When I explore content of awareness these days, and especially the content centered in the head area of space, I can more clearly see how a sense of subject and object is created.
In short, the sense of subject and object, or seer and seen, comes from thoughts (ideas of subject and object), placed on or oriented in relationship to sensations, all overlaid on ideas of space and continuity, in turn overlaid on pure perception.
It sounds hopelessly abstract when expressed that way, but is something that can be seen directly as it happens.
For instance, there are sensations in the forehead area, and these serve as an anchor or location for the idea of a subject or a seer. Anywhere else in the field then becomes a potential seen or object. And when something comes into a conscious focus as an object, there is a polarity between seer (located somewhere in the forehead area) and seen (located somewhere else). And it all unfolds on top of an image of space, distributing it all in space, and also of continuity, memories of what was.
I also see that the image of a seer is often located a little out and above from the sensations in the forehead, so these sensations serve as a reference point for this image, more than an identical location for it. Since what is seen, in these explorations, happens mostly within and around the head area, placing the sense of a seer just outside of this area makes sense. It creates more space and distance between the idea of seer and seen, so they can more easily be kept apart and distinct from each other.
And that is, of course, exactly how the whole impression of a seer and seen, and the separation between the two, is created and maintained. And when the gestalt of it all is taken as real and substantial, and not inquired into this way, the sense of a seer separate from the seen appear very real and substantial as well.