You can never be certain that the world you perceive in your wakened state is not an illusion. When you sleep and dream, your dream is absolutely real to you. Yet every object, every person in your dream is created by you, from the contents of your own mind, and is, therefore — you! You are both the creator and the witness of your dreams. Furthermore, to your dreaming self, the world you know when awake does not exist at all! When you wake up, you realize your dream was an illusion, a very real illusion. And in your “awake” state, your world seems very real to you indeed, just like your dream did. One thing is a constant in both your awake state and your dreaming state: the witness of those states. That witness never changes. The only thing you can be sure of is that there is witnessing taking place, and there is awareness of that witnessing.
Notes to myself while reading “Journey From Many To One”, P. 63, Swami Bhaskarananda