Theory and Analysis:Rei's Ghostly Appearances and Quantum Mechanics
In Episode 01, Shinji sees a "vision" of Rei standing in the road wearing her school uniform soon after he is introduced, right before Misato arrives in her car to pick him up. Obviously this couldn't have been the "real" Rei simply physically traveling from Shinji's position to Tokyo-3, as Rei has been seriously injured and is at Nerv HQ (wearing her plug suit) under constant medical surveillance. This shot effectively forms half of two "bookends" for the series: when Shinji comes to Tokyo-3 here he sees a vision of Rei wearing her school uniform, and in the penultimate scene of The End of Evangelion, Shinji sees a vision of Rei wearing her school uniform standing over the Sea of LCL after Instrumentality's rejected (and after Lilith has physically died) which then vanishes. What "really happened" in this appearance of Rei?
- Shinji plainly could not have been hallucinating about Rei, as he had never met her before. Also, in Episode 2 when Shinji is thinking about his experiences thus far at Nerv, including meeting his father and Rei, he recalls seeing the vision of Rei on the street, thus indicating that he is making the connection. His vision, therefore, must have been reality.
- It is impossible to say so because of the distance at which Rei is seen, but she appears to have "Sachiel eyes" like the Rei form that burst out of Armisael and the Rei-Adam-Lilith being in End of Evangelion in Episode 01. Her eyes are not visible in the final scene of End of Evangelion, but appear to be shaded over instead.
- During several episodes of the series (Episode 16, Episode 20) Shinji has internal mind-trips in which he appears to be talking to Rei. In these scenes it is unlikely that Shinji is simply hallucinating (talking to his own subconscious feelings, etc.) because in Episode 19, Toji has an almost identical vision of a Rei/Shinji conversation, and these scenes bear too close a resemblance to the "train" scene in EoE in the earliest stages of Instrumentality to be coincidence. Another possibility is that "Rei" is an Angel or Eva Unit 01 trying to contact his mind using the image of Rei. Yet another possibility is that in these instances Rei actually reached out and contacted Shinji's mind, and the "Rei" in his internal visions in Episodes 16 and 20 actually was Rei, contacting him. In a reversal of Rei contacting Shinji mentally, in the End of Evangelion, Rei abandons Gendo for Shinji soon after she has a vision of Shinji screaming in anguish. Yet another theory is that because Rei is made of the DNA of Yui Ikari and the soul of Lilith, it is possible the "Ghostly Rei" represents the two "mothers" watching over Shinji. Yui as Shinji's mother, and Lilith as the mother of Lilin. This can extend to episode 16 and 20 where Shinji is having these "mind trips" while inside the entry plug of Unit-01. While the actual "Rei" could not contact him here, Yui could, seeing as how her soul is contained in Unit-01. It is possible Yui is using the vision of Rei to reach Shinji. This Rei/Yui/Lilith trinity is a running theme.
It's unclear exactly what was happening in these conversations, but there are clues that suggest an explanation for Rei's appearance to Shinji in Ep.01.
- In Ep.23, when Ritsuko shows Shinji and Misato the room where Rei was born, the words "Top", "Bottom", and "Strangeness" are written on the wall. These are terms from Quantum Mechanics, and as it is emphasized that this was Rei's room, they must have been put there as a clue as to Rei's nature. Quantum Mechanics describes the behavior of subatomic particles. The basic subatomic particle, so far as we know, is the quark. Top, bottom, and strange quarks are three of the six kinds of quarks known to exist. The reason that this is relevant is that quarks behave in ways that would be impossible in normal physics. For instance, a single quark can be in more than one place at a time. As we see in EoE, after absorbing Adam and re-joining with Lilith, Rei can be everywhere at once, collecting the souls of all mankind. Another property of quarks is that time has no meaning for them. At the sub atomic level, effects can happen before their causes, and particles can arrive at their destinations before starting on their journeys.
- In light of all this, it seems likely that the Rei Shinji sees in Ep.01, in his internal mind-trips during various episodes, and in Ep.26' is Rei 3, who has transcended time after gaining god-like powers as Lilith at the end of the story. Also, like the Rei Shinji sees, Rei 3 is shown wearing her school uniform as she collects souls in EoE, as well as the aforementioned scenes in Episodes 01, 16, 19, 20 and The End of Evangelion.