https://en.wikipedia.org/wiki/Ayin_and_Yesh
Tzimtzum, "contraction", proposes that the physical world is infinite somethingness/nothingness (essentially equal representations of one thing) made manifest in the realm of light/waves and distinctions.
I had thought that the nature of the void (i.e. nothingness), or rather, its lack of a nature is what allowed stuff to freely appear into existence (as many times as it wants).
the void imposes no restrictions because it is not really there to impose them.
stuff pops freely into being without requiring any reasoning; requiring a reason would be a restriction which would need to be somehow imposed.
in contrast, they say that, in fact, there wasn't a void, there was only a God entity filling up everything until this entity withdrew from a part of itself (from another part of itself I suppose) so form a space (or a void?) into which creation subsequently appeared