Different Dualities
When awareness functions in a dualistic way, it is due to abstractions. There is a belief in a thought, and awareness functions dualistically: Experiencer and experienced, I and other, etc.
Human Self as I
From the field of what is happening in the present, we often make this human self into an "I" and everything else "other". This is what we see most typically in the world today. I am an object in a world of infinite objects.
In this situation, it may be helpful to recognize that "I" am really pure awareness, or space & awareness, or capacity for the world, or whatever else may work. "I" am no form to forms. No pain to the pain. No death to the death. No contraction to the contraction. This human self arises within me along with everything else. I discover that there is no boundary between this human self and anything else, it is just one seamless field.
This in itself is a tremendous liberation. I no longer have to be blindly caught up in what happens, everything comes and goes as guests - clouds, rooms, scenery, tastes, sensations, human beings, thoughts, emotions, etc. And as there is no longer anything to resist, I can be more fully engaged in this human life.
No I
At some point, after having explored this for a while and integrated it more into our human life, we may discover that there is still more of a duality here than what is given in the immediate experience. There is still an "I" - now as pure awareness, capacity, space & awareness etc. - and an "other" - the world of phenomena.
And here, there is a realization that even this "I" is a construct, an abstraction, a belief in a thought. What really is, is just what is - as it is. The sounds of the traffic, cold breeze on the skin, computer screen, tapping on the keyboard, bird squeaks, pressure under the feet. It is just what is, crystal clear.
There is awareness, and there is a human self, but no belief in a thought of any of these as "I".
And of course, even believing a thought that there is no "I" is also stuckness, being caught up in and clouding it up with an abstraction.