In the Vedanta sampradaya there are two basic approaches to non-duality: mystic non-duality and non-mystic non-duality. When you first become interested in non-duality the distinction is unimportant, but as your understanding becomes more sophisticated, the distinction becomes important.
Mystic and non-mystic non-dualists agree on three points: (1) karma yoga is for purification of the mind, (2) direct non-dual knowledge, not indirect non-dual knowledge, liberates and (3) the world needs to be eliminated. Indirect knowledge is knowledge of something that one can’t perceive. Direct knowledge is knowledge of something that is present.
But they disagree thereafter. The mystic non-dualist says that because you are in a dualistic state when you get non-dual knowledge, the knowledge is indirect and so you need to enter the non-dual state to convert it to direct knowledge. He says that to enter into the non-dual state you need to remove the world so that you exist as the self alone.
The non-mystic argues that it is not in the power of an individual to eliminate the world insofar as only the Creator could do that, assuming something is to be gained by the world’s elimination. The mystic’s argument that the world is eliminated in deep sleep doesn’t hold water, because common sense tells us that the world exists when I’m asleep. In fact I only go to sleep happily because I know my worldly life goes on. My wife, kids and job are still there when I wake up. So non-perception of the world is not elimination of the world. Furthermore, the law of the conservation of energy says that if I do destroy something it just appears in a different form.
How can you say that the mystic state where there are no objects to divide the state is a non-dual state? It isn’t a non-dual state, because there is an object present and that object is the absence of objects. If there is only you, how will you know that there are no objects? And even when you come out of your mystic non-dual state, the world is still present. So it was not eliminated.
The mystic tries to wiggle out of this fact by saying that you can’t talk about this state, because it is transcendental, meaning inexplicable, so you just have to enter it and see for yourself.
But the non-mystic argues that getting in this state is a lot of work and he would like some kind of assurance that it is worth the trouble. To this argument the mystic says that the experience of mystics everywhere is proof, so get to work meditating so you can convert your indirect knowledge to direct knowledge.
The non-mystic, however, argues that the world is not real in the first place. Something that is not real is as good as non-existent. So how can you eliminate it? He argues that the belief that the world is real needs to be eliminated. In fact the “non-dual” mystic is very much a dual mystic because he gives equal status to the self and the world. Therefore if you have one you don’t have the other, like day and night, cold fire, etc.
But the non-mystic non-dualist says that the world and the self are not in the same order of the non-dual reality. Both exist as consciousness, but one is real and the other isn’t, so there is no contradiction. Just as you don’t count your image in a mirror as a second you, you can’t count the world as a second object.
If this is true, then the mystic’s contention that I was in a state of duality when I heard the non-dual teachings of Vedanta is not true. So there is no reason for me to meditate to convert indirect knowledge to direct knowledge, because if I am paying attention, the teaching simply removes the ignorance of ever-present, ever-experienced, non-dual self, and the experience of limitless bliss, which is always present, is now available; it was only “hidden” by the belief that reality is a duality.
If a qualified inquirer needs to meditate at all – and most require some meditation – it is not to eliminate the world, it is to internalize self-knowledge.
Summary: there is no dual or non-dual “state.” There is only ever-present, non-dual consciousness, which means that I am non-dual consciousness with knowledge of who I am or ignorance of who I am. If this is true, which scripture claims, I am always only experiencing non-dual consciousness. Any attempt to gain a discrete mystic non-dual experience is not only redundant, it is impossible.