Many of people get very wrong about the teachings given here. By illusion it literally doesn't mean that there is nothing.
If I say a rock which falls down is illusion then many of you can ask is this some kind of joke? Because we could literally see a rock that throws up comes down so how come it can be illusion.
See when say illusion it doesn't mean that rock doesn't exists or that law of gravity doesn't exist. It means simply how you are receiving is wrong. How we are receiving it wrong?
There are two things working here and these both two things actually what creates this falling down of rock. The experience of gravity and the experiencer itself.
I said from the perspective of ultimate truth the simply falling of rock is illusion but when that falling of rock is see by seer is what when that illusion transform from illusion to ultimate truth or you can call it oneness.
So everything we do or we experience is illusion if there is no experiencer involved in it. But if experiencer involved in it then that illusion automatically converts into ultimate truth of union i e. Oneness.
See here those who actually understand this concept of oneness can see right through that Oneness always present because for a rock to fall and see by seer this is the always the case from eternal ultimate perspective. Then how come it becomes illusion? It becomes illusion because lack of awareness. Awareness of what? Self awareness because awareness can come and go that is why illusion can also sometimes become illusion or very same illusion become truth.....
So what comes and goes is awareness not the ultimate truth. If you are aware of self then that very same illusion transform into ultimate truth. To remain in such state of awareness all time is called choosing oneness not natural oneness.
What is choosing oneness? It is simply to become aware of oneness to become aware of the fact that experience and experiencer are same part they always exsist all the time for eternal.
Natural oneness? Natural oneness is nothing simply how everything working in actual truthful way is natural oneness.