This quote from “A Report to an Academy” shows the protagonist pretending to have made a rational conclusion, when in reality he has not.

Rosemary acknowledges that Fern’s departure was harder for the other family members, who were old enough to understand it all. On the flip side, they all had personas from before Fern arrived to return to, whereas Rosemary did not. Without Fern to touch and be touched by all the time, Rosemary began to pick at herself. The two had often walked as one connected being, which made Rosemary feel unstoppable. Rosemary feels that the pain of her separation from Fern was close to the pain that real twins feel when one of the pair dies, which is considered the most severe form of human loss. Eventually, Rosemary came to feel that everything she had to say did not matter anymore, now that it was not data in an experiment.

Rosemary shares a wall with her parents and overhears many things as a result. Often, it’s her father fretting about his career, especially after Fern’s departure. She also hears her parents fret about Lowell’s change in personality and her own lack of non-imaginary friends.