That’s not really the subjective experience though. Why would we feel as though there was an observer who is perceiving both the external and internal world? If you sit quietly you can very quickly be overwhelmed by a tumult of images, thoughts, bits of music, sensations and memories all clamouring for attention. You can consciously direct that spotlight of attention as well. To me this seems more like the self part of the brain is the part responsible for higher order command and coordination of the other parts although not fully in control of everything. Sort of like how the captain of a ship is supposed to be in full control but the crew still have their own wills and desires and perform their jobs autonomously when not being directly ordered to do something.