My understanding at this moment is that this 'apparent duality' is explained as
Tzimtzum
Tzimtzum is, according to the ARI z"l's Kabbalah, the primordial act preparatory to the creation of the universe, in which God contracted himself in order to create a void in which something other than God might exist.
Later Kabbalists modified that concept in various ways, for various reasons, although clearly many were troubled by a postulation that implied that our entire universe's existence was defined by a lack of God's presence. The early Hasidic masters had several ways of reinterpreting tzimtzum, but most still lead to the notion of tzimtzum as a kind of paradox, wherein God can be absent and yet still present.
It was the Alter Rebbe's
chiddush (novellum) that tzimtzum be understood not as a literal contraction of God's being, but as a contraction of God's integrated consciousness. This gets very complicated, as it involves an extremely subtle and occasionally precariously-balanced reinterpretation of Lurianic Kabbalistic cosmogony in all its elements. Tzimtzum alone is not the Alter Rebbe's explanation, he also involves a unique revisioning of
shevirat hakelim ("The Breaking of The Vessels") a central doctrine of Lurianic Kabbalah that proposes that Creation was essentially accidental, in that the Divine energies leading to the existence of the universe were released in a kind of primordial cataclysm, when certain interior boundaries between different parts of God's emanated aspects shattered, which led to the existence of negative energy (the
sitra achra) and of lost sparks (
netzotzot) of Divine energy that must be reintegrated into the Ein Sof (God's eternal, transcendant, ineffable core) and, eventually, to the created universe. The Alter Rebbe revisions these things as symbolic of the fragmenting of God's consciousness and self-integrity, and the establishment of the illusion of created reality.
I still don't care for it. And in any case, I find the ARI z"l's original Kabbalah problematic, also, in that I have never cared for the notion of
shevirat hakelim, or the resultant
netzotzot, nor the Lurianic envisioning of the
sitra achra. (And, again, I am not the only one to feel so.)
I never cared at all for the idea of tzimtzum,either, until I figured out how to spin it a different way. In my personal opinion, when God performed tzimtzum, He contracted Himself, but not entirely. Luria was painting his picture in only two dimensions, but I think to make this work, you need at least three or four dimensions. God contracted Himself not in the sense of withdrawing to leave a void or vacuum, but in the sense of "thinning" or "decohering" His essential energies, to leave room for something to exist in the "in-between" space.
Think of it this way: fish live in water. Water flows through them. They cannot exist outside of water. Water surrounds and sustains them. Like most creatures on this planet, water makes up part of their elemental structure. Yet they themselves are not water, but are creatures that live in water, that move through water, that are in water but not part of it-- their being is separate from the water, though they need it to survive. The universe and every being in it is like fish in water, where the water is God's essence. Those parts of God where the universe is not, must be more akin to ice-- still water, but too compacted to have room within it for fish or other organisms to exist.
That kind of tzimtzum is an idea I can live with.