The Arcana are the predominant “flavours” of the Supernal that mages are capable of accessing.
The 10 Arcana are not an exhaustive list of all possible Arcana, as indeed many Archmagi have managed to cast spells beyond the purview of seemingly any know Arcana, but they do represent all of the magical forces that can be perceived by ordinary mages.
Almost all phenomena in the Fallen World can be observed and described by one or more Arcana; it is the source of most magic and is the direct action of a Supernal Realm upon the world.
Not all phenomena in the world are caused by Awakened Magic using the Arcana, just as the sea is not caused by the existence of thermometers or barometers.
These are the 10 elemental principles through which a mage understands the Tapestry. A mage’s Arcanum lore is the mechanism by which she draws down the laws of the Supernal; her Gnosis is the connection to that Realm.
Gross and Subtle Arcana
Gross Arcana: These are the five Arcana that govern the tangible, manifest facets of the Fallen World; Forces, Life, Matter, Space, and Time.
Subtle Arcana: The five Arcana that govern intangible, unseen facets of the Fallen World; Death, Fate, Mind, Prime, and Spirit.