This is for discussion of levels in the perceptual hierarchy, how to recognize them by objective criteria and subjective experience, relationships between them, point of view (upon level n from level n+1), and kindred topics.
Bill Powers identified levels phenomenologically, by subjective introspection, and was able to validate the lowest levels in terms of physiology and biophysics. His list of levels evolved and shifted over time, and he repeatedly cautioned against taking all of this as established fact. The interconnections in working computer simulations often do not conform in tidy ways.