As they say in Buddhism, the same remedy can be medicine in one situation and poison in another. And this is one reason why there are so many remedies.
For instance, for someone beginning sitting practice, it can be very helpful to count the breath to calm the activity of the mind. After a while, the same counting can be a distraction from just being what is.
And when we are exclusively identified as a human self, it may be helpful to simply shift this “I” from the human self to pure awareness. “I” am now pure awareness, or capacity for the world, and “other” is the world of phenomena. Here, we can see how the world of phenomena is a seamless whole (the human self does not have any fixed or separate existence), and we can allow anything to just come and go as guests. There is still equally much a duality here, but in a different way and that can be helpful.
After a while, this duality becomes less helpful. We see that any “I”, whether it is attached to our human self, pure awareness, or anything else, still is from a layer of abstraction added to what is. It does not correspond to our immediate experience, which we now see more clearly is just what is – as it is. There is only what is, with no “I” to be found anywhere. Nothing has changed, the content of “what is” is the same, but there is no “I” anywhere and thus no sense of duality. It is just an effortless lack of duality, which is what always is no matter whether we add to it or not.
It is interesting to see how the Douglas Harding experiments often can be used in either of these two ways. Sometimes they are helpful in just shifting the sense of “I”, from the human self or a habitual pattern of the human self to pure awareness or capacity for the world. Other times, it is more helpful to see the emptiness/fullness of what is, as it is – with no “I” to be found anywhere.