First is the outer world where there is a concept ok others and physical world. This is the world is beyond our control. There is suffering in this world.
Next is the dream state where we can control everything. This is illuminated by our own mind. Even then there is limits of what we can do. Continuous lucid dreaming gives us fatigue for those experiences.
Third is dreamless state where there is nothing but pure consciousness. This is one of the best states as there is only self and nothing else. You can experience this during general anesthesia etc.
Fourth which Advaita vedanta calls the ultimate realization is where you realize that you are the self and there is only self. That the pure consciousness is singular and same for all. In fact there is no all. There is just consciousness.
I think we are approaching the same line of thinking but via biology.