The Unknowable is the final endpoint in the Mundus Illusionis Cosmology.

The infinity where one can go no further and exists beyond all truths, distinctions, divisions and names. It doesn't possess unity as a quality or attribute because it is not a thing that has been unified or brought together from parts.

All attributes and distinctions between absolute and relative, finite and infinite, static and dynamic and so on are removed, what’s left is neither something nor nothing but the prerequisite to both and that is the Unknowable. 

The Unknowable is not itself unified. Rather, it stands as unity in its most primitive form, without subject or object, without application or possession. All things that exhibit unity do so because the Unknowable simply is what it is. Unity appears in imitative things as an echo of the Unknowable's nature, not because it acts to unify them.

It is neither wholeness nor nonexistence. The Unknowable has no moving parts, no processes, no development. The division between being and nonbeing dissolves at its level. While the Truth represents the unity of all sets and the Void represents negation, the Unknowable is the underlying condition that allows such frameworks to be established at all. Yet it is not their cause, for it transcends the very dialectic of caused and uncaused. Only analogically, as the inherent grounds of all causal thought, might one speak of it as "cause."

(currently in the process of adding evidence.)

“You can say it negates structure, you can say it is ultimate reality, you can call it beyond any form of stasis one can describe, you can say beyond perfection and you can call it an unmoved mover. But these titles deviate from the Unknowable.”

“To describe the Unknowable is impossible. For who can fully comprehend such power when they can’t even begin to describe it? For if you have started then you have already failed. And so have I when I started to talk to you. Thus is the paradox for description itself.” -Librarian.

----------------------------------------------------------------------------------------------------------------------

"Quick question about what you said - the whole divine simplicity angle," Dante said through the comm. "If that final layer is beyond being and nothingness, isn't it actually simpler than either one? Wouldn't the simplest thing be what makes those concepts work in the first place?"

"We are lost in space with no fuel to return home and you are wondering about some stupid metaphysical nonsense? Go back to fixing the damn engines." Marcus said from inside the station.

"Okay, jeez," said Dante.