
Frederick asks whether part of his fear of removing all filters and limits is not knowing whether he could still experience existence; the Wonders confirm it.
He assumes the core self is without limits, and they correct him: the core self has limits too, because it is an incarnation of an incarnation of an incarnation, and separation still exists between his core self and them.
It is more limitless than the ego personality, but not limitless — otherwise it would be them.
Eventually he will reconnect with them, but only after removing layer upon layer of filters, including those of the core self.
As the ego personality expands, the core self expands, and as that expands its own core self expands in turn, until he reaches where they are.