.

--- My theory here is that this arises from the Prologue scene in which the reader observes Sayaka in a hospital. I think this scene actually represents her revival, as opposed to her death. The reader assumes that this is Keiko, causing Sayaka and Keiko to become one. However, at this time, Self is only an observer who does not influence any of the events. Self takes over Satoru's body when he falls from the clock tower, but Satoru falls unconscious immediately, so Self is still unable to influence anything. The reader does not observe anything between the clock tower fall / plane crash and the second teleportation (the VN only shows the OP between this period), so the entire cycle for the first teleportation is completed while Selforu is unconscious. There are no lingering consciousnesses in the first teleportation since Kokoro is outside the Cabin Circle, Utsumi hasn't entered the Hoturabi Circle yet, and Sayaka is not born in the SPHIA Circle yet either. At the time of the second teleportation, Self finally wakes up inside Satoru, causing Self's perspective of Keiko = Sayaka to become a reality. Therefore, the consciousnesses of Satoru and Sayaka linger in Aosagi during the second teleportation (and on most future teleportations from that point on).

--- On a related note, I believe Sayaka's revival is one of Satoru's primary motives for the YUKIDOH plan. This is not stated in the chronology, but this is because the listed objectives for the revised plan only describe the officially presented objectives and excludes Satoru's hidden goals. This is more apparent when we consider the listed objectives for the original plan, which is simply on-site data acquisition, but we know that Satoru likely had an ulterior motive involving Sayaka at that time, which the chronology indicates when Satoru proposes a plan to Enomoto in 2009.

--- I think Sayaka's original death in 2001 didn't actually have anything to do with Self. Satoru was at least partially responsible though, and is why he sought to blame Self for his involvement in Sayaka's death. I suspect that when Satoru climbed the clock tower, he did something that would cause Self to observe the scene with Sayaka in the hospital, timing it so that Self assumes Sayaka = Keiko, which would cause Sayaka to revive if Self takes over. It may sound farfetched for Satoru to be able to force Self to observe a certain scene, but Satoru definitely knows a lot about Self and is able to deliberately summon and trap Self into this infinity loop, so projecting a scene to Self's perspective doesn't seem as crazy imo.

--- The chronology does indicate that the "existence of Sayaka is lost forever" in 2001. I believe the Sayaka that awakens in SPHIA 2012 is considered a different existence, since she was subconsciously created by Self. Her relationship with Satoru still holds, since it was demonstrated in the scene that Self witnessed of her (even though Self didn't actually recognize Satoru or hear the "Onii" part). However, she likely does not even know her own name (it wasn't part of the scene that Self witnessed, especially since she was scared of her DID there), and I think she genuinely believes that she is Suzukage Hotori (which she heard from Yuni). In a sense, her situation is very similar to the protagonist Satoru that we follow. Even though Enomoto's body (blonde) does not actually carry the original Satoru's consciousness in SPHIA 2012 after the Prologue, Self's perception causes it to be occupied by a "Satoru" (with Satoru memories that Self observes during Kokoro route) who is a sibling to the "Sayaka" in Keiko's body.

Questions

- Q: Why was Hoturabi Circle vacated in July 17th? Wouldn't it endanger Satoru/Sayaka/Kokoro/Hotori during Day 6?
The Hoturabi Circle was vacated in preparation for the two teleportation cycles that occur in Day 7. It is important that Kokoro's consciousness does not linger in January 17th 2011 (ensured by Hotori dying), since she would not be able to teleport to 2012 and become saved. This would endanger Alpha, who would not have a host when the Center Circle teleports to Akakura. Therefore, Utsumi is taken out of the Center Circle before this happens, while 2012 Satoru should leave the SPHIA Circle, so there are no lingering consciousnesses in any of the three locations.
Note that the first teleportation in Day 7 occurs early in the morning, even before dawn, so the natural time to bring Utsumi out of the Center Circle would be on the previous day, i.e., July 17th (Day 6). She may have been released at night even; the chronology does not specify a time. In fact, the wording on January 16th 2011 (Day 7) in the chronology seems to emphasize that the Center Circle is empty "after January 17th", as opposed to "during January 17th", though I'm not sure how accurate the translation is.

- Q: Was Satoru aware of Hotori when preparing the YUKIDOH plan?
Given that the rescue team arrived on January 17th 2011, they likely would have determined that Hotori died several days later than all the other corpses. This would catch Satoru's attention, and he would probably investigate further and find out that she was inside the circle, which would explain her delayed death due to teleporting to Aosagi 2012. This might raise the question of why Satoru didn't plan to save Hotori along with the others.

--- But if Hotori is Kokoro's sister, this is likely something that Satoru would discover (Lieblich has connections) and would also explain why Hotori wasn't saved. If sibling consciousnesses linger, it would be impossible to bring both Kokoro's and Hotori's consciousnesses to Aosagi 2012 from a single teleportation cycle. They could both be saved in two cycles, but it would be a much more difficult task, particularly since at least one sister would have to leave the circle and stay outside in Akakura 2012 for at least 66 minutes, likely with no access to an indoor location (both SPHIA and the Center are locked, and there are other issues to deal with if they are unlocked). Possibly the third route was planned to have an everyone-is-saved happy end that includes Hotori. In any case, it seems the default plan is to sacrifice Hotori to save Kokoro, and the "ideal" outcome (unreleased third route) probably involves Self's memories of this sacrificed-Hotori timeline.

- Q: How did Satoru and Enomoto switch bodies once without switching back?
While it clearly involves a similar teleportation (and this was confirmed in the chronology), the actual events haven't been shown and there is very little data to work with, leaving this as pure speculation.

--- My primary theory is that the selection of what gets teleported depends on the "strength" of the teleportation. I believe that for a stronger teleportation, we would have:
* A larger distance between locations being teleported
* A larger time difference between the periods being teleported
* A larger radius of the area being teleported
* A larger time period for each stage of the teleportation cycle (the 33 minutes)
* A larger set of components being teleported
These are all implied or confirmed except the last one, which is my speculation. The teleportation always includes the physical matter, but may have some limitations regarding more abstract components, like the taste of coffee or human consciousness. Even though these components arise directly from the physical state, they are still experiential in nature. FWIW, I'm not expressing my personal philosophical views here, but I'm just speculating on the perspective that R11 might have assumed.

--- Enomoto in Satoru Day 4 demonstrated a weak teleportation that transfers coffee, but fails to transfer the "taste" of the coffee (despite the particles responsible for taste being transferred just fine). The large-scale teleportation between Cabin, Center, and SPHIA is a much stronger teleportation that transfers taste (those hard tacks don't taste like Utsumi's cooking) and even captures most consciousnesses as well, but fails to capture these consciousnesses that have a "sibling" nearby. More specifically, it might fail because these consciousnesses have some deeper subconsciousness connection that isn't covered by the knowledge of the inidividuals (which is transferred just fine), i.e., the individual must be unaware that they have a close relation nearby in order for their consciousness to linger (so Utsumi in Center 2011 still teleports to Akakura and Aosagi).

--- As for Satoru and Enomoto switching bodies, this is implied to be stronger than the coffee example (their entire bodies fit inside the teleportation radius) but weaker than the Cabin-Center-SPHIA teleportations (the entire cycle was completed in less than 6 months, since the bodies weren't transferred in July 7th 2011 yet). My theory is that this medium-strength teleportaton simply outright fails to capture any consciousnesses at all (regardless of sibling presence), so the bodies can be switched by simply remaining inside the circle until your consciousness cycles to the body you want to be in, and then walking out of the circle before the next teleportation.

--- I think the coffee transfers and the Satoru-Enomoto body switches involved teleportations between two locations, instead of three. The third location was only necessary for the Cabin-Center-SPHIA teleportations because Akakura 2011 lacked the setup (equipment, etc) for the teleportation. Even if it did involve three points, the Satoru-Enomoto body switch could be done if there were at least two other people involved.

- Q: If one body from the set of three leaves the circle, does it prevent the other two from experiencing a transfer?
My perspective is that NO, this is not the case. The lingering siblings theory does not require this whatsoever. Despite this being a very popular idea, I strongly disagree with it for several reasons:

--- It adds yet another level of exceptions to be applied to the exception of which consciousnesses do not teleport (the general rule is that the consciousness would teleport alongside the body). This is an unnecessary layer of complexity, which really hurts the elegance of the system.

--- It is inconsistent with many Bad Ends, where one of Kokoro or Satoru die, but the other one still experiences a "transfer".

--- It is difficult to reconcile with Enomoto's presence at SPHIA while his consciousness does not linger. Theories that involve some specific characteristic of the individual (e.g., twins) would have to accommodate Enomoto too, while theories that rely on a comparative scale (e.g., youngest bodies/minds) should continue to apply even if some individuals are absent.

--- It has problematic implications on how the system runs. Basically, whether Kokoro lingers in Akakura 2011 depends on Satoru's state in SPHIA 2012 and Alpha's state in Center 2011, and the specific details are conveniently perfect for ensuring that the lingering consciousness has a living host. This sounds like the outcome arises from deliberate design, which contradicts the established scenario that the specific details of the teleportations are actually not controlled, and that Satoru/Yuni/Lieblich are just carefully adapting their plans based on their (thorough) knowledge of how it works.

An alternative argument might be that Kokoro lingers in Akakura 2011 only if there will be an available vessel in the Center that teleports to Akakura 2011, and so on, treating it as a natural outcome as opposed to deliberate design. This, of course, is a huge violation of causality (current effect depends on future outcome). Despite all the ridiculous sci-fi stuff in R11, including several causality-relevant issues (Cabin Yuni, terabyte disc, etc), the VN is actually very respectful of its own flow of causality. Stuff like Cabin Yuni and the terabyte disc, despite having a circular recursive origin, still obey causality along their own personal timelines (which differs from the regular linear flow of time).

--- It is inconsistent with the science of how the transfers work. I know, there are loads of problems with the scientific explanation about the teleportations, but this is still worth some consideration. In simple terms, the data from Cabin (January 2011) is "transmitted" (through quantum teleportation, faster than the speed of light) to Hoturabi (July 2011), where this data is then used to reconstruct the state of the Cabin (Jan 2011) after destroying the Center (July 2011). It doesn't make much sense for the data of Cabin (January 2011) to exclude Kokoro's consciousness based on the state of the Center 2011 (or SPHIA 2012), nor for Akakura (January 2011) to skip destroying Kokoro's consciousness (while everything else in Cabin 2011 is destroyed), nor for Hoturabi (July 2011) to skip the reconstruction of Kokoro's consciousness. What makes a lot more sense imo is that Akakura (January 2011) never even reads Kokoro's consciousness, so it is neither transmitted nor destroyed, and this implies that the exception of Kokoro's consciousness lingering arises due to conditions within Akakura (January 2011) itself and not from the other two areas.

Some final thoughts about the sibling theory:

- Hotori being Kokoro's sister fits well with the other two pairs of lingering consciousnesses, where both Satoru-Sayaka and Alpha-Beta are sibling pairs. That being said, Kokoro-Hotori is a little different from the other pairs since they are both of the same gender and are not twins. It is possible that Hotori's birthday (as shown in the license) is fake, but there isn't really anything that implies this AFAIK.

- It is likely that Satoru's choice of SPHIA for this big project was because that was Keiko's location (in addition to the convenient features like being closed to outsiders and having a wall surrounding it). The decision to choose Keiko's location for the point opposite Akakura 2011, and for having Utsumi with pregnant twins in the Center, both suggest that Satoru was aware that there would be two lingering consciousnesses at each location.

- From a meta Doylist perspective, I find it unlikely that Hotori, an important character introduced so late in the story, has no relation to any of the other characters and is just a random passenger that got caught up in this mess. But if it was originally planned that she would eventualy be revealed as Kokoro's sister, her presence makes a lot more sense.

- Also meta, but without the lingering siblings theory, I don't see much point in even having a second trio of personality transfers. They provide some interesting interactions (like how Kokoro and Satoru see different personalities inside Keiko), but they're basically just fluff (even if it's well-written thought-provoking fluff) and the personality exchange experiences for the second trio is otherwise irrelevant to the main plot points presented. On the other hand, if sibling consciousnesses were to linger, then the resolution in Satoru's arc becomes significantly trickier imo, since it needed to be done after Hotori died and Hoturabi 2011 was evacuated, though Satoru himself (that we observe) does not seem to be aware of these challenges (and kinda just got lucky that the outcome worked out, despite his incorrect assumptions). I expect if we got a third route as originally planned, the lingering siblings would be a lot more relevant, especially if Hotori's survival becomes an objective.

- I also guess (but this is pure speculation) that the lingering siblings are also relevant for other notable issues, like on Sayaka's birth in Keiko's body. While 3 might be the arc number of Remember11, I think there is also significant emphasis on the concept of duality, which fits the lingering siblings.