Here are three ways subject and object may appear…
Subject and object: this human self and the wider world of form
When there is an exclusive identification with this human self, this human self appears as a subject and the wider world of form appears as an object.
There is the field of seeing and seen, absent of I. It believes in the idea of I, and this human self seems to be the most likely candidate. After all, there is a functional connection with this particular human self, and the perceptual inputs comes through it.
If there is an I anywhere, it is most natural to first put it on this human self.
Subject and object: seeing and the whole world of form as object
Then, we may notice that the seen is always changing, so how can there be an I there? How can this human self be an I, when it just consists of fleeting components such as sights, sounds, sensations and thoughts? They all come and go, but something does not come and go, and that is the seeing itself.
So then the sense of I is placed on the seeing itself.
The seeing appears as a subject, and the whole world of form becomes the object.
As a side effect, the whole world of form is revealed as a seamless field. There is no longer any inside or outside. It is all just one field. This human self and the wider world of form is a seamless field, with no absolute boundaries anywhere. There is a disidentification with this human self, and thoughts, sensations, choices, behaviors and anything else arises just as clouds, mountains, rain, sunshine. It all comes and goes on its own, living its own life.
Whole field of seeing and seen as absent of subject and object, and as a whole as subject and object
Finally, when the field awakens to itself as the field of seeing and seen, absent of I anywhere, the whole sense subject and object falls away.
When there is no sense of I and Other, there is no sense of subject or object.
Or we can say that the field as a whole becomes subject and object. It is, as a whole, its own subject and object.