Torg Axioms

A bit of preliminary discussion of the issue of 'dimensions/planes/spirit realms':

A single cosm may contain multiple 'universes' which cannot easily be transitioned between.  All of these universes obey the same axiom set, but they may have different world laws.  Thus, the Elemental Plane of Fire may have a world law to the effect of 'Everything is Flammable' which does not apply to the 'prime' plane within the cosm.  Alternate universes may contain a local axiom shift of a single axiom to a higher or lower level than is normal for the cosm.  Those alternate universes which contain a changed Tech axiom are known as 'dimensions', those which contain a changed Magic axiom are known as 'planes' and those which contain a changed Spirit axiom are known as 'spirit realms'.  Such universes may well be postulated (and come into existence) before they can actually be reached by the axiom level they are attuned to; it is possible, however, to use a power based on a different axiom to travel to them once they have been postulated to exist.   For the Tech Axiom, for example, alternate universes gain a scientific basis at Tech 22, but the technology to try to visit them does not exist until Tech 25.  Magical Planes gain a basis in magical theory at Magic 10, but can't be divined until Magic 13, apported to until Magic 15 or visited through portals until Magic 18.

Magic Axiom
Advanced Magical Cultures divide the axiom levels into ages: 

Social Axiom

Spiritual Axiom

Tech Axiom