Hyperreality

Although the world of mortals is seemingly mundane and natural, the supernatural and divine manifest in it. This is one of the primary sources of magic; this is embodied in the thinnies and nascent portals to higher and lower realms with the shifting folds of the Rift. Hierophanies are examples of this. However, not all manifestations of the super- or supranatural come from other realms, instead, part of the mundane realm is overlaid with various spirit realms—primal elemental, shadow, fae, realms of subtle bodies—all of which exist bound in the same space and time, but are, in a very real sense, stacked on top of each other. Occasionally, these levels of reality can be perceived; occasionally, these levels of reality collapse onto each other and their overlaid barriers dissolve. These occurrences can lead to the creation of naturally occurring portals, sacred sites of nature, crossings over of beings from different levels of reality all of which call the world home.
The nature of such hyperreality is not unlike a vast tower with layers of subtleties becoming less substantive as one ascends, more mundane and solid as one descends. For most, each level above it is completely imperceptible, and incorporeal. However, for those beings on layers above, they can and do perceive the realms below and occasionally are able to interact with them. Manifestations of spirits in the material world can be considered this. Incorporeal beings are made of subtle bodies that exist simultaneously on two or more layers of this hyperreal column. Only through special circumstances, invoked magic, second site, or ancient artifice can these incorporeal forms be perceived.
Incoproreal spirits of the dead are thought to be trapped between these layers of hyperreality, occassionally able to manifest in the lowest tier, the mundane realm.