Conor Cunningham on Plotinus and the non-being of the One in Genealogy of Nihilism:

The One cannot be alone. The One cannot be alone because that which proceeds from its plenitude does no necessarily. Furthermore, the One many well require that which emanantes so that it can itself be the One....If there were no emanations there would be the nihilism of pure undifferentiated "being" which may threaten the possibility of the One. As Plotinus says, "something besides unity (the One) there must be or all would be indiscernibly buried, shapeless within that unbroken whole." If there was only the One it might be unable to be the One, for we know for certain it must produce. But if the One requires company, that which accompanies it must be nothing because of this necessity, if simplicity is to be protected. In being nothing the One and the many are equivalent; this many is but the one that comes from the One. In this way the one that is produced is nothing. The One needs this one which is nothing. But in needing nothing it needs nothing but itself (for the One is non-being).

Fascinating stuff! Interesting to compare this mirrored nihilism with Schopenhauer, where will and representation essentially dissolve into nothing at the conclusion of The World as Will and Representation (the implied unity of the title would seem to necessitate this). I don't know much about Cunningham, or "Radical Orthodoxy" for that matter, but just a few pages in this book seems pretty remarkable. Also interesting to compare it with systems theory: the necessary distinction between system and environment which requires excluding the nothing (environment) in the service of coherence (system), but nevertheless requires including it because the distinction is itself the founding self-reference that makes meaning. (Yeah, it's difficult stuff!)