Absolutely nothing

How can the separation and the universe have happened if all is complete oneness?

I think this is one of these things we just can't understand with a human (ego) mind. The human mind is completely based on time and space, and can't think with them not being there.

One of the early experiences I had when practicing these materials is that I was looking at the Universe from outside, willing to see it as it really is. And then I saw it as being nothing. And what really impacted on me was that I saw that it was not just "nothing really" or "ultimately nothing", it is absolutely nothing.

That is a great relief (or will be), and obviously a fact which changes everything.