Answer: An illusion is anything that doesn’t resemble the Creator. And reality is any part of the Creator I perceive. That is, it is an immense field, which I correctly perceive to the degree of my similarity to it. This field is perceived by me as the Creator and it is not an illusion but the truth.
The true reality – Upper Light or the Creator – is found at absolute rest. But our perception of this reality can change. The change depends on correction. If a person completely corrects himself, then nothing changes in his perception any more.
Everything is measured only relative to a person.
From the Kabbalah Lesson in Russian 9/18/16